Researchers Weigh Benefits of Mercury Contaminated Fish

Auburn University Nutrition and Food Science Professor Dr. Margaret Craig-Schmidt is a nutritional biochemist specializing in the health effects of omega-3 fatty acids. Dr. Chris Newland, Auburn University Alumni Professor of psychology, is a behavioral neuroscientist who has spent most of the past decade exploring the toxic effects of methyl mercury.

Recently, they decided to join forces in a study funded by the National Institutes of Health to explore one of the most contentious issues in nutrition: balancing the nutritional benefits of saltwater fish with the potentially serious health effects associated with methyl mercury contamination.

The educated guess they’ve already formulated about mercury contamination challenges conventional notions. It could be that omega-3 fatty acids obtained from eating saltwater fish may counterbalance the adverse effects associated with mercury contamination in fish.

“It’s only preliminary, but one of the things we’re beginning to see in our research is that there may be some protection from mercury that is conferred by eating fish,” Newland said. “And we find this incredibly exciting.”

Craig-Schmidt said that pregnant women, a segment of the population of special concern to researchers, currently receive conflicting advice about fish. They are advised to eat saltwater fish because it is rich in DHA, an omega-3 fatty acid that is especially important to retinal and brain development, even as they are warned about the dangers of eating fish contaminated with mercury.

“It is important to realize that not all fish are the same. Salmon still appears to be a relatively safe source of DHA with low levels of mercury," she said. "There may also be some alternative sources of DHA that people, especially pregnant women, can eat.”

One of the alternatives Craig-Schmidt has explored is an algal source, which she says is “brewed up like some antibiotics” that are made in vats and isolated from other sources during preparation.

“It is a purified source of omega-3 fatty acids without any mercury contamination. This oil contains DHA that is very important for brain development,” she said. “It’s from the sea, and it’s the same source from which fish derive their fatty acids.”

The algal substance, which can be added to infant formula, already has been tested with pregnant and lactating women.

Craig-Schmidt also has conducted research with DHA-enriched eggs from chickens that were fed a diet rich in omega-3 fatty acids. These eggs were then fed to lactating women to influence the omega-3 content of their breast milk.

“Two eggs a day gave them three times the DHA of normal breast milk,” she said.

Getting enough dietary omega-3 is a perennial challenge for millions of Americans who are striving to reduce their risk of cardiovascular disease and mental decline that often accompany aging. But it is an even bigger challenge for pregnant and nursing mothers who want to ensure their children get adequate amounts of fatty acids during the most crucial period of their lives. Up to now, saltwater sporting fish, such as tuna and salmon, have been the only readily available sources for omega-3 fatty acids for most Americans.

Recently, the federal government began drafting a warning about saltwater fish consumption that may hurt more than help, the two researchers fear.

“One thing that concerns me is that these advisories are confusing,” Newland said. “My concern is that people may throw up their arms in despair and quit eating fish entirely. I’ve even heard people say they’ll just eat more French fries instead, which would be a terrible alternative.”

[Sources: Dr. Margaret Craig-Schmidt, Auburn University Professor of Nutrition and Food Science, (334) 844-3263; Dr. Christopher Newland, Auburn University Alumni Professor of Psychology, (334) 844-4412; Writer: Jim Langcuster, Extension Communications Specialist, News and Public Affairs, (334) 844-5686.]

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