The effect of maternal DHA supplementation on body fat mass in children at 7 years: follow-up of the DOMInO randomized controlled trial

BACKGROUND

Animal studies have suggested that an increased supply of omega-3 long chain polyunsaturated fatty acids (LCPUFA), in particular docosahexaenoic acid (DHA), during the perinatal period can prevent later excess body fat mass. However, previous human studies have produced inconsistent findings, and few have assessed potential effects beyond 6 years of age.

OBJECTIVE

To evaluate the effect of supplementing women in the second half of pregnancy with omega-3 LCPUFA, chiefly as DHA, on the percentage body fat of children at 7 years of age, as assessed by two methods: air displacement plethysmography (BOD POD) and bioelectrical impedance spectroscopy (BIS).

DESIGN

A time-restricted follow up at 7 years of age of children born to mothers enrolled in DOMInO (DHA to Optimise Maternal Infant Outcome) randomized controlled trial, in which women took either high-DHA tuna oil (800mg/day DHA) or placebo capsules from 20 weeks' gestation to delivery, at Adelaide-based centers. Primary outcomes were the percentage body fat at 7 years of age as assessed by both BOD POD and BIS. Weight, height, waist/hip circumferences and BMI were also recorded.

RESULTS

A total of 252 DOMInO children (n=135 males, n=117 females) completed the follow up study. There were no differences between the DHA and placebo groups in percentage body fat as assessed by either BOD POD [adjusted mean difference: -0.35, 95% CI: -1.46, 2.16; P=0.71] or BIS [adjusted mean difference: 0.64, 95% CI: -0.99, 2.27; P=0.44]. BMI z-scores were also similar between groups [adjusted mean difference: 0.18, 95% CI: -0.10, 0.45; P=0.21]. There were also no differences in height, weight or waist and hip circumference between the DHA and placebo groups at 7 years of age.

CONCLUSION

DHA supplementation in the second half of pregnancy has no effect on childhood growth or fat mass at 7 years of age, supporting findings from follow ups of the DOMInO children at 3 and 5 years.

The effects of antidiuretic hormone on urine flow and composition in the chronically-cannulated ovine fetus

The fetuses of nine pregnant ewes were chronically cannulated between 86 and 130 days with cannulae in one carotid artery, one jugular vein, the fetal bladder and the amniotic cavity. The effects of infused AVP on fetal urine flow rate and composition were studied. A dose of 35 pmol. h-1 always caused an increase in urine osmolality and a decrease in flow rate and free water clearance without change in blood pressure. Higher doses (140 pmol.h-1) were significantly pressor and caused increased excretion of sodium, chloride, urea and creatinine. Although this dose always caused an increase in urine osmolality, in five experiments the flow rate also rose. It is concluded that the ovine fetus has the ability to control its own urine flow and composition, and possibly also amniotic fluid volume and composition.

Effect of aldosterone on urine composition in the chronically cannulated ovine foetus

* Department of Physiology, University of Melbourne, Parkville, Victoria 3052, Australia, † Department of Surgery, Austin Hospital, Studley Road, Heidelberg, Victoria 3084, Australia, and ‡ Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria 3052, Australia

(Received 19 October 1977)

Aldosterone is present in the peripheral blood of ovine foetuses from at least 60 days until term at 147 ± 5 days (Wintour, Brown, Denton, Hardy, McDougall, Oddie & Whipp, 1975). To determine the biological significance of this steroid in the foetus, infusions of aldosterone were made into foetuses bearing chronic vascular and bladder cannulae and the urinary sodium: potassium Na+: K+) ratio was measured before, during and after infusion. Silastic cannulae (0·76 mm internal diameter, 1·65 mm outer diameter) were placed 6–8 cm into the left carotid arteries and right jugular veins of seven ovine foetuses between 86 and 120 days of gestation and a