Letter: Fish oil debate
I appreciate Scott Tesoro’s comments in his letter to the editor in the March 25 PI, in response to my recent health tip column about plant versus animal sources of omega-3. But I feel some corrections are in order.
One of the nutritional researchers I respect the most is Michael Greger, M.D., who with his staff analyzes all the English-language scientific papers that come out on nutrition every year (there are thousands of them). He has a wonderful website, nutritionfacts.org, and recently came out with an excellent, evidence-based, well-referenced book called “How Not to Die” (from heart disease, prostate cancer, breast cancer, etc.).
On page 20 of his book, he talks about a recent metaanalysis in the Journal of the American Medical Association that looked at the best randomized clinical trials evaluating consumption of fish and/or fish oil supplements in relation to life span, cardiac death, sudden death, heart attack and stroke. No protective benefit was found. The researchers also found no benefit in people trying to prevent a second heart attack. The director of lipids and metabolism at Mount Sinai’s cardiovascular institute said that “given this and other negative metaanalyses, our job as doctors should be to stop highly marketed fish oil supplementation to all our patients.”
I totally agree with Scott that indeed, we do need omega 3 for other aspects of health, and the World Health Organization and the European Food Safety Authority say you should get at least 0.5 percent of your daily calories from the short-chain omega 3 ALA, which you can easily get by eating a tablespoon of ground flaxseed a day (or chia seed or walnuts), which your body then elongates into the long-chain omega-3s EPA and DHA.
As Dr. Greger points out on pages 410 and 411 of his book, the question is whether the body can convert enough for optimal brain health. So to be on the safe side, he recommends 250 mg. a day of algae-derived omega 3, which is totally free of pollutants. This is somewhat more costly than fish oil capsules, but I have found some that is quite cost-effective at Vitamin Cottage.
The problem with fish is that unfortunately, these days, our oceans and many of our rivers have become polluted by PCBs, heavy metals and other industrial contaminants, which may help explain the studies that found adverse effects of fish consumption on cognitive function in adults and children. In one study, even people who ate tuna or snapper just three-four times a month had elevated mercury levels and some cognitive decline. According to Dr. Greger, “even purified (distilled) fish oil has been found to be contaminated with considerable amounts of PCBs and other pollutants, so much so that taken as directed, salmon, herring and tuna oils would exceed the tolerable daily intake of toxicity.”
Greg Feinsinger, M.D.
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