The effect of supplementation with fish oil during pregnancy on breast milk immunoglobulin A, soluble CD14, cytokine levels and fatty acid composition

Use of advanced cluster analysis to characterize fish consumption patterns and methylmercury dietary exposures from fish and other sea foods among pregnant women

On account of the interspecies variability in contamination and nutrient contents, consumers must balance the risks and benefits of fish consumption through their choice of species, meal size and frequency. The objectives of this study were to better characterize the risk of methylmercury (MeHg) exposure in a sample of 161 French pregnant women consuming sea food, including fish, molluscs and crustaceans, and to explore the use of unsupervised statistical learning as an advanced type of cluster analysis to identify patterns of fish consumption that could predict exposure to MeHg and the coverage of the Recommended Daily Allowance for n-3 polyunsaturated fatty acid (PUFA). The proportion of about 5% of pregnant women exposed at levels higher than the tolerable weekly intake for MeHg is similar to that observed among women of childbearing age in earlier French studies. At the same time, only about 50% of the women reached the recommended intake of 500 mg/day n-3 PUFA. Cluster analysis of the fish consumption showed that they could be grouped in five major clusters that are largely predictable of the intake of both MeHg and n-3 PUFA. This study shows that a global increase in seafood consumption could lead to MeHg exposure above the toxicological limits for pregnant women, thereby questioning the overall balance between this potential risk and potential beneficial effects of n-3 PUFA intakes. Only pregnant women consuming a high proportion of fatty fish meet the n-3 PUFA intake requirements without exceeding the toxicological limit for MeHg. The clusters identified suggest that different intervention strategies may be needed to address the dual purpose of ensuring high PUFA intakes at acceptable MeHg exposures.

Low breast milk TGF-beta2 is induced by Lactobacillus reuteri supplementation and associates with reduced risk of sensitization during infancy

The immunological composition of breast milk differs between mothers. The reasons for these differences and the consequences for the breast-fed infants are poorly understood. The aim of this study was to evaluate the effect of probiotic Lactobacillus reuteri supplementation on the immunological composition of breast milk in relation to sensitization and eczema in the babies. Total IgA, secretory IgA (SIgA), TGF-beta1, TGF-beta2, IL-10, TNF, soluble CD14 (sCD14), and Na/K ratios were analyzed in colostrum and mature milk obtained from women treated with L. reuteri (n = 54) or placebo (n = 55) from gestational week 36 until delivery. Bacteriological analyses of L. reuteri were performed in faecal samples of the mothers. The infants were followed prospectively for 2 yr regarding development of eczema and sensitization as defined by a positive skin prick test and/or circulating allergen-specific IgE antibodies at 6, 12, and 24 months of age. Supplementation of L. reuteri during pregnancy was associated with low levels of TGF-beta2 and slightly increased levels of IL-10 in colostrum. For TGF-beta2, this association was most pronounced in mothers with detectable L. reuteri in faeces. Infants receiving breast milk with low levels of TGF-beta2 were less likely to become sensitized during their first 2 yr of life. A similar trend was observed for development of IgE-associated eczema. The levels of total IgA, SIgA, TGF-beta1, TNF, sCD14, and Na/K ratios in breast milk were not affected by the intake of L. reuteri. None of these parameters correlated with sensitization or development of eczema in the infant, except for high Na/K ratios that associated with increased risk of sensitization. Supplementation with L. reuteri during late pregnancy reduces breast milk levels of TGF-beta2, and low levels of this cytokine are associated with less sensitization and possibly less IgE-associated eczema in breast-fed infants.

Long-chain polyunsaturated fatty acids influence the immune system of infants

Several events occur during the first months of life that allow the immune system to become competent and functional. The aim of this article is to review the rationale and evidence of an influence of (n-3) long-chain PUFA (LCPUFA) on the immune system of infants. The (n-3) LCPUFA exert their immunomodulatory activities at different levels. The (n-3) LCPUFA metabolites induce eicosanoid production, alter gene expression, and modify lipid raft composition, altering T-cell signaling; all contribute to immunological functional changes. However, the roles of these mechanisms and the types of T or other immunological cells involved remain unclear at present. Moreover, the effect of (n-3) LCPUFA on the immune system of infants may vary according to dose, time of exposure, and profile of the immune system (T-helper, Th1/Th2). Most of the interventional studies in infancy have been performed for the prevention of allergy. They all confirmed influence on T-cell function and cytokine profiles, but clinically beneficial effects are more conflicting. Supplementation of the maternal diet in pregnancy or early childhood with (n-3) LCPUFA is potentially a noninvasive intervention strategy to prevent the development of allergy, infection, and possibly other immune-mediated diseases. However, any long-term in vivo effects on (n-3) LCPUFA early in life for immunomodulatory defense in infants and later on immune status and health remain to be assessed.

Impact of PUFA on early immune and fetal development

It has recently been reported that the increased prevalence in childhood allergy may be linked to deviations in fetal immune development. One reason may be impaired nutrient supply. Hence, a well-differentiated placenta together with an optimal fetal nutrition via the mother are important prerequisites for the establishment of a functional immune system with normal immune responses. Fatty acids and their derivatives can influence both the early immune development and immune maturation by regulating numerous metabolic processes and the gene expression of important proteins such as enzymes and cytokines. The present review summarises the impact of nutritional fatty acids on the development of the immune system as well as the fetal development. It describes the mechanisms of action of PUFA, trans fatty acids and conjugated linoleic acids in programming the fetus with regard to its risk of acquiring atopic diseases in childhood.

Docosahexaenoic acid-enriched fish oil consumption modulates immunoglobulin responses to and clearance of enteric reovirus infection in mice

We hypothesized that consumption of the (n-3) PUFA, docosahexaenoic acid (DHA), modulates the mucosal immune response to enteric infection with respiratory enteric orphan virus (reovirus), a model intestinal pathogen. Mice were fed either AIN-93G control diet, containing 10 g/kg corn oil and 60 g/kg high oleic acid safflower oil, or AIN-93G, containing 10 g/kg corn oil and 60 g/kg DHA-enriched fish oil, for 4 wk and then orally gavaged with reovirus strain Type 1 Lang, (T1/L). Reovirus-specific IgA antibody was first detectable in the feces of mice fed a control diet at 6 d postinfection (PI) and was further elevated at 8 and 10 d PI. IgA responses in DHA-fed mice were similar at 6 and 8 d PI but greater at 10 d PI (P < 0.05). Both reovirus-specific serum IgA and IgG(2a) were comparably induced in mice fed control or DHA diets. Reovirus-specific IgA and IgG(2a) secretion by ex vivo Peyer's patch, lamina propria, and spleen cultures derived from control and DHA groups were comparable. Although both groups carried similar numbers of reovirus plaque forming units per intestine, DHA-fed mice shed nearly 10 times more viral RNA in feces than control mice at 2, 4, and 6 d PI (P < 0.05). However, viral RNA was not detectable in either group at 8 and 10 d. Taken together, these data suggest that DHA consumption did not markedly alter mucosal or systemic Ig responses to reovirus but delayed clearance of the virus from the intestinal tract.

Soluble CD14: role in atopic disease and recurrent infections, including otitis media

Soluble CD14 (sCD14) is a part of innate immunity that has been implicated in many diseases, including allergic diseases. However, many influencing factors and confounders, including gender-gene-environment interactions, may complicate interpretations of the observed associations to allergic diseases. In this paper, we review current literature describing the functions of sCD14 and its associations with common (recurrent) infections and with allergic diseases. Because sCD14 is involved with immunologic responses to infections, and exposure to microbial compounds is debated as a protective or a trigger factor for allergy development, these factors-which include genotypes, gender, age, microbial agents (from the environment and infection), and tobacco smoke-cannot be assessed independently. We conclude that confounding effects are important and must be considered to understand the role of sCD14 in allergic development.

The immunological components of human milk

Breast-feeding is generally accepted as the optimal method of feeding infants. However, we have yet to fully understand the complex mixture of bioactive compounds contained in human milk. Epidemiological studies have indicated that breast-feeding is associated with health benefits in the infant for many immune-related conditions. Breast milk contains various antimicrobial substances, factors that promote immune development, constituents that promote tolerance/priming of the infant immune system, as well as anti-inflammatory components. This chapter identifies and discusses the immunological compounds in human milk and the available evidence for their effect on the immune system of the infant. Current feeding regimens recommended for infants are based primarily on the current understanding of the nutritional requirements of the neonate, but perhaps will be modified to reflect the consequences on immune function both immediate and later in life.

CD14: a soluble pattern recognition receptor in milk

An innate immune system capable of distinguishing among self, non-self, and danger is a prerequisite for health. Upon antigenic challenge, pattern recognition receptors (PRRs), such as the Toll-like receptor (TLR) family of proteins, enable this system to recognize and interact with a number of microbial components and endogenous host proteins. In the healthy host, such interactions culminate in tolerance to self-antigen, dietary antigen, and commensal microorganisms but in protection against pathogenic attack. This duality implies tightly regulated control mechanisms that are not expected of the inexperienced neonatal immune system. Indeed, the increased susceptibility of newborn infants to infection and to certain allergens suggests that the capacity to handle certain antigenic challenges is not inherent. The observation that breast-fed infants experience a lower incidence of infections, inflammation, and allergies than formula-fed infants suggests that exogenous factors in milk may play a regulatory role. There is increasing evidence to suggest that upon exposure to antigen, breast milk educates the neonatal immune system in the decision-making processes underlying the immune response to microbes. Breast milk contains a multitude of factors such as immunoglobulins, glycoproteins, glycolipids, and antimicrobial peptides that, qualitatively or quantitatively, may modulate how neonatal cells perceive and respond to microbial components. The specific role of several of these factors is highlighted in other chapters in this book. However, an emerging concept is that breast milk influences the neonatal immune system's perception of "danger." Here we discuss how CD14, a soluble PRR in milk, may contribute to this education.

Influence of adding fish oil to parenteral nutrition on gut-associated lymphoid tissue

BACKGROUND

Lack of enteral nutrition reduces gut-associated lymphoid tissue (GALT) mass and function, a mechanism underlying the increased morbidity of infectious complications in severely injured or critically ill patients. Strategies to restore parenteral nutrition (PN)-induced changes of GALT mass and function have been pursued. However, the influences of adding fish oil to PN on gut immunity remain to be clarified.

METHODS

Male Institute of Cancer Research (ICR) mice (n = 50) were randomized to 4 groups: ad libitum chow (chow), fat free PN (fat (-)-PN), PN + fish oil (FO-PN), and PN + safflower oil (SO-PN). The PN groups were given isocaloric and isonitrogenous PN solutions. The FO- and SO-PN groups received 20% of total calories from fat emulsions. After 5 days of feeding, lymphocytes from Peyer's patches (PPs), the intraepithelial space (IE), and the lamina propria (LP) of the entire small intestine were isolated. GALT lymphocyte numbers and phenotypes (CD4+, CD8+, alphabetaTCR+, gammadeltaTCR+, B220+ cells) were determined. Immunoglobulin A (IgA) levels of small intestinal washings were also measured by enzyme-linked immunosorbent assay. Another set of mice (n = 24) was used to determine plasma fatty acid compositions after feeding.

RESULTS

Lymphocyte numbers from PPs and the LP and intestinal IgA levels were significantly lower in the PN groups than in the chow group, with no significant differences between any 2 PN groups. The FO- and SO-PN groups showed moderate recovery of IE cell numbers compared with the fat (-)-PN group. Omega-3 and omega-6 fatty acid levels were increased with fish and safflower oil additions, respectively, compared with the fat (-)-PN group.

CONCLUSIONS

Adding fish oil to PN does not exacerbate PN-induced GALT changes but rather partially reverses these changes, with increased plasma omega-3 fatty acid levels.

The effects of fish oil supplementation in pregnancy on breast milk fatty acid composition over the course of lactation: a randomized controlled trial

This study evaluated the longitudinal effect of fish oil in pregnancy on breast milk fatty acid composition and infant outcomes. In a randomized, controlled trial, 98 women received 2.2 g docosahexaenoic acid (DHA) and 1.1 g eicosapentaenoic acid (EPA) or olive oil from 20 wk of gestation until delivery. Fatty acid composition in breast milk (at 3 d, 6 wk, and 6 mo) and infant erythrocyte membranes (at 1 y) were determined by gas liquid chromatography. Breast milk fatty acids were examined in relationship to growth and development. Compared with control group, breast milk from women who received fish oil had proportionally higher DHA and EPA levels at 3 d and 6 wk after delivery, but this difference was no longer apparent by 6 mo. Infant DHA status at 1 y of age was directly related to DHA levels at 3 d, 6 wk, and 6 mo postpartum (but not to antenatal supplementation). Both EPA and DHA in breast milk were positively correlated with Griffith's developmental scores including hand and eye coordination. Thus, supplementation in pregnancy was associated with increased n-3 long-chain polyunsaturated fatty acids (LCPUFAs) in breast milk, particularly in early lactation, and this was positively associated with infant DHA status at 1 y.

Consumption of omega3-fatty acids during perinatal life: role in immuno-modulation and allergy prevention

Epidemiological data suggest that dietary factors may have a role in recent increases of the prevalence of allergic diseases. One food-related component might be the reduced consumption of omega3-polyunsaturated fatty acids observed especially in the Western societies; yet, clinical trials supplementing omega3-fatty acids to adults with established allergies and bronchial asthma have generally been disappointing. However, it is known that the immature immune system is highly susceptible to immuno-modulatory environmental conditions particularly in the pre- and postnatal period. This review discusses the immuno-modulatory effects of omega3-fatty acids supplementation in the perinatal life phase on the immune system of the child. Evidence exists that perinatal omega3-fatty acid exposure affects T-cells and antigen presenting cells of the neonates likely due to altered eicosanoid metabolism. Although animal experiments strongly suggest a role of maternal omega3-fatty acid intake on allergic immune responses in the offspring, the beneficial effect of omega3-fatty acid supplementation has been studied in a small number of clinical trials. In these studies perinatal supplementation had some positive effects on distinct clinical phenotypes of the atopic syndrome. However, more studies are needed to fully explore the opportunity of perinatal immuno-modulation.

Maternal fish intake during pregnancy and atopy and asthma in infancy

BACKGROUND

There is growing evidence that n-3 fatty acids have anti-inflammatory properties and may modulate immune response. Dietary intake of these nutrients during pregnancy could play a role in the risk of asthma and atopy in the offspring.

METHODS

Using data from a cohort of women (n=462) enrolled during pregnancy and whose offspring were followed up to 6 years, we evaluated the impact of fish consumption during pregnancy on the incidence of atopy and asthma. Dietary intake was assessed by food frequency questionnaire (42 items) applied by an interviewer.

RESULTS

Thirty-four percent of infants had a medical diagnosis of eczema at age 1 year, 14.3% of the children were atopic [based on skin prick test (SPT) at 6 years], and 5.7% had atopic wheeze at age 6 years. After adjusting for potential confounding factors, fish intake during pregnancy was protective against the risk of eczema at age 1 year, a positive SPT for house dust mite at age 6 years and atopic wheeze at age 6 years [odds ratio (OR)=0.73 95% confidence interval (CI) 0.55-0.98, OR=0.68, 95% CI 0.46-1.01 and OR=0.55, 95% CI 0.31-0.96, respectively]. For an increase in fish intake from once per week to 2.5 times per week, the risk of eczema at age 1 year decreased by 37%, and the risk of positive SPT at age 6 years by 35%. Stratification by breastfeeding showed that fish intake was significantly related to a decrease risk in persistent wheeze among non-breastfed children (P for interaction<0.05). No protective effect was observed among breastfed children.

CONCLUSION

Our data suggest a protective effect of fish intake during pregnancy on the risk of atopy-related outcomes.

Breast milk fatty acids may link innate and adaptive immune regulation: analysis of soluble CD14, prostaglandin E2, and fatty acids

In addition to its role in sensing intraluminal microbial antigens, soluble (s)CD14 may regulate immune responses by its lesser known function as a lipid carrier with possible influences in the production of fatty acid-derived eicosanoids. We investigated the interrelations of fatty acids, prostaglandin E2 (PGE2), and sCD14 and their role in infant atopic eczema during the first year of life. Serum and breast milk samples from mothers and serum samples from their infants were collected at infant's age 3 mo and analyzed for sCD14 and PGE2 concentrations and for fatty acid compositions. The main correlation of sCD14 was with arachidonic acid (20:4n-6) (AA). Dihomo-gamma-linolenic acid (20:3n-6) (DHGLA) and the ratio of n-6 to n-3 fatty acids correlated positively and docosahexaenoic acid (22:6n-3) (DHA) and sum of n-3 fatty acid negatively with PGE2 in mother's serum and linoleic acid (LA) negatively with PGE2 in breast milk. Soluble CD14 tended to be higher and LA, total polyunsaturated fatty acid (PUFA), and sum of n-6 fatty acids were lower in breast milk received by infants with atopic eczema compared with those without. These results suggest that fatty acids contribute to the regulation of innate and adaptive immune responses and link intraluminal exposures, mother's diet, and microbes.

Role of breast milk in a mouse model of maternal transmission of asthma susceptibility

Epidemiologic data suggest a link between nursing by asthmatic mothers and increased risk of allergy in babies. We sought to experimentally test the potential contribution of breast milk mediator(s) in a mouse model of maternal transmission of asthma risk by evaluating the effect of adoptive nursing on asthma susceptibility in the offspring. We measured airway hyperresponsiveness (AHR) and allergic airway inflammation (AI) after an intentionally suboptimal OVA Ag sensitization, tested the allergen independence of the maternal effect by using a second allergen, casein, for sensitization of the baby mice, and tested the potential role of cytokines by measuring their levels in breast milk. Offspring of asthmatic, but not normal, mothers showed AHR and AI, indicating a maternal transfer of asthma risk. After adoptive nursing, both groups (litters born to asthmatic mothers and nursed by normal mothers, and normal babies nursed by asthmatic mothers) showed AHR (enhanced pause after methacholine aerosol, 50 mg/ml, 3.7 +/- 0.7, 4.2 +/- 0.5, respectively, vs 1.1 +/- 0.1 normal controls, n = 25, p < 0.01) and AI, seen as eosinophilia on histology and bronchoalveolar lavage (40.7 +/- 4.5%, 28.7 +/- 3.7%, vs 1.0 +/- 0.5% normals, n = 25, p < 0.01) after OVA sensitization. Similar results using casein allergen were observed. Multiplex assays for cytokines (IFN-gamma, IL-2, IL-4, IL-5, TNF-alpha, and IL-13) in breast milk were negative. Breast milk is sufficient, but not necessary, to mediate allergen-independent maternal transmission of asthma risk to offspring.

Consumption of fish, butter and margarine during pregnancy and development of allergic sensitizations in the offspring: role of maternal atopy

It has been suggested that changes in dietary habits, particularly increased consumption of omega-6 polyunsaturated fatty acids (PUFA) and decreased consumption of omega-3 PUFAs may explain the increase in atopic disease seen in recent years. Furthermore, it seems possible that it is mainly prenatal or very early life environmental factors that influence the development of allergic diseases. It has also been suggested that intrauterine risk factors may act differently if mother themselves suffer from allergic disease. The aim of this study was to investigate whether the consumption of fish, butter and margarine during pregnancy might influence the development of allergic sensitizations in the offspring. The study population was divided into the offspring of allergic and non-allergic mothers. This was a retrospective cohort study enrolling 295 offspring of allergic mothers and 693 of non-allergic mothers. Information regarding maternal intake of fish, butter and margarine during pregnancy as well as other prenatal and perinatal confounding factors were retrospectively assessed by parental report via a standardized questionnaire. Atopy was determined by skin-prick tests (SPT) to eight prevalent inhalant allergens and two foods. In the allergic mothers' group there is no clear correlation between maternal intakes of fish, butter and margarine and sensitizations to food or inhalants. In the non-allergic mothers' group there was no correlation between butter and margarine intake and food or inhalant sensitizations. On the contrary, a protective effect of fish intake on SPT positivity was observed. In particular, frequent maternal intake ('2-3 times/wk or more') of fish reduced the risk of food sensitizations by over a third (aOR 0.23; 95% CI: 0.08-0.69). A similar trend, even if not significant, was found for inhalants. Finally, even in the whole study population, i.e. allergic group plus non-allergic group, there was a similar trend between increased consumption of fish and decreased prevalence of SPT positivity for foods. This study shows that frequent intake of fish during pregnancy may contrast the development of SPT sensitizations for foods in the offspring of mothers without atopic disease. Therefore, larger prospective studies are needed, enrolling mothers with and without allergic disease, to confirm these results.

Transient environmental exposures on the developing immune system: implications for allergy and asthma

PURPOSE OF REVIEW

Early environmental exposures have been extensively studied as potential causes of the observed increase in allergic disease over time. Transient fetal or neonatal exposures in particular are of interest in that they may occur during critical windows of immune system development. Due to the tremendous complexity of variables in early life, as well as the difficulty in randomizing many interventions, it is very difficult to properly study these exposures. Some progress, however, has been made and some more candidates for study may be emerging. Of particular interest are micronutrients, whose ever-changing use and immunomodulatory capabilities make them prime targets for study.

RECENT FINDINGS

New risk factors for atopic disease have emerged from the pool of early life interventions, such as caesarian section, prolonged labor and infant multivitamin supplementation. Data are emerging regarding micronutrient status and supplementation and their effects on the developing immune system and risk for allergic disease. Clinical trials have yet to demonstrate much causality but, in some cases, it is too early to make any judgments.

SUMMARY

The gold standard of randomized clinical trials has not borne out a number of proposed early-life allergic risk factors, while other trials are too incomplete to draw any conclusions so far. Properly designed studies for other risk factor interventions may still be achievable, provided that there is a proper understanding of the interventions, populations and outcomes.

A randomized controlled trial of the effect of fish oil supplementation in late pregnancy and early lactation on the n-3 fatty acid content in human breast milk

The aim of this research was to investigate the effect of fish oil supplementation, in the third trimester of pregnancy and early lactation period of healthy pregnant Danish women. Forty-four pregnant women were randomly allocated to fish oil supplementation (1.3 g EPA and 0.9 g DHA per day) from week 30 of gestation (FO-group) or to a control regimen (olive oil or no oil; controls). The FO-group was randomly subdivided into women stopping fish oil supplementation at delivery IFO(pregn)], and women continuing supplementation for an additional 30 d [FO(pregn/lact)]. Thirty-six women agreed to collect milk samples at days 4, 16, and 30 postpartum. The FA composition of the milk samples was determined by GLC. At days 4, 16, and 30 in lactation, FO(pregn/lact) women (n = 12) had, respectively 2.3 (P = 0.001), 4.1 (P = 0.001), and 3.3 (P = 0.001) times higher mean contents of LCPUFA(n-3) in their breast milk compared with controls (n = 13), and 1.7 (P = 0.005), 2.8 (P = 0.001), and 2.8 (P = 0.001) times higher LCPUFA(n-3) contents, respectively, at these days compared with FO(pregn) women (n = 11). The latter group did not differ significantly from controls with regard to LCPUFA(n-3) content in the breast milk. Similar results were obtained when analyzing separately for effects on the milk content of DHA. Dietary supplementation with 2.7 g LCPUFA(n-3) per day from week 30 of gestation and onward more than tripled the LCPUFA(n-3) content in early breast milk; supplementation limited to pregnancy only was much less effective.

Does fish oil supplementation in pregnancy reduce the risk of allergic disease in infants?

PURPOSE OF REVIEW

Parallel increases in many inflammatory diseases over the last 40 years suggest that common environmental changes are promoting inflammatory immune responses and/or inhibiting the processes that normally keep these in check. One key change during this period has been declining intakes of anti-inflammatory dietary factors, including omega-3 polyunsaturated fatty acids (n-3 PUFA). As allergic diseases often first manifest in early infancy, prevention strategies need to be targeted early, even in utero. This review will examine recent evidence for the use of fish oil during this early period as a primary prevention strategy for allergic disease.

RECENT FINDINGS

N-3 PUFA have well documented anti-inflammatory effects in vitro and have also been demonstrated to have health benefits in a range of chronic inflammatory diseases, including cardiovascular disease, rheumatoid arthritis and diabetes, supporting their role in modulating inflammation in vivo. Although the effects of fish oil supplementation in established allergic disease are less convincing, there is accumulating evidence that dietary n-3 PUFA may have greater effects before allergic responses are established.

SUMMARY

Supplementation of the maternal diet in pregnancy with n-3 PUFA may provide a non-invasive intervention with significant potential to prevent the development of allergic and possibly other immune-mediated diseases.

Essential fatty acids and their derivatives

PURPOSE OF REVIEW

This review will address recent research in metabolism of essential fatty acids and their long chain derivatives. Our main focus will be the association between essential fatty acid status and various disease states, as well as the effects of supplementation with essential fatty acids or their derivatives on a number of clinical outcomes.

RECENT FINDINGS

There have been several papers over the last few years that show links between supplementation with fish oil (n-3 polyunsaturated fatty acids) and cardiovascular disease. Recent data suggest that the use of fish oil (containing n-3 fatty acids) in a variety of disorders such as cystic fibrosis, coronary disease and in the prevention of sudden death is beneficial. Several papers show reductions in systemic markers of inflammation. More widespread use of essential fatty acid derivatives in infant formula can certainly be questioned on the basis of the recent data. Fewer benefits are seen with ingestion of the essential fatty acids themselves, likely related to limited conversion to their long chain derivatives in humans.

SUMMARY

Derivatives of essential fatty acids have the potential to modify a number of disease states, either ingested in greater quantities in the diet, or taken as supplements in the form of fish oil.

N-3 fatty acids and pregnancy outcomes

PURPOSE OF REVIEW

To discuss new data from the literature on the relationship between the supply of n-3 polyunsaturated fatty acids during pregnancy and pregnancy outcomes, evaluated as the fatty acid composition of blood and breast milk, fetal and infantile development and maternal health.

RECENT FINDINGS

Supplementation of alpha-linolenic acid in high doses or docosahexaenoic acid in low doses did not result in a significant enhancement of the blood docosahexaenoic acid status of the offspring. In contrast, supplementation of docosahexaenoic acid in relatively high doses led to significant increases in infantile docosahexaenoic acid values and to a significant enhancement of breast milk docosahexaenoic acid content. Electroretinogram data obtained during the first week of life and pattern-reversal visual evoked potentials investigated at 50 and 66 weeks postconception were significantly associated with the docosahexaenoic acid status of the infant at birth. Children whose mothers received docosahexaenoic acid supplementation during pregnancy and lactation scored better in mental processing tests carried out at 4 years than children whose mothers received placebo.

SUMMARY

Beneficial health outcomes are more likely to result from supplementation with docosahexaenoic acid itself, rather than its precursor alpha-linolenic acid. Trials have shown that a higher maternal docosahexaenoic acid intake during pregnancy may be favourable for the visual and cognitive development of the offspring. The significant positive association between maternal docosahexaenoic acid intake during pregnancy and the children's mental processing scores at 4 years suggest that optimization of the docosahexaenoic acid status of expectant women may offer long-term developmental benefits to their children.

An introduction to dietary/supplemental omega-3 fatty acids for general health and prevention: Part II

The correction of a subtle nutritional deficiency that may reduce the risk of a future chronic disease is indeed a challenge. However, some specific examples in the past, such as the addition of folic acid to prevent neural tube defects and calcium and vitamin D to prevent osteoporosis, should provide some encouragement that some conditions can be prevented with the appropriate addition of a deficient compound. One of the most intriguing current and future impacts on public health may come from a higher intake of omega-3 fatty acids, such as alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The omega-3 fatty acids continue to accumulate research that suggests that they may prevent a variety of diverse chronic diseases and potentially some acute clinical scenarios. In the first part of this article, the potential for these compounds to prevent certain cardiovascular conditions are discussed. In the second part, the potential for an impact in arthritis, numerous areas of cancer research, depression, maternal and child health, neurologic diseases, osteoporosis, and other medical disciplines are also briefly covered. The future appears bright for these agents, but specifically which conditions, who qualifies, testing, frequency, adequate sources, future trials, and numerous other questions need to be addressed and answered before the potential impact can catch up to the recent hype.