Current advice warns women not to eat fish containing high quantities of mercury.
The findings, which combined analysis of over 4,131 expectant women from the UK’s Children of the 90s study with comparable extensive investigations in Seychelles, were recently published in the journal NeuroToxicology.
Importantly, the researchers discovered that eating any sort of fish appears to be safe since the fish’s essential nutrients may act as protection against the mercury the fish contains. What mattered more was whether or not the woman ate fish. This is in contrast to existing guidelines cautioning women who are expecting not to consume certain fish types that have comparatively high levels of mercury.
Despite the fact that several studies have considered this question, this investigation examined two contrasting studies of populations where mercury levels were assessed during pregnancy and the children were followed at frequent intervals throughout childhood.
The first is a study that focused on a Seychelles community where almost all pregnant women consume fish. The second study examined data analyses from the Children of the 90s study, conducted by the University of Bristol in a relatively industrialized region of southwest England where fish consumption is much less common. This study is also referred to as the Avon Longitudinal Study of Parents and Children (ALSPAC). There has never been a summary of the study’s findings published before.
Although it has been known for some time that the children of women who eat fish in pregnancy are likely to benefit in various ways in regard to their eyesight and intellectual abilities, official advice has included the warning not to eat certain types of fish that have relatively high levels of mercury. As a result, there is the possibility that some women will stop eating any fish “to be on the safe side.”
Dr. Caroline Taylor, Senior Research Fellow and co-author of the study, said: “We found that the mother’s mercury level during pregnancy is likely to have no adverse effect on the development of the child provided that the mother eats fish. If she did not eat fish, then there was some evidence that her mercury level could have a harmful effect on the child. This could be because of the benefits from the mix of essential nutrients that fish provides, including long-chain fatty acids, iodine, vitamin D, and selenium.”
Professor Jean Golding, co-author and Emeritus Professor of Paediatric and Perinatal Epidemiology at the University of Bristol, said: “It is important that advisories from health professionals revise their advice warning against eating certain species of fish. There is no evidence of harm from these fish, but there is evidence from different countries that such advice can cause confusion in pregnant women. The guidance for pregnancy should highlight ‘Eat at least two portions of fish a week, one of which should be oily’ – and omit all warnings that certain fish should not be eaten.”
Reference: “The benefits of fish intake: Results concerning prenatal mercury exposure and child outcomes from the ALSPAC prebirth cohort” by Jean Golding, Caroline Taylor, Yasmin Iles-Caven, and Steven Gregory, 4 May 2022, NeuroToxicology.
The study was funded by the UK Medical Research Council and the UK Wellcome Trust.