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Can Healthy Omega 3 Fatty Acids Give You Mercury Poisoning?
Dr. Mark Hyman
En Espagnol: Puede Omega Sana 3 Ácidos Grasos Darle Envenenamiento de Mercurio?

Ninety-nine percent of Americans are deficient in omega-3 fatty acids-which are often found in fish oil-but unless your careful getting this important nutrient could poison you!

Research suggests that the omega-3s in certain fish may cure or treat most chronic illnesses, including depression(i),(ii), heart disease, Alzheimer's disease(iii), cancer, dementia, autism, ADHD(iv), inflammation, and autoimmune diseases. In fact, about 60 percent of your brain is, or should be, made of fish oil.

Unfortunately, getting the omega-3s you need can be dangerous. For example, a recent laboratory study of tuna sushi from a selection of New York City restaurants found levels of mercury so high that they exceeded the safe limits set by the Environmental Protection Agency (EPA) and would allow the Food and Drug Administration to take legal action to remove the fish from the market.(v)

You've likely heard about problems with mercury in fish. We've had plenty of media coverage on the issue. However, many are still confused about what's safe and what isn't. Should we eat fish or shouldn't we? Today, I'm going clear up the confusion.

Government Opinion Does Not Reflect the Real Danger

Government experts say that if you are a pregnant or breast-feeding woman or a child, you shouldn't eat any fish. The rest of us fish-eaters, well, we can have sushi once every three weeks. I guess the government thinks it's fine to poison men and older women.

This doesn't make any sense. If something is a proven toxin - and mercury is the second most common toxin known to humans - then why would we want to eat ANY of it?

Of course, there are times when I just can't resist a piece of fresh-off-the-boat, line-caught, deep red, thinly sliced, bluefin tuna that melts in my mouth. However, I have to be very careful about my intake. I suffered from mercury poisoning from growing up on tuna fish, eating too much fish while I lived in China, and breathing the dark black coal-soaked winter air of Beijing for too long.
Chronic mercury toxicity, like I had, is one of the most common things I see and treat in my medical practice. It is also something I learned nothing about in medical school. Yet day after day, I find toxic levels in the blood and bodies of patients with depression, heart disease, dementia and memory loss, cancer, autism, ADHD, autoimmune diseases, chronic fatigue and fibromyalgia, neurological problems, insomnia, digestive problems, and more.

In fact, I think screening for mercury should be standard in our toxic world. Everyone should have their mercury level checked. If you have been exposed to mercury, there are ways to get it out of your body using special foods, supplements, saunas, and chelation therapy. (See my blog on mercury detoxification for more information.)

Reducing your total toxic burden and getting rid of mercury while learning how to boost and optimize your detoxification system is a large part of healing from many chronic illnesses. Once you get the mercury out, your depression lifts, your memory returns, your energy surges, your digestion normalizes, and your joints no longer hurt.

You can limit your mercury exposure by getting your omega-3s from safe sources. I'll tell you how to do that in a moment, but first I'd like to explain more about mercury.

A Frighteningly Common Toxic Substance

Mercury is emitted from coal-burning industrial facilities at the rate of 2,900 tons (or over 6 million pounds) per year. The chemical is toxic at greater than 1 part per million (ppm), and the EPA has declared the “safe” level of mercury exposure to be less than 0.1 micrograms/kilogram of body weight/day. What this means is that we are in big trouble.

That mercury-laden pollution floats through the air from China and our own coal-burning plants and lands in the oceans, rivers, and soil of our planet. It occurs in larger concentrations as you move up the food chain - especially in fish.

In my medical journal, I reported on a conference at Tulane University on the effects of mercury on human health. You can download the report for free if you want to read more.
And a new 2006 report from the National Academy of Sciences Institute of Medicine called “Seafood Choices: Balancing Benefits and Risks” highlights new research that links mercury not only to neurological diseases, but also to heart disease and cancers.

What are most frightening are autopsy studies on mercury-exposed people. Adult brains show damage in only a few areas - the ones responsible for dementia and depression. But if exposure to mercury occurs in the womb or early in life, it is deposited in the entire brain and completely disrupts normal brain development. (viii)

Clearly, you should avoid mercury! But if you want all the health benefits of omega-3s, what should you do? There's good news …

Get Your Omega-3 Fats without the Mercury

1. Eat only small fish that fit in your pan. These include sardines, herring, small wild salmon, and some organic farm-raised salmon (although they are not as high in omega-3 fats).

2. Stay away from tuna, swordfish, shark, tilefish, and sea bass, as well as nearly all river fish.

3. Take a fish oil supplement every day. But buy ONLY from companies that document distilled or purified fish oil that's 100 percent free of industrial pollutants, especially mercury. Everyone should take 1,000 to 2,000 mg of fish oil a day.

4. Vegetarians can get the same benefits. Eat plant sources of omega-3 fats such as walnuts, and ground flax seeds, and purslane (a green vegetable). Plus, you should supplement with algae-derived DHA (one of the most important omega-3 fats needed for brain function). Take 100 to 200 mg of DHA twice a day.

The following are the most common tests for mercury and detect ONLY recent exposure over the last few months. But even if they are normal, you can't be sure you are home free.

1. Hair analysis. This tests only methylmercury levels from fish consumption. Ideal levels are lower than 1 ppm.

2. Urine test after a provocation or chelation challenge with DMSA or DMPS, followed by a six-hour urine collection. This is the ONLY way to know if you have accumulated a lot of mercury in your body over a lifetime. Ideal levels are less then 5-micrograms/gram creatinine. Use Doctor's Data Laboratory or Genova ( for testing.

3. Urinary porphyrin testing is a noninvasive way to tell if the mercury is poisoning your cells

Take a good look at your life, your symptoms, and your diet. You might need a (fish) oil change. And remember, you can have your fish and eat it too! In fact, it's an essential step toward lifelong vibrant health.

(i) Parker G., Gibson N.A., Brotchie H., et al. (2006). Omega-3 fatty acids and mood disorders. American Journal of Psychiatry. 163(6): 969–78. Review. Erratum in: American Journal of Psychiatry. 163(10): 1842.
(ii) Freeman M.P. (2006). Omega-3 fatty acids and perinatal depression: A review of the literature and recommendations for future research. Prostaglandins Leukot Essent Fatty Acids. 75(4-5): 291–7.
(iii) Freund-Levi Y., Basun H., Cederholm T., et al. (2007). Omega-3 supplementation in mild to moderate Alzheimer's disease: Effects on neuropsychiatric symptoms. International Journal of Geriatric Psychiatry. 23(2): 161–169.
(iv) Richardson A.J. (2004). Long-chain polyunsaturated fatty acids in childhood developmental and psychiatric disorders. Lipids. 39(12): 1215–22. Review.
(vi) Choi, B.H. (1989.) The effects of methylmercury on the developing brain. Progress in Neurobiology. 32(6): 447–70. Review.