S.R. de Vriese

Estimation of dietary fat intake of Belgian pregnant women. Comparison of two methods.

Aim: To evaluate the validity and usefulness of a food frequency questionnaire (FFQ) which was designed to evaluate individual fat consumption for a Dutch population relative to 7-day estimated records (7d ER). The FFQ has been validated previously and was adapted to the Belgian situation. Methods: Longitudinal study in 26 healthy pregnant women; FFQ and 7d ER were obtained during the 1st and 3rd trimesters. Results: FFQ was validated with 7d ER. Fat and fatty acid intake estimated by the FFQ did not differ significantly (p < 0.01) from data obtained by the 7d ER except for 18:2n–6. Pearson correlation coefficient between the 2 methods ranged from 0.62 to 0.68. On average, 47% of the women were classified in the same quartile with the 2 methods and less than 2% in the opposite quartile. Total fat intake, calculated from FFQ, was on average 87.9 (SD 18.1) g/day. The mean intake of linoleic acid was 13.3 (SD 5.4) g/day and of α-linolenic acid was 1.4 (SD 0.5) g/day. The dietary intake of the saturated, monounsaturated and polyunsaturated fatty acids was respectively 34.7 (SD 10.0) g/day, 29.6 (SD 8.1) g/day and 15.7 (SD 5.9) g/day. Conclusion: The FFQ gives similar results for fat intake as the 7d ER and is thus considered an appropriate method for classifying individuals to the right part of the distribution of dietary fat intake.

Oxidative stability of low density lipoproteins and vitamin E levels increase in maternal blood during normal pregnancy.

In 24 healthy pregnant women, parameters related to the oxidative stability of low density lipoproteins (LDL) were determined at three times during pregnancy and shortly after delivery. The fatty acid composition of plasma phospholipids (PL) and the plasma concentrations of vitamin E, vitamin A, and β-carotene were assessed in the same samples. Total triglyceride (TG), total cholesterol, LDL-cholesterol, and high density lipoprotein (HDL)-cholesterol concentrations were also determined. The length of the lag phase of isolated LDL challenged with Cu2+ ions significantly increased with the progression of pregnancy. The oxidation rate and the amount of conjugated dienes formed increased and reached a maximum at 29–37 wk of pregnancy. Total TG, cholesterol, and LDL-cholesterol reached a maximum in the third trimester of pregnancy. β-Carotene remained stable, vitamin A decreased, and vitamin E significantly increased throughout pregnancy. Vitamin E plasma concentration correlated positively with the length of the lag phase. The increased levels of vitamin E could contribute to the higher resistance of LDL toward oxidation with progressing gestation, measured by the prolonged lag phase. Furthermore, vitamin E plasma levels correlated positively with TG concentration but not with LDL-cholesterol. The level of polyunsaturated fatty acids in PL decreased with the progression of pregnancy. No correlation was found between the fatty acid composition of plasma PL, nor with the cholesterol concentration, and the parameters studied related to the oxidative stability of LDL. The major finding of this study is the increased oxidative resistance of LDL with progressing gestation.

FA composition of cholesteryl esters and phospholipids in maternal plasma during pregnancy and at delivery and in cord plasma at birth.

The purpose of this study was to assess the FA composition of both cholesteryl esters (CE) and phospholipids (PL) in maternal plasma during pregnancy and at delivery and in umbilical plasma at birth. A longitudinal study of 32 normal pregnant women was carried out with three cutoff points during pregnancy (first, second, and third trimester) and at delivery. Few significant differences occurred in the FA profile of maternal CE: 18∶1n−9 increased, 18∶2n−6 dropped slightly, and 18∶3n−3 decreased with progressing gestation. In maternal PL, long-chain highly unsaturated FA concentrations dropped and were replaced by saturated FA as gestation progressed. Additionally, changes in saturated FA in PL occurred: Shorter-chain 16∶0 was higher whereas longer-chain 18∶0 was lower at delivery compared to early pregnancy. The FA profile of umbilical venous plasma was strikingly different from that of maternal plasma at delivery. Cord plasma CE contained more saturated and monounsaturated FA than maternal CE. The polyunsaturates 18∶2n−6 and 18∶3n−3 are lower in umbilical CE than in maternal CE whereas 20∶4n−6 and 22∶6n−3 are twice as high in umbilical CE. Cord plasma PL have a higher content of long-chain highly unsaturated FA than maternal plasma PL at delivery. In contrast to maternal plasma PL, 16∶0 was lower and longer-chain saturated FA were higher in cord plasma PL. The FA profile of umbilical plasma at birth shows preferential accumulation of 20∶4n−6 and 22∶6n−3, with low concentrations of 18∶2n−6 and 18∶3n−3 in CE and PL, indicating a preferential supply of the fetus with long-chain highly unsaturated FA needed for fetal development.

Fat absorption and metabolism in bile duct ligated rats.

Background: Bile excretion is obstructed in children with extrahepatic bile duct atresia (EHBA) resulting in fat malabsorption and disturbed lipid metabolism. Aim: Investigate if the bile duct ligated rat exhibits similar deviations as patients with EHBA under different feeding conditions. Methods: 6 bile duct ligated Wistar rats and 12 matched paired controls were randomised over 3 feeding groups. Rats were killed 16 or 30 days postsurgery. Faeces, blood and livers were collected. Fat absorption was evaluated, markers for cholestasis and the fatty acid composition of serum phospholipids (PL) and cholesterol esters (CE) were determined. Fatty acid desaturation activities in liver microsomes were measured. Results: Cholestatic bile duct ligated rats have a lower fat absorption coefficient and a lower fraction of 18:2n–6 and 18:3n–3 in serum triglycerides than their controls. This demonstrates that bile duct ligated rats suffer from fat malabsorption. In contrast to the observations in serum triglycerides, 18:2n–6 and 18:3n–3 were not reduced in serum PL and CE of cholestatic rats. Overflow of 18:2n–6 rich biliary PL in the general circulation could contribute to this observation. In agreement with what was found in man, serum PL of cholestatic rats have a higher 16:0/18:0 ratio, increased monoenes and reduced unsaturated fatty acids. However, no differences were observed in microsomal desaturation activities. Conclusion: Cholestatic bile duct ligated rats exhibit similar deviations in serum fatty acid composition as found in patients with EHBA, therefore they can be used as a model for this human disease.

Fatty acid composition of phospholipids and cholesteryl esters in maternal serum in the early puerperium.

The fatty acid composition of serum phospholipids (PL) and cholesteryl esters (CE) in 26 healthy pregnant women at the end of term and 1 and 3 days after delivery was analysed in order to determine whether the maternal serum fatty acid composition changes in the early puerperium. The composition of the saturated fatty acids significantly changes in the PL fraction: 16:0 decreased and 18:0 increased. Both 20:4n-6 and 20:5 n-3 significantly increased after parturition in serum PL while 22:6n-3 remained constant at the three sampling time points. The sum of HUFA was slightly higher 3 days postpartum compared to the prepartum data. The essential fatty acid index significantly increased after delivery. In the CE fraction too differences occurred during puerperium: 18:2n-6 and 20:4n-6 increased and 18:1n-9 decreased after parturition. The sum of the n-3 fatty acids in CE remained unaltered. The EFA index significantly improved both in PL as in CE after delivery. In conclusion, the previously reported changes in the fatty acid composition of PL and CE during normal pregnancy diminish shortly after delivery. In fact, very soon after delivery the maternal fatty acid composition returns to more normal values.