For pregnant mothers, the question of whether or not it’s okay to eat fish despite its known mercury content is one that is constantly debated. How much is too much or too little? Is any amount safe at all during the prenatal stages?
 
According to a recent study published in JAMA Network, the currently health recommendation of eating fish one to three times per week while pregnant ought to be followed.  
 
Children whose mothers ate fish one to three times weekly during pregnancy were more likely to have a better metabolic profile as they grew- a significant level of benefit which outweighed a more marginal risk of exposure to mercury. The benefit was not found in pregnant mothers who only ate less than once a week.  
 
The researched child benefits were attributed to the high presence of omega-3s found in fish, which are important to prenatal development as an anti-inflammatory agent. Some types of fish, however, have higher levels of mercury than others, and this potent toxin can cause not only permanent neurological damage, but also greater detriments to children’s metabolic profiles which counters the benefits of omega-3s.
 
Overall, researchers analyzed 805 mother-child pairs from five European countries participating in a project called the HELIX study, which continues to follow mothers and their children from the prenatal stages onward.
 
Women were asked about their weekly fish consumption, and were tested for mercury exposure. When children were between six and 12 years old, they underwent a clinical examination including measurements of waist circumference, blood pressure, high-density lipoprotein cholesterol, triglyceride levels, and insulin levels, to calculate a metabolic syndrome score. High metabolic scores indicate an increased susceptibility to a variety of metabolic diseases.
 
 It was fond that the children of women who ate fish one to three times weekly had a lower (better) metabolic syndrome than those who are fish less than once a week. However, metabolic syndrome scores went back up in women who are fish more often than thrice weekly- which was correlated with mercury concentration in a woman’s blood, showing a potential link between pollutant concentration in fetuses and metabolic syndrome later in life.
 
“Fish is an important source of nutrients, and its consumption should not be avoided,” Leda Chatzi, MD, PhD, senior investigator in the study and associate professor of preventive medicine at USC said. “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.”
 
Additionally, children of mothers with a high fish intake had higher levels of cytokines and adipokines, two biomarkers related to inflammation which contribute to metabolic syndrome. This is the first human study to indicate that these biomarkers could be the mechanism associated with maternal fish consumption and child metabolic health.
 
Researchers plan to look at how different types of fish vary in prenatal consumption, and hope to identify the impacts of different nutrient and mercury levels. The goal is to follow up on the children in the HELIX Study until they are 14 or 15 years old.