Just a few weeks ago, I told you about new research on the benefits of fish oil. In two new studies, scientists found even more evidence that the omega-3 fatty acids found in fish oil can significantly improve cardiovascular health and cut your risk of heart attack in half.
In that e-Alert (“Fish in fashion” 4/10/02), I suggested that you can increase your consumption of omega-3 fatty acids by taking fish oil supplements, or by increasing your fish intake. Dark meat fish like mackerel, salmon, sardines, bluefish, and swordfish are the most concentrated sources, with an average of 1.51 grams of omega-3s per serving. Most other fish, including canned tuna, provide about .45 grams per serving, while shrimp, lobster and scallops contain about .32 grams per serving.
But along with all of those good omega-3s, some of those fish can also contain the harmful substance, mercury. So when we sent the original e-Alert, Dr. Rick Cohan, an HSI Panelist, responded with this note: “We need to caution our members that swordfish in some areas is a particularly bad choice to obtain omega -3’s due to high mercury levels that have been recorded in samples. Even tuna has relatively high levels and only the ‘lite’ water-packed variety is recommended to be consumed in limited quantities especially during pregnancy.”
The risks of consuming too much mercury – which include a possible exposure to carcinogens and neurological damage to children of women who consume mercury during pregnancy – certainly cancel out the benefits of the omega-3s. The danger is especially high for pregnant women and nursing mothers, who can pass mercury on to their children and cause birth defects and growth problems. So I thought it was important to revisit the list of sources of omega-3s – and show you how you can protect yourself from mercury overload while still protecting your heart.
What not to eat
The mercury problem is not new. A few years ago, an advocacy group called the Environmental Working Group (EWG) issued an unsettling statement, saying, “Fish from more than 1,660 U.S. waterways are so contaminated with mercury that they should not be eaten or eaten only in limited amounts.” Not very encouraging news. Then earlier this year, the FDA got into the act, releasing a list of fish that contain unsafe levels of mercury. Not surprisingly, the EWG list of fish to avoid is more than three times as long as the FDA list. While the EWG listed 13 seafoods with high mercury content (swordfish, tuna, king mackerel, halibut, sea bass, tilefish, pike, walleye, largemouth bass, white croaker, marlin, shark, and Gulf coast oysters), the FDA only acknowledged four dangerous items (swordfish, tuna, king mackerel, and shark). I don’t know about you, but I’d rather err on the side of caution and go with the EWG list – especially considering the FDA’s track record.
If you live in the U.S., you can go to the EWG web site to find information about what fish are best to avoid in your area. You can access their “Fish advisories of mercury by state” at this address: www.ewg.org/reports/BrainFood/advisory/.
Now for some good news
Yes, there is some good news. As I mentioned in that earlier e-Alert, fish oil supplements are readily available at health food stores, and as little as one gram per day can reap very positive long term benefits for cardiovascular health.
But remember, fish oil benefits more than just your heart. Last year, researchers at the University of Guelph in Canada reported that DHA (docosahexaenoic acid) and other omega-3 fatty acids may help ward off Alzheimer’s disease and other forms of dementia. The research team discovered that Alzheimer’s patients and elderly patients with various types of dementia all had lower levels of DHA than subjects with normal cognitive functioning. Julie Conquer, director of Guelph’s Human Nutraceutical Research Unit said, “Low DHA levels are already affiliated with several disorders. Given that our research indicates that decreased levels of DHA also appear to accompany cognitive impairment with aging, we think this is a sign we should all be eating more fish.”
Good advice. Most of us could probably use a daily omega-3 supplement or a nice fish for dinner. Just be sure that the fish you’re eating isn’t on the mercury list. It would be a shame if your healthy meal did more harm than good.
To Your Good Health,
Jenny Thompson
Health Sciences Institute
4/10/02 EA http://www.hsionline.com/ea2002/ea_020410.shtml
Environmental Working Group, ewg.org
Dr. Joseph Mercola, mercola.com
Press release, University of Guelph, January 2, 2001
NAS report on Toxicological Effects of Mercury, nap.edu/catalog/9899
Copyright 1997-2002 by Institute of Health Sciences, L.L.C.
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