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N-3 fatty acids in the Mediterranean diet
ARTICLE IN PRESS
Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133 www.elsevier.com/locate/plefa
N-3 fatty acids in the Mediterranean diet C. Galli, F. Marangoni Department of Pharmacological Sciences, University of Milan, Via Balzaretti, 9, 20233 Milan, Italy
Abstract Fats in the diet of countries in the Mediterranean basin are typically represented by olive oil, but the high consumptions of vegetables and to some extent also of fish result in appreciable intakes of n-3 fatty acids. In fact, various plant foods are relatively rich in the 18 carbon n-3 fatty acid, alpha linolenic acid, ALA, while the generally moderate consumption of fish, except for certain communities living close to the sea, contributes to the intake of the long-chain n-3. Although the amounts of fats in ALA-containing plant foods are low, the relatively high concentrations of this fatty acid and the large size of the portions consumed allow to reach appreciable doses of ALA, an n-3 fatty acid that has been shown to exert favourable effects on various relevant factors in cardiovascular protection. In addition, consumption of relatively small amounts of certain typical dry fruit components of the diet such as walnuts, provides a sizable supply of ALA that is also rather efficiently converted to the ALA derivative eicosapentaenoic acid (EPA). Additional rather typical wild food components of the diet in certain countries, i.e. snails and frogs, are also appreciable sources of ALA. It appears thus that the consumption of typical Mediterranean foods provides relevant intakes of n-3 fatty acids, especially ALA, that appears to be efficiently absorbed and also transformed at least to the long-chain derivative EPA. r 2006 Elsevier Ltd. All rights reserved.
1. General features of the Mediterranean diet The Mediterranean diet is a nutritional model inspired by the traditional dietary patterns of the Countries of the Mediterranean basin, particularly Southern Italy, Greece and Spain [1]. In reality, the term ‘‘diet’’ refers more correctly to the whole lifestyle, which included also behavioural aspects such as relevant physical activity and exposure to very limited environmental pollution. The contributions of diets in the major North African Countries, predominantly located along the Mediterranean Coast (Egypt, Lybia, Algeria, Tunisia), and also from the diet of Countries on the Eastern shores of the Mediterranean are relevant although less studied. As to the typical food components of the Mediterranean diet, listed in Table 1, the major ones were the type of fat, i.e. olive oil, plant foods, such as fruit and various types of Corresponding author.
E-mail address: [email protected] (C. Galli). 0952-3278/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.plefa.2006.05.007
vegetables, while dairy products, fish, poultry and to some extent eggs were consumed in moderate quantities, and red meat was consumed only few times/week. The consumption of olive oil, obtained from a fruit, mainly through simple physical pressure, typically provided the intake not only of the fats, mainly mono-unsaturated fatty acids (MUFA) per se endowed of favourable effects on health [2], but also of minor amphiphilic compounds of phenolic nature. These are typically present in fruits in the Mediterranean climate and have been shown to favourably affect various parameters in the cardiovascular system [3]. In addition, olive oil is generally consumed uncooked as a component of salad dressing and for the preparation of sauces, thus providing an additional contribution to the health status. Wine was also part of the diet consumed in more or less moderate quantities. The above features were typical, on a large scale, of the diet in the Mediterranean areas of the indicated countries until the end of the 50s, but appreciably changes occurred, especially in urban populations, since then. However,
ARTICLE IN PRESS 130
C. Galli, F. Marangoni / Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133
Table 1 Components of the Mediterranean diet Consumptions High
Moderate
Low
Olive oil (MUFA) Fruits Vegetables Legumes Cereals Beans Nuts
Dairy products Fish Poultry Wine
Red meat
Eggs
a recent study carried out in a community in Sicily revealed that the typical features of the Mediterranean diet were maintained [4]. In general, the typical Mediterranean diet was based on the consumption of ‘‘natural’’ foods, i.e. the consumption of parts of organisms (cells, tissues and organs) rather than of processed ingredients. In these types of foods, a ‘‘physiological’’ balance between various components of biological (structural and functional) relevance has been reached through adaptive processes in the course of evolution. These complex mixtures of structured ingredients, which would include bioactive components, are then transferred to the organism that is ingesting the food. In essence, in all Mediterranean countries a relevant role was played by the features of local food production and use, as a combination of the agricultural traditions and of the consumption of wild foods obtained from non-cultivated plants and wild, unbred animals.
2. N-3 FA in the Mediterranean diet The type of visible fat consumed in countries in the Mediterranean area has been, and to a large extent it is still represented mainly by olive oil, rich in MUFA typically in the form of oleic acid. Changes have been taking place however in the last decades with enhanced consumption of other types of vegetable (seed) oils. Olive oil consumption was associated with low intakes of saturated fatty acids (SFA) as a consequence of the low intakes of animal foods, especially bovine meat. Consumptions of poly-unsaturated fatty acids (PUFA) were not particularly high, but they are increasing, mainly as linoleic acid (LA, 18:2 n-6) in association with the increased use of seed oils. In this context, intakes of n-3 FA are still presently rather relevant, at least in nutritional terms more than in relative proportions. Consumptions of long-chain poly-unsaturated fatty acids (LCP) of the n-3 series, typically present in fish and derivatives in the Mediterranean countries, are for instance appreciable, but not higher, with the exception
of Spain, than in Northern European countries. In addition, levels of n-3 LCP are generally more elevated in fish from cold waters, such as the Atlantic Ocean and Northern European areas, than from warm waters, such as the Mediterranean Sea. On the other side, the Mediterranean diet is rather rich in alpha linolenic acid (ALA, 18:3 n-3), present in a large number of plant-derived foods. Intakes of ALA, in the range of 1–2 g/day, i.e. higher amounts than in current diets, have been shown to exert protective effects [5–7]. It is not completely clear, however, whether the beneficial effects of this FA are related to ALA itself or to the LCP metabolically derived from it. In fact, it appears that at least the production of the major 22 C compound, docosahexaenoic acid (DHA, 22:6 n-3) is not very efficient in terrestrial animals [8]. On the other side, the advantage of ALA consumption rather than, or in addition to, that of the n-3 LCP, is that sources are practically inexhaustible due to the abundance of this FA in plants.
3. ALA contents in Mediterranean foods The contents in ALA expressed as g/portions in some major food items of the Mediterranean diet as well as in conventional meals, assessed in our lab through lipid extraction and quantitative FA analysis by GLC are shown in Table 2. The total fat contents of vegetables and legumes are rather low, but their relative richness in ALA, associated with the large size of the average portions and the high rates of consumption, result in appreciable levels of intakes. A regular portion of spinach and beans, e.g., provides significant amounts of this n-3 FA, almost reaching through spinach, over 400 mg ALA, i.e. about 25–30% of the recommended daily intakes (1–2 g). Even higher relative proportions of ALA are found in various edible plants growing in the Mediterranean basin, especially in the wild state [9], and for instance purslane, a plant that grows mainly in the wild state in countries such as Greece, has a high relative content of ALA [10]. Information on the general consumption rates (possibly high in certain communities) is however limited. Dry fruits such as nuts provide very high amounts of ALA, even in relatively low doses, due to both the high fat contents and the high proportions of ALA (over 1 g in about 20 g of nuts corresponding to four nuts).
4. Bioavailability and metabolic conversion of n-3 FA Recommendations for the daily intakes of selected n-3 FA have been made by various organizations, values
ARTICLE IN PRESS C. Galli, F. Marangoni / Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133
131
Table 2 Total lipid (TL) and ALA contents of various foods Foods
g TL/100 g
mg ALA/portion (average values)
Portions (g)
Legumes Beans Lentils Chickpeas Lupins Green lentils Peas
11.0 (Eyed) 1.1 2.4 2.6 0.8 1.1
290 185 100 77 64
135 135 161 100 135 135
0.7 0.3
475 64
250 80
47.3 40.6 25.8
792 24 15
15 15 15
1.8 0.9
28 29
100 100
Vegetable Spinach Lettuce Various dry fruits South Italy nuts Pine seed (Naples) Pine seed (Liguria) Meat from wild animals Snails Frogs
Data are from our laboratory. Portion sizes adapted from: USDA Food Composition Tables (http://www.nal.usda).
ranging in the order of 1–2 g for ALA and of somewhat lower amounts (0.5–1.0 g) for EPA (eicosapentaenoic acid, 20:5 n-3)+DHA [11]. Indications concerning the form of supplementation, natural foods versus formulations, are not generally considered, although the bioavailability from foods may be rather different. We have shown, e.g., that the increments of plasma n-3 FA in humans after the consumption of fish providing relatively low amounts of EPA and DHA are remarkably greater than that following the ingestion of much higher amounts of the same FA as an encapsulated preparation, after 6 weeks of treatment [12]. Although this finding does not reduce or minimize the relevance of n-3 FA treatments through the use of more practical formulations for n-3 intakes, it raises the issue of the bioavailability of FA when ingested in different matrixes. Appreciable increments in body n-3 FA might be obtained by strategies based mainly on the consumption of natural sources. The higher dilution of these compounds in foods, and their incorporation within the total fat load of the food item may in fact favour the processes that are involved in fat digestion and absorption at the intestinal level. These include the activation of lipolytic reactions for fat digestion, of the secretion of agents favouring the absorption of the digested products and the high surface of interaction between the food components and the intestinal walls. The availability of a simplified analytical approach for the collection of a drop of blood from a fingertip and for the preparation of samples for FA analysis [13] has allowed us to reinvestigate this issue, by re-evaluating the comparative impact of the consumption of fish
versus capsules in more realistic conditions (lower amounts of both fish and encapsulated n-3 FA preparations). The intakes of 200 g/week of salmon providing about 100 mg EPA and 150 mg DHA/day resulted (Fig. 1) in increments (about +17% and 42%, respectively) in their blood levels rather similar (+17% and 77%, respectively) to those obtained by ingesting encapsulated formulations providing 350 mg EPA and 300 mg DHA (2- and 3.5-fold higher, respectively) per day. In addition, after washout, blood levels of EPA tended to remain elevated after fish while they declined after capsules, although levels of DHA tended to increase after both treatments. We have also assessed the effects of the ingestion of four nuts/day for 3 weeks on blood levels of ALA and its longer-chain derivatives in healthy subjects. Consumption of the above quantities of nuts for over a 3-weeks period of time resulted in significant elevations not only of ALA but also of EPA [14] (Fig. 2). Other types of dry fruits have instead somewhat lower contents in this n-3 FA. Among animal foods, frogs and snails provide also appreciable amounts of ALA, at least with respect to other meats, although they are negligible when compared to plant foods.
5. Conclusions The types of fats in the diets of Mediterranean Countries still retain some of the original features, i.e., low SFA, relatively high intakes of MUFA and PUFA,
ARTICLE IN PRESS 132
C. Galli, F. Marangoni / Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133
Salmon 200g/week 4 % of total fatty acids
3 N =5 97 mgEPA+ 151mg DHA/day
2 1
EPA, 20:5 n-3 0 0
1
2
Washout
3
11
3 % of total fatty acids
n-3 FA Supplementation and blood levels
DHA, 22:6 n-3
weeks
DHA, 22:6 n-3
2
1 cps/day N=5 350 mg EPA+300 mg DHA/day
1 EPA, 20:5 n-3 0 0
1
2
11 weeks
Washout
3
Fig. 1. Percentage levels of 20:5 and 22:6 n-3 in blood lipids of healthy subjects after consumption of salmon (200 g/week) providing 97 mg EPA and 151 mg DHA/day (5 subjects), or after ingestion of formulations providing 350 mg EPA and 300 mg DHA/day (5 subjects), for a period of 3 weeks followed by an 8-week period of washout.
1.20 1.00
N = 10 Age 23-30
o 18:3 n-3 20:5 n-3
Wt % FA
0.80 0.60 0.40 0.20
1
3
2
4
5 Weeks
4 nuts/day washout Fig. 2. Percentage levels of 18:3 n-3 (ALA) and 20:5 n-3 (EPA) in total lipids from the whole blood of 10 healthy subjects after consumption of four nuts/day providing 1.2 g ALA for a period of 3 weeks followed by a 2-week period of washout.
but attention should be paid to avoid the changes that are presently taking place in large segments of the population, due to the introduction of new types of fats. As to the presence and intakes of n-3 fatty acids, the sources of ALA in various vegetable foods should be carefully considered. It becomes therefore mandatory that strategies are proposed at the national and international levels with
the aim of defining and promoting the consumption of foods typical of the Mediterranean diet, known to provide the types of fats that have been shown to be protective for our health. In addition, practical and large-scale projects should be activated aimed at designing menus that can be followed both for homeprepared, family-based meals, and in the preparation of meals for communities or restaurants.
ARTICLE IN PRESS C. Galli, F. Marangoni / Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133
References [1] A. Trichopoulou, T. Cistacou, C. Bamia, D. Trichopoulos, Adherence to a Mediterranean Diet and survival in a Greek population, N Engl. J. Med. 348 (2003) 2599–2608. [2] F. Perez-Jimenez, J. Lopez-Miranda, P. Mata, Protective effect of dietary monounsaturated fat on arteriosclerosis: beyond cholesterol, Atherosclerosis 163 (2002) 385–398. [3] F. Visioli, C. Galli, Biological properties of olive oil phytochemicals, Crit. Rev. Food Sci. Nutr. 42 (3) (2002) 209–221. [4] C.M. Barbagallo, G. Cavera, M. Sapienza, D. Noto, A.B. Cefalu`, F. Polizzi, F. Onorato, G.B. Rini, G. Di Fede, M. Pagano, G. Montalto, M. Rizzo, G.C. Descovich, A. Nortarbartolo, M.R. Averna, Nutritional characteristics of a rural southern Italy population: the Ventimiglia di Sicilia project, I. Am. Coll. Nutr. 21 (2002) 523–529. [5] W.S. Harris, Alpha linolenic acid a gift from the land? Circulation 111 (2005) 2872–2874. [6] M. De Lorgeril, P. Salen, J.L. Martin, I. Monjaud, J. Delaye, N. Mamelle, Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study, Circulation 99 (1999) 779–786. [7] L. Djousse, D.K. Arnett, J.J. Carr, J.H. Eckfeldt, P.N. Hopkins, M.A. Province, C. Ellison, Dietary linolenic acid is inversely
[8]
[9] [10] [11] [12]
[13]
[14]
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associated with calcified atherosclerotic plaque in the coronary arteries: the National Heart, Lung, and Blood Institute Family Heart Study, Circulation 111 (2005) 2921–2926. G. Burdge, Alpha-linolenic acid metabolism in men and women: nutritional and biological implications, Curr. Opin. Clin. Nutr. Metab. Care 7 (2004) 137–144. A.P. Simopoulos, Omega 3 fatty acids and antioxidants in edible plants, Biol. Res. 37 (2) (2004) 263–277. A.P. Simopoulos, Purslane: a plant source of omega 3 fatty acids and melatonin, J. Pineal Res. 39 (2005) 331–332. http://www.issfal.org.uk/Welcome/GlobalRecomendations.asp F. Visioli, P. Rise´, M.C. Barassi, F. Marangoni, C. Galli, Dietary intake of fish vs. formulations leads to higher plasma concentrations of n-3 fatty acids, Lipids 38 (2003) 415–418. F. Marangoni, C. Colombo, C. Galli, A method for the direct evaluation of the fatty acid status in a drop of blood from a fingertip in humans: applicability to nutritional and epidemiological studies, Anal. Biochem. 326 (2004) 267–272. F. Marangoni, C. Colombo, A. Martiello, A. Poli, R. Paoletti, C. Galli, Levels of the n-3 fatty acid eicosapentaenoic acid in addition to those of alpha linolenic acid are significantly raised in blood lipids by the intake of four walnuts a day in humans. Nutr. Metab., Cardiovasc. Dis., in press.
Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133 www.elsevier.com/locate/plefa
N-3 fatty acids in the Mediterranean diet C. Galli, F. Marangoni Department of Pharmacological Sciences, University of Milan, Via Balzaretti, 9, 20233 Milan, Italy
Abstract Fats in the diet of countries in the Mediterranean basin are typically represented by olive oil, but the high consumptions of vegetables and to some extent also of fish result in appreciable intakes of n-3 fatty acids. In fact, various plant foods are relatively rich in the 18 carbon n-3 fatty acid, alpha linolenic acid, ALA, while the generally moderate consumption of fish, except for certain communities living close to the sea, contributes to the intake of the long-chain n-3. Although the amounts of fats in ALA-containing plant foods are low, the relatively high concentrations of this fatty acid and the large size of the portions consumed allow to reach appreciable doses of ALA, an n-3 fatty acid that has been shown to exert favourable effects on various relevant factors in cardiovascular protection. In addition, consumption of relatively small amounts of certain typical dry fruit components of the diet such as walnuts, provides a sizable supply of ALA that is also rather efficiently converted to the ALA derivative eicosapentaenoic acid (EPA). Additional rather typical wild food components of the diet in certain countries, i.e. snails and frogs, are also appreciable sources of ALA. It appears thus that the consumption of typical Mediterranean foods provides relevant intakes of n-3 fatty acids, especially ALA, that appears to be efficiently absorbed and also transformed at least to the long-chain derivative EPA. r 2006 Elsevier Ltd. All rights reserved.
1. General features of the Mediterranean diet The Mediterranean diet is a nutritional model inspired by the traditional dietary patterns of the Countries of the Mediterranean basin, particularly Southern Italy, Greece and Spain [1]. In reality, the term ‘‘diet’’ refers more correctly to the whole lifestyle, which included also behavioural aspects such as relevant physical activity and exposure to very limited environmental pollution. The contributions of diets in the major North African Countries, predominantly located along the Mediterranean Coast (Egypt, Lybia, Algeria, Tunisia), and also from the diet of Countries on the Eastern shores of the Mediterranean are relevant although less studied. As to the typical food components of the Mediterranean diet, listed in Table 1, the major ones were the type of fat, i.e. olive oil, plant foods, such as fruit and various types of Corresponding author.
E-mail address: [email protected] (C. Galli). 0952-3278/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.plefa.2006.05.007
vegetables, while dairy products, fish, poultry and to some extent eggs were consumed in moderate quantities, and red meat was consumed only few times/week. The consumption of olive oil, obtained from a fruit, mainly through simple physical pressure, typically provided the intake not only of the fats, mainly mono-unsaturated fatty acids (MUFA) per se endowed of favourable effects on health [2], but also of minor amphiphilic compounds of phenolic nature. These are typically present in fruits in the Mediterranean climate and have been shown to favourably affect various parameters in the cardiovascular system [3]. In addition, olive oil is generally consumed uncooked as a component of salad dressing and for the preparation of sauces, thus providing an additional contribution to the health status. Wine was also part of the diet consumed in more or less moderate quantities. The above features were typical, on a large scale, of the diet in the Mediterranean areas of the indicated countries until the end of the 50s, but appreciably changes occurred, especially in urban populations, since then. However,
ARTICLE IN PRESS 130
C. Galli, F. Marangoni / Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133
Table 1 Components of the Mediterranean diet Consumptions High
Moderate
Low
Olive oil (MUFA) Fruits Vegetables Legumes Cereals Beans Nuts
Dairy products Fish Poultry Wine
Red meat
Eggs
a recent study carried out in a community in Sicily revealed that the typical features of the Mediterranean diet were maintained [4]. In general, the typical Mediterranean diet was based on the consumption of ‘‘natural’’ foods, i.e. the consumption of parts of organisms (cells, tissues and organs) rather than of processed ingredients. In these types of foods, a ‘‘physiological’’ balance between various components of biological (structural and functional) relevance has been reached through adaptive processes in the course of evolution. These complex mixtures of structured ingredients, which would include bioactive components, are then transferred to the organism that is ingesting the food. In essence, in all Mediterranean countries a relevant role was played by the features of local food production and use, as a combination of the agricultural traditions and of the consumption of wild foods obtained from non-cultivated plants and wild, unbred animals.
2. N-3 FA in the Mediterranean diet The type of visible fat consumed in countries in the Mediterranean area has been, and to a large extent it is still represented mainly by olive oil, rich in MUFA typically in the form of oleic acid. Changes have been taking place however in the last decades with enhanced consumption of other types of vegetable (seed) oils. Olive oil consumption was associated with low intakes of saturated fatty acids (SFA) as a consequence of the low intakes of animal foods, especially bovine meat. Consumptions of poly-unsaturated fatty acids (PUFA) were not particularly high, but they are increasing, mainly as linoleic acid (LA, 18:2 n-6) in association with the increased use of seed oils. In this context, intakes of n-3 FA are still presently rather relevant, at least in nutritional terms more than in relative proportions. Consumptions of long-chain poly-unsaturated fatty acids (LCP) of the n-3 series, typically present in fish and derivatives in the Mediterranean countries, are for instance appreciable, but not higher, with the exception
of Spain, than in Northern European countries. In addition, levels of n-3 LCP are generally more elevated in fish from cold waters, such as the Atlantic Ocean and Northern European areas, than from warm waters, such as the Mediterranean Sea. On the other side, the Mediterranean diet is rather rich in alpha linolenic acid (ALA, 18:3 n-3), present in a large number of plant-derived foods. Intakes of ALA, in the range of 1–2 g/day, i.e. higher amounts than in current diets, have been shown to exert protective effects [5–7]. It is not completely clear, however, whether the beneficial effects of this FA are related to ALA itself or to the LCP metabolically derived from it. In fact, it appears that at least the production of the major 22 C compound, docosahexaenoic acid (DHA, 22:6 n-3) is not very efficient in terrestrial animals [8]. On the other side, the advantage of ALA consumption rather than, or in addition to, that of the n-3 LCP, is that sources are practically inexhaustible due to the abundance of this FA in plants.
3. ALA contents in Mediterranean foods The contents in ALA expressed as g/portions in some major food items of the Mediterranean diet as well as in conventional meals, assessed in our lab through lipid extraction and quantitative FA analysis by GLC are shown in Table 2. The total fat contents of vegetables and legumes are rather low, but their relative richness in ALA, associated with the large size of the average portions and the high rates of consumption, result in appreciable levels of intakes. A regular portion of spinach and beans, e.g., provides significant amounts of this n-3 FA, almost reaching through spinach, over 400 mg ALA, i.e. about 25–30% of the recommended daily intakes (1–2 g). Even higher relative proportions of ALA are found in various edible plants growing in the Mediterranean basin, especially in the wild state [9], and for instance purslane, a plant that grows mainly in the wild state in countries such as Greece, has a high relative content of ALA [10]. Information on the general consumption rates (possibly high in certain communities) is however limited. Dry fruits such as nuts provide very high amounts of ALA, even in relatively low doses, due to both the high fat contents and the high proportions of ALA (over 1 g in about 20 g of nuts corresponding to four nuts).
4. Bioavailability and metabolic conversion of n-3 FA Recommendations for the daily intakes of selected n-3 FA have been made by various organizations, values
ARTICLE IN PRESS C. Galli, F. Marangoni / Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133
131
Table 2 Total lipid (TL) and ALA contents of various foods Foods
g TL/100 g
mg ALA/portion (average values)
Portions (g)
Legumes Beans Lentils Chickpeas Lupins Green lentils Peas
11.0 (Eyed) 1.1 2.4 2.6 0.8 1.1
290 185 100 77 64
135 135 161 100 135 135
0.7 0.3
475 64
250 80
47.3 40.6 25.8
792 24 15
15 15 15
1.8 0.9
28 29
100 100
Vegetable Spinach Lettuce Various dry fruits South Italy nuts Pine seed (Naples) Pine seed (Liguria) Meat from wild animals Snails Frogs
Data are from our laboratory. Portion sizes adapted from: USDA Food Composition Tables (http://www.nal.usda).
ranging in the order of 1–2 g for ALA and of somewhat lower amounts (0.5–1.0 g) for EPA (eicosapentaenoic acid, 20:5 n-3)+DHA [11]. Indications concerning the form of supplementation, natural foods versus formulations, are not generally considered, although the bioavailability from foods may be rather different. We have shown, e.g., that the increments of plasma n-3 FA in humans after the consumption of fish providing relatively low amounts of EPA and DHA are remarkably greater than that following the ingestion of much higher amounts of the same FA as an encapsulated preparation, after 6 weeks of treatment [12]. Although this finding does not reduce or minimize the relevance of n-3 FA treatments through the use of more practical formulations for n-3 intakes, it raises the issue of the bioavailability of FA when ingested in different matrixes. Appreciable increments in body n-3 FA might be obtained by strategies based mainly on the consumption of natural sources. The higher dilution of these compounds in foods, and their incorporation within the total fat load of the food item may in fact favour the processes that are involved in fat digestion and absorption at the intestinal level. These include the activation of lipolytic reactions for fat digestion, of the secretion of agents favouring the absorption of the digested products and the high surface of interaction between the food components and the intestinal walls. The availability of a simplified analytical approach for the collection of a drop of blood from a fingertip and for the preparation of samples for FA analysis [13] has allowed us to reinvestigate this issue, by re-evaluating the comparative impact of the consumption of fish
versus capsules in more realistic conditions (lower amounts of both fish and encapsulated n-3 FA preparations). The intakes of 200 g/week of salmon providing about 100 mg EPA and 150 mg DHA/day resulted (Fig. 1) in increments (about +17% and 42%, respectively) in their blood levels rather similar (+17% and 77%, respectively) to those obtained by ingesting encapsulated formulations providing 350 mg EPA and 300 mg DHA (2- and 3.5-fold higher, respectively) per day. In addition, after washout, blood levels of EPA tended to remain elevated after fish while they declined after capsules, although levels of DHA tended to increase after both treatments. We have also assessed the effects of the ingestion of four nuts/day for 3 weeks on blood levels of ALA and its longer-chain derivatives in healthy subjects. Consumption of the above quantities of nuts for over a 3-weeks period of time resulted in significant elevations not only of ALA but also of EPA [14] (Fig. 2). Other types of dry fruits have instead somewhat lower contents in this n-3 FA. Among animal foods, frogs and snails provide also appreciable amounts of ALA, at least with respect to other meats, although they are negligible when compared to plant foods.
5. Conclusions The types of fats in the diets of Mediterranean Countries still retain some of the original features, i.e., low SFA, relatively high intakes of MUFA and PUFA,
ARTICLE IN PRESS 132
C. Galli, F. Marangoni / Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133
Salmon 200g/week 4 % of total fatty acids
3 N =5 97 mgEPA+ 151mg DHA/day
2 1
EPA, 20:5 n-3 0 0
1
2
Washout
3
11
3 % of total fatty acids
n-3 FA Supplementation and blood levels
DHA, 22:6 n-3
weeks
DHA, 22:6 n-3
2
1 cps/day N=5 350 mg EPA+300 mg DHA/day
1 EPA, 20:5 n-3 0 0
1
2
11 weeks
Washout
3
Fig. 1. Percentage levels of 20:5 and 22:6 n-3 in blood lipids of healthy subjects after consumption of salmon (200 g/week) providing 97 mg EPA and 151 mg DHA/day (5 subjects), or after ingestion of formulations providing 350 mg EPA and 300 mg DHA/day (5 subjects), for a period of 3 weeks followed by an 8-week period of washout.
1.20 1.00
N = 10 Age 23-30
o 18:3 n-3 20:5 n-3
Wt % FA
0.80 0.60 0.40 0.20
1
3
2
4
5 Weeks
4 nuts/day washout Fig. 2. Percentage levels of 18:3 n-3 (ALA) and 20:5 n-3 (EPA) in total lipids from the whole blood of 10 healthy subjects after consumption of four nuts/day providing 1.2 g ALA for a period of 3 weeks followed by a 2-week period of washout.
but attention should be paid to avoid the changes that are presently taking place in large segments of the population, due to the introduction of new types of fats. As to the presence and intakes of n-3 fatty acids, the sources of ALA in various vegetable foods should be carefully considered. It becomes therefore mandatory that strategies are proposed at the national and international levels with
the aim of defining and promoting the consumption of foods typical of the Mediterranean diet, known to provide the types of fats that have been shown to be protective for our health. In addition, practical and large-scale projects should be activated aimed at designing menus that can be followed both for homeprepared, family-based meals, and in the preparation of meals for communities or restaurants.
ARTICLE IN PRESS C. Galli, F. Marangoni / Prostaglandins, Leukotrienes and Essential Fatty Acids 75 (2006) 129–133
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