Subscribe to Cancer NewslettersSubscribe Now
Fish, Omega-3 Fats and Mercury Contamination – what you need to know
James Meschino DC, MS, ROHP
You know that the omega-3 fats found in fish help to reduce heart disease, and are appear to also with reduce cancer risk, dementia, help contain inflammation and improve skin smoothness. However the dark side of fish consumption is the risk of ingesting too much mercury.
Mercury is a mineral that exists naturally, but thousands of tons are released into the air each year through pollution and waste. Bacteria and natural processes can transform mercury into methylmercury, which is a poisonous substance.
Methylmercury accumulates in streams and oceans and thus ends up in the fish we eat. As larger fish eat smaller fish, the larger fish tend to accumulate the most mercury and that is why the oldest and largest fish, such as shark or swordfish, have the highest levels. Studies show that methylmercury levels are higher in people who regularly eat fish of virtually any kind
The effects of methylmercury toxicity include paraesthesia (a pricking, tingling or creeping sensation on the skin), depression, and blurred vision. Research also suggests prenatal and infant exposure can affect attention span, language, visual-spatial skills, memory, and coordination. The National Academy of Sciences estimates that nearly 60,000 children each year are born at risk for neurological problems due to methylmercury exposure in the womb.
Omega-3 Fats From Fish
Fish that contain more than 1,000 mg of omega-3 fats per serving (approximately 3 ounces or 100 grams) and are low in mercury include spiny dogfish, herring, sardines, pilchards, lake trout, Atlantic sturgeon, wild Pacific salmon, anchovies, sprats, bluefish, and mullet. The following is the advice provided by the US Department of Health and Human Services (and The Environmental Protection Agency) in counseling pregnant women about fish consumption. It is a guideline for the rest of as well.
- Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.
- Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury:
- Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
- Another commonly eaten fish, albacore (“white”) tuna, has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.
What’s The Game Plan
This is what I recommend that you do:
Eat two fish servings per week, choosing fish that have the highest omega-3 fat content and the lowest mercury content. Second, take a supplement each day that contains:
400 mg of fish oil
400 mg of flaxseed oil
400 mg of borage seed oil
I take 2-3 capsules per day of a supplement with these exact ingredients and doses. The fish oil is high in omega-3 fats (50% omega-3 fat) and is devoid of mercury and all other contaminants. The flaxseed oil is a rich source of an omega-3 fat (58% omega-3 fat) that the body can convert to the same omega-3 fats you get from fish. The borage seed oil contains a unique essential fat that helps to suppress inflammation, improves skin softness and blocks the formation of prostaglandins that are associated with increased cancer risk.