Linoleic acid is associated with lower long-chain n-6 and n-3 fatty acids in red blood cell lipids of Canadian pregnant women.

BACKGROUND: Arachidonic (ARA), eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids are important in membrane glycerophospholipids. Higher maternal blood ARA, EPA, and DHA concentrations in gestation are associated with higher maternal-to-fetal transfer of ARA, EPA, and DHA, respectively, which emphasizes the importance of maternal fatty acid status in gestation. As in the brain, red blood cell (RBC) ethanolamine phosphoglycerides (EPGs) are high in plasmalogen, ARA, and DHA. OBJECTIVE: We determined the relation between dietary n-6 (omega-6) and n-3 (omega-3) fatty acid intakes and n-6 and n-3 fatty acids in RBC EPGs and phosphatidylcholine in near-term pregnant women. DESIGN: The subjects were 105 healthy Canadian pregnant (36 wk gestation) women. Fatty acid intakes were estimated by food-frequency questionnaire, and fasting venous blood samples were collected. RESULTS: DHA and EPA intakes were positively associated with RBC EPG and phosphatidylcholine concentrations of DHA (rho = 0.309 and 0.369, respectively; P < 0.001) and EPA (rho = 0.391 and 0.228, respectively; P < 0.001) and inversely associated with RBC EPG 22:4n-6 and 22:5n-6 (P < 0.001). In RBCs, concentrations of linoleic acid (LA, 18:2n-6) were inversely associated with DHA, EPA, and ARA, respectively, in EPGs (r = -0.432, P < 0.01; r = -0.201, P < 0.04; and r = -0.303, P < 0.01) and phosphatidylcholine (r = -0.460, -0.490, and -0.604; P < 0.01 for all). CONCLUSIONS: Membrane fatty acids are influenced by the amount and balance of fatty acid substrates. Our results suggest the competitive interaction of LA with ARA, EPA, and DHA, with no evidence that higher LA increases ARA. Biochemical indicators to suggest that DHA is limiting are present in our population. This trial was registered at clinicaltrials.gov as NCT00620672.

Dietary arachidonic acid to EPA and DHA balance is increased among Canadian pregnant women with low fish intake.

Arachidonic [ARA, 20:4(n-6)], eicosapentaenoic [EPA, 20:5(n-3)], and docosahexaenoic acids [DHA, 22:6(n-3)] occur in the diet in animal tissue lipids, play important roles in human development and health, but have interactive and opposing functions. Meat and poultry have higher ARA and fish are richer in EPA and DHA. National databases were recently revised to include complete data on ARA in foods. We used a validated FFQ and the revised nutrient databases to quantify the distribution of ARA, EPA, and DHA intakes and balance for 204 healthy Canadian pregnant women. We focused on intake distributions because risk of adverse health effects increases at lower nutrient intakes. RBC fatty acids were analyzed concurrenly with dietary assessment. The distribution of ARA, EPA, and DHA intakes were skewed (P < 0.001), with a median (5-95th percentile) of 107 (41-225), 65 (10-228), and 105 (10-430) mg/d ARA, EPA, and DHA, respectively. Fish provided 66 and 76% of EPA and DHA, respectively, whereas eggs, poultry, and meats provided 81% of ARA. Women consuming <101 g fish/wk consumed less EPA and DHA and had markedly elevated median dietary ARA:EPA and ARA:DHA ratios and RBC lipid ARA:EPA + DHA ratios compared with women consuming >or=101 g fish/wk (P < 0.001). Relatively small increases in fish intake of 1-2 servings (25-50 g)/wk corrected the distorted dietary (n-6):(n-3) fatty acid balance among women consuming meats, but not fish. Median fish and DHA intakes below the recommended 1-2 servings/wk fish for pregnant women suggest major changes in the availability, cost, or acceptance of fish are needed.

Essential n-3 fatty acids in pregnant women and early visual acuity maturation in term infants.

BACKGROUND: Docosahexaenoic acid (DHA) is important to neural development. Whether DHA intakes are low enough in some pregnant women to impair infant development is uncertain. OBJECTIVE: We sought to determine whether DHA deficiency occurs in pregnant women and contributes to poor infant development. DESIGN: Biochemical cutoffs, dietary intakes, or developmental scores indicative of DHA deficiency are not defined. Infant development has a distribution in which an individual's potential development is unknown. This was a randomized intervention to establish a distribution of developmental scores for infants of women with DHA intakes considered to be above requirements against which to compare the development of infants of mothers consuming their usual diet. DHA (400 mg/d; n = 67) or a placebo (n = 68) was consumed by the women from 16 wk gestation until delivery. We determined maternal red blood cell ethanolamine phosphoglyceride fatty acids, dietary intakes at 16 and 36 wk gestation, and infant visual acuity at 60 d of age. RESULTS: We described an approach to identify DHA deficiency when biochemical and functional markers of deficiency are unknown. In multivariate analyses, infant visual acuity was related to sex (beta = 0.660, SE = 0.93, and odds ratio = 1.93) and maternal DHA intervention (beta = 1.215, SE = 1.64, and odds ratio = 3.37). More infant girls in the placebo than in the DHA intervention group had a visual acuity below average (P = 0.048). Maternal red blood cell ethanolamine phosphoglyceride docosatetraenoic acid was inversely related to visual acuity in boys (rho = -0.37, P < 0.05) and girls (rho = -0.48, P < 0.01). CONCLUSIONS: These studies suggest that some pregnant women in our study population were DHA-deficient.

Relationship of dimethylglycine, choline, and betaine with oxoproline in plasma of pregnant women and their newborn infants.

Choline and glycine are inter-related through their roles in methyl metabolism. Choline is metabolized to betaine, which donates a methyl group to homocysteine to form methionine, also generating dimethylglycine, which is further metabolized to glycine. Choline is transported across the placenta and is higher in fetal than maternal plasma. Placental glycine transfer, however, is limited and poor glycine status has been suggested in preterm infants. Insufficient glycine for glutathione (GSH) synthesis results in increased metabolism of gamma-glutamyl cysteine to 5-oxoproline. We measured plasma 5-oxoproline as a metabolic indicator to address whether choline, via dimethylglycine, contributes physiologically relevant amounts of glycine in pregnancy. Blood was collected from healthy term pregnant women and their newborn infants at delivery (n = 46) and nonpregnant healthy women (n = 19) as a reference group. Plasma choline, betaine, dimethylglycine, homocysteine, methionine, and 5-oxoproline were quantified by HPLC-tandem MS. Plasma choline was 45% higher, but betaine was 63% lower and dimethylglycine was 28% lower in pregnant than nonpregnant women (P < 0.01). Higher white blood cell choline dehydrogenase messenger RNA levels in a random subset of pregnant (n = 8) than nonpregnant women (n = 7) (P < 0.01) suggest increased betaine and dimethylglycine turnover rather than decreased synthesis. Plasma choline, betaine, and dimethylglycine were higher (P < 0.001) in fetal plasma (36.4 +/- 13, 29.4 +/- 1.0, and 2.44 +/- 0.12 micromol/L, respectively) than maternal plasma (15.3 +/- 0.42, 14.1 +/- 0.6 and 1.81 +/- 0.12 micromol/L, respectively). Concentrations of 5-oxoproline and dimethylglycine were inversely (P < 0.05) correlated in maternal (Spearman rho = -0.35) and fetal plasma (Spearman rho = -0.32), suggesting that choline, via dimethylglycine, contributes glycine for GSH synthesis in human development.