- Email: [email protected]
Third Nutrition and Health Conference
Trends in Food Science & Technology 14 (2003) 392–394
Conference report
Third Nutrition and Health Conference: 29–30 November 2002, Excel Conference Centre London Carol Ottley The Laurels, Kirby Bedon, Norwich NR14 7DY, UK (e-mail: [email protected])
This conference provided a snap-shot of recent developments in nutrition and health. A wide range of topics were covered including cancer, heart disease, brain nutrition and gut health. This report provides an update for food technologists and others who are keen to keep abreast of current thinking and some new developments in these areas.
New WHO/FAO Report for 2003 During 2003 a new WHO/FAO report entitled Diet, Nutrition and the Prevention of Chronic Disease will be published based on an expert consultation that took place in Geneva in 2002. Although the report will cover the prevention of many diseases including diabetes, heart disease, dental caries and osteoporosis, Professor Tim Key from the Cancer Research and Epidemiology Department at Oxford University focused on the main findings in relation to diet and cancer (draft available at www.who.int/hpr/nutrition/). It is estimated that dietary factors account for about 30% of cancers in western societies, making diet second only to tobacco as a preventable cause of cancer. However research has so far revealed few definite relation0924-2244/03/$ - see front matter # 2003 Published by Elsevier Science Ltd. doi:10.1016/S0924-2244(03)00056-6
ships. A grid (Table 1) was developed to summarise the level of evidence relating to each of possible cancer risk factor. After tobacco, overweight and obesity appear to be the most important avoidable causes of cancer. This is why the two main public health recommendations suggested are: 1. Adults should maintain their weight in the normal range with a body mass index (a measure of body weight relative to height) between 18.5 and 25 kg/m2 and not gain weight as they get older. 2. Indulge in regular physical activity. More specifically it is important to be active most days of the week. Moderate exercise like walking for an hour would help maintain weight in sedentary individuals, whereas more vigorous activity may give additional benefits for cancer prevention. More specific food based recommendations are also suggested and include the following: Alcohol is not recommended and if consumed should not exceed two units per day (one small glass of wine or beer or one measure of spirits counts as a unit) Exposure to aflatoxin in foods should be minimised At least 400 g of fruit and vegetables should be eaten every day Non vegetarians should moderate their consumption of preserved meat like sausages, salami bacon and ham, and red meats such as beef, pork and lamb. Do not consume thermally hot food and drink. Moderate consumption of salt preserved foods and salt.
Cancer EPIC Of course investigations into dietary factors and cancer continue and one major prospective study is EPIC— The European Prospective Investigation into Cancer and Nutrition. EPIC involves about 500,000 men and women in 10 countries across Europe. The factors being investigated include specific foods such as fruit, vegetables and meat, nutrients including fat, vitamins and
C. Ottley / Trends in Food Science & Technology 14 (2003) 392–394
393
Table 1. Level of evidence of lifestyle risk factors for cancer Evidence
Decreased risk
Increased risk
Convincing
Physical activity (colorectal)
Overweight and obesity (oesophagus, colorectum, breast, endometrium, kidney) Alcohol (oral cavity, pharynx, larynx, liver, breast) Aflatoxin (liver) Chinese-style salted fish (nasophyarynx)
Probable
Fruit and vegetables (oral cavity, oesophagus, stomach colorectum) Physical activity (breast)
Preserved meat (colorectum) Salt preserved foods and salt (stomach) Thermally very hot drinks and food (oral cavity, pharynx, oesophagus)
Possible/insufficient
Fibre, soya, fish, n-3 fatty acids, carotenoids, various vitamins and minerals and non-nutrient plant constituents such as flavenoids and lignans
Animal fats, heterocyclic amines (such as from burnt and BBQ foods), polycyclic aromatic hydrocarbons and nitrosamines
fibre, hormones, metabolic factors and genetic disposition. Preliminary finding from the UK leg of the study were presented by Dr. Naomi Allen. The first phase of studies has demonstrated that alcohol and tobacco increase the risk of upper GI tract cancers. It has also been found that smoking and drinking work synergistically to greatly increase the risk. Drinking six glasses of beer a day presents a ninefold risk of developing cancer, as does being a heavy smoker, but someone who both drinks and smokes heavily was associated with a staggering 50 fold risk of developing upper GI tract cancer. It has also been found that fruit, vegetables and particularly tomatoes protect against cancer. Those with the highest consumption of fruit have a 17% reduction in cancer risk compared to the group with the lowest fruit consumption, whilst those with the highest vegetable intake have a 29% drop in risk compared with the lowest vegetable consumers. One exception however is prostate cancer which shows no evidence of a protective effect from fruit and vegetable intake and a higher level of lycopene—a marker for tomato intake, was associated with a slight increase in the risk of prostate cancer. Updates on EPIC Norfolk results can be accessed at www.slr.cam.ac.uk/epic
Brain fats may keep us happy According to Dr. Alex Richardson there is accumulating evidence that imbalances between the omega 3 and omega 6 families of polyunsaturated fatty acids may contribute to behavioural and learning difficulties associated with several common childhood complaints including ADHD (Attention Deficient Hyperactivity Disorder) dyslexia, dyspraxia and autism. People who are depressed and those suffering from schizophrenia may also have a similar fatty acid imbalance.
Omega-3s are a family of fatty acids derived from alinolenic acid. The highly unsaturated omega 3s (HUFAs) are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The omega-6 fats are derived from another essential fatty acid, linoleic acid the HUFAs derived from linolenic acid are dihomogammalinolenic acid (DGLA) and arachidonic acid (AA). These HUFAs are known to play an important role in brain development and function and their concentrations and relative balance can affect almost every aspect of cell signalling in the brain and body. These two families of fats compete for the same enzymes during metabolism, which means that a relative excess of one family will mop-up important enzymes needed by the other. Due to changes in our food supply in response to the call for less saturated fat there have been changes in animal feeding practice and an increased use of oils like sunflower and corn oil which are particularly rich in omega 6 fatty acids. This has resulted in a relative lack of omega 3s, in fact it is estimated that the ratio of omega 6 to omega 3s was about 1:1 in the early 1900s— today it is 25:1 or higher. It may be time for consumers and food producers to choose oils or oil mixes that provide a more balanced fatty acid profile. Apart from the relative lack of omega 3 fatty acids in the diet, the ability to convert the simple omega 3 fatty acids into the highly unsaturated complex versions, EPA and DHA that are used for signalling in the brain may be inefficient in some individuals. The only way of getting sufficient DHA and EPA directly from the diet is by consuming large amounts of oily fish on a regular basis. Often this is impractical and marine oil supplements cannot be taken in large quantities due to the high levels of vitamin A they contain which is toxic in large doses. Dr. Richardson presented the results of a number of randomised controlled studies examining the
394
C. Ottley / Trends in Food Science & Technology 14 (2003) 392–394
effect of HUFA supplements. These demonstrated that a pure EPA supplement provided the most benefit for her patients. Visit www.dyslexic.org.uk for more information.
Does cholesterol matter? Two speakers discussed the subject of blood cholesterol levels in the management of heart disease. Professor Michel de Lorgeril from the University of Grenoble highlighted that although there is a correlation between blood cholesterol levels and heart disease in Northern Europe and the USA this correlation is weaker in Mediterranean countries and non-existent in other countries such as Japan. In long term trials diets that are specifically designed to reduce cholesterol levels, including boosting the ratio of polyunsaturated to saturated fats, have so far provided disappointing results with no effect on subsequent cardiac events or total mortality. In Professor Lorgeril’s opinion focusing on achieving ‘normal’ cholesterol levels is not particularly helpful as it does not improve an individual’s prognosis. Instead a diet should be adopted where the beneficial effects on health have already been clinically proven. For example the Lyon Diet Heart Study demonstrated that a Mediterranean style diet including plenty of fruits, vegetables, nuts, fish and omega-3 rich margarine (but no increase in polyunsaturated fats) was associated with a dramatic reduction in cardiac and all cause mortality (De Lorgeril et al., 1999). The mechanisms behind the success of this type of diet are still under investigation including the role of omega 3 fatty acids. Once again the complex long-chain derivatives EPA and DHA found in oily fish appear to be particularly beneficial and this may be down to their vasodilatory and anti-inflammatory properties. But it is not just the fish that are of benefit. It has also recently been found that a vegetarian diet (Mediterranean style diet without the fish) rich in a-linolenic acid, the precursor of EPA and DHA, also led to a reduced level of cardiac events compared to a diet similar to that recommended by the American Cholesterol Education Programme (Singh et al., 2002). Never-the-less the search for new dietary strategies to cut cholesterol goes on and Professor Tom Sanders provided an overview of how we are getting on. Apart from weight loss and modifying the intake of saturated fatty acid, a number of novel food methods have been tested. Small reductions in plasma cholesterol can be achieved by increasing the amount of soluble fibre such as oatbran breakfast cereals. More dramatic reductions in LDL in the order of 9–10% can be achieved using foods fortified with plant phytosterols. The use of soy products can also substantially reduce plasma cholesterol. For example 25 g of soy protein/day results in a 0.23 mmol/l decrease in plasma cholesterol. Professor Sanders calculates that by combining all the above dietary methods it would be possible to reduce plasma cholesterol in the middle aged population by about 20%—from around 5.8 mmol/l to below 5 mmol/
l. This would involve weight control, a decrease in saturated fat intake along with an increased consumption of soluble fibre, soy products, oils rich in monounsaturated fats, and the use of pytosterol enriched yogurts and yellow fats.
Probiotics in babies When babies are breast-fed their gut is initially colonised by protective bacteria which activate the immune system and protect against infection. Bottle-fed babies do not get this natural protection but Dr. Mieke Van Den Driessche from the University of Leuven presented the results of a number of studies demonstrating how probiotics might help. In children consuming an infant formula fortified with probiotics, a reduced incidence of rotavirus, constipation and nappy rash was found compared to regular formula. For children with intestinal disease adding probiotics to oral rehydration therapy was found to decrease the duration of the disease. Antibiotics are known to knock out the natural protective flora in the gut and so adding probiotics to antibiotics has been shown as a way to ameliorate their effects. Probiotics may also help reduce allergy and lactose intolerance (Isolauri et al., 2002). Dr. Van Den Driessche concluded that probiotics are promising therapeutic agents in paediatrics and may be useful against infection and inflammatory disease. However she did warn that not all probiotic products contain what they claim on the label. A recent study examined 55 probiotic products which are currently available on the European market. It was found that 11 of the products contained no viable bacteria at all, many contained far fewer bacteria than claimed, and a few contained the wrong strain (Temmerman et al., 2002). Clearly this would reduce their probiotic potential and could even be dangerous in some circumstances. In general dairy products were found to be more reliable than the dried food supplements, never-the-less this study highlights the need for regulation of these products.
References De Lorgeril, M., Salen, P., Martin, J. L., Monjaud, I., Delaye, J., & Mamelle, N. (1999). Final report of the Lyon Diet Heart Study. Circulation, 99, 779–785. Isolauri, E., da Costa Ribeiro, H., Gibson, G., Saavedra, J., Salminem, S., Vanderhoof, J., & Varavithya, W. (2002). Functional foods and probiotics: working group report of the first world congress of pediatric gastroenterology, hepatology and nutrition. Journal of Pediatric Gastroenterology and Nutrition, 35, S106–S109. Singh, R. B., Dubnov, G., Mohammad, A. N., Ghosh, S., Singh, R., Rastogi, S. S., Manor, O., & Pella, D. (2002). Effect of an IndoMediterranean diet on progression of coronary artery disease in high risk patients (Indo-Mediterranean Diet Heart Study): a randomised single blind trial. The Lancet, 360, 1455–1461. Temmerman, R., Pot, B., Huys, G., & Swings, J. (2002). Identification and antibiotic susceptibility of bacterial isolates from probiotic products. International Journal of Food Microbiology, 81, 1–10.
Conference report
Third Nutrition and Health Conference: 29–30 November 2002, Excel Conference Centre London Carol Ottley The Laurels, Kirby Bedon, Norwich NR14 7DY, UK (e-mail: [email protected])
This conference provided a snap-shot of recent developments in nutrition and health. A wide range of topics were covered including cancer, heart disease, brain nutrition and gut health. This report provides an update for food technologists and others who are keen to keep abreast of current thinking and some new developments in these areas.
New WHO/FAO Report for 2003 During 2003 a new WHO/FAO report entitled Diet, Nutrition and the Prevention of Chronic Disease will be published based on an expert consultation that took place in Geneva in 2002. Although the report will cover the prevention of many diseases including diabetes, heart disease, dental caries and osteoporosis, Professor Tim Key from the Cancer Research and Epidemiology Department at Oxford University focused on the main findings in relation to diet and cancer (draft available at www.who.int/hpr/nutrition/). It is estimated that dietary factors account for about 30% of cancers in western societies, making diet second only to tobacco as a preventable cause of cancer. However research has so far revealed few definite relation0924-2244/03/$ - see front matter # 2003 Published by Elsevier Science Ltd. doi:10.1016/S0924-2244(03)00056-6
ships. A grid (Table 1) was developed to summarise the level of evidence relating to each of possible cancer risk factor. After tobacco, overweight and obesity appear to be the most important avoidable causes of cancer. This is why the two main public health recommendations suggested are: 1. Adults should maintain their weight in the normal range with a body mass index (a measure of body weight relative to height) between 18.5 and 25 kg/m2 and not gain weight as they get older. 2. Indulge in regular physical activity. More specifically it is important to be active most days of the week. Moderate exercise like walking for an hour would help maintain weight in sedentary individuals, whereas more vigorous activity may give additional benefits for cancer prevention. More specific food based recommendations are also suggested and include the following: Alcohol is not recommended and if consumed should not exceed two units per day (one small glass of wine or beer or one measure of spirits counts as a unit) Exposure to aflatoxin in foods should be minimised At least 400 g of fruit and vegetables should be eaten every day Non vegetarians should moderate their consumption of preserved meat like sausages, salami bacon and ham, and red meats such as beef, pork and lamb. Do not consume thermally hot food and drink. Moderate consumption of salt preserved foods and salt.
Cancer EPIC Of course investigations into dietary factors and cancer continue and one major prospective study is EPIC— The European Prospective Investigation into Cancer and Nutrition. EPIC involves about 500,000 men and women in 10 countries across Europe. The factors being investigated include specific foods such as fruit, vegetables and meat, nutrients including fat, vitamins and
C. Ottley / Trends in Food Science & Technology 14 (2003) 392–394
393
Table 1. Level of evidence of lifestyle risk factors for cancer Evidence
Decreased risk
Increased risk
Convincing
Physical activity (colorectal)
Overweight and obesity (oesophagus, colorectum, breast, endometrium, kidney) Alcohol (oral cavity, pharynx, larynx, liver, breast) Aflatoxin (liver) Chinese-style salted fish (nasophyarynx)
Probable
Fruit and vegetables (oral cavity, oesophagus, stomach colorectum) Physical activity (breast)
Preserved meat (colorectum) Salt preserved foods and salt (stomach) Thermally very hot drinks and food (oral cavity, pharynx, oesophagus)
Possible/insufficient
Fibre, soya, fish, n-3 fatty acids, carotenoids, various vitamins and minerals and non-nutrient plant constituents such as flavenoids and lignans
Animal fats, heterocyclic amines (such as from burnt and BBQ foods), polycyclic aromatic hydrocarbons and nitrosamines
fibre, hormones, metabolic factors and genetic disposition. Preliminary finding from the UK leg of the study were presented by Dr. Naomi Allen. The first phase of studies has demonstrated that alcohol and tobacco increase the risk of upper GI tract cancers. It has also been found that smoking and drinking work synergistically to greatly increase the risk. Drinking six glasses of beer a day presents a ninefold risk of developing cancer, as does being a heavy smoker, but someone who both drinks and smokes heavily was associated with a staggering 50 fold risk of developing upper GI tract cancer. It has also been found that fruit, vegetables and particularly tomatoes protect against cancer. Those with the highest consumption of fruit have a 17% reduction in cancer risk compared to the group with the lowest fruit consumption, whilst those with the highest vegetable intake have a 29% drop in risk compared with the lowest vegetable consumers. One exception however is prostate cancer which shows no evidence of a protective effect from fruit and vegetable intake and a higher level of lycopene—a marker for tomato intake, was associated with a slight increase in the risk of prostate cancer. Updates on EPIC Norfolk results can be accessed at www.slr.cam.ac.uk/epic
Brain fats may keep us happy According to Dr. Alex Richardson there is accumulating evidence that imbalances between the omega 3 and omega 6 families of polyunsaturated fatty acids may contribute to behavioural and learning difficulties associated with several common childhood complaints including ADHD (Attention Deficient Hyperactivity Disorder) dyslexia, dyspraxia and autism. People who are depressed and those suffering from schizophrenia may also have a similar fatty acid imbalance.
Omega-3s are a family of fatty acids derived from alinolenic acid. The highly unsaturated omega 3s (HUFAs) are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The omega-6 fats are derived from another essential fatty acid, linoleic acid the HUFAs derived from linolenic acid are dihomogammalinolenic acid (DGLA) and arachidonic acid (AA). These HUFAs are known to play an important role in brain development and function and their concentrations and relative balance can affect almost every aspect of cell signalling in the brain and body. These two families of fats compete for the same enzymes during metabolism, which means that a relative excess of one family will mop-up important enzymes needed by the other. Due to changes in our food supply in response to the call for less saturated fat there have been changes in animal feeding practice and an increased use of oils like sunflower and corn oil which are particularly rich in omega 6 fatty acids. This has resulted in a relative lack of omega 3s, in fact it is estimated that the ratio of omega 6 to omega 3s was about 1:1 in the early 1900s— today it is 25:1 or higher. It may be time for consumers and food producers to choose oils or oil mixes that provide a more balanced fatty acid profile. Apart from the relative lack of omega 3 fatty acids in the diet, the ability to convert the simple omega 3 fatty acids into the highly unsaturated complex versions, EPA and DHA that are used for signalling in the brain may be inefficient in some individuals. The only way of getting sufficient DHA and EPA directly from the diet is by consuming large amounts of oily fish on a regular basis. Often this is impractical and marine oil supplements cannot be taken in large quantities due to the high levels of vitamin A they contain which is toxic in large doses. Dr. Richardson presented the results of a number of randomised controlled studies examining the
394
C. Ottley / Trends in Food Science & Technology 14 (2003) 392–394
effect of HUFA supplements. These demonstrated that a pure EPA supplement provided the most benefit for her patients. Visit www.dyslexic.org.uk for more information.
Does cholesterol matter? Two speakers discussed the subject of blood cholesterol levels in the management of heart disease. Professor Michel de Lorgeril from the University of Grenoble highlighted that although there is a correlation between blood cholesterol levels and heart disease in Northern Europe and the USA this correlation is weaker in Mediterranean countries and non-existent in other countries such as Japan. In long term trials diets that are specifically designed to reduce cholesterol levels, including boosting the ratio of polyunsaturated to saturated fats, have so far provided disappointing results with no effect on subsequent cardiac events or total mortality. In Professor Lorgeril’s opinion focusing on achieving ‘normal’ cholesterol levels is not particularly helpful as it does not improve an individual’s prognosis. Instead a diet should be adopted where the beneficial effects on health have already been clinically proven. For example the Lyon Diet Heart Study demonstrated that a Mediterranean style diet including plenty of fruits, vegetables, nuts, fish and omega-3 rich margarine (but no increase in polyunsaturated fats) was associated with a dramatic reduction in cardiac and all cause mortality (De Lorgeril et al., 1999). The mechanisms behind the success of this type of diet are still under investigation including the role of omega 3 fatty acids. Once again the complex long-chain derivatives EPA and DHA found in oily fish appear to be particularly beneficial and this may be down to their vasodilatory and anti-inflammatory properties. But it is not just the fish that are of benefit. It has also recently been found that a vegetarian diet (Mediterranean style diet without the fish) rich in a-linolenic acid, the precursor of EPA and DHA, also led to a reduced level of cardiac events compared to a diet similar to that recommended by the American Cholesterol Education Programme (Singh et al., 2002). Never-the-less the search for new dietary strategies to cut cholesterol goes on and Professor Tom Sanders provided an overview of how we are getting on. Apart from weight loss and modifying the intake of saturated fatty acid, a number of novel food methods have been tested. Small reductions in plasma cholesterol can be achieved by increasing the amount of soluble fibre such as oatbran breakfast cereals. More dramatic reductions in LDL in the order of 9–10% can be achieved using foods fortified with plant phytosterols. The use of soy products can also substantially reduce plasma cholesterol. For example 25 g of soy protein/day results in a 0.23 mmol/l decrease in plasma cholesterol. Professor Sanders calculates that by combining all the above dietary methods it would be possible to reduce plasma cholesterol in the middle aged population by about 20%—from around 5.8 mmol/l to below 5 mmol/
l. This would involve weight control, a decrease in saturated fat intake along with an increased consumption of soluble fibre, soy products, oils rich in monounsaturated fats, and the use of pytosterol enriched yogurts and yellow fats.
Probiotics in babies When babies are breast-fed their gut is initially colonised by protective bacteria which activate the immune system and protect against infection. Bottle-fed babies do not get this natural protection but Dr. Mieke Van Den Driessche from the University of Leuven presented the results of a number of studies demonstrating how probiotics might help. In children consuming an infant formula fortified with probiotics, a reduced incidence of rotavirus, constipation and nappy rash was found compared to regular formula. For children with intestinal disease adding probiotics to oral rehydration therapy was found to decrease the duration of the disease. Antibiotics are known to knock out the natural protective flora in the gut and so adding probiotics to antibiotics has been shown as a way to ameliorate their effects. Probiotics may also help reduce allergy and lactose intolerance (Isolauri et al., 2002). Dr. Van Den Driessche concluded that probiotics are promising therapeutic agents in paediatrics and may be useful against infection and inflammatory disease. However she did warn that not all probiotic products contain what they claim on the label. A recent study examined 55 probiotic products which are currently available on the European market. It was found that 11 of the products contained no viable bacteria at all, many contained far fewer bacteria than claimed, and a few contained the wrong strain (Temmerman et al., 2002). Clearly this would reduce their probiotic potential and could even be dangerous in some circumstances. In general dairy products were found to be more reliable than the dried food supplements, never-the-less this study highlights the need for regulation of these products.
References De Lorgeril, M., Salen, P., Martin, J. L., Monjaud, I., Delaye, J., & Mamelle, N. (1999). Final report of the Lyon Diet Heart Study. Circulation, 99, 779–785. Isolauri, E., da Costa Ribeiro, H., Gibson, G., Saavedra, J., Salminem, S., Vanderhoof, J., & Varavithya, W. (2002). Functional foods and probiotics: working group report of the first world congress of pediatric gastroenterology, hepatology and nutrition. Journal of Pediatric Gastroenterology and Nutrition, 35, S106–S109. Singh, R. B., Dubnov, G., Mohammad, A. N., Ghosh, S., Singh, R., Rastogi, S. S., Manor, O., & Pella, D. (2002). Effect of an IndoMediterranean diet on progression of coronary artery disease in high risk patients (Indo-Mediterranean Diet Heart Study): a randomised single blind trial. The Lancet, 360, 1455–1461. Temmerman, R., Pot, B., Huys, G., & Swings, J. (2002). Identification and antibiotic susceptibility of bacterial isolates from probiotic products. International Journal of Food Microbiology, 81, 1–10.