Essential fatty acid requirements of vegetarians in pregnancy, lactation, and infancy

Maternal diet and human milk composition: an updated systematic review

Context

Exclusive breastfeeding for 6 months after birth provides infants with the best start for life. A review by Bravi et al. summarized the importance of maternal diet as a determinant of human milk composition based on data up to 2015, but evidence on nutrient intake level was limited.

Objective

We updated the review by Bravi et al., critically assessed differences in study designs and sampling methods, and graphically visualized trends and associations.

Data sources

PubMed was systematically searched for articles published between January 2015 and March 2021.

Data extraction

Article screening, selection, and data extraction was done by two independent researchers, including a risk of bias assessment based on 11 criteria. Articles were eligible when including: quantitative information, commonly used effect estimates, healthy mother-infant dyads.

Results

Twenty seven observational and five intervention studies were identified (n = 7,138) and combined with results of Bravi et al. Fatty acids were still the most studied human milk components in relation to maternal diet (n = 17 studies) with maternal fish intake being predominantly positively associated with milk ALA (r = 0.28-0.42), DHA (r = 0.24-0.46), and EPA (r = 0.25-0.28) content. PUFAs from diet were generally positively correlated with their concentrations in milk, while SFA intake was negatively associated with several fatty acids in milk. Studies on associations with maternal diet and milk carbohydrates, proteins, vitamins and minerals were limited in number and varied in methods and results.

Conclusion

This updated review shows that evidence on the association between maternal diet and human milk fatty acids is rapidly increasing, but still diversified in methodology and results. Further studies, preferably intervention studies, assessing diet and milk carbohydrates, proteins, vitamins and minerals are needed to be able draw conclusions on the importance of maternal diet for human milk composition as a whole.

What Is the Evidence for Dietary-Induced DHA Deficiency in Human Brains?

Docosahexaenoic acid (DHA) is a major constituent of neural and visual membranes and is required for optimal neural and visual function. DHA is derived from food or by endogenous synthesis from α-linolenic acid (ALA), an essential fatty acid. Low blood levels of DHA in some westernised populations have led to speculations that child development disorders and various neurological conditions are associated with sub-optimal neural DHA levels, a proposition which has been supported by the supplement industry. This review searched for evidence of deficiency of DHA in human populations, based on elevated levels of the biochemical marker of n-3 deficiency, docosapentaenoic acid (22:5n-6). Three scenarios/situations were identified for the insufficient supply of DHA, namely in the brain of new-born infants fed with high-linoleic acid (LA), low-ALA formulas, in cord blood of women at birth who were vegetarians and in the milk of women from North Sudan. Twenty post-mortem brain studies from the developed world from adults with various neurological disorders revealed no evidence of raised levels of 22:5n-6, even in the samples with reduced DHA levels compared with control subjects. Human populations most likely at risk of n-3 deficiency are new-born and weanling infants, children and adolescents in areas of dryland agriculture, in famines, or are refugees, however, these populations have rarely been studied. This is an important topic for future research.

Nutrition Benefits and Considerations for Whole Foods Plant-Based Eating Patterns

Whole foods plant-based approaches to eating place an emphasis on the intake of fruits, vegetables, whole grains, and legumes and have many health benefits. While there are key nutrients and phytochemicals that can contribute to the purported health benefits, practitioners and patients should also be advised of key nutrients for which intake may be compromised when following this dietary pattern. With careful planning and utility of dietary supplements, individuals can achieve optimal intake of calcium, iron, vitamin D, omega 3 fatty acid-docosahexaenoic acid (DHA), and vitamin B12 and experience the health benefits of a dietary fiber and a host of phytochemicals. This article presents the health benefits of these food substances and approaches for overcoming nutrients of concern when following whole food plant-based eating patterns.

The Safe and Effective Use of Plant-Based Diets with Guidelines for Health Professionals

Plant-based diets, defined here as including both vegan and lacto-ovo-vegetarian diets, are growing in popularity throughout the Western world for various reasons, including concerns for human health and the health of the planet. Plant-based diets are more environmentally sustainable than meat-based diets and have a reduced environmental impact, including producing lower levels of greenhouse gas emissions. Dietary guidelines are normally formulated to enhance the health of society, reduce the risk of chronic diseases, and prevent nutritional deficiencies. We reviewed the scientific data on plant-based diets to summarize their preventative and therapeutic role in cardiovascular disease, cancer, diabetes, obesity, and osteoporosis. Consuming plant-based diets is safe and effective for all stages of the life cycle, from pregnancy and lactation, to childhood, to old age. Plant-based diets, which are high in fiber and polyphenolics, are also associated with a diverse gut microbiota, producing metabolites that have anti-inflammatory functions that may help manage disease processes. Concerns about the adequate intake of a number of nutrients, including vitamin B12, calcium, vitamin D, iron, zinc, and omega-3 fats, are discussed. The use of fortified foods and/or supplements as well as appropriate food choices are outlined for each nutrient. Finally, guidelines are suggested for health professionals working with clients consuming plant-based diets.

Vegan Diet Health Benefits in Metabolic Syndrome

Plant-based diets (PBDs) are increasingly consumed by the Italian population and around the world. In particular, among PBDs, the vegan diet is a food pattern characterized by the exclusion of all animal-origin foods. What drives people to adopt this model are mainly ethical, health and environmental reasons. A vegan diet, if well-balanced and varied, can help in achieving and maintaining an optimal state of health. However, this nutritional approach, if not well-balanced, can cause deficiencies in proteins, ω-3 fatty acids, iron, vitamin D and calcium, zinc, iodine and, above all, vitamin B12. Oral food supplements especially fortified foods are recommended in these cases to restore the nutritional deficiencies. A vegan diet generally reduces the risk of developing chronic non-communicable degenerative diseases, such as metabolic syndrome (MetS) and, in addition, requires fewer natural resources for food production than an omnivorous diet. The aim of this review is to analyze the possible impact of the vegan diet on MetS onset and its treatment.

Vegan or vegetarian diet and breast milk composition - a systematic review

It is known that nutritional composition of breast milk is, to a certain extent, related to maternal diet. The question of nutritional adequacy of mothers' milk is often raised whenever a vegetarian or vegan diet during the lactation process is concerned. For this reason, in some countries, the recruitment of vegan lactating women as milk donors is excluded by milk banks. The purpose of this systematic review is to summarize existing knowledge on variability of specific nutrients in breastmilk of mothers adhering to a plant-based diet. The databases, including MEDLINE (Pubmed) and Scopus, were used to identify relevant publications. Data extraction and analysis were conducted following a PRISMA protocol. Thirteen publications concerning the impact of dietary pattern and levels of animal-origin food intake on breast milk composition were included. The systematic review has shown that all non-vegetarian, vegetarian and vegan mothers produce breast milk of comparable nutritional value. Several differences are primarily attributed to fatty acids and some micro-components, primarily vitamin B12. Regardless of dietary choices, nourishment and adequate nutrition have a significant impact on human milk composition - on the basis of the current evidence, vegetarian and vegan mothers are capable of producing nutritionally valuable milk for their infants, as far as the appropriate supplementation compensating for breastfeeding mother's nutritional requirements is provided. Dietary choices should not be a permanent exclusion criterion for donor candidates in human milk banks.

The Effects of Vegetarian and Vegan Diet during Pregnancy on the Health of Mothers and Offspring

Vegetarian and vegan diets have increased worldwide in the last decades, according to the knowledge that they might prevent coronary heart disease, cancer, and type 2 diabetes. Althought plant-based diets are at risk of nutritional deficiencies such as proteins, iron, vitamin D, calcium, iodine, omega-3, and vitamin B12, the available evidence shows that well planned vegetarian and vegan diets may be considered safe during pregnancy and lactation, but they require a strong awareness for a balanced intake of key nutrients. A review of the scientific literature in this field was performed, focusing specifically on observational studies in humans, in order to investigate protective effects elicited by maternal diets enriched in plant-derived foods and possible unfavorable outcomes related to micronutrients deficiencies and their impact on fetal development. A design of pregestational nutrition intervention is required in order to avoid maternal undernutrition and consequent impaired fetal growth.

Vegan diets: practical advice for athletes and exercisers

With the growth of social media as a platform to share information, veganism is becoming more visible, and could be becoming more accepted in sports and in the health and fitness industry. However, to date, there appears to be a lack of literature that discusses how to manage vegan diets for athletic purposes. This article attempted to review literature in order to provide recommendations for how to construct a vegan diet for athletes and exercisers. While little data could be found in the sports nutrition literature specifically, it was revealed elsewhere that veganism creates challenges that need to be accounted for when designing a nutritious diet. This included the sufficiency of energy and protein; the adequacy of vitamin B12, iron, zinc, calcium, iodine and vitamin D; and the lack of the long-chain n-3 fatty acids EPA and DHA in most plant-based sources. However, via the strategic management of food and appropriate supplementation, it is the contention of this article that a nutritive vegan diet can be designed to achieve the dietary needs of most athletes satisfactorily. Further, it was suggested here that creatine and β-alanine supplementation might be of particular use to vegan athletes, owing to vegetarian diets promoting lower muscle creatine and lower muscle carnosine levels in consumers. Empirical research is needed to examine the effects of vegan diets in athletic populations however, especially if this movement grows in popularity, to ensure that the health and performance of athletic vegans is optimised in accordance with developments in sports nutrition knowledge.

Food for thought: dietary changes in essential fatty acid ratios and the increase in autism spectrum disorders

The last decades have shown a spectacular and partially unexplained rise in the prevalence of autism spectrum disorders (ASD). This rise in ASD seems to parallel changes in the dietary composition of fatty acids. This change is marked by the replacement of cholesterol by omega-6 (n-6) fatty acids in many of our food products, resulting in a drastically increased ratio of omega-6/omega-3 (n-6/n-3). In this context, we review the available knowledge on the putative role of fatty acids in neurodevelopment and describe how disturbances in n-6/n-3 ratios may contribute to the emergence of ASDs. Both clinical and experimental research is discussed. We argue that a change in the ratio of n-6/n-3, especially during early life, may induce developmental changes in brain connectivity, synaptogenesis, cognition and behavior that are directly related to ASD.

Docosahexaenoic acid and human brain development: evidence that a dietary supply is needed for optimal development

Humans evolved a uniquely large brain among terrestrial mammals. Brain and nervous tissue is rich in the omega-3 polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA). Docosahexaenoic acid is required for lower and high order functions in humans because of understood and emerging molecular mechanisms. Among brain components that depend on dietary components, DHA is limiting because its synthesis from terrestrial plant food precursors is low but its utilization when consumed in diet is very efficient. Negligible DHA is found in terrestrial plants, but in contrast, DHA is plentiful at the shoreline where it is made by single-celled organisms and plants, and in the seas supports development of very large marine mammal brains. Modern human brains accumulate DHA up to age 18, most aggressively from about half-way through gestation to about two years of age. Studies in modern humans and non-human primates show that modern infants consuming infant formulas that include only DHA precursors have lower DHA levels than for those with a source of preformed DHA. Functional measures show that infants consuming preformed DHA have improved visual and cognitive function. Dietary preformed DHA in the breast milk of modern mothers supports many-fold greater breast milk DHA than is found in the breast milk of vegans, a phenomenon linked to consumption of shore-based foods. Most current evidence suggests that the DHA-rich human brain required an ample and sustained source of dietary DHA to reach its full potential.

The impact of long-chain n-3 polyunsaturated fatty acids on human health

A considerable literature has been published on the health benefits of fish, oil-rich fish and fish oils and their constituent long-chain (LC) n-3 PUFA. Evidence from epidemiological studies highlights the cardioprotective attributes of diets rich in fish, especially oil-rich fish. Data from intervention trials are consistent in suggesting that LC n-3 PUFA lower the risk of CVD, probably by the multiple mechanisms of lowering serum triacylglycerols, improving the LDL:HDL ratio, anti-arrhythmic effects on heart muscle, improved plaque stability, anti-thrombotic effects and reduced endothelial activation. Research indicates LC n-3 PUFA provision has an impact during development, and there is preliminary evidence that docosahexaenoic acid supplementation during pregnancy could optimise brain and retina development in the infant. LC n-3 PUFA are also postulated to ameliorate behavioural and mental health disturbances such as depression, schizophrenia, dementia and attention deficit hyperactivity disorder. However, despite some positive evidence in each of these areas, use of LC n-3 PUFA in these conditions remains at the experimental stage. In the case of immune function, there is little doubt that LC n-3 PUFA have a positive effect. Although intervention trials in rheumatoid arthritis show strong evidence of benefit, evidence for efficacy in other inflammatory conditions, including Crohn's disease, ulcerative colitis, psoriasis, lupus, multiple sclerosis, cystic fibrosis and asthma, is inconsistent or inadequate. More promising evidence in some conditions may come from studies which attempt to modify the fetal environment using LC n-3 PUFA supplementation during pregnancy.

Health Implications of a Vegetarian Diet

There is now a significant amount of research that demonstrates the health benefits of vegetarian and plant-based diets, which have been associated with a reduced risk of obesity, diabetes, heart disease, and some types of cancer as well as increased longevity. Vegetarian diets are typically lower in fat, particularly saturated fat, and higher in dietary fiber. They are also likely to include more whole grains, legumes, nuts, and soy protein, and together with the absence of red meat, this type of eating plan may provide many benefits for the prevention and treatment of obesity and chronic health problems, including diabetes and cardiovascular disease. Although a well-planned vegetarian or vegan diet can meet all the nutritional needs of an individual, it may be necessary to pay particular attention to some nutrients to ensure an adequate intake, particularly if the person is on a vegan diet. This article will review the evidence for the health benefits of a vegetarian diet and also discuss strategies for meeting the nutritional needs of those following a vegetarian or plant-based eating pattern.

Intakes and breast-milk concentrations of essential fatty acids are low among Bangladeshi women with 24–48-month-old children

Maternal fat intake and adipose reserves are major sources of PUFA during lactation. The present study examined the cross-sectional relationship between prolonged breast-feeding and maternal BMI, assessed adequacy of fat intake among lactating and non-lactating mothers of children 24–48 months of age and determined breast-milk fatty acid composition. Multi-stage sampling was used to select a representative sample of mothers from two rural districts in Bangladesh (n474). Dietary data were collected during two non-consecutive 24 h periods via 12 h in-home daytime observations and recall. The National Cancer Institute method for episodically consumed foods was used to estimate usual intake distributions. Breast milk samples were collected from ninety-eight women, and breast-milk fatty acid methyl esters were quantified using GC. Approximately 42 % of lactatingv.26 % of non-lactating mothers were underweight (BMI < 18·5 kg/m2;P = 0·0003). The maternal diet was low in total fat (approximately 8 % of mean total energy) and food sources of PUFA, including oil and animal source foods, resulting in a low estimated mean total consumption of PUFA (5·1 g/d). Almost all women were estimated to consume less than the recommended intake levels for total fat, total PUFA, α-linolenic acid (ALA) and DHA. Median breast-milk linoleic acid (8·5 % weight) and ALA (0·2 %) concentrations were among the lowest reported in the literature, in contrast with arachidonic acid (0·5 %) and DHA (0·3 %) concentrations, which were mid-range. Bangladeshi women in general, and especially those who practise prolonged breast-feeding, may benefit from increased consumption of food sources of PUFA.

An impact of the diet on serum fatty acid and lipid profiles in Polish vegetarian children and children with allergy

BACKGROUND/OBJECTIVES

Vegetarian diet has become an increasing trend in western world and in Poland. The frequency of allergies is growing, and the effectiveness of vegetarian diet in allergic diseases is a concern for research. We aimed to study an effect of vegetarian diet on lipid profile in serum in a group of Polish children in Poland and to investigate lipid parameters in healthy vegetarian children and in omnivorous children with diagnosed atopic disease.

SUBJECTS/METHODS

Serum lipid profiles (triglycerides, total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, fatty acids) were assessed in groups of children: healthy vegetarians (n=24) and children with diagnosed atopic diseases (n=16), with control group of healthy omnivores (n=18). Diet classification was assessed by a questionnaire.

RESULTS

No differences were observed in serum triglycerides, LDL cholesterol and saturated and monounsaturated fatty acids level in all groups. In the group of Polish vegetarian children, we recorded high consumption of vegetable oils rich in monounsaturated fatty acid, and sunflower oil containing linoleic acid. This observation was associated with higher content of linoleic acid in serum in this group. Among polyunsaturated n-6 fatty acids, linoleic acid revealed significantly (P<0.05) lower levels in allergy vs vegetarian groups. In case of eicosapentaenoic acid (n-3 fatty acid), the allergy group showed higher levels of this compound in comparison to vegetarians.

CONCLUSIONS

Significantly higher concentration of linoleic acid in vegetarian children in comparison to allergy group indicated possible alternative path of lipid metabolism in studied groups, and in consequence, some elements of vegetarian diet may promote protection against allergy.

DHA status of vegetarians

BACKGROUND

Docosahexaenoic acid (22:6n-3; DHA) is absent from vegan diets and present in limited amounts in vegetarian diets.

OBJECTIVE

To review DHA status in vegetarians and vegans.

DESIGN

To identify published studies and review their findings.

RESULTS

Dietary analyses show that vegan diets are devoid of DHA and vegetarian diets that included dairy food and eggs only provide about 0.02 g DHA/d. Vegetarian and especially vegan diets supply more linoleic acid (18:2n-6) than omnivore diets. The intake of alpha-linolenic acid (18:3n-3) also tends to be similar or greater but depends on culinary oils used. The proportions of DHA in plasma, blood cells, breast milk, and tissues are substantially lower in vegans and vegetarians compared with omnivores. The lower proportions of DHA are accompanied by correspondingly higher proportions of the long-chain derivatives of linoleic acid, indicating that the capacity to synthesize long-chain polyunsaturated fatty acids is not limited. Short-term dietary supplementation with alpha-linolenic acid increases the proportion of eicosapentaenoic acid (20:5n-3) but does not increase the proportion of DHA in blood lipids. Small amounts of preformed DHA (as low as 200mg) result in a large increase in the proportion of DHA in blood lipids in vegetarians and vegans. There is no evidence of adverse effects on health or cognitive function with lower DHA intake in vegetarians.

CONCLUSIONS

Preformed DHA in the diet of omnivores explains the relatively higher proportion of this fatty acid in blood and tissue lipids compared with vegetarians. The pathophysiological significance of this difference remains to be determined.

Nutritional counseling for vegetarians during pregnancy and lactation

A woman's nutritional status directly affects pregnancy outcome and the quality of breast milk after birth. Clinicians who provide prenatal care have an important role in assessing the nutritional status of women and directing them to appropriate resources while respecting their choices. Vegetarian and vegan diets may present with unique nutrient deficiencies that can be addressed during prenatal nutritional counseling.

Docosahexaenoic acid, the aquatic diet, and hominin encephalization: difficulties in establishing evolutionary links

Distinctive characteristics of modern humans, including language, tool manufacture and use, culture, and behavioral plasticity, are linked to changes in the organization and size of the brain during hominin evolution. As brain tissue is metabolically and nutritionally costly to develop and maintain, early hominin encephalization has been linked to a release of energetic and nutritional constraints. One such nutrient-based approach has focused on the n-3 long-chained polyunsaturated fatty acid docosahexaenoic acid (DHA), which is a primary constituent of membrane phospholipids within the synaptic networks of the brain essential for optimal cognitive functioning. As biosynthesis of DHA from n-3 dietary precursors (alpha-linolenic acid, LNA) is relatively inefficient, it has been suggested that preformed DHA must have been an integral dietary constituent during evolution of the genus Homo to facilitate the growth and development of an encephalizing brain. Furthermore, preformed DHA has only been identified to an appreciable extent within aquatic resources (marine and freshwater), leading to speculation that hominin encephalization is linked specifically to access and consumption of aquatic resources. The key premise of this perspective is that biosynthesis of DHA from LNA is not only inefficient but also insufficient for the growth and maturation demands of an encephalized brain. However, this assumption is not well-supported, and much evidence instead suggests that consumption of LNA, available in a wider variety of sources within a number of terrestrial ecosystems, is sufficient for normal brain development and maintenance in modern humans and presumably our ancestors.

The composition of milk from Bolivian squirrel monkeys (Saimiri boliviensis boliviensis)

Squirrel monkeys (genus Saimiri) give birth to relatively large neonates with large, fast-growing brains. Maternal energy expenditure during gestation and infant development is argued to be high, but may be offset by the provisioning of offspring by females other than the mother (allonursing). Milk composition is an important component of maternal energy expenditure, but has been examined in only a small number of primate species. Here, we report on the milk composition from laboratory-housed Bolivian squirrel monkey (Saimiri boliviensis boliviensis) dams (n = 6) and allomothers (n = 2). Milk samples (n = 16) representing mid-lactation were assayed for fat, sugar, dry matter (DM), crude protein (CP), and fatty acids. Gross energy (GE) was calculated from these constituents (excepting fatty acids). The goals of this project were: (1) to provide descriptive data on milk composition of squirrel monkeys, including the range of intraspecific variation; (2) to determine if milk produced by allomothers differs from milk from dams; and (3) to compare squirrel monkey milk to that of other small New World monkeys, the callitrichines. Squirrel monkey samples averaged 4.56% fat, 3.59% CP, 6.98% sugar, 16.59% DM, and 0.91 kcal/g. The proportion of the medium chain fatty acids 8:0 and 10:0 was 40 times greater than that reported for human milk samples, and 18:1 and 18:2n-6 comprise more than 60% of total fatty acids. Milk from allomothers was lower than dams in fat, DM, and GE, which may relate to variation in maternal condition between these two groups. Excluding allomothers, milk from squirrel monkeys was higher in mean GE than captive common marmosets, but did not differ in the proportion of energy from fat, CP, and sugar relative to total GE. The consistency in energy from protein between species suggests this may be a shared-derived trait of New World monkeys.

Ácidos graxos poliinsaturados ômega-3 e ômega-6: importância e ocorrência em alimentos

Os ácidos graxos poliinsaturados abrangem as famílias de ácidos graxos ômega-3 e ômega-6. Os ácidos graxos de cadeia muito longa, como os ácidos araquidônico e docosaexaenóico, desempenham importantes funções no desenvolvimento e funcionamento do cérebro e da retina. Esse grupo de ácidos graxos não pode ser obtido pela síntese de novo, mas pode ser sintetizado a partir dos ácidos linoléico e alfa-linolênico presentes na dieta. Neste artigo são considerados os principais fatores que podem inibir a atividade das enzimas dessaturases envolvidas na síntese dos ácidos graxos de cadeia muito longa. São apresentadas as recomendações da razão ômega-6/ômega-3 na dieta, propostas em diversos países, sendo verificada a convergência para o intervalo de 4 a 5:1. São relacionados alimentos que podem contribuir para aumentar a ingestão do ácido alfa-linolênico e dos ácidos graxos de cadeia muito longa. A essencialidade dos ácidos graxos de cadeia muito longa é muito dependente do metabolismo do indivíduo, sendo que a razão n-6/n-3 da dieta exerce grande influência nesse sentido.

Health effects of vegetarian and vegan diets

Vegetarian diets do not contain meat, poultry or fish; vegan diets further exclude dairy products and eggs. Vegetarian and vegan diets can vary widely, but the empirical evidence largely relates to the nutritional content and health effects of the average diet of well-educated vegetarians living in Western countries, together with some information on vegetarians in non-Western countries. In general, vegetarian diets provide relatively large amounts of cereals, pulses, nuts, fruits and vegetables. In terms of nutrients, vegetarian diets are usually rich in carbohydrates, n-6 fatty acids, dietary fibre, carotenoids, folic acid, vitamin C, vitamin E and Mg, and relatively low in protein, saturated fat, long-chain n-3 fatty acids, retinol, vitamin B(12) and Zn; vegans may have particularly low intakes of vitamin B(12) and low intakes of Ca. Cross-sectional studies of vegetarians and vegans have shown that on average they have a relatively low BMI and a low plasma cholesterol concentration; recent studies have also shown higher plasma homocysteine concentrations than in non-vegetarians. Cohort studies of vegetarians have shown a moderate reduction in mortality from IHD but little difference in other major causes of death or all-cause mortality in comparison with health-conscious non-vegetarians from the same population. Studies of cancer have not shown clear differences in cancer rates between vegetarians and non-vegetarians. More data are needed, particularly on the health of vegans and on the possible impacts on health of low intakes of long-chain n-3 fatty acids and vitamin B(12). Overall, the data suggest that the health of Western vegetarians is good and similar to that of comparable non-vegetarians.

Levels of persistent organic pollutants (POPs) in a coastal northern Norwegian population with high fish-liver intake

Recent research has again raised the issue regarding the potential health effects of long term exposure to persistent organic pollutants (POPs) in the context of a risk-benefit analysis. There remains clear evidence of the beneficial effects of fish consumption on public health and in particular fatty fish with its essential fatty acids. In addition to providing fatty acids, fish fat constitutes an essential source to vitamin D for the northern Norwegian population. Norwegian Food Control Authorities have recommended that children and women of childbearing age should not consume fish liver due to the risk associated with high intake of POPs. The aim of this study was to assess the influence of fish liver intake on the levels of PCBs and chlorinated pesticides in a rural coastal community (n = 31) in northern Norway, applying a cross-sectional design. The geometric mean plasma levels of sum of PCBs (14 congeners) and p,p'-DDE was found to be 558 microg kg(-1) lipids and 179 microg kg(-1) lipids, respectively. These levels were not significantly affected by the reported intake of fish liver, when age and gender were considered. Age in particular, but also gender were significant predictors for most compounds. When merging the dataset with an urban population with considerable lower intake of fish liver, the intake of cod liver still did not significantly affect the levels of PCBs and p,p'-DDE when adjusted for age and gender. Age and gender remain the strongest predictors of plasma levels of POPs in this study whereas fish liver intake was not significantly associated with the POPs.

The health benefits of omega-3 polyunsaturated fatty acids: a review of the evidence

The UK dietary guidelines for cardiovascular disease acknowledge the importance of long-chain omega-3 polyunsaturated fatty acids (PUFA) - a component of fish oils - in reducing heart disease risk. At the time, it was recommended that the average n-3 PUFA intake should be increased from 0.1 to 0.2 g day(-1). However, since the publication of these guidelines, a plethora of evidence relating to the beneficial effects of n-3 PUFAs, in areas other than heart disease, has emerged. The majority of intervention studies, which found associations between various conditions and the intake of fish oils or their derivatives, used n-3 intakes well above the 0.2 g day(-1) recommended by Committee on Medical Aspects of Food Policy (COMA). Furthermore, in 2004, the Food Standards Agency changed its advice on oil-rich fish creating a discrepancy between the levels of n-3 PUFA implied by the new advice and the 1994 COMA guideline. This review will examine published evidence from observational and intervention studies relating to the health effects of n-3 PUFAs, and discuss whether the current UK recommendation for long-chain n-3 PUFA needs to be revisited.

Dietary polyunsaturated fatty acids and anorexia nervosa: is there a link?

There has been little research examining the link between dietary fat intake and the symptoms and consequences of anorexia nervosa. In this selective literature review, the potential significance of poly-unsaturated fatty acids is discussed. It is hypothesised that dietary restriction causes essential fatty acid deficiencies and poly-unsaturated fatty acid abnormalities, which might contribute to the physical and mental symptoms and the maintenance of the disorder. The examination of epidemiology, symptoms, co-morbidity, and consequences suggest that poly-unsaturated fatty acid and phospholipid abnormalities are significant in anorexia nervosa. This will be an important area for future research, and may lead to the development of new interventions.

Meat‐Adaptive Genes and the Evolution of Slower Aging in Humans

The chimpanzee life span is shorter than that of humans, which is consistent with a faster schedule of aging. We consider aspects of diet that may have selected for genes that allowed the evolution of longer human life spans with slower aging. Diet has changed remarkably during human evolution. All direct human ancestors are believed to have been largely herbivorous. Chimpanzees eat more meat than other great apes, but in captivity are sensitive to hypercholesterolemia and vascular disease. We argue that this dietary shift to increased regular consumption of fatty animal tissues in the course of hominid evolution was mediated by selection for "meat-adaptive" genes. This selection conferred resistance to disease risks associated with meat eating also increased life expectancy. One candidate gene is apolipoprotein E (apoE), with the E3 allele evolved in the genus Homo that reduces the risks for Alzheimer's and vascular disease, as well as influencing inflammation, infection, and neuronal growth. Other evolved genes mediate lipid metabolism and host defense. The timing of the evolution of apoE and other candidates for meat-adaptive genes is discussed in relation to key events in human evolution.

Serum fatty acid composition in primary school children is associated with serum cholesterol levels and dietary fat intake

OBJECTIVE

To examine the serum fatty acid composition, serum cholesterol levels, and dietary fat intake associated with body composition in primary school children of both urban and rural regions in Taiwan.

DESIGN

Subjects were randomly stratified by region and primary school. The sample consisted of 870 children aged 10 and 11 y old. The sample was equally distributed between an urban region (Kaohsiung City) and a rural region (Yunlin County). The gender ratio of samples from each area was matched. Food record-assisted 24-h dietary recalls and serum lipid measurements were collected for each child, and associations between serum total cholesterol (TC) and fatty acids composition as well as between body mass index (BMI) and triceps skinfold (TSF) were evaluated for both urban and rural regions.

RESULTS

Compared with students in the urban region, those in the rural region had significantly lower total fat intake, BMI, TSF, TC, and LDL cholesterol (LDL-C) and higher HDL-cholesterol (HDL-C) (P<0.05). Increased total fat (P<0.05) as a proportion of total energy was associated with increased TC and LDL-C. Lauric, myristic, and oleic acid levels in the serum of urban boys were significantly higher (P=0.0001, 0.0003, and 0.0398, respectively) than those of rural boys. In girls, the different fatty acid compositions affected TC concentrations, and palmitic and stearic acids of serum in the high-TC group were significantly lower (P=0.0179 and 0.0001, respectively) than those in the low-TC group.

CONCLUSIONS

Urban children had a dietary fat intake that both quantitatively and qualitatively differed from the traditional rural Chinese diet in Taiwan as reflected in rural children. Consumption of total fat was positively associated with BMI, TSF, TC, and LDL-C levels in Taiwanese children aged 10 and 11 y.

SPONSORSHIP

This study was partly sponsored by a research grant from the Department of Health, Taiwan, ROC.

Fluctuations in human milk long-chain PUFA levels in relation to dietary fish intake

Within the Danish population, milk DHA (22:6n-3) levels vary by more than a factor of 10. This paper deals with fluctuations in the milk content of 22:6n-3 and other long-chain PUFA (LCPUFA) and the acute effects of fish meals and fish oil supplements on milk levels of LCPUFA. Twelve fish-eating mothers with 4-mon-old infants provided one blood and one adipose tissue sample, and seven consecutive morning hind-milk samples with dietary records from the previous days. Another 12 lactating women were given fish oil (2-8 g) for breakfast and delivered 6-12 milk samples during the following 24 h. The mean milk 22:6n-3 content of the fish-eating mothers was 0.57+/-0.28 FA% (= percentage of total area of FAME peaks in GLC) and the day-to-day variation (SD/mean) within the individual was 35+/-17%. Mean milk 22:6n-3 content on mornings with no fish the day before was 0.42+/-0.15 FA%; this was increased by 82+/-17% (n = 9, P = 0.05) if the mother had eaten fatty fish. Fish oil resulted in a twofold increase in milk 22:6n-3 levels, which peaked after 10 h and lasted for 24 h. The EPA content of milk was also increased by fish meals and fish oil supplements, but these had no effect on the level of arachidonic acid. The study showed that diurnal and day-to-day fluctuations in levels of milk n-3 LCPUFA are large, which makes it difficult to assess the 22:6n-3 intake of breast-fed infants from a single milk sample. In studies of the functional outcome of dietary 22:6n-3 in breast-fed infants it is suggested also to use a measure of maternal 22:6n-3 status.