How Safe is Fish?

Previous blogs have discussed the evidence that omega-3 polyunsaturated fatty acids may reduce the risk of heart disease and AMD.

• Lutein/zeaxanthin and Omega-3 poly-unsaturated fatty acids and AMD
• Dietary Fat and AMD
  
• The US Department of Agriculture (USDA) - Nutrient Database for Standard Reference
  

The Age-Related Eye Disease Study 2 (AREDS 2) is testing, among other things, whether supplementation with one gram of docosahexaenoic acid (DHA), one of the omega-3 fatty acids, per day reduces the progression of AMD. Recently there have been warnings that fish may be contaminated with mercury, dioxins, and polychlorinated biphenyls (PCBs). People with AMD, or at risk for AMD, may wonder if the benefit of eating fish outweighs the risk.

A recent article in JAMA evaluated all the articles that dealt with the benefit of eating fish along with the articles that dealt with its contamination. The article’s conclusion was that the benefit, (reducing the risk of coronary artery disease), outweighs the risks. They recommended that women of child-bearing age should also eat fish but avoid the species that have the highest concentrations of mercury.

In general, the highest mercury concentrations are found in long-living predator fish such as swordfish and shark and lower levels are found in shorter-living species such as shellfish and salmon. Oily fish with low levels of mercury may the best such as: sardines, herring, salmon, mussels, and oysters. The paper recommended though, that one should eat a variety of seafood.

We should remember that it hasn’t yet been proven that the intake of omega-3 polyunsaturated fatty acids reduces the risk of AMD. We also don’t know how much omega-3 is necessary although we believe that it’s a modest amount. Therefore, if you’re not too keen on seafood, eating it twice a week is probably plenty.

Reference:

Mozaffarian D, Rimm EB. Fish intake, contaminants, and human health: evaluating the risks and the benefits. JAMA. 2006 Oct 18;296(15):1885-99.