In Terms of Environmental Toxins
Most major waterways in the world are contaminated with mercury, heavy metals, and chemicals like dioxins, PCBs, and other agricultural chemicals that wind up in the environment. This is why, as a general rule, I no longer recommend getting your omega-3 requirements from fish. However, I do make two exceptions.
One is authentic, wild-caught Alaskan sockeye salmon; the nutritional benefits of which I believe still outweigh any potential contamination. The risk of sockeye accumulating high amounts of mercury and other toxins is reduced because of its short life cycle, which is only about three years. Additionally, bioaccumulation of toxins is also reduced by the fact that it doesn’t feed on other, already contaminated, fish. Whenever I consume fish, I always seek to consume it with a handful of chlorella tablets.
The chlorella is a potent mercury binder and if taken with the fish will help bind the mercury before you are able to absorb it, so it can be safely excreted in your stool.
The second exception is smaller fish with short lifecycles, which also tend to be better alternatives in terms of fat content, so it’s a win-win situation — lower contamination risk and higher nutritional value. A general guideline is that the closer to the bottom of the food chain the fish is, the less contamination it will have accumulated. This includes:
If you insist on eating typical, store-bought fish and want to know more about the extent of your mercury exposure, I urge you to check out the online mercury calculator4 at GotMercury.org to get an idea of the risks. Additionally, as mentioned above, you may want to consider taking a natural mercury chelators with any fish dinner. This includes zeolite (green clay), chlorella, and fermented vegetables.
Larger fish, which tend to live longer and have the highest contamination levels and should be avoided include (please note this is not an exhaustive listing):
Do Detoxifying Nutrients in Fish Cancel Out Harm from Mercury Contamination?
While some believe that methylmercury in seafood is counteracted by other nutrients in the fish, such as selenium, which help your body eliminate the toxins, recent research has shown that this hypothesis is likely false. A French research team sought to determine whether mercury from fish is less harmful than other dietary mercury,5 and whether beneficial nutriments from fish might counterbalance the deleterious effects of fish-associated mercury. Mice were one of these three diets:
- Fish-based methylmercury diet: A diet that included fishmeal produced from fish containing five micrograms of methylmercury contamination per gram
- Added methylmercury diet: A special diet higher in DHA and EPA, with added methylmercury chloride (considered more toxic than fish-associated methylmercury) also totaling five mcg/g
- Control diet without mercury
Apart from mercury and selenium content, the three diets were comparable. Interestingly, only the fish group suffered significant behavioral abnormalities at the end of 58 days! The authors concluded:
The two mercury-containing diets are differing by the fact that mercury was brought by the addition of either pure methylmercury chloride or by mercurial species associated to fish. Therefore, any differential effects observed between MeHg-containing and fish-containing diets should be attributed to different chemical species of mercury present in one diet and absent from the other and vice-versa along with the possible intervening role of fish PUFA and selenium.
If the beneficial role of fish nutriments such as PUFA and selenium was to counteract MeHg effects, the pattern of effects displayed after exposure to the fish-containing diet should appear less severe than that observed with the MeHg-containing diet. But in the present study, the mice fed the fish-containing diet displayed worse behavioral performances than those fed the control and the MeHg-containing diets, although the brain structures of both mercury-contaminated groups of mice contained comparable levels of mercury and even less in the striatum of those fed the fish diet.
Therefore, the different chemical species of mercury within fish flesh are likely to explain the deficit in cognitive performance in the Y maze and the decreased locomotory activity in the open-field maze.
By Dr. Joseph Mercola (articles.mercola.com)
Learn more about chlorella benefits and side effects