Nutritional Role of Omega-3 Fatty Acids During the Perinatal Period

Maternal Supply of Both Arachidonic and Docosahexaenoic Acids Is Required for Optimal Neurodevelopment

During the last trimester of gestation and for the first 18 months after birth, both docosahexaenoic acid,22:6n-3 (DHA) and arachidonic acid,20:4n-6 (ARA) are preferentially deposited within the cerebral cortex at a rapid rate. Although the structural and functional roles of DHA in brain development are well investigated, similar roles of ARA are not well documented. The mode of action of these two fatty acids and their derivatives at different structural-functional roles and their levels in the gene expression and signaling pathways of the brain have been continuously emanating. In addition to DHA, the importance of ARA has been much discussed in recent years for fetal and postnatal brain development and the maternal supply of ARA and DHA. These fatty acids are also involved in various brain developmental processes; however, their mechanistic cross talks are not clearly known yet. This review describes the importance of ARA, in addition to DHA, in supporting the optimal brain development and growth and functional roles in the brain.

Effects of Arachidonic and Docosohexahenoic Acid Supplementation during Gestation in Rats. Implication of Placental Oxidative Stress

Arachidonic and docosahexaenoic acids (ARA and DHA) are important during pregnancy. However, the effects of dietary supplementation on fetal growth and oxidative stress are inconclusive. We aimed to assess the effect of high ARA and DHA diet during rat gestation on: (1) ARA and DHA availability in plasma and placenta, (2) fetal growth, and (3) placental oxidative stress, analyzing the influence of sex. Experimental diet (ED) was prepared by substituting soybean oil in the control diet (CD) by a fungi/algae-based oil containing ARA and DHA (2:1). Rats were fed with CD or ED during gestation; plasma, placenta, and fetuses were obtained at gestational day 20. DHA, ARA, and their precursors were analyzed in maternal plasma and placenta by gas chromatography/mass spectrophotometry. Fetuses and placentas were weighed, the proportion of fetuses with intrauterine growth restriction (IUGR) determined, and placental lipid and protein oxidation analyzed. ED fetuses exhibited lower body weight compared to CD, being >40% IUGR; fetal weight negatively correlated with maternal plasma ARA, but not DHA. Only ED female placenta exhibited higher lipid and protein oxidation compared to its CD counterparts; lipid peroxidation is negatively associated with fetal weight. In conclusion, high ARA during gestation associates with IUGR, through placental oxidative stress, with females being more susceptible.

Fish oil diet in pregnancy and lactation reduces pup weight and modifies newborn hepatic metabolic adaptations in rats

PURPOSE

To determine the effects of a diet containing fish oil (FD) during pregnancy and lactation in rats on the metabolic adaptations made by the offspring during early extrauterine life and to compare it to an olive oil diet (OD).

METHODS

Rats were mated and randomly allocated to OD or FD containing 10 % of the corresponding oil. During lactation, litters were adjusted to eight pups per dam. Fetuses of 20 days and pups of 0, 1, 10, 20 and 30 days of age were studied.

RESULTS

Body weight and length were lower in pups of the FD group from birth. The diet, milk, pups' plasma and liver of FD group had higher proportions of n-3 LCPUFA, but the content of arachidonic acid (ARA) was lower. Plasma glucose was higher, but unesterified fatty acids, triacylglycerols (TAG), 3-hydroxybutyrate and liver TAG in 1-day-old pups were lower in the FD group, and differences in some of these variables were also found in pups up to 30 days old. Liver lipoprotein lipase activity and mRNA expression, and the expression of carnitine palmitoyl transferase I, acyl-CoA oxidase and 3-hydroxy 3-methyl glutaryl-CoA synthase increased more at birth in pups of the FD group, but the expression of sterol regulatory element binding protein-1c and Δ6-desaturase mRNA was lower in the FD group.

CONCLUSIONS

Maternal intake of high n-3 LCPUFA retards postnatal development, which could be the result of impaired ARA synthesis, and affects hepatic metabolic adaptations to extrauterine life.

Role of nutritional factors at the early life stages in the pathogenesis and clinical course of type 1 diabetes

Nutrition has been suggested as an important environmental factor other than viruses and chemicals in the pathogenesis of type 1 diabetes (T1D). Whereas various maternal dietary nutritional elements have been suggested and examined in T1D of both humans and experimental animals, the results largely remain controversial. In a series of studies using T1D model nonobese diabetic (NOD) mice, maternal dietary n-6/n-3 essential fatty acid ratio during pregnancy and lactation period, that is, early life stages of the offspring, has been shown to affect pathogenesis of insulitis and strongly prevent overt T1D of the offspring, which is consistent with its preventive effects on other allergic diseases.

Docosahexaenoic acid (DHA): an ancient nutrient for the modern human brain

Modern humans have evolved with a staple source of preformed docosahexaenoic acid (DHA) in the diet. An important turning point in human evolution was the discovery of high-quality, easily digested nutrients from coastal seafood and inland freshwater sources. Multi-generational exploitation of seafood by shore-based dwellers coincided with the rapid expansion of grey matter in the cerebral cortex, which characterizes the modern human brain. The DHA molecule has unique structural properties that appear to provide optimal conditions for a wide range of cell membrane functions. This has particular implications for grey matter, which is membrane-rich tissue. An important metabolic role for DHA has recently been identified as the precursor for resolvins and protectins. The rudimentary source of DHA is marine algae; therefore it is found concentrated in fish and marine oils. Unlike the photosynthetic cells in algae and higher plants, mammalian cells lack the specific enzymes required for the de novo synthesis of alpha-linolenic acid (ALA), the precursor for all omega-3 fatty acid syntheses. Endogenous synthesis of DHA from ALA in humans is much lower and more limited than previously assumed. The excessive consumption of omega-6 fatty acids in the modern Western diet further displaces DHA from membrane phospholipids. An emerging body of research is exploring a unique role for DHA in neurodevelopment and the prevention of neuropsychiatric and neurodegenerative disorders. DHA is increasingly being added back into the food supply as fish oil or algal oil supplementation.

Maternal dietary n-6/n-3 fatty acid ratio affects type 1 diabetes development in the offspring of non-obese diabetic mice

Environment factors, including maternal or infant dietary nutrition have been reported to have an influence on the pathogenesis of type 1 diabetes. In the present study, to investigate the effect of maternal or post-weaning offspring's nutrition, in particular the essential fatty acid ratio (n-6/n-3) on the development of type 1 diabetes, we prepared two kinds of chows with n-6/n-3 ratios of 3.0 (L) and 14.5 (H), and provided them to mothers of non-obese diabetic (NOD) mice during gestation and lactation and to the offspring after weaning. The n-6/n-3 ratios in breast milk and erythrocyte membrane of NOD offspring became nearly the same with that of the maternal diet at 2 weeks after birth. In the L chow-fed offspring from L chow-fed mother (LLL), levels of insulitis were higher than those in the H chow-fed offspring from H chow-fed mother (HHH) at 4 weeks of age, while the levels in the LLL offspring became lower than those in the HHH after 6 weeks. Early insulin autoantibody expressions were found from 2 to 6 weeks in the HHH offspring, but not in the LLL. The LLL offspring exhibited strong suppression of overt diabetes development in regard to the onset and accumulated incidence of diabetes compared to the HHH. The study with combined L and H chows during gestation, lactation in mother and in post-weaning offspring revealed that only the LLH chow significantly suppressed the development of diabetes with similar kinetics to LLL chow, although the other combinations may delay the onset of diabetes. The present findings suggest that n-6/n-3 ratio of the maternal diet during gestation and lactation rather than that of offspring after weaning strongly affects the development of overt diabetes in NOD mice.

Nutrition and neurodevelopment: mechanisms of developmental dysfunction and disease in later life

Nutrition plays a central role in linking the fields of developmental neurobiology and cognitive neuroscience. It has a profound impact on the development of brain structure and function and malnutrition can result in developmental dysfunction and disease in later life. A number of diseases, including schizophrenia, may be related to neurodevelopmental insults such as malnutrition, hypoxia, viruses or in utero drug exposure. Some of the most significant findings on nutrition and neurodevelopment during the last three decades, and especially during the last few years, are discussed in this review. Attention is focused on the underlying cellular and molecular mechanisms by which diet exerts its effects. Randomized intervention studies have revealed important effects of early nutrition on later cognitive development, and recent epidemiological findings show that both genetics and environment are risk factors for schizophrenia. Particularly important is the effect of early nutrition on development of the hippocampus, a brain structure important in establishing learning and memory, and hence for cognitive performance. A major aim of future research should be to elucidate the molecular mechanisms underlying nutritionally-induced impairment of neurodevelopment and specifically to determine the mechanisms by which early nutritional experience affects later cognitive performance. Key research objectives should include: (1) increased understanding of mechanisms underlying the normal processes of ageing and neurodegenerative disorders; (2) assessment of the role of susceptibility genes in modulating the effects of early nutrition on neurodevelopment; and (3) development of nutritional and pharmaceutical strategies for preventing and/or ameliorating the adverse effects of early malnutrition on long-term programming.

Maternal dietary omega fatty acid intake and auditory brainstem-evoked potentials in Mexican infants born at term: cluster analysis

OBJECTIVE

To identify biological and socioeconomic factors associated with the neurological development of Mexican infants born at term, as measured by brainstem auditory-evoked potentials (BAEPs).

SUBJECTS AND METHODS

We conducted a cohort study among 76 women with low risk pregnancies recruited in their third trimester of pregnancy and followed their infants until 12 months of age. BAEP tests were conducted on the infants before 3 months of age during physiologic sleep, using 100 msec bipolar clicks. Maternal dietary intake was evaluated by food frequency questionnaire. Two BAEP groups (short latency, long latency) were identified by cluster analysis. The association between BAEP group and maternal PUFAs was estimated using logistic regression models adjusted for socioeconomic and biological factors.

RESULTS

Short latency BAEPs were associated with a maternal diet rich in arachidonic acid (OR=3.63, 95% CI 1.23-10.67) after adjusting for age (in days) sex, head circumference and gestational age but was not significantly associated to a maternal diet rich in docosahexaenoic acid (DHA).

CONCLUSIONS

Our results suggest the importance of arachidonic acid intake during pregnancy for short latency BAEPs and adequate fetal myelination.

Fatty acid ethyl esters in meconium: are they biomarkers of fetal alcohol exposure and effect?

BACKGROUND

Biomarkers of fetal exposure to alcohol are important to establish so that early detection and intervention can be made on these infants to prevent undesirable outcomes. The aim of this study was to analyze long-chain fatty acid ethyl esters (FAEEs) in meconium as potential biomarkers of fetal alcohol exposure and effect.

METHODS

Fatty acid ethyl esters were analyzed in the meconium of 124 singleton infants by positive chemical ionization gas chromatography/mass spectrometry (GC/MS) and correlated to maternal ethanol use.

RESULTS

A total of 124 mother/infant dyads were enrolled in the study: 31 were in the control group and 93 were in the alcohol-exposed group. The incidence (28% vs 9.7%, p = 0.037) of ethyl linoleate detected in meconium was significantly higher in the alcohol-exposed groups than the control groups. Similarly, when the concentrations of ethyl linoleate in meconium were grouped (trichotomized), there was a significant linear by linear association between alcohol exposure and group concentrations of ethyl linoleate (p = 0.013). Furthermore, only alcohol-exposed infants were found in the group with the highest ethyl linoleate concentration. The sensitivity of ethyl linoleate in detecting prenatal alcohol exposure was only 26.9%, and its specificity and positive predictive value were 96.8 and 96.2%, respectively. There was no significant correlation between the concentration of ethyl linoleate in meconium and absolute alcohol consumed (oz) per drinking day across pregnancy, although a trend toward a positive correlation is seen at lower amounts of alcohol consumed. Among the polyunsaturated, long-chain FAEEs, there was weak evidence that the incidence (21.5% vs 6.5%, p = 0.057) and concentration (p = 0.064) of ethyl arachidonate (AA) were significantly higher in the alcohol-exposed groups than the control groups. Ethyl linolenate and ethyl docosahexanoate (DHA) in meconium were found only in the alcohol group, although not at statistically significant levels. Highly significant correlations were found among the concentrations of ethyl linoleate, ethyl linolenate, ethyl AA, and ethyl DHA in meconium (correlations ranged between rs = 0.203, p = 0.024; and rs = 0.594, p < 0.001).

CONCLUSION

We conclude that FAEEs in meconium, particularly ethyl linoleate and ethyl AA, are biomarkers of high specificity for prenatal exposure to alcohol in newborn infants. We also propose that ethyl AA and DHA could be potential biomarkers of fetal alcohol effects on the developing fetal brain and should be investigated further.

Time for an oil check: the role of essential omega-3 fatty acids in maternal and pediatric health

Deficiency of omega-3 fatty acids (omega3FAs) is an often unrecognized determinant of clinical disease; the adequate availability of these essential nutrients may prevent affliction or facilitate health restoration in some pregnant women and developing offspring. The human organism requires specific nutrients in order to carry out the molecular processes within cells and tissues and it is well established that omega3FAs are essential lipids necessary for various physiological functions. Accordingly, to achieve optimal health for patients, care givers should be familiar with clinical aspects of nutritional science, including the assessment of nutritional status and judicious use of nutrient supplementation. In view of the mounting evidence implicating omega3FA deficiency as a determinant of various maternal and pediatric afflictions, physicians should consider recommending purified fish oil supplementation during pregnancy and lactation. Furthermore, omega3FA supplementation may be indicated in selected pediatric situations to promote optimal health among children.

Human biomonitoring to optimize fish consumption advice: reducing uncertainty when evaluating benefits and risks

National fish consumption advisories that are based solely on assessment of risk of exposure to contaminants without consideration of consumption benefits result in overly restrictive advice that discourages eating fish even in areas where such advice is unwarranted. In fact, generic fish advisories may have adverse public health consequences because of decreased fish consumption and substitution of foods that are less healthy. Public health is on the threshold of a new era for determining actual exposures to environmental contaminants, owing to technological advances in analytical chemistry. It is now possible to target fish consumption advice to specific at-risk populations by evaluating individual contaminant exposures and health risk factors. Because of the current epidemic of nutritionally linked disease, such as obesity, diabetes, and cardiovascular disease, general recommendations for limiting fish consumption are ill conceived and potentially dangerous.

Relationship between plasma fatty acid profile and antioxidant vitamins during normal pregnancy

OBJECTIVE

To study the changes of plasma fatty acids and lipophilic vitamins during normal pregnancy.

DESIGN

Plasma fatty acid profile and the concentration of carotenoids, tocopherols and retinol were measured in healthy women at the first and third trimesters of pregnancy, at delivery, and in cord blood plasma.

RESULTS

Maternal plasma cholesterol and triglycerides increased from the first to the third trimester of gestation, while free fatty acids progressively increased from the first trimester through the third trimester to delivery, suggesting an enhanced lipolytic activity. Plasma levels of alpha- and gamma-tocopherols, lycopene and beta-carotene also progressively increased with gestation, but values in cord blood plasma were lower than in mothers at delivery. Retinol levels declined with gestational time and values in cord blood plasma were even lower. The proportion of total saturated fatty acids increased with gestation, and it further increased in cord blood plasma. Total n-9 fatty acids remained stable throughout pregnancy, and slightly declined in cord blood plasma, the change mainly corresponding to oleic acid. Total n-6 fatty acids declined with gestation and further decreased in cord blood plasma, and a similar trend was found for linoleic acid. However, arachidonic acid declined in women at the third trimester and at delivery as compared to the first trimester, but was enhanced in cord blood plasma. The proportion of total n-3 fatty acids remained stable throughout pregnancy at the expense of decreased alpha-linolenic acid at delivery but enhanced eicosapentaenoic acid, with small changes in docosahexaenoic acid. The proportion of these n-3 fatty acids was similar in cord blood plasma and maternal plasma at delivery.

CONCLUSIONS

Owing to the different placental transfer mechanisms and fetal capability to metabolize some of the transferred fatty acids and lipophilic vitamins, the fetus preserves the essential compounds to assure their appropriate availability to sustain its normal development and to protect itself from the oxidative stress of extrauterine life.

SPONSORSHIP

The studies reported herein have been carried out with financial support from the Commission of the European Communities, specific RTD programme 'Quality of Life and Management of Living Resources', QLK1-2001-00138 'Influence of Dietary Fatty Acids on the Pathophysiology of Intrauterine Foetal Growth and Neonatal Development' (PeriLip). It does not necessarily reflect its views and in no way anticipates the Commission's future policy in this area.

Erythrocyte cell membrane phospholipid levels compared against reported dietary intakes of polyunsaturated fatty acids in pregnant Mexican women

OBJECTIVE

To evaluate the validity of a food-frequency questionnaire (FFQ) for assessment of the dietary intakes of polyunsaturated fatty acids (PUFAs) against a biochemical marker of fat intake, erythrocyte cell membrane phospholipid levels, during pregnancy.

DESIGN

Cross-sectional analysis.

SETTING

Developmental Neurobiology Department, National Institute of Perinatology, Mexico City.

SUBJECTS

One hundred forty-six healthy pregnant women during the last trimester of pregnancy. Among women enrolled, the first 35 pregnant women (24%) had their erythrocytes analysed for fatty acid status.

METHODS

We administered an FFQ and compared intakes of PUFAs against their erythrocyte cell membrane concentrations, processed by gas chromatography.

RESULTS

Pearson correlation coefficients among alpha-linolenic acid (ALN), docosahexaenoic acid (DHA) and eicosapentaenoic acid in erythrocyte cell membranes against their crude dietary counterparts were 0.32, 0.35 and 0.36 (each P < 0.05). In a simple linear regression, erythrocyte DHA and arachidonic acid (AA) were significantly related to their respective dietary intakes (beta = 0.30, 95% confidence interval (CI): 0.007-0.60, P=0.045 for DHA; beta = 0.49, 95% CI: 0.010-0.98, P=0.044 for AA). Erythrocyte cell membrane ALN concentration (%/total) was only marginally related to ALN dietary intake (mg day-1) (beta = 0.52, 95% CI: -0.020-1.10, P=0.061). However, after adjustment for long-chain n-3 PUFA/AA, this association reached significance (beta = 0.44, 95% CI: 0.026-0.825, P=0.038). Main dietary sources for n-3 PUFAs were canned tuna fish and fresh catfish; for n-6 these were eggs and cow's milk. The use of this FFQ in these pregnant Mexican women provided estimates of average long-term intakes of PUFAs and correlated reasonably well with their erythrocyte cell membrane phospholipid status. However, we need to consider that, during pregnancy, there is a faster turnover of PUFAs from fat storage that may modify the profile of erythrocyte PUFAs and lower the correlation between dietary intake and erythrocyte PUFAs.

Implications of dietary fatty acids during pregnancy on placental, fetal and postnatal development--a review

During pregnancy, the mother adapts her metabolism to support the continuous draining of substrates by the fetus. Her increase in net body weight (free of the conceptus) corresponds to the accumulation of fat depots during the first two-thirds of gestation, switching to an accelerated breakdown of these during the last trimester. Under fasting conditions, adipose tissue lipolytic activity is highly enhanced, and its products, free fatty acids (FFA) and glycerol, are mainly driven to maternal liver, where FFA are converted to ketone bodies and glycerol to glucose, which easily cross the placenta and sustain fetal metabolism. Lipolytic products reaching maternal liver are also used for triglyceride synthesis that are released in turn to the circulation, where together with an enhanced transfer of triglycerides among the different lipoprotein fractions, and a decrease in extrahepatic lipoprotein lipase activity, increase the content of triglycerides in all the lipoprotein fractions. Long chain polyunsaturated fatty acids (LCPUFA) circulate in maternal plasma associated to lipoprotein triglycerides, and in a minor proportion in the form of FFA. Despite the lack of a direct placental transfer of triglycerides, diffusion of their fatty acids to the fetus is ensured by means of lipoprotein receptors, lipoprotein lipase activity and intracellular lipase activities in the placenta. Maternal plasma FFA are also an important source of LCPUFA to the fetus, and their placental uptake occurs via a selective process of facilitated membrane translocation involving a plasma membrane fatty acid-binding protein. This mechanism together with a selective cellular metabolism determine the actual rate of placental transfer and its selectivity, resulting even in an enrichment of certain LCPUFA in fetal circulation as compared to maternal. The degree to which the fetus is capable of fatty acid desaturation and elongation is not clear, although both term and preterm infants can synthesize LCPUFA from parental essential fatty acids. Nutritional status of the mother during gestation is related to fetal growth, and excessive dietary intake of certain LCPUFA has inhibitory effects on Delta-5- and Delta-6-desaturases. This inhibition causes major declines in arachidonic acid levels, as directly found in pregnant and lactating rats fed a fish oil-rich diet as compared to olive oil. An excess in dietary PUFA may also enhance peroxidation and reduce antioxidant capacity. Thus, since benefit to risks of modifying maternal fat intake in pregnancy and lactation are not yet completely established, additional studies are needed before recommendations to increase LCPUFA intake in pregnancy are made.

Estimation and validation of mercury intake associated with fish consumption in an EPIC cohort of Spain

OBJECTIVE

To estimate mercury intake due to fish consumption among the individuals from Gipuzkoa participating in the European Prospective Investigation into Cancer (EPIC), and to validate the estimation of mercury exposure through diet, by measuring blood mercury level.

DESIGN AND SETTING

The population for the EPIC Gipuzkoa cohort was recruited from 1992 to 1995. Each individual's diet was assessed regarding habitual intake over the previous year, using the diet history method. Blood samples were taken at the time of the interview. The mercury content of the fish species consumed was supplied by the Food Chemical Surveillance Programme in the Basque Country.

SUBJECTS

For the estimation, 8417 volunteers, men and women, aged 35-65 years, of the EPIC cohort; for the validation, a random sample of 120 individuals stratified by fish intake was taken.

RESULTS

The validation study confirmed the relationship between fish consumption and mercury intake, as well as between fish consumption and mercury in erythrocytes. 99.9% of individuals have intakes below 75% of the Provisional Tolerable Weekly Intake (PTWI) of mercury established by the World Health Organization. But the limit dosage recommended by the United States Environmental Protection Agency, measured by the average risk index, would be exceeded often.

CONCLUSIONS

No individual from the cohort would exceed the PTWI of mercury. Nevertheless, owing to the amount of fish consumed, certain individuals would have mercury intakes approaching the recommended limits. With a view to the future, we believe mercury in fish must continue to be monitored closely in order to assess the risks for the population.

Docosahexanoic acid and omega-3 fatty acids in depression

Geographic areas where consumption of DHA is high are associated with decreased rates of depression. DHA deficiency states, such as alcoholism and the postpartum period, also are linked with depression. Individuals with major depression have marked depletions in omega-3 FAs (especially DHA) in erythrocyte phospholipids compared with controls. These data suggest that DHA may be associated with depression, and the limited data available on supplementation with DHA or other omega-3 FAs seem to support the hypothesis that DHA may have psychotropic effects. Overall, the use of EFAs is promising, particularly in view of the many illnesses potentially treatable with these substances; however, larger, carefully designed studies are needed to establish whether DHA is an effective and safe antidepressant, mood stabilizer, or antipsychotic. A few preliminary trials of DHA are in progress, but no studies comparing DHA against placebo or against an established antidepressant have been carried out. Studies to address this issue are being developed at the Massachusetts General Hospital. Studies likely will require escalating doses of DHA, eventually reaching high levels so as to ensure that patients will avoid a potentially ineffective subclinical dose. Careful monitoring of dietary intake among subjects also will necessary because a high intake of omega-3-rich foods may confound results. Finally, large-scale, placebo-controlled, double-blind trials comparing the efficacy and safety of DHA against standard antidepressants are required before psychiatrists can recommend DHA therapy as effective and safe for the treatment of depression and other mood disorders. Given the popularity of self-medication by patients who already are taking marketed antidepressants, studies examining the use of DHA as an augmentor to standard antidepressants may answer whether DHA can occupy a niche as an augmenting agent for patients who have made a partial response or have not responded to conventional antidepressants. Considering that natural medications generally seem best for treating mild to moderate illness, the role of DHA as a therapy for minor and subsyndromal depression also should be considered. It is hoped that studies of these types will help to clarify some of the knowledge gaps outlined in this article.

The effect of supplementation with docosahexaenoic and arachidonic acid derived from single cell oils on plasma and erythrocyte fatty acids of pregnant women in the second trimester

This study was performed to investigate whether supplementation of docosahexaenoic acid (DHA) and arachidonic acid (AA) to pregnant women would enhance their DHA levels, both in plasma and in erythrocyte phospholipids, without reducing the content of n-6 long-chain ployenes (LCP) usually seen when DHA is supplemented alone. Healthy pregnant women, in the second trimester, were randomly assigned to either the control group (n=12) or the intervention group (n=12). The control group received no supplements and the intervention group received daily during 4 weeks encapsulated algae-derived DHA oil (0.57 g DHA/day) and fungal-derived AA oil (0.26 g AA/day). The fatty acid compositions of plasma and erythrocyte phospholipids were determined in weekly-collected blood samples. DHA and n-6 LCP levels of the control group were unchanged after 4 weeks. Compared to the control group, DHA levels in plasma an erythrocytes of the intervention group increased significantly. No significant reductions were found in the levels of AA and total n-6 LCP. The supplement proved to be effective in increasing the DHA levels in both plasma and erythrocyte without a concomitant decline of the n-6 LCP.

Correlation between the content of intermediate chain-length fatty acids and copper in the milk of Fulani women

Intermediate chain-length fatty acids (C10-C14) in human milk triglycerides provide an easily absorbable fuel that provide a significant amount of the energy needed for growth during the first few months of life. The C10-C14 fatty acid and trace mineral content of human milk is variable. In this report we examined the relationship between the content of calcium, copper, magnesium, manganese, phosphorus, and zinc, and the weight percentage of C10-C14 fatty acids in milk from 33 Fulani women in northern Nigeria between 2 and 24 weeks post-gestation. The milk from these women contained proportions of C10-C14 fatty acids that were comparable to those reported for other populations around the world, as were the concentrations of Ca, Cu, Mg, Mn, Zn and P. Significant correlations were observed between the milk content of Cu and the wt% of C10 (P=0. 005, r=0.475), C12 (P=0.001, r=0.539), C14 (P=0.44, r=0.352) and the total intermediate chain-length fatty acids (P=0.008, r=0.450). No correlations were observed between these fatty acids and any of the other five minerals. We speculate that the relationship between Cu and fatty acids could be related to a requirement for Cu by an enzyme required for C10-C14 fatty acid biosynthesis (e.g. decanoyl deacylase) in mammary tissue, or to some unique Cu binding properties of the intermediate chain length fatty acids.

Mothers, infants, and DHA. Implications for nursing practice

The purpose of this article is to describe the professional literature and current controversies concerning the relationship between essential fatty acids, especially Docohexaenoic Acid (DHA), and neurologic function. Although there is debate in the literature concerning just how much DHA is required for optimal neurologic functioning of infants, it is known that adequate DHA levels are dependent on an adequate dietary intake. However, common dietary practices today may not provide enough DHA. Because pregnancy and lactation are key times of rapid brain growth for the developing fetus and infant, nurses can be instrumental in teaching pregnant and lactating women diet-related information and promoting practices that help increase DHA levels. By understanding the importance of DHA in pregnancy and infancy, the nurse can take a more active role in essential health education.

Nutrition and the eye

The topic "nutrition and the eye" cannot adequately be covered in a single review article; indeed, dozens of books and hundreds of articles have been written on the subject. This review concentrates on three areas in which specific nutrients are known or theorized to have a major impact on vision and the visual system: vitamin A deficiency; antioxidants and their proposed role in the prevention of age-related cataract and macular degeneration; and nutritional optic neuropathies, including those of the recent Cuban epidemic. In addition, this article touches on nutritional treatments that have been suggested for several less common eye diseases and, finally, considers several less prevalent conditions in which deficiency of or excess exposure to a particular nutrient has been associated with ocular pathology.

Some current controversies on nutritional requirements of full-term and pre-term newborn infants

Many controversial topics have still to be resolved regarding the nutritional requirements of the newborn, and in particular of the pre-term infant. The term 'controversy' bears the connotation of prolonged dispute and such a situation has arisen for various reasons: (a) from inadequate research methodologies; (b) from the misinterpretation of, or bias within, the results of studies undertaken; (c) from not taking into account the multifactorial etiology of physiopathological situations or illnesses suffered by suckling neonates and newborn infants. Nevertheless, controversy as such is not always a negative factor, as investigation and discussion enable advances in therapeutic methods.

Nutrition supplements and the eye

PURPOSE

A review of the role of vitamins, minerals, carotenoids and essential fatty acids in relation to eye health. The mode of action may be directly on the eye or by promoting bodily health on which the eye depends.

RESULTS

The lens and retina suffer oxidative damage and the anti-oxidant vitamins A, C and E are implicated as protective. Studies in man give indifferent support to the role of nutrition in the development of cataract. In the elderly, vitamin intake may be inadequate, so that a vitamin supplement may be reasonable. Zinc has a role in retinal metabolism and may be beneficial in macular degeneration. Selenium has an anti-oxidant role. Other minerals including copper have a less defined role. Carotenoids are concentrated at the macula and have an anti-oxidant role. A reduced risk of macular degeneration is found in relation to a high serum level. The essential fatty acid, gamma-linolenic acid (GLA), is useful in Sjögren's syndrome and may help in other dry eye conditions. Omega-3 fatty acids are important in retinal development and have a role in preventing cardiovascular disease.

CONCLUSION

All persons should be encouraged to maintain healthy nutrition. Middle-aged and elderly patients may benefit from a supplement. An intake in excess of the recommended daily intake may be beneficial, but this is not proven. Further clinical trials are indicated to define the advisability of vitamin, mineral and other supplements. Dosages for recommended intake and for supplements are given.

Physical findings in nutritional deficiencies

Manifestations of deficiencies of protein, calories, vitamins, and trace elements are described. These findings are placed in the context of the functions, food sources, and causes of deficiency of each micronutrient.

Specificity of hydroperoxy fatty acid inhibition of cell growth and the lack of effect on tumour necrosis factor-induced cytotoxicity in WEHI clone 13 cells

We have examined whether different omega6-hydroperoxy fatty acids affect tumour cell growth or modulate TNF-induced toxicity in a fatty acid specific way in WEHI clone 13 fibrosarcoma cells. The omega6-hydroperoxides were synthesized from 8 different n - 6 and n - 3 PUFAs by soybean lipoxygenase. The omega6-hydroperoxy fatty acids inhibited cell growth in a concentration-dependent way by a mechanism that is related to the hydroperoxy moiety. Intracellular GSH seemed to protect since the GSH synthase inhibitor L-buthionine-S,R-sulfoximine (BSO) increased cell growth inhibition further. The antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene and alpha-tocopherol did not affect the toxicity. The extent of growth inhibition varied between the hydroperoxides, but the difference was relatively small. The most toxic was hydroperoxy-alpha-linolenic acid which reduced cell survival by 56% after 44 h incubation at 35 microM, while the least toxic, hydroperoxy-gamma-linolenic acid, reduced cell survival by only 10%. The data also show that there is no correlation between toxicity and degree of unsaturation of the hydroperoxy fatty acids. None of the 8 different hydroperoxy fatty acids potentiated TNF-induced toxicity. This, together with the differential effects of BHA and BSO on TNF- and hydroperoxy fatty acid toxicity, indicate that neither the hydroperoxides nor their metabolites are involved in mediating or modulating the TNF-effect.

Nutrition and cognitive function

The work of the Medical Research Council Dunn Nutrition Unit, Cambridge, on the influence of early diet on the development of preterm infants is reviewed. Then further consideration is given to the implication of the findings. Malnutrition during a sensitive period may result in disease in adult life, and studies strongly suggest the development of the brain and retina can be affected. This may be due to the lack of essential fatty acids, and will particularly involve premature babies born at a time when cell membrane development is especially vulnerable. These findings must sometimes be viewed with caution, as genetic and environmental influences can be paramount. There are many reasons to favour breast feeding, rather than giving formula feeds, including improved cognition and visual function. For example breast milk contains docosahexaenoic acid and arachidonic acid, essential for normal brain development, and often absent or in short supply in formula feeds. Although the advantages in developmental status may be due, in part anyhow, to factors such as the mother's ability and education, and to the child being given greater opportunities, the evident importance of the composition of human breast milk cannot be denied. Formula feeds do contain a higher nutrient value than breast milk, which can result in improved height and weight of infants fed in this way: if it is necessary to use them the challenge for future research is to improve their composition. Although this may be of more importance for premature babies, term babies can also be affected; this has both medical and social implications.