Researchers at the Harvard Medical School examined the relationship between the type of fat a mother consumed at mid-pregnancy and whether her child was obese at age 3.
April 29, 2011
Researchers at the Harvard Medical School examined the relationship between the type of fat a mother consumed at mid-pregnancy and whether her child was obese at age 3. To determine whether a child was obese, they used the child’s body mass index and by taking two skinfold measurements.
More than one-third of the mothers were overweight or obese before pregnancy. A fifth of them ate more than two fish meals per week at mid-pregnancy, but only about half of the women achieved the recommend intake of DHA, a long-chain omega-3 important for fetal and infant development. The recommended intake of DHA in pregnancy and lactation is 200 mg per day. This observation suggests that even though the women ate fish, they did not consume enough of the fatty species, such as salmon, tuna, mackerel, rainbow trout, sardines, and herring, to meet the recommended DHA intake. Only 3% of the women consumed 200 mg/day of DHA in the last month of pregnancy. This is the time when large amounts of DHA are transferred from the mother to the infant to support its brain growth spurt.
The researchers calculated the odds for obesity in the offspring at age 3 according to the mother’s omega-3 fatty acid intake and the level of omega-6s and omega-3s in cord blood at delivery. The odds of obesity in the 3-year-old offspring were 2–4 times higher when the amount of omega-6s relative to the amount of omega-3s in cord blood was high. A similar pattern was seen for dietary fatty acid intake and mid-pregnancy blood fatty acid values.
In contrast, the odds of obesity were 32% lower when the mother’s consumption of omega-3s was higher or she had higher cord blood omega-3 fatty acids. The child’s intake of fish was not related to the development of obesity. This study is the first indication in humans that low intakes of omega-3s in the presence of large amounts of omega-6s during pregnancy might affect the chance of obesity in the offspring.
The researchers warned that more studies need to be conducted to confirm these results.
Press release