Progressive Decrease in Plasma omega 3 and omega 6 Fatty Acids During Pregnancy: Time Course and Effects of Dietary Fats and Antioxidant Nutrients

Abstract

As part of a previously reported comprehensive study of the nutritional and environmental factors contributing to oxidative stress during pregnancy, breath ethane, a volatile alkane produced during peroxidation of w 3 fatty acids (FAs), was used as a non-invasive measure of oxidative stress. This study investigates relationships between the plasma concentration of w 3 FAs, breath ethane, nutrient intake and serum concentration of selected antioxidant nutrients. The study design included measurement of breath ethane, the plasma phospholipid fatty acid (PLF A) pro® le, serum vitamins A, C, E, carotene, selenium, zinc, copper and manganese and dietary intake of 44 women studied at the 28-week gestation (2T) routine outpatient visit. Plasma lipids were extracted, phospholipids (PL) w ere isolated, and the FA compositions were measured by capillary gas chromatography. None of the plasma w 3 FAs correlated with breath ethane, serum concentration or dietary intake of antioxidants. Since the PLF A pro® le of the 2T group revealed decreased plasma w 6 and w 3 FAs compared to healthy (previously reported) non-pregnant females (NPF) of child-bearing age, a crosssectional study was done to compare the PLFA pro® le of the 2T group to that of w omen in the ® rst (1T) and third (3T) trimester of pregnancy to determine if there were de® ciencies that progressed during pregnancy. The 1T group (n 5 16) w as studied at 11± 14 weeks gestation; the 2T group as above; and the 3T group (n 5 19, previously reported), at 34± 39 weeks as well as during labor. In comparison to values for NPF (n 5 59), there was a progressive decrease during pregnancy of most w 3 and w 6 essential FAs. The sum of w 6 FAs (expressed as % of total FA in PL of plasma) decreased from 41.75 6 0.29% for NP F to 38.36 6 0.50% (1T), 36.80 6 0.32% (2T) and 34.55 6 0.41% (3T). The sum of w 3 FAs was 5.50 6 0.16% for NP F, 5.80 6 00.2% (1T), 4.99 6 0.12% (2T) and 3.16 6 0.19% (3T). The results of this cross-sectional study suggest a progressive transfer of w 6 and w 3 fatty acids from mother to fetus during pregnancy, as lipid peroxidation and dietary de® ciency seem less likely explanations for these de® ciencies.Keywords: w 3 and w 6 fatty acids, pregnancy, antioxidant nutrients, ethane, lipid peroxidation. INTRODUCT IONW e recently reported [1] results of a com prehensive study of nutritional and environmental

Influence of sociodemographic, lifestyle and genetic characteristics on maternal DHA and other polyunsaturated fatty acid status in pregnancy: A systematic review

“…A single cohort study assessed the association between breath ethane (a marker of oxidative stress) and maternal omega-3 status in a sample of 44 women in the second trimester of pregnancy [32]. There was no correlation between breath ethane concentrations and maternal concentrations of ALA, EPA, DPA, DHA or total omega-3 PUFA (µmol/l) in this study.…”

“…Oleic acid and vitamin A. One cohort study assessed the association between the dietary intakes of oleic acid and vitamin A and maternal omega-3 DPA status in a sample of 44 women in the second trimester of pregnancy [32].…”

“…One study chose to focus on assessing relationships with maternal DPA status, and identified that maternal DPA status was negatively related to oleic acid intakes, and positively related with serum vitamin A concentrations [32]. The major dietary sources of oleic acid are plant oils and animal products, which also contain omega-6 LA and AA.…”

“…Thus, it is possible that the strong negative relationship is more a reflection of the competition between short-chain omega-3 and omega-6 PUFA for desaturation and elongation, than a direct relationship between dietary intake of oleic acid and PUFA status [41], but the exact mechanisms remain unclear. In relation to vitamin A, it is possible that the strong positive relationship may be due to the antioxidant properties of vitamin A acting to protect DPA from oxidation [32]. However, since only associations with DPA were assessed, further studies are needed to determine whether these same associations are present with other omega-3 LCPUFA.…”

Effects of dietary nutrients on volatile breath metabolites

“…Breath pentane is derived from the oxidation of n -3 and n -6 fatty acids which appear to be transferred from mother to fetus during pregnancy ( 62 ) . However, in women in their last trimester, who have smoked during pregnancy, it has been reported that breath ethane was higher than for a control group of non-smokers, and inversely related to serum vitamin C ( 63 ) .…”