Mercury levels in fish have been a concern for pregnant women for years. Now, a study published in JAMA Network Open suggests that children whose mothers ate fish one to three times a week during pregnancy were more likely to have a better metabolic profile than children whose mothers ate fish rarely (less than once a week).
Researchers looked at 805 mother and child pairs from five European countries participating in a collaborative research project known as the HELIX study, which is following women and their children from pregnancy onwards. During their pregnancy, the women were asked about their weekly fish consumption and tested for mercury exposure. When the children were aged 6–12, they underwent a clinical examination with various measurements, including waist circumference, blood pressure, high-density lipoprotein cholesterol, triglyceride levels, and insulin levels. These measures were combined to calculate a metabolic syndrome score.
The children of women who ate fish one to three times a week had lower metabolic syndrome scores than the children of women who ate fish less than once a week. But the benefit declined if women ate fish more than three times a week. The study found that higher mercury concentration in a woman’s blood was associated with a higher metabolic syndrome score in her child.
The study also examined how fish consumption by the mother affected the levels of cytokines and adipokines in her child. These biomarkers are related to inflammation, a contributor to metabolic syndrome. Compared with low fish intake, moderate and high fish consumption during pregnancy were associated with reduced levels of proinflammatory cytokines and adipokines in the children.
“Fish is an important source of nutrients, and its consumption should not be avoided,” said study author Leda Chatzi, associate professor of preventive medicine at the University of Southern California’s Keck School of Medicine, in a university press release. “But pregnant women should stick to one to three servings of fish a week as recommended, and not eat more, because of the potential contamination of fish by mercury and other persistent organic pollutants.”