The study’s authors looked at the behavior, fine motor skills and IQ’s of the offspring of 11,875 British women who had earlier assessed their seafood consumption at 32 weeks gestation. Researchers found that the children of women who ate less than 12 ounces of seafood a week had an increased risk of poor social development and low verbal IQ. Meanwhile, women who ate more than 12 ounces of seafood a week while pregnant saw beneficial effects on their children’s development. Yikes—tuna sandwiches for everyone? NEWSWEEK’s Karen Springen spoke with Dr. Joseph R. Hibbeln of the National Institutes of Health (NIH), the lead author of the study. Excerpts:
NEWSWEEK: What should pregnant women who have been avoiding fish, or aren’t fish eaters anyway, take away from this study? Joseph Hibbeln: The data in this study indicate that the children of women who ate no seafood at all had the greatest risk of low IQ and they had the greatest risk of poor social development and poor neurological development. So they should consider these findings in their overall food choices. I want also to make clear that at the NIH, we don’t give health advice. We just do the scientific study. The EPA and the FDA and other government agencies, filled with very smart scientists and policymakers, will consider these data as they assess their health advice. Now that said, this study was a test or an evaluation of the health advice of the 2004 advisory [recommending that pregnant women limit seafood consumption to 12 ounces per week].
You found that women needed to eat more than 12 ounces of seafood per week to see beneficial effects on their children’s development. Isn’t that a lot of fish? It depends on where you live. If you’re in Iceland, that’s lunch.
But for many American women, doesn’t 12 ounces sound huge? That would be two or three fish meals a week.
What kind of fish should women eat? In this study, we assumed a pretty normal distribution of fish. We didn’t make any specific distinctions. In general, women don’t make distinctions between types of fish. They either eat fish or do not eat fish.
You’re not getting into which types of fish are more likely to contain mercury? The 2004 advisory was designed to protect against the toxic effects of mercury. However, the advisory didn’t calculate in the beneficial effects of the nutrients in seafood.
Everyone focuses on mercury. What other contaminants are you talking about? There has been concern about PCB’s [a toxic compound once used for insulation and cooling]. But in this study, the level of PCB’s is very low. It’s all toxic effects of the fish vs. all the benefits of the fish. And indeed, we find that the nutritional benefits of the fish far outweigh the toxic effects of these trace contaminates. Specifically, the advisory was calculated to prevent problems in verbal development [linked to toxic contaminates]. And these data indicate there’s an increased risk of problems in verbal development [among children whose mothers ate less than 12 ounces per week].
How did the FDA and EPA get it so wrong? That’s not really something that is part of this manuscript. I think it is best said that these data indicate that the toxic effects of mercury may have been overestimated in relationship to the nutritional benefits of seafood.
Will the FDA and EPA change their guidelines? We as scientists at the NIH aren’t trying to get them to do anything. We simply do the study, and they assess it carefully and will or will not change the advisory as they so choose. We’ve assessed the advisory, and we’ve concluded that the advisory causes the harm it intended to prevent.
What about taking omega-3 supplements instead of eating an actual fish? This study looks only at seafood. Now there is separate data from other studies that have fairly consistently and uniformly showed benefits when pregnant women take supplements. And in fact, Joshua Cohen at Harvard has recently published a very careful analysis of the benefits of omega-3 fatty acids in pregnant women. It’s very consistent.
Is the actual fish better than any supplements? It’s likely to be better.
Do supplements have lower levels of toxins than fish? In most manufactured supplements, levels of contaminants are very difficult to detect. If women choose not to eat fish, the supplements are a good alternative.
Should non-fish-eaters consider taking other supplements, or just omega-3 supplements? It’s best to just stick with the omega-3 fish oils, which we believe are a major source of the benefit.
This study had no industry sponsorship, right? To be absolutely clear, I’m a commander in the United States Public Health Service. There is absolutely no support from the fish industry or other significantly affected organizations, either from the NIH or from the University of Bristol, where the study was conducted.
The women in the study were British. Would the results be any different if the women were American? In comparison to the prior studies on fish intake and outcomes in children, done in the Seychelles Islands [in the Indian Ocean] and Faroe Islands [between the Norwegian Sea and the North Atlantic Ocean], I would say that the [British] study is much more representative of a Western population. This study included nearly eight times as many women and children as did either of those two studies, and it included women representative of the Western population.
Are there any other factors about the way the study was conducted that could affect your results? [In] these large studies, there’s always a question about the effect of dropout—those women who didn’t come back for testing. This study is unique in that regardless of whether they dropped out or not, all the children who were in the British school system had standardized tests at age 7. So we could test the effects of low seafood consumption in pregnancy on these standardized academic test scores. When we examined that, there was a trend toward lower test scores when mothers ate less fish, both among those who continued in the cohort [study group] and in those who dropped out of the cohort, but the effect in the dropout group was even bigger. This indicates that we have probably underestimated the impact of low fish consumption.
You’re lead clinical investigator for the National Institute on Alcohol Abuse and Alcoholism. How did the NIAAA get interested in omega-3s and pregnant women? The reason we’re interested in this issue at NIAAA is that in the adult brain, alcohol can deplete these omega-3 fatty acids in the brain by half. So for 15 years, I’ve been examining the question as to whether or not low levels of omega-3 fatty acids increase the risk of depression and increase the risk of violence in adults. And last December, the American Psychiatric Association issued treatment guidelines that depressed patients should take omega-3 fatty acids to prevent depression.
In the United States, doesn’t it seem as though mercury is always under attack—in vaccines, and in fish? We have now eight large epidemiological studies that definitively find there is no association between vaccines and increased risk of autism. Yet the perception persists. And in that case, it impairs children from getting vaccinated. So it is most prudent to carefully assess both the benefits and the risks.
Did your wife eat fish when she was pregnant? It’s irrelevant. [But] yes, she did.
Are you happy she did? Oh, yeah.
