The Bioavailability of Nutrients That Have a Health-Promoting Effect on Nervous System Function

CHAPTE R 7

The Bioavailability of Nutrients That Have a Health-Promoting Effect on Nervous System Function Mariusz Jaworski*,**, Anna Fabisiak* *Warsaw School of Tourism and Hospitality Management, Vistula Group of Universities, Warsaw, Poland; **Department of Teaching and Outcomes of Education, Faculty of Health Science, Medical University of Warsaw, Warsaw, Poland

1 Introduction Keeping correct health is an important part of modern health promotion. Health promotion is important to medical science, which helps people change their lifestyle. In this context, the main change of lifestyle is to achieve optimal health, as well as to restore harmony at all levels of human existence, especially at: physical level (e.g., avoiding overeating and using harmful substances); emotional level (e.g., through stress management); social level (e.g., a support network of family, friends, community members); intellectual level (e.g., through general education or practical training); and spiritual level (e.g., through feelings of love and hope). It should be stressed that there are four areas of action that help to achieve optimal health status. Among these four actions are: health education; public policy interventions (legal and fiscal); community development and empowerment; clinical interventions (screening) (Gheorghe et al., 2015). In the context of health promotion, many studies emphasize the role of the biopsychosocial model (BPS) of health and disease. This model dominates in current medical practice, because it considers biological, psychological, and social factors and their complex interactions in understanding health and illness. For this reason, there are three main criteria of unhealthy promotion, including: first, the “disease” conceptualized as a pathological term (biological). Second, “illness” is thought to be an internal and individual experience (psychological). Third, “sickness” is considered as an external, public mode involving interaction between the person, other people, and environment (sociological) (Uddin, 2014). Additionally, the epidemiological studies suggest that appropriate behavior can have a positive impact on the somatic and psychological health on the one hand, and could be an Food Quality http://dx.doi.org/10.1016/B978-0-12-811442-1.00007-9

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226  Chapter 7 important factor in preventing some diseases on the other hand. It should be emphasized that this health-related behavior is closely associated with lifestyle (Havelka et al., 2009).

2  Healthy Lifestyle Lifestyle is an important element of modern human function. It should be stressed that the first attempts at lifestyle definitions were prepared by Max Weber, who was a sociologist in the 1920s, and shortly after him, Alfred Adler, who was a psychologist. Today, there are many lifestyle concepts, but they are still not well defined. In the 1980s, the World Health Organisation (WHO) defined “lifestyles” like “a patterns of (behavioral) choices from the alternatives that are available to people according to their socio-economic circumstances and the ease with which they are able to choose certain ones over others” (WHO, 1986). All in all, a new concept of lifestyle can be defined as: “the individual’s pattern of those cognitions, emotions, and actions that contribute to the personal and social identity of the individual” (Thirlaway and Upton, 2009). There are some publications which stressed that lifestyle is very often related to health. For that reason, some researchers created “health-related lifestyle” concept. Accordingly, there are two forms of this concept. The first type has a positive influence on health (healthy lifestyle). It is the importance for treating multiple psychopathologies, for fostering psychological and social well being, and for preserving and optimizing cognitive capacities and neural functions. The second type contributes to multiple psychopathologies (unhealthy lifestyle) (Thirlaway and Upton, 2009; Walsh, 2011).

2.1  Health-Promoting Lifestyle Factors Both healthy and unhealthy lifestyles are associated with some specific factors. Lifestyle factors are the most important in the context of a healthy lifestyle and a health-promoting model, because they could be potent in determining both physical and mental health. Among these factors, the researchers emphasize: individual characteristics and experience, cognition, emotions, and establishing action plans. Therefore, it is necessary to carry out studies, which examine these factors in order to enhance health-promoting lifestyles in each phase of human life (Kim, 2012). 2.1.1  Diseases determined by lifestyle It should be stressed that there are some diseases that are strongly determined by lifestyle. In clinical practice, these diseases are often called lifestyle diseases (diseases of longevity or diseases of civilization). The occurrence of these diseases are based on the people’s daily habits, especially bad food habits, wrong body posture, physical inactivity, and disturbed biological clock (Sharma and Majumdar, 2009). The most common diseases of civilization are cardiovascular disorders, obesity, diabetes, and cancer. There are many

The Bioavailability of Nutrients  227 studies that emphasize that there are four main lifestyle factors associated with lifestyle diseases—adequate physical activity, a healthy and varied diet, a reduction of smoking, and reduced alcohol intake. Most studies analyzed these factors in the context of the prevalence of these diseases (Walsh, 2011). 2.1.2  Lifestyle and stress It should be noted that the current human life associated with high levels of stress could have influence on the frequency of health behavior undertaking. There are many stress deninitons in psychology, but the most well-known is Lazarus’ theory of stress. In his theory, stress is defined as “Psychological stress refers to a relationship with the environment that the person appraises as significant for his or her well-being and in which the demands tax or exceed available coping resources” (Lazarus and Folkman, 1986). It should be noted that Lazarus’ theory of stress also stresses the importance of the individual’s analysis, as well as subjective appraisal of the stressful events that occur within their environment. It should be stressed that there are two main processes, which are central mediators within the person–environment transaction, such as cognitive appraisal and coping (Lazarus and Folkman, 1986). There are many studies that have shown that a high level of stress has a negative influence on human somatic and psychological function, especially the nervous system (NS). Cordner and Tamashiro (2016) carried out a study with a wild-type mouse model. The main aim of this study analyzed the relationship between chronic variable stress and cognitive function. Sixty male mice were used and randomly assigned to experimental groups. The result of the presented study showed that stress could lead to cognitive impairment between both, young adult (especially, hippocampal, and cortical function) and aged mice (especially, hippocampal function). The most important information from this study is that chronic variable stress increased the expression of Bace1 in the hippocampus (in the case of young adult mice) and in the hippocampus, the prefrontal cortex and amygdala (in the case of aged mice). The authors stressed that Bace1 is critically important in Alzheimer’s disease, because it codes for the β-secretase enzyme. There is one study that analyzed the relationship between family environment, and salivary cortisol measurements on the one hand, and children’s memory and executive function performance on the other hand. This study was carried out by Piccolo Lda et al. (2016). The study group consisted of 70 children aged between 9 and 10 years old. The Child Brief Neuropsychological Assessment Battery (NEUPSILIN-INF) was used to assess cognitive function. NEUPSILIN-INF consists of three main tasks: 1. working memory tasks, including forward and backward digit span, pseudowords span and a visual working memory task; 2. verbal memory, including immediate recall of a word list and figures; 3. executive function, including inhibitory control tasks, such as orthographic and semantic verbal fluency and auditory go/no-go tasks.

228  Chapter 7 The researchers showed that children’s stress levels and family functioning were associated with children’s cognitive functioning. It was especially reported in the context of executive functioning and working memory. Highly important is the fact that any family environment variables and changes in cortisol levels explained about 20% of the variance in performance of cognitive tasks. Wagner et al. (2015) carried out a study that examined relationships between child cortisol, parenting stress, parent coping, and daycare quality in relation to executive functions. Group of subjects consisted of 101 children aged 3–5 years old (53 girls, 48 boys, mean age 4.24 years ±0.74). In this study, researchers showed that higher levels of salivary cortisol are characteristic for children with poorer executive functioning. Similar findings were observed for higher parenting stress. The parents of children with poorer executive functioning are characteristic of a higher parenting stress. The subject of the relationship between lifestyle and the functioning of the nervous system (NS) has become a very important area of research. This is due to the need to develop effective methods of prevention of neurodegenerative diseases on the one hand, and increases in the human adaptability to change environmental conditions on the other. A science of nutrition has particular importance in this context.

2.2  The Structural and Functional Aspect of Nervous System It should be noted that two main elements are part of the structural human NS. There are the central nervous system (CNS) and the peripheral nervous system (PNS). In the context of the CNS, there are two most important elements: (1) the brain, and (2) the spinal cord. The brain is contained within the cranial cavity of the skull, and the spinal cord is contained within the vertebral cavity of the vertebral column. The next very important division of the NS is the PNS, which is made up of the nerve fibers. Each nerve fiber branches off from the spinal cord and extends to all parts of the body. It should be emphasized that both the PNS and the CNS are made of the basic working unit—so-called neuron. The neurology case studies reported that each neuron consists of a cell body containing the nucleus, and special extensions called axons (pronounced AK-sonz), as well as dendrites (pronounced DEN-drahytz). The scientists showed that axons and dendrites are very important for the communication process between neurons. In this process, a neuron sends an electrical signal down the length of its axon. Next, this signal is converted into a chemical signal at the end of axons, which releases this chemical signal by using neurotransmitters into a synapse—the space between the end of an axon and the tip of a dendrite from another neuron (Darby and Walsh, 2005; de Groot et al., 2016). The NS could also be divided in two options on the basis of its functions. The first basic functions of the NS are: •

Sensation (sensory functions). It is associated with receiving information about the environment. It is necessary to gain information about what is happening outside the body by using taste, smell, touch, sight, and hearing.

The Bioavailability of Nutrients  229 • •

Integration. The received stimuli are communicated to the NS and afterward they are processed. Response (motor functions). It is a voluntary or involuntary response on the basis of the stimuli perceived by sensory structures. The voluntary/conscious response is associated with contraction of skeletal muscle, but involuntary response, for example, contraction of smooth muscles, regulation of cardiac muscle, activation of glands.

The second basic function is control of the body by using the autonomic NS (ANS) and the somatic NS (SNS). SNS is associated with conscious perception and voluntary motor responses, while ANS is responsible for involuntary control of the body, especially regulation of the internal environment (Darby and Walsh, 2005). It should be noted that the studies that analyze the relationship between lifestyle factors (e.g., an adequate physical activity, a healthy and varied diet, and a reduction of smoking and alcohol intake) and the structure, as well as function of the CNS have become more common in medical sciences. It is particularly important in the context of the structure and function of the brain.

2.3  The Structural and Functional Aspect of the Brain In psychoneurology and neurology, the brain is analyzed in the function and context. The brain consists white and gray matter. The brain studies reported that the white matter is known, as the entire central core of the brain, as well as it comprises fiber tracts, which mediate communication between neurons. But the gray matter is mainly composed of neuronal cell bodies and unmyelinated axons. It should be stressed that the white and gray matter of the brain create specific and characteristic areas, for example: hippocampus, the postcentral gyrus, frontal operculum, putamen, and middle frontal gyrus (so-called brain region involved in the regulation of taste, reward, and behavioral control) (Darby and Walsh, 2005). There are studies that show that improper diet can lead to abnormalities of brain structure, particularly the reduction of gray and white matter. These observations have been reported in relation to persons with obesity whose diet was high caloric and rich in fat, but not all. There are some studies that used animal models. For instance, Gan et al. (2015) suggested that intake of a high fat diet is associated with altered consumptive behavior, hippocampal damage, and cognitive deficits. Authors prepared a study with male rats, which were fed either a control diet (10% fat by kcal) or high fat diet (45% fat by kcal) for 72 h. In this study, the most important element was change in brain. These authors provide evidence that acute consumption of a high fat diet impacts on hippocampus, because of an increase in brain-derived neurotrophic factor (BDNF). Lin et al. (2015) prepared a study that examined the role of high-fat-diet intake in Alzheimer’s disease (AD). In a discussed study, a mouse model of AD and control wild-type mice were used by the authors. All groups of mice

230  Chapter 7 were fed (1) high-fat diet or (2) control diet for 10 weeks. Researchers found that the high fat diet significantly enhanced cerebrovascular β-amyloid (Aβ) deposition (P < 0.05) and impaired cognitive function (P < 0.05). Additionally, it was observed that a high fat diet enhanced hippocampal oxidative stress (P < 0.05) and NADPH oxidase subunits, gp91(phox) (P < 0.01) and p22 (phox) (P < 0.01). However, these observations were related to a mouse model of AD, but not in control wild-type mice. This study provides evidence that a high fat diet significantly promotes the progression of AD-like pathology through enhancement of cerebral amyloid angiopathy and oxidative stress. Kuhla et al. (2013) carried out a study with an animal model that consisted of 70 female mice. In this study, the authors focused on a lifelong caloric restriction and its relationship with neuronal damage and neurodegenerative diseases. It should be stressed that the major finding of this study is that a lifelong caloric restriction aggravated the age-related loss of spontaneous motor and increased spatial learning and working memory. It is a very important observation, especially in the context of spatial learning ability, which is associated with hippocampal function. Probably, caloric restriction might cause regenerative processes in the hippocampus. In this study, the authors pointed out that caloric restriction could stimulate the production of new neurons from stem cells (in neurogenesis) and enhance synaptic plasticity. Another study also confirmed that calorie restriction is argued to positively affect general health, and normally occurring age-related reduction of cognition (Kaptan et al., 2015). Kaptan et al. (2015) analyzed the relation between a low-calorie diet (LCD) during adolescence and level of hippocampal and prefrontal BDNF on the one hand, and neuron numbers in dentate gyrus on the other hand in an animal model. It should be noted that the neuron numbers in dentate gyrus positively affected spatial memory in adulthood. The discussed results pointed out that LCD feeding during adolescence can improve cognitive functions in adult rats, because of the increase of neurogenesis and BDNF of hippocampus and prefrontal cortex, as well as decreased serum glucose and hippocampus malondialdehyde (MDA) levels. The major finding of this study is that learning and memory were improved in adult female rats fed with 15% LCD in adolescence. These results reveal the importance of nutrition for cognitive function. The functional aspect of the brain is associated with cognitive function. These functions are defined as all mental processes that are involved in symbolic operations, such as executive function, memory, attention, perception, memory, creation of imagery, and thinking. It must be noted that most studies examine relationships between lifestyle factors and changes in cognitive function, such as executive function, memory, and attention. Most of these studies are based on animal models, while studies involving humans focus mainly on people with obesity, eating disorders, and neurodegenerative diseases. 2.3.1  Executive function Executive function is a very important part of individual cognitive function, because these skills are involved in the control and monitoring of other cognitive functions and also in

The Bioavailability of Nutrients  231 planning, mental flexibility, problem solving, and monitoring behaviors (Cicerone et al., 2000). Executive functions typically are “… described as: integrated cognitive processes that determine goal-directed and purposeful behavior and are superordinate in the orderly execution of daily life functions, which includes the ability to formulate goals; to initiate behavior; to anticipate the consequences of actions; to plan and organize behavior according to the spatial, temporal, topical, or logical sequences; and to monitor and adapt behavior to fit a particular task or context” (Cicerone et al., 2000). 2.3.2 Attention Attention, as a cognitive process, is defined very intuitively. Adding to this, there is the problem of carrying out systematic studies that are analyzed for attention. For instance, Moray (1970) suggested that there are six different meanings of the term attention. Another researcher proposed that “attention has three components: orienting to sensory events, detecting signals for focused processing, and maintaining a vigilant or alert state” (Posner and Boies, 1971). Richards (2004) stresses that attention may be defined as the selective enhancement of a certain behavior at the expense of another behavior. 2.3.3 Memory Memory is defined as a multicomponent system that is specialized in encoding storage retrieval of information. In neuropsychology, there are two forms of memory, such as: • •

A short-term memory (or temporary working memory). This type of memory is often thought of as retention of bits of information for the span of few seconds. A long-term memory (permanent memory store). This type of memory stores information in the long term and it is the part of the memory system. A long-term memory could be subdivided in declarative (episodic and semantic) and nondeclarative (procedural) memory (Darby and Walsh, 2005; Hirst et al., 2015).

2.3.4  Diet and cognitive function There are also scientific studies that suggest that appropriate eating habits can improve cognitive functioning. All studies that analyzed the association between diet and cognitive function can be divided into two groups: the first group analyzed the relationship between a single nutrient and cognitive functions; and the second analyzed dietary pattern approaches and cognitive functions. The single-nutrient approach could be helpful in various public health problems, but many researchers stress that people do not eat individual nutrients (such as protein, fat, carbohydrates, vitamins, minerals) separately. With this realization, it is necessary to promote studies that analyze a dietary pattern, but not only the single-nutrient approach. There are evidences that emphasize that an appropriate dietary pattern has a positive influence on neurological function, especially diets low in saturated fat, high in legumes, fruits, and vegetables, and moderate in ethanol.

232  Chapter 7 One of the most analyzed dietary patterns is the Mediterranean diet (Allès et al., 2012; Cheung et al., 2014).

2.4  Mediterranean Diet 2.4.1  Health aspects There are many publications that stress that the Mediterranean diet is a model of healthy eating, which has a positive influence on human health (Maillot et al., 2011; Serra-Majem et al., 2006; Sofi et al., 2008). One important health benefit of the traditional Mediterranean diet is associated with reduction of incidence of cardiovascular events (e.g., coronary heart disease) and mortality (Zazpe et al., 2011). There are some studies that showed that this type of diet is associated with a lower incidence of the metabolic syndrome (Kastorini et al., 2011; Kesse-Guyot et al., 2012) and of type 2 diabetes (Martínez-González et al., 2008), as well as of developing various types of cancers (Vernele et al., 2010). 2.4.2  The traditional Mediterranean diet The traditional Mediterranean diet comes from specific regions of the Mediterranean. This diet was a typical dietary pattern in this region in the early 1960s. The traditional Mediterranean diet was characterized by high consumption of plant foods, such as vegetables and fruits (up to 400 g/day in Greece), legumes, grains, pasta, bread, nuts, and seeds. A common element of the traditional Mediterranean diet is a high consumption of monounsaturated fatty acids due to olives and olive oil. It should be stressed that the main sources of dietary fat were fish, poultry, dairy products, and eggs (Boskou, 2015). 2.4.3  The modern Mediterranean diet It should be stressed that the Mediterranean diet has three major elements. First, an increase in the consumption of saturated lipids (e.g., meat, dairy products); second, an increase in the consumption of sugar; third, a decrease in the consumption of complex carbohydrates (e.g., cereals and legumes) (Maillot et al., 2011). These major elements are presented in the Mediterranean diet pyramid that was developed during the Third International CIISCAM Conference, held in Parma, Italy (CIISCAM, 2009). In 2010, this Mediterranean diet pyramid was revised at the Eighth International Congress on the Mediterranean diet, held in Barcelona, Spain (Dernini et al., 2012) (Table 7.1). According to the new Mediterranean diet pyramid, this diet consists of large amounts of plant products, such as fruit, nuts, legumes, and unprocessed cereals. Therefore, the dominant protein in this diet is a plant protein, and the content of animal proteins is limited. Evidence showed that plant proteins have a better influence on human health than animal proteins. It is associated with a reduction of insulin resistance and stimulation of lipid metabolism resulting

The Bioavailability of Nutrients  233 Table 7.1: Portions in the Mediterranean diet pyramid (University of Wisconsin Hospitals and Clinics Authority, 2009). Food Group

Portion

Serving Sizes, Examples, and Notes

Nonstarchy vegetables

4–8 servings/day

1/2 cup cooked vegetables, 1 cup raw vegetables

Comments

Nonstarchy vegetables include all vegetables except: potatoes, corn, peas, and winter squash

Fruit

2–4 servings/day

Comments

Whole fruits are preferred because of the fiber and other nutrients they contain; fruits canned in light syrup or their own juice, and frozen fruit with little or no added sugar are also good choices; use only small amounts of fruit juice (8 oz. per day or less), since even unsweetened juices can contain as much sugar as regular soda

Low-fat dairy products

1–3 servings/day

Comments

Soy milk, soy yogurt, and soy cheese can take the place of dairy products; if servings of dairy or fortified soy are less than 2/day, a calcium and vitamin D supplement is advised

Whole grains and starchy vegetables

4–6 servings/day

Comments

Whole grains are high in fiber and have less effect on blood sugar and triglyceride levels than refined, processed grains like white bread and pasta; whole grains also keep the stomach full longer, making it easier to control hunger

Legumes and nuts

1–3 servings/day

Comments

Aim for 1–2 servings of nuts or seeds and 1–2 servings of legumes per day; legumes are high in fiber, protein, and minerals; nuts are high in unsaturated fat, and may increase HDL without increasing LDL

Fish or shellfish

2–3 servings/week

Comments

Bake, sauté, broil, roast, grill, or poach your fish; choose fatty fishes like salmon, herring, sardines, or mackerel often. The fat in fish is high in omega-3 fats, so it has healthy effects on triglycerides and blood cells

Healthy fat

4–6 servings/day

Comments

These fats are mostly unsaturated and contain little or no trans fat, so they will not increase LDL cholesterol levels; all fats are a concentrated source of calories, so try to keep the servings small

Poultry, if desired

1–3 servings/week

One small fresh fruit, 1/2 cup juice, 1/4 cup dried fruit

1 cup of skim milk or light yogurt, 1 oz. of low-fat cheese

1 slice whole wheat bread; 1/2 cup potatoes, corn, peas, or winter squash; 1/2 large whole grain bun; 1 small whole grain roll; 6-inch whole-wheat pita; 6 whole-grain crackers; 1/2 cup cooked whole grain cereal; 1/2 cup cooked whole wheat pasta, brown rice, or barley

2 tablespoons sunflower or sesame seeds; 1 tablespoons peanut butter; 7–8 walnuts or pecans; 20 peanuts; 12–15 almonds; 1/4 cup fat free refried beans or baked beans; 1/2 cup kidney, black, garbanzo, pinto, soy, navy beans, split peas, or lentils

3 ounces (about the size of a deck of cards)

1 teaspoon olive or canola oil; 2 teaspoons light margarine; 1 tablespoon regular salad dressing; 2 tablespoons light salad dressing, made with oil; 1 teaspoon regular mayonnaise; 1/8 of an avocado; 5 olives

3 oz. (about the size of a deck of cards) (Continued)

234  Chapter 7 Table 7.1: Portions in the Mediterranean diet pyramid (University of Wisconsin Hospitals and Clinics Authority, 2009). (cont.) Food Group

Portion

Comments

Bake, sauté, stir fry, roast, or grill the poultry you eat, and eat it without the skin

Alcohol

No more than one One drink equals one 12-oz. beer, 4 ounces of wine, or 1 and 1/2 oz. drink/day for wom- liquor (whiskey, vodka, brandy, and so on) en or two drinks/ day for men People with high blood pressure or high triglycerides, or those taking certain medicines may be advised to avoid all alcohol. Ask your doctor to be sure

Comments

Serving Sizes, Examples, and Notes

by lowering total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C) (Lin et al., 2015). Virgin olive oil. The fundamental Mediterranean diet component is virgin olive oil, which is reach in monounsaturated fatty acids (Boskou, 2015). Studies have shown that fat contained in olive oil increases the enzyme Paraoxonase 1 (PON1) activity. PON1 is a very important aspect of prevention of cardiovascular disease development, especially atherosclerosis (Lou-Bonafonte et al., 2015). Virgin olive oil contains bioactive phenols. The bioactive phenols, which are included in virgin olive oil, are: the dialdehydic forms of elenolic acid linked to tyrosol, hydroxytyrosol, oleuropein, ligstroside aglycons, tyrosol, hydroxytyrosol, lignans, phenolic acids, flavonoids, derivatives of phenolic alcohols, hydroxyisochromans, and traces of glycosides (oleuropein, ligstroside). Other important nonpolar bioactive constituents are α-tocopherol and nonphenolic compounds, mainly squalene hydroxyterpenic acids, triterpene dialcohols, phytosterols, and carotenoids (Boskou, 2015; Trichopoulos and Trichopoulos, 2009). Fish. Fish are an important element of the Mediterranean diet. According to recommendations, health specialists suggest consuming fish at least twice a week. Fish are characterized by low fat content, especially cholesterol. There is also a reach source of high-value proteins, vitamins (e.g., A-, D-, B- groups) and minerals (e.g., calcium, zinc, iron, selenium). In the case of fat, the fish fat is made up of polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) (Prato and Biandolino, 2015). Wine. Moderation alcohol consumption is allowed in the Mediterranean diet, but generally in the form of wine. It should be stressed that there are two very important nonalcoholic components of wine, such as resveratrol and quercetin. Some studies show that the wine polyphenols protect neuronal cells by attenuating oxidative stress and cell damage. According to this observation, many researchers suggest that regular consumption of wine could be associated with a reduced incidence of neurodegenerative diseases (Carollo and Caimi, 2012).

The Bioavailability of Nutrients  235 Dried fruits. The next fundamental Mediterranean diet component is dried fruit, such as raisins, figs, dates, apricots, and so on, because of contained polyphenols. The studies focused on polyphenols have shown that there are bioactive polyphenols in: • • • •

dates (e.g., quercetin, apigenin, and luteolin); prunes (e.g., chlorogenic acid); dried apricots and peaches (e.g., carotenoids—precursors of vitamin A and antioxidants); and dried figs (e.g., luteolin-3,7-di-O-glucoside, luteolin 7-glucoside, apigenin-7-O-rutinoside, rutin, quercetin-3-glucoside, and cyanidin-3-O-rutinoside) (Russo et al., 2014).

Sesame seeds. Sesame seeds are considered as a source of many biologically important compounds that have a positive influence on human health. The most well-known bioactive compounds in sesame seeds are: phytosterols, some vitamins and minerals, polyunsaturated fatty acids, tocopherols, lignans (such as sesamin and sesamolin) (Mahendra Kumar and Singh 2015; Pathak et al., 2014). Diary products. Another very important aspect of Mediterranean diet is low consumption of dairy products. The exceptions are the long-preservable cheeses (Boskou, 2015). It should be noted that the discussed food products in the Mediterranean diet contain many bioactive components. Studies have shown that these bioactive components are characterized by a positive impact on the cognitive functions of the human brain. In this connection, we discuss more in the next section.

3  Bioavailability of Food Products—Physiological Aspect The nutrients supplied to the human body with food, and in some cases, even with water, or in the form of pharmaceutical formulations and supplements are used to varying degrees in the organism. The extent to which the ingested nutrient, after the release of the connection in which it is found in the body can be absorbed and utilized by the body is defined as relative bioavailability. Bioavailability is not only changes that take place in the gastrointestinal tract, the transport and uptake by tissues. These forms can create reserves or meet a variety of physiological functions. Bioavailability is thus a collection of different processes that favor or restrict the use of the body-consumed nutrient (Table 7.2). The degree of utilization of nutrients depends on many factors. The first group consists of nutritional factors related to the chemical composition and physical characteristics of the product or meal, such as the amount and chemical form in which the ingredient is present. An important element is also the presence of substances to facilitate digestion and absorption of both substances facilitating and hindering transport inside the body and the use of

236  Chapter 7 Table 7.2: Stages of the use of nutrients in the organism (Gawe˛cki, 2012). Consumption

Food Stuffs, Water, Supplements

Bioavailability Digestibility

Digestion-transformation in the form of absorbable

Enzymatic degradation, transforming into a form readily soluble binding ligands

Absorption

Penetration of the mucosal cells of the gastrointestinal tract, transport through the cell, absorption into the blood or lymph

Metabolism Excretion

Transport to the tissues, the synthesis of substances metabolically active, storage, distribution Urine, feces, and by saliva, and so on

metabolism. Another group is the physiological factors that are associated with the organism. These factors include the presence of digestive enzymes, kidney function, the economy in the body, and nutritional status (age, sex, physiological status, disease, use of medications, supplements). To assess the degree of utilization of nutrients used, methods are based on the availability of a given component and examine the actual use of the ingredient in a living organism. In vitro methods are mainly used for comparison purposes; the component is accessible potential (potential digestibility) of various products or the influence of processing or storage. Bioavailability studies are also conducted in animal studies and include a balance sheet and study-specific component (the level metabolite or enzyme in the blood (Gronowska-Senger, 2004).

3.1  The Bioavailability of Selected Nutrients The bioavailability of a nutrient comprises the consumed part of the component, which after digestion and absorption is transported to tissues and stopped or converted into a biologically active form. The bioavailability concept applies to all nutrients and is particularly important in the case of trace elements because their level of use in the body is affected by numerous factors. These include systemic factors, such as age, sex, physiological status, health, degree of nourishing the body with particular elements, stress, and dietary factors. Nutritional factors include the type of selected diet and the content of a given component in the diet. The content of minerals in the diet has a close relation to its chemical form. In the case of minerals, they play an important role also as compounds. The methods used in the assessment of food: • •

ex vivo methods are used for the preliminary assessment of the nutritional value of foods. This group also includes methods of in vitro digestion in vivo methods determine the suitability nutrient for the organism. This group also includes biological methods taking into account the body’s response to a given

The Bioavailability of Nutrients  237 component. In order to determine the nutritional value of food for vitamins it is necessary to know their biological activity. Bioactivity and bioavailability involve bioconversion. Bioconversion concerns only vitamin precursors, which are present in the form of inactive provitamins. The bioactivity of vitamins is affected by external and internal factors. The external factors include: • • • •

source chemical nutrients interaction food additives

The internal factors concern: • •

genetics interaction with medication

The chemical structure, polarity, and connection type in which these chemicals are present in food are important external factors. Most water-soluble vitamins are in protein-bound form. Some vitamins require the presence of specific enzymes, for example, the biotinidase enzyme or biotin for hydrolysis with a phosphatase to release the compound before absorption (thiamine, riboflavin, pyridoxine). In the case of fat-soluble vitamins, their degree of absorption is determined by their chemical structure and polarity. Food additives and food processing may inactivate vitamins or have a positive or negative impact on their bioavailability. The bioavailability of vitamins from foods of plant origin is much lower than from animals. The presence of fat in the diet has a direct impact on the absorption of soluble vitamins. A low fat and high protein content reduce the absorption and in turn the bioavailability of vitamins. The internal factors that affect the bioavailability include nutrition level. Aging and impaired gastrointestinal functions deteriorate the bioavailability of vitamins, especially vitamin D, B12, and increase the bioavailability of vitamin A and β-carotene. In addition, nonenzymatic oxidation systems and a plurality of drug interactions cause reductions in bioavailability (Rein et al., 2013).

3.2 Vitamins Vitamins are low-molecular organic compounds of various chemical structures prevalent in the world of plants and animals. Vitamins have many functions. They are catalysts for biochemical reactions, and are part of enzymes and coenzymes essential for the growth and maintenance of vital functions. For many organisms, including humans and animals, they are generally exogenous compounds and must be supplied with food. Some vitamins can also occur in the human body, but their production is not sufficient and does not cover our

238  Chapter 7 physiological needs. This applies to B vitamins and vitamin K (prepared by the microflora in the intestines), vitamin D2 (synthesized in the skin as provitamin D), vitamin PP (produced from the amino acid tryptophan). To distinguish them from other essential nutrients, vitamins are substances that act in very small quantities, with the exception of ascorbic acid, the daily requirement of vitamins do not exceed 20 mg. Some vitamins are produced by animals from suitable compounds synthesized by plants. Such compounds are called provitamins, for example, β-carotene. The source of vitamins and provitamins is plants and bacteria in digestive tract tissues, as well as animal tissues. The actual need for each vitamin is difficult to identify due to the synergistic effect of many of them. It depends on individual differences, state of health, and human life period. Vitamins are divided into two groups of solubility: •

•

fat-soluble vitamins (A, D, E, and K), which have the ability to accumulate in our tissues, and their bioavailability is dependent on the presence of fat in the diet and proper absorption water-soluble B vitamins (B1, B2, B6, B12, PP, biotin, folacin, pantothenic acid) and vitamin C. These vitamins are excreted in the urine; they do not accumulate in the body so they must be supplied with food.

Recently, another division of vitamins has been observed, based on the differences in the mechanism of action in the organism. According to this, vitamins regulating metabolic processes in the body constitute the vitamin B group, while the compounds performing the function of regulating the vitamins should include those that do not contain nitrogen (A, D, E, K, C). In the case of vitamins, in addition to the concept of bioavailability, the concept of biological activity has been formulated. This is due to differences in the chemical structure of vitamins, differences in solubility and stability, and the variable absorption from the gastrointestinal tract, and effect of interaction in the body. The biological activity (bioactivity) determines the degree to which the particular compound is absorbed from food, converted into an active form of vitamin, and prevents the symptoms of deficiency. In addition to factors that affect the bioavailability of vitamins, factors that influence bioactivity include disorders related to metabolic diseases, the use of drugs, and the level of proteins that transport specific forms of the vitamin, for example, proteins that bind to retinol (retinol-binding protein) and transfer it from the liver to tissues or the intrinsic factor—binding vitamin B12 (Fabisiak, 2016). The biological activity of the compounds of vitamins A and E is shown in Table 7.3. 3.2.1  Water-soluble vitamins Vitamin B1 (thiamine). Thiamine is widespread in plant tissues (in free form) and animal tissues (as pyrophosphate, 80%). Thiamine is present in food in a variety of forms, including free and thiamine pyrophosphate, which is a coenzyme of many enzymes, for example, pyruvate decarboxylase.

The Bioavailability of Nutrients  239 Table 7.3: The biological activity of vitamins A and E (Gronowska-Senger, 2004). Form of Vitamin A

Bioavailability (%)

Form of Vitamin E

Bioavailability (%)

Trans-retinol Cis-retinol α-Carotene β-Carotene γ-Carotene

100 23–75 8 17 5

α-Tocopherol β-Tocopherol γ-Tocopherol α-Tocoretinol β-Tocoretolol

100 50 10 30 5

Thiamine is a vitamin that must be ingested with food. Unfortunately, it is widespread in food in small quantities. After absorption from the intestine it is transported into the bloodstream in combination with albumin. Vitamin B1 is an important factor in the combustion reactions of carbohydrates in cells. The role of vitamin B1 in the activities and regeneration of the NS is especially important. Thiamine is mainly deposited in muscle, liver, and kidneys. The human body contains approximately 30 mg thiamine, but it must be constantly supplied with food. The presence of dietary fiber is important for the bioavailability of thiamine. Fiber amounting to 10% in the diet leads to a reduction in the bioavailability of thiamine by blocking its absorption in the intestine (Moszczyński and Pyc´, 1998a). The most important source of thiamine is cereal products: rice, cereal, flour, and all kinds of breads and legumes. Consumption of bread covers about 40% of the body’s need for this vitamin. But most of the vitamin is found in the grain and the aleuronic layer in cereals. In the case of rice, which is subjected to flaking and polishing, a significant part of this vitamin is lost. In animal products vitamin content depends on the share of fat, muscle, and tissue. Most of this vitamin is in the muscle tissue, the richest kind of meat is pork (1 mg/100 g), while meat, poultry, veal, and beef contain less than 1 mg/100 g. In the case of deficiency of vitamin B1, the transformation of pyruvic acid is difficult, and, therefore, this acid accumulates in tissues and organs in excessive amounts. The NS is most susceptible to the disorders. Disturbances in heart rate, changes in sensation, and ailments of the digestive system, especially digestion of carbohydrates, all may occur. A common symptom of vitamin deficiency is also impaired memory, concentration, and swelling of the upper and lower limbs. In certain states of the organism (pregnancy, lactation), prolonged physical effort, the demand for thiamine must be increased. Hypervitaminosis of this vitamin is very rare and is characterized by symptoms, such as headaches, muscle shivering, and allergies (Bourre, 2006). Vitamin B2 (riboflavin). Riboflavin is a component of many enzymes and most often occurs as a flavoprotein in free form. Riboflavin is a component of two coenzymes. Small amounts of this vitamin are synthesized by intestinal microflora, but their availability is negligible. Riboflavin is absorbed in the jejunum and the thick body can absorb up to about 27 mg. The major route of excretion of riboflavin is urine, in which 60%–70% is free form. The presence of fiber increases the bioavailability of vitamins from food, increasing the

240  Chapter 7 possibility of absorption. Vitamin B2 is a photostable vitamin, resulting in a decrease in the vitamin level of food products when exposed to sunlight. Riboflavin is found in larger amounts in meat, cured pork. Given the frequency of eating, the main source of this vitamin is milk and milk products. Thiamine, riboflavin occurs in cereals (bran and germ). Products containing the least riboflavin include barley, white rice, potatoes, cucumbers, apples, or oranges (below 0.05 mg/100 g). Riboflavin is involved in oxidation and reduction and determines the proper functioning of the NS, along with vitamin A, which is involved in the proper functioning of mucous membranes and respiratory tract. Riboflavin takes part in the metabolism of amino acids and lipids, and is responsible for the functions of the eye. A lack of riboflavin leads to cracking of the corners of the mouth and inflammation of the cornea. The daily requirement for this vitamin is between 1.5 and 3 mg (Belinda, 2014; Moszczyński and Pyc´, 1998b. Vitamin B3 (niacin). Vitamin PP, or nicotinic acid (pyridine-3-carboxylic acid) and its amide of niacin are termed as a pyridine derivative, which is the main component of a nontoxic nicotine present in tobacco. Both compounds are formed in the organism from tryptophan derived from food or from the breakdown of protein tissue. Niacin is absorbed in the stomach and upper small intestine. A large part of accumulated niacin in the organism comes from absorbed food, while the rest comes from the synthesis of tryptophan in the liver. Niacin is kept in the liver, in the kidney and skeletal muscles, and, in the case of shortage, the organism retrieves this compound. Tryptophan present in foods can be a good source of niacin, so its bioavailability is dependent on protein digestibility. The content of this vitamin is expressed in equivalents (equivalent to 1 = 60 mg tryptophan). Unfortunately, as much as 95% of niacin in food is in linked form, and only an alkaline environment and food processing release nicotinic acid. Vitamin PP is found in substantial amounts in meat (poultry, pork), in the liver, in cereals and potatoes. The major route of excretion of niacin is urine. This vitamin is involved in the regulation of blood sugar levels (production of energetic compounds). Niacin plays an important role in the regulation of cholesterol levels, lowering LDL while increasing HDL. It also affects the corresponding condition of the skin and also participates in the regulation of blood flow. Niacin also has the ability to widen blood vessels, which is used for relieving circulatory problems in the elderly. Niacin deficiency may be associated with inflammation of the skin or interference with the brain and NS. The resulting gastrointestinal disorders caused by the absence of niacin lead to gastroenteritis (diarrhea). Excess of synthetic vitamin B3 leads to an increase in blood glucose levels, symptoms can also be headache, tingling, or tinnitus (Kenned, 2016). Vitamin B6 (pyridoxine). This vitamin is composed of naturally occurring pyridine. Vitamin B6 is transformed in the body. The main place of its storage is muscles (90%, i.e., 40–50 mg). The remaining 10% is in the liver and other tissues. It is excreted primarily as 4-pirydoxine urine (Moszczyński and Pyc´, 1998a).

The Bioavailability of Nutrients  241 The bioavailability of vitamin B6 depends on the form, but pyridoxal and pyridoxamine are less active than pyridoxine. The bioavailability from foods for the vitamin is higher with products of animal origin than plant. Vitamin B6 is available for humans in wheat bran, rice, and maize. Dietary fiber prevents bioavailability, and the presence of protein positively affects assimilation. Vegetarians are particularly vulnerable to reduced bioavailability because they consume quite a lot of foods rich in fiber. Meat is a rich source of vitamin B6, and its consumption covers about 40% of demand. Consuming vegetables covers about 22%, while 12% of the daily requirement comes from dairy products. Vitamin B6 is involved in the formation of antibodies, and is responsible for the immunity of the organism. It also helps in the conversion of tryptophan vitamin PP, and is essential in the production of red blood cells and hormones (histamine, serotonin). Due to the fact that pyridoxine is synthesized by bacterial flora of the human digestive tract, deficiencies (which cause symptoms, such as inflammation of the skin, changes in the NS) are very rare (Hellmann, 2010). Pantothenic acid (vitamin B5). Pantothenic acid is an amide of pantothenic acid and β-alanine. It is a component of coenzyme A, and takes part in the synthesis of citric acid, fatty acids, cholesterol, or acetylcholine. This compound helps hair pigmentation and is responsible for skin regeneration. Pantothenic acid is widely distributed in foods; it is present in both free form and bound (CoA). Rich sources are yeast, liver, eggs, milk, walnuts, or Camenbert cheese. In the light of the latest research, there is no information on the impact of food on bioavailability. Food processing causes a loss of 50%–75%. However, consumption of cooked and fried products like potato chips, pizza, pasta, or too much sugar can cause deficiency of this vitamin. Symptoms include burning feet syndrome, fatigue, weakness, abdominal pain, abnormal pigmentation of hair, and spasms of the arms and legs (Kelly, 2011). Folic acid (vitamin B9). Folic acid belongs to the complex of vitamin B2. In its composition it contains a derivative of pteridine, p-aminobenzoic acid, and glutamic acid. The active form of folic acid is involved as coenzyme F (CoF) in the transfer of one-carbon residues. Folic acid is accountable for the synthesis of purine and pyrimidine bases, as well as amino acids, such as serine, methionine, and histidine. This acid is also involved in the formation of nucleic acids—DNA and RNA. Absorption of folic acid takes place in the small intestine. Stocks of folate are up to 10 g, of which 50% is accumulated in the liver. These compounds are mainly excreted in the urine and feces. Folic acid derivatives occur naturally in foods, their bioavailability varies and amounts to 72% in the case of egg yolk, and for liver it is 56%, for orange juice 21%, while for some vegetables it is only 6%. The bioavailability of folate is not affected by food fiber, but is dependent on the appearance of an inhibitor, which is present in products, such as cabbage, oranges, tomatoes, beans, or causes a reduction and absorption of vitamin B9. The bioavailability of folate also depends on the physiological condition of the digestive system. The increase in the pH in the intestines causes a decrease in absorption; an additional factor reducing the bioavailability is also excessive consumption of alcohol. Congenital malformations in newborns are most often the result of low consumption

242  Chapter 7 of folic acid by women who are pregnant. However, the dose above 15 mg may lead to a NS disorder (Kenned, 2016). Vitamin B12 (cyanocobalamin). This vitamin belongs to a group of corrinoids, which includes the corrinoid system in its composition. Vitamin B12 can be absorbed by the human body only in the presence of endogenous glycoproteins, which occur in the gastric mucosa. None of these factors are possible in people with pernicious anemia. Vitamin B12 is involved in the formation of red blood cells, participates in the metabolism of fats and carbohydrates, and in the proper functioning of the NS. Cyanocobalamin activates iron substances in the body and allows the absorption of vitamin A. Vitamin B12 reserves are stored in the liver. Consumption of large amounts of the vitamin does not cause adverse side effects. It is not found in plant products, and with products of animal origin it is found mainly in animal organs (liver, kidney, heart) (Gronowska-Senger, 2004) (Table 7.4). Table 7.4: Foods rich in B-group vitamins (USDA National Nutrient Database for Standard Reference, 2009). Foods Rich In

Food Products

Vitamin (in Portion)

Vitamin (in 100 g)

Vitamin B1

Trout Seeds (sunflower) Macadamia nuts Green peas Almonds Mackerel Egg (hard-boiled) Sesame seeds Cooked yellow-fin tuna Cooked chicken breast Sunflower seeds Avocado Trout Avocado Sunflower seeds Sweet potato (baked) Sunflower seeds Pistachio nuts Tuna Dried fruit (prunes) Black-eyed peas (cooked) Lentils (cooked) Spinach Asparagus (cooked) Lettuce (cos or romaine) Cooked clams Silken tofu Mackerel Crustaceans (crab)

0.26 mg/fillet (62 g) 0.41 mg/ounce (28 g) 0.20 mg/ounce (28 g) 0.23 mg/1/2 cup (80 g) 0.28 mg/ounce (28 g) 0.49 mg/3 ounce (85 g) 0.26 mg/egg (50 g) 0.13 mg/ounce (28 g) 6.3 mg/ounce (28 g) 12.7 mg/1/2 breast (80 g) 2.3 mg/ounce (28 g) 3.5 mg/fruit (201 g) 1.90 mg/3 ounce (85 g) 2.8 mg/fruit (201 g) 1.98 mg/ounce (28 g) 1.01 mg/potato (114 g) 0.38 mg/ounce (28 g) 0.31 mg/ounce (28 g) 0.88 mg/3 ounce (85 g) 0.49 mg/1/2 cup (66 g) 58 µg/ounce (28 g) 22 µg/tablespoon (12 g) 263 µg/cup (cooked: 180 g) 89 µg/4 spears (60 g) 64 µg/cup (shredded: 47 g) 187.9 µg/20 small clams (190 g) 2.2 µg/1/5 package (91 g) 16.7 µg/fillet (80 g) 15.4 µg/leg (134 g)

0.43 mg 1.48 mg 0.71 mg 0.28 mg 1.10 mg 0.58 mg 0.51 mg 0.47 mg 22.1 mg 14.8 mg 8.3 mg 1.7 mg 2.24 mg 1.4 mg 7.06 mg 0.88 mg 1.35 mg 1.12 mg 1.04 mg 0.75 mg 208 µg 181 µg 194 µg 149 µg 136 µg 98.9 µg 2.4 µg 19.0 µg 11.5 µg

Vitamin B2

Vitamin B3

Vitamin B5

Vitamin B6

Vitamin B9

Vitamin B12

The Bioavailability of Nutrients  243 Vitamin C (ascorbic acid). It consists of two active compounds, acid, l-ascorbic acid and l-dehydroascorbic having the same vitamin activity. Vitamin C is involved in the production of collagen and basic proteins (bone, cartilage, tendons, and ligaments). It also plays an important role in detoxification reactions and immunity, protecting it from oxidation processes. It is involved in the metabolism of fats, cholesterol, and bile acids. It is a stabilizing factor for the immune system and inhibits the formation of carcinogenic nitrosamines in the stomach. Vitamin C also has antioxidant properties that protect the body against the harmful effects of oxidative stress. Long-term aspirin intake reduces the excretion of the vitamin. Vitamin C deficiency results in a slower healing of wounds, pale skin disorders, the formation of collagen, fatty acid metabolism, impaired brain function, and also reduces immunity. The bioavailability of vitamin C is determined by the mechanism of absorption, its form, and stability before and during absorption. Vitamin C is absorbed by the body on the principle of active transport (low to moderate intake) and by current transport. It plays an important role in levels of consumption, because at 20–120 mg per day it is absorbed at 90%, and lowered to 16% when the dietary intake is 12 g. Among nutrients, bioflavonoids have a positive effect on the bioavailability of vitamin C, while fiber affects the process according to spoil fraction, that is, hemicellulose enhances absorption, whereas pectins have a negative effect. Iron also inhibits this process. On average, about 75% of vitamin C is absorbed from food. This vitamin is present in considerable quantities in fruits and vegetables, as well as in animal organs (brain, liver, kidney). Cereals, milk, and meat contain only trace amounts of vitamin C (Sikorski, 1994; Subasree, 2014) (Table 7.5). 3.2.2  Vitamin A and its provitamin Vitamin A is a group of compounds consisting of β-ionone and exhibiting the activity of alltrans retinol. They belong to carotenoids (provitamin A). The main storage source of vitamin A is the liver. Among the provitamin of carotenoids βcarotene has the highest activity. A third of β-carotene is absorbed when consumed with food, Table 7.5: Foods rich in vitamin C (USDA National Nutrient Database for Standard Reference, 2009). Food Products Foods rich in vitamin C Peppers (yellow bell peppers) Guavas Kale Kiwifruit Broccoli Strawberries Oranges Papaya

Vitamin (in Portion)

Vitamin (in 100 g)

341.3 mg/large pepper (186 g) 125.6 mg/fruit (55 g) 80.4 mg/cup chopped (67 g) 64 mg/fruit (69 g) 81.2 mg/cup chopped (92 g) 10.6 mg/1 large strawberry (18 g) 69.7 mg/orange (131 g) 95.6 mg/1 small papaya (157 g)

183.5 mg 228.3 mg 120 mg 92.7 mg 89.2 mg 58.8 mg 53.2 mg 60.9 mg

244  Chapter 7 of which 50% is converted to retinol, therefore bioactivity with respect to retinol is 1:6. While the bioactivity ratio containing vegetables amounts to 1:12. Bioactivity and bioavailability of carotenoids depends on the type of carotenoid, the quantity of food consumed, the efficiency of absorption, biotransformation-dependent lipids, and the interaction of fiber and pectin. If the amount of provitamin A consumed is less than 1 mg it is converted to vitamin A in the intestine. Larger quantities increase absorption. The bioavailability may also come from the amount of vitamin A formed from the provitamin, therefore, the total bioavailability of this vitamin is unknown. It is known, however, that only β-carotene is an effective antioxidant and consuming large amounts of this compound may provide the required dose of vitamin A. Vitamin A has an effect on the reproductive function of the body and in the process of vision. If there is a deficiency of this vitamin in the organism, disorders related to the adaptation of the eye, or inflammation and infection of the gums, are displayed (Moszczyński and Pyc´, 1998a). 3.2.3  Vitamin E (tocopherol) Vitamin E belongs to a group of compounds named tocol and tocopherols, from an unsaturated and saturated phytyl chain. Tocol includes α-, β-, γ, and δ-tocopherols. The most active form is α-tocopherol. There is not much information on the bioavailability of vitamin E from food. Biological activity is associated with forms of occurrence and stereoisomers are more absorbable in configuration α than β. Another factor influencing the bioavailability is the level of consumption and a balanced diet brings with it absorption varying from 20%–80%. Important factors are for the organism its interaction with other nutrients, such as fats, vitamin C, carotenoids. Consumption of protein or high levels of vitamin A reduces the bioavailability of the vitamin E. The richest source of tocopherols is oils from the seeds of cereals (sunflower, soybean), eggs, and butter. Vitamin E interacts with vitamin A and C, carotenoids and bioflavonoids, and selenium reduce risk of cancer and the formation of free radicals. Tocopherols stimulate the production of anticoagulants substances. Deficiency causes abnormalities in the functioning of bones and muscle weakness (Borel et al., 2013; Subasree, 2014) (Table 7.6). Table 7.6: Foods rich in vitamin E (USDA National Nutrient Database for Standard Reference, 2009). Food Products Foods rich in Vitamin E Cooked spinach Almonds Sunflower seeds Avocados Rainbow trout Olive oil Broccoli Kiwifruit

Vitamin (in Portion)

Vitamin (in 100 g)

5.8 mg/10 oz. pack (raw: 284 g) 7.3 mg/ounce (28 g) 10.2 mg/ounce (28 g) 4.2 mg/avocado (201 g) 2.0 mg/fillet (71 g) 0.7 mg/teaspoon (5 g) 2.6 mg/stalk (180 g) 1 mg/fruit (69 g)

2.1 mg 26.2 mg 36.3 mg 2.1 mg 2.8 mg 14.4 mg 1.5 mg 1.5 mg

The Bioavailability of Nutrients  245 Table 7.7: Foods rich in zinc (USDA National Nutrient Database for Standard Reference, 2009). Foods rich in Zinc

Food Products

Zn (in Portion)

Zn (in 100 g)

Cooked oysters Cooked lean beef shortribs Wheat germ (toasted) Spinach Broccoli Pumpkin and squash seeds Cashews Cocoa and chocolate

33.0 mg/6 oysters (42 g) 14.2 mg/1 lean rib-eye fillet (129 g) 4.7 mg/ounce (28 g) 0.5 mg/100 g (raw) 81.2 mg/cup chopped (92 g) 2.9 mg/ounce (28 g) 1.6 mg/oz. (28 g) 0.3 mg/tablespoon (5 g)

78.6 mg 12.3 mg 16.7 mg 0.8 mg 89.2 mg 10.3 mg 5.6 mg 6.8 mg

3.3 Zinc Zinc (Zn) is a very important microelement to the immune, reproductive, and CNS. This mineral is present in many areas of the brain, especially in the hippocampus and amygdala. There are some studies that showed that zinc influences brain structure and function. The Zn deficiency is associated with slower wound healing, as well as delayed physical and cognitive development (Maylor et al., 2006) (Table 7.7).

3.4 Phytoestrogens Phytoestrogens are microelements that have a very similar structure to estrogens (natural and synthetic). The natural source of phytoestrogens are plants. The scientists have discovered three categories of phytoestrogens: • • •

Isoflavones (e.g., genistein, daidzein, and formononetin): Isoflavones are found in soy products, beans, peas, nuts, tea, and coffee. Lignans: The main source of lignans is plant food, especially oilseeds, linseeds, broccoli, and berries. Coumestans: The main source of coumestans is alfalfa and broccoli.

It should be stressed that a recent study suggested that isoflavones might have a positive affect cognition function of the brain. However, there is too little data about the relation between phytoestrogens and cognitive function (Franco et al., 2005).

3.5  Fatty acids (n−3) Differences in the area depend on the composition of nonglycerin fat fractions and the composition of fatty acids. EFA includes acids, which must be supplied with food. The n−3 acids include α-linolenic acid, eicosapentaenoic acid (EPA), and (DHA). These acids are essential to the brain, reduce LDL, and improve the functioning of the heart and circulatory system. Regular consumption of fish and omega-3 fatty lowers blood pressure. A good source

246  Chapter 7 Table 7.8: List of foods with high omega 3 to omega 6 ratios (USDA National Nutrient Database for Standard Reference, 2009). Food Products

Omega 3 to Omega 6 Ratio

Omega-3 (in Portion)

Caviar Striped bass, cooked Salmon Mungo beans (e.g., urad dal, black gram, black lentil) Peppermint Spinach, cooked Papaya Flaxseeds Iceberg lettuce

84.2 51.0 32.0 14.0

1905 mg/ounce (28 g) 1199 mg/3 ounce (85 g) 1559 mg/3 ounce (85 g) 603 mg/cup (180 g)

6.3 5.4 4.3 3.9 2.5

13 mg/2 tablespoons (3 g) 166 mg/cup (180 g) 74 mg/papaya (157 g) 2281 mg/tablespoon (10 g) 46 mg/serving (89 g)

of these fatty acids is marine fish, flaxseed, walnuts, canola oil and soybean oil, and green leafy vegetables. The bioavailability of fatty acids mainly relates to methods for ex vivo and in vivo (Block and Pearson, 2006) (Table 7.8).

4  Processes and Bioavailability As humans searched for methods of manufacturing food, its processing developed. There are new technologies that have enriched the food market with products that are convenient to use, microbiologically safe, with high organoleptic values. Consequently, the biological value of food is not only connected to its chemical composition but also the availability of nutrients. This, however, depends on the type and form of food consumption level, the interaction between nutrients, the presence of antinutritional substances. It is also an important state of nutrition and the physiological condition of the gastrointestinal tract. Changes in processed foods can have a favorable or unfavorable effect, which stems from the necessity of subjecting raw food to technological or culinary processes. The effect of different processes to changes in nutritional value of the food is shown in Table 7.9. Table 7.9: The effect of various process changes the nutritional value of food (Gronowska-Senger, 2004). Change Processes Mechanical Diffusion Chemical Biotechnology Thermal

Benefit

Adverse + + +

+ +

+

The Bioavailability of Nutrients  247 Mechanical processes, which can include peeling, soaking, grinding, and shredding are associated mostly with the initial preparation of raw materials for consumption or further processing and have an unfavorable effect on its nutritional value (Fabisiak, 2016).

4.1  Losses in Technological Processes and the Possibility of Their Limitations B vitamins are nutrients that show the greatest sensitivity to the method of processing. Pretreatment is mainly related to a 25% loss of vitamin C, and soaking dry seeds of legumes causes some vitamins to be soaked up in the water. Cooked pulses retain 40% thiamine, 50% riboflavin, and 80% nicotinic acid. The pretreated rice grits and water diffuse nutrients, particularly vitamins present in the surface layer of grits or rice. During this process, losses of thiamin range from 6% to 43%, losses of riboflavin range from 10% to 25% and losses of nicotine acid can be up to 23%. During processing, the cell walls of food are disrupted, and the cell content is exposed to oxygen. Tissue damage to vegetables or fruits causes oxidation of ascorbic acid. Carotenoids and tocopherols can be decomposed by lipoxygenase found in plant tissue. Loss of vitamin B during the grinding process is small. In order to reduce vitamin losses, oxygen should be limited by adding oil or sauce to the salad, or lowering the pH by sprinkling chopped vegetables with lemon juice. Adverse effects due to culinary thermal processing cause quantitative and qualitative food loss. The quantitative mass loss is caused by evaporation of water and volatiles from the steam passage of the components soluble in water, leaking of juice and the melting of the fat tissue. The amount of these losses is related to the type of heat treatment. When preparing meat, special attention is required in order to maintain levels of vitamin B. Maintaining the levels of vitamin B depends on the method of heat treatment, diffusion processes, the heating time and the size of the heated meat. Thiamine is maintained at 70% for barbecued pork or beef, whereas stewing leads to a loss of this vitamin of up to 40% for pork and 30% for beef. During roasting a large loss of vitamin B is observed, in particular B6 (30%) and B2 (20%), as well as vitamins A and E (20%) (Gronowska-Senger, 2004). Meat can lose up to 75% of vitamins when treated with heat. An important factor during the heat treatment of meat is to achieve the right temperature in the center of the geometrical dishes, not only for technological reasons but also for microbiological reasons. The heat treatment temperature and the processing time must be selected in order to deactivate pathogenic microorganisms. The temperature of the beef should be at least 63°C, in the middle of the carcasses of poultry and pork the temperature should be at least 74°C (72°C for 2 min), and for poultry, because of possible Salmonella, the temperature should be up to 80°C (Fabisiak, 2016). Riboflavin, niacin, and folic acid are the most heat-resistant alongside thiamine and vitamin B6 (Table 7.10) (Gawęcki, 2002). During the heating process of the vegetables, ascorbinase contributes to significant losses of vitamin C, especially as it is active at elevated temperatures (optimum 45°C). During

248  Chapter 7 Table 7.10: The behavior of B vitamins in meat dishes (Gawe˛cki, 2002). Vitamin

Method of Heat Treatment

Preservation (%)

B1

Cooking in water Frying Microwave heating Cooking in water Stewing All heating methods

25–30 50–90 85–95 50–70 70–85 60–95 50–70 50–70

PP B2 B6 Folic acid

cooking, meat and fish losses of vitamin C can reach 50%, while during the suffocation vegetable loss of 30%. The vitamin value of vegetable dishes is especially reduced when the components are subjected to different culinary techniques, such as preparing casseroles, which is preceded by the process of baking cooked vegetables. A protective effect on vitamin C is seen in amino acids, proteins, starch, phenolic compounds, anthocyanins, carotenoids, and vitamins A, E, B1. In the case of treating legumes to heat, due to the long cooking time, vitamin loss can be as much as 60%. However, during the heat treatment of rice thiamine losses can be as high as 75%. When cooking barley or buckwheat the loss of thiamine can be up to 26%. Vitamin loss is associated with the preparation of chosen dishes as shown in Table 7.11 (Gawęcki, 2002). Biotechnological processes, which include fermentation, may have a positive effect on bioavailability, particularly vitamin B. The fermentation of dough used for the production of bread leads to an increase in vitamin B because in the presence of phytase, phytate is decomposed. However, during the baking process up to 30% of thiamine and pyridoxine is lost. Losses of vitamin A and carotenoids in the cooking process are 25% and 15%, respectively. The composition of fatty acids should be taken into account for the appropriate use of fats in thermal processes. The decisive criterion for the suitability of fats and oils Table 7.11: Vitamin loss (%) (Gawe˛cki, 2002). Dish

Process

B1

B2

PP

B6

C

A

β-Carotene

E

Soup Meat, fish

Cooking Cooking Frying Backing Cooking Stewing Salad Cooking Cooking Cooking Cooking

30 40 25 30 40 20 10 30 25 50 20

10 20 10 10 30 10 10 10 25 20 10

10 30 10 10 40 10 10 25 20 40 10

10 30 25 30 40 20 10 25 20 30 20

50

10 20 20 20 20 20 20 20 20 20 20

10 20 20 20 20 20 20 20 20 20 20

10 20 20 20 20 20 20 20 20 20 20

Vegetables

Potato Pasta Rice Groats

— 50 30 20 75 — — —

The Bioavailability of Nutrients  249 for frying is their composition. Fats containing polyunsaturated fatty acids are considered most susceptible to thermal decomposition. Pouring a high content of linolenic and linoleic acid, such as sunflower oil, soybean oil, grape seed oil causes the greatest susceptibility to oxidation. The oxidative stability of rapeseed oil and olive oil with its high content of oleic acid is much higher. Hydrolysis or oxidation occurs during the frying or baking process, which with limited access to oxygen, may cause thermal polymerization. It is worth noting that the use of butter for frying is possible as long as the temperature does not exceed its smoke point, which for butter is 120–208°C. Processes, such as culinary cooking, have little impact on the biological value of fats (Fabisiak 2016; Saguy and Dina, 2003). Food storage will cause changes not only in fats but also vitamins. Improper storage results in hydrolytic or enzymatic degradation of fats, and their autoxidation, the resulting products substantially reduce the nutritional value of the fat, which is also due to the degradation of fat-soluble vitamins, the degradation of vitamin B, vitamin C, and pantothenic acid. Vitamin loss also depends not only on lack of access to light, but time of storage. Storing foodstuffs at a temperature of (−18°C) for 5 months leads to a loss of vitamin B6 of up to 60%. Storage of flour of 5 months amounts to a loss of α-tocopherol varying from 20% to 60% (Gawęcki, 1997; Gronowska-Senger, 2004). Knowledge of the bioavailability of nutrients from food is crucial for the production and processing or storage of food. This knowledge may be especially important in new technologies, food processing, and other mechanisms and can improve the processes, which are already applied. Heavy metals belong to the substances that lower bioavailability. Science of the bioavailability of nutrients from food can lead to the improvement of public health (Czarniecka-Skubina and KorzeniowskaGinter, 2013).

5 Conclusions The issue of the relationship between dietary components and the functioning of the NS is very important and a new study area. There are studies that have shown that proper diet, such as the Mediterranean diet, which contains a lot of antioxidants (vitamin C, vitamin E, carotenoids), B-group vitamins, and unsaturated fatty acids may have a positive impact on cognitive functions. The main problem is the bioavailability of these components. For this reason, it seems to be justified that future studies should prepare methods that will increase the bioavailability of nutrients that have a health-promoting effect on the NS function on the one hand, and develop new forms of functional foods designed for it on the other hand.

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Further Reading Boskou, D., 2016. Mediterranean diet food: strategies to preserve a healthy tradition. J. Exp. Food Chem. 1, 104. Lin, B., Hasegawa, Y., Takane, K., Koibuchi, N., Cao, C., Kim-Mitsuyama, S., 2016. High-fat-diet intake enhances cerebral amyloid angiopathy and cognitive impairment in a mouse model of Alzheimer’s disease, independently of metabolic disorders. J. Am. Heart Assoc. 13 (5(6)).