Does maternal omega-­3 fatty acid supplementation reduce body fat mass at 7 years of age?

Docosahexaenoic acid (DHA) is an n­3 long chain polyunsaturated fatty acid (LCPUFA) which is important for optimum health of the mother and growth and development of the fetus. During the prenatal period, the time before birth, the only source of LCPUFAs for the fetus is from the mother via transfer across the placenta. The last trimester of gestation is the major period of n­3 LCPUFA accumulation in fetal tissues, including fetal fat tissue. The n­3 LCPUFAs inhibit fat cell formation and lipid accumulation in adults and this has led to the suggestion that prenatal exposure to an increased supply of n­3 LCPUFA could reduce the subsequent accumulation of fat tissue in childhood, and hence the risk of obesity and diabetes later in life. However, results of the studies which have attempted to study this question to date have been inconclusive. The DOMInO trial (DHA to Optimise Mother Infant Outcome) was designed to evaluate the effects of supplementing women with 800mg DHA/day during the second half of pregnancy on maternal and infant outcomes. The growth andinsulin resistance follow­up of children in this study was undertaken when they were 3 and 5 years old and aimed to determine whether increasing the amount of n­3 LCPUFA in the diet during pregnancy could reduce the risk of obesity and diabetes in the children. In the present study, we are proposing to extend this follow­up of the DOMInO children to 7 years of age. This is important, since major changes in body composition (the balance of muscle and fat) occur in the first few years after children start school. Capturing the growth and body composition of the DOMInO children at 7 years of age will therefore provide a more complete picture of changes in body composition over this critical period of growth and will enable us to determine the effects of maternal n­3 LCPUFA supplementation on the body fat mass at school age. The body fat mass of children at school age is also a stronger predictor of their body fat mass and metabolic health later in development than fat mass at earlier ages. The primary outcome of the current study is to assess if omega 3 LCPUFA supplementation during pregnancy is associated with a reduced body fat mass later in childhood. This will be achieved by measuring body composition and body mass index (BMI) z-scores in children (n=252) of mother's who were enrolled in the DOMInO trial at 7 years of age. The findings from this study will provide valuable information as to whether maternal n­3 LCPUFA supplementation in pregnancy has the potential to reduce body fat mass in children at school age, and therefore reduce their future risk of obesity.