Is there a relation between docosahexaenoic acid concentration in mothers' milk and visual development in term infants?

Fish are central in the diet of Amazonian riparians: should we worry about their mercury concentrations?

The Amazon rain forest extends over an area of 7.8x10(6)km(2) in nine countries. It harbors a diverse human population distributed in dense cities and isolated communities with extreme levels of infrastructure. Amazonian forest people, either autochthons or frontier riparians (ribeirinhos) living in isolated areas, share the same environment for survival and nutritional status. The peculiarities of the hydrological cycle determine disease patterns, agricultural conditions, and food availability. Feeding strategies depend heavily on cassava products and fish. These two foods carry toxic substances such as linamarin (naturally present in cassava) and monomethyl mercury (MMHg) (bioconcentrated in fish flesh) that cause neurotoxic diseases in other parts of the world but not in Amazonia, where neurotoxic cases of food origin are rare and not related to these staples. While cassava detoxification processes may partly explain its safe consumption, the Hg concentrations in Amazonian fish are within traditionally safe limits for this population and contribute to an important metabolic interaction with cassava. The gold rush of the 1970s and 1980s brought large-scale environmental disruption and physical destruction of ecosystems at impact points, along with a heavy discharge of metallic Hg. The discharged Hg has not yet impacted on MMHg concentrations in fish or in hair of fish consumers. Hair Hg concentration, used as a biomarker of fish consumption, indicates that the Amazonian riparians are acquiring an excellent source of protein carrying important nutrients, the lack of which could aggravate their existing health problems. Therefore, in a scenario of insufficient health services and an unhealthy environment, food habits based on fish consumption are part of a successful survival strategy and recommendations for changes are not yet justifiable.

Perinatal supply and metabolism of long-chain polyunsaturated fatty acids: importance for the early development of the nervous system

The long-chain polyunsaturated fatty acids, arachidonic (AA) and docosahexaenoic acid (DHA), are essential structural lipid components of biomembranes. During pregnancy, long-chain polyunsaturated fatty acids (LC-PUFA) are preferentially transferred from mother to fetus across the placenta. This placental transfer is mediated by specific fatty acid binding and transfer proteins. After birth, preterm and full-term babies are capable of converting linoleic and alpha-linolenic acids into AA and DHA, respectively, as demonstrated by studies using stable isotopes, but the activity of this endogenous LC-PUFA synthesis is very low. Breast milk provides preformed LC-PUFA, and breast-fed infants have higher LC-PUFA levels in plasma and tissue phospholipids than infants fed conventional formulas. Supplementation of formulas with different sources of LC-PUFA can normalize LC-PUFA status in the recipient infants relative to reference groups fed human milk. Some, but not all, randomized, double-masked placebo-controlled clinical trials in preterm and healthy full-term infants demonstrated benefits of formula supplementation with DHA and AA for development of visual acuity up to 1 year of age and of complex neural and cognitive functions. From the available data, we conclude that LC-PUFA are conditionally essential substrates during early life that are related to the quality of growth and development. Therefore, a dietary supply during pregnancy, lactation, and early childhood that avoids the occurrence of LC-PUFA depletion is desirable, as was recently recommended by an expert consensus workshop of the Child Health Foundation.

Effect of emulsifier on oxidation properties of fish oil-based structured lipid emulsions

The effects of the emulsifiers lecithin, Tween 20, whey protein isolate, mono-/diacylglycerols, and sucrose fatty acid ester on oxidation stability of a model oil-in-water emulsion prepared with enzymatically synthesized menhaden oil-caprylic acid structured lipid were evaluated. Oxidation was monitored by measuring lipid hydroperoxides, thiobarbituric acid reactive substances, and the ratio of combined docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contents to palmitic acid in the emulsion. After high-pressure homogenization, all emulsions, except those prepared with lecithin, had similar droplet size distributions. All structured lipid emulsions, except for the lecithin-stabilized emulsions, were stable to creaming over the 48-day period studied. Emulsifier type and concentration affected oxidation rate, with 0.25% emulsifier concentration generally having a higher oxidation rate than 1% emulsifier concentration. Overall, oxidation did not progress significantly enough in 48 days of storage to affect DHA and EPA levels in the emulsion.

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.