Are mercury levels in tuna dangerous?

By T. Venuto

According to the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA), the fish most likely to be contaminated with unsafe levels of mercury are those highest up on the food chain, including shark, king mackerel, tilefish and swordfish. These larger, longer-lived predatory fish feed on the smaller fish and retain in their bodies the contaminants that were in the small fish.

The FDA released a mercury advisory warning in 1994, which advised the public that these fish were safe as part of a balanced diet if eaten no more than once per week. In 2001, the FDA upgraded their advisory, recommending that pregnant women, nursing women or women of childbearing age who may become pregnant, avoid the high-risk fish completely because mercury can harm the nervous system of a developing unborn baby.

According to the FDA, the fish with the least mercury are salmon, trout, catfish, haddock, flounder, crab or shrimp. And what about tuna fish – that classic bodybuilding and fitness staple food?

The FDA says that certain species of large tuna, usually sold as fresh tuna, tuna steaks or sushi, can have mercury levels above the FDA’s danger level of 1 part per million. The smaller tuna species such as albacore and skipjack, have much lower levels of mercury (that’s why canned tuna is less likely to be contaminated with mercury than fresh tuna).

In a recent report on tuna and mercury published by the Center for Science in the Public Interest (CSPI), they recommend the equivalent of only 1 can of white (albacore) tuna per week or 2 cans of light tuna. However, they added that men, older children or women beyond childbearing age could probably safely consume 2 to 3 times these amounts. (This would increase their recommended limit to just under a can a day).

I know a lot of bodybuilders who eat can after can of tuna every day... some literally live on it as their prime protein source. In the 60’s and 70’s some of the bodybuilders of that era were famous (or infamous) for their Spartan "tuna and water" diets for getting ripped very quickly. Today, unfortunately, this practice appears unwise.

I used to be one of those 2-3 cans of tuna a day guys too. Even though it was bland, it was a fast and easy way to get lean protein for a bodybuilding diet. Today I eat a much wider variety of lean proteins, including salmon or trout two or three times per week, and I recommend the same to my clients.

Most health organizations still recommend including high fat fish such as salmon, herring, trout, sardines or mackerel at least twice per week in order to provide the healthy omega three essential fatty acids (EFA’s). In light of the Mercury scare, many people are turning to fish oil pills to get their EFA’s, which is not a bad idea and may have benefits beyond providing EFA’s. Personally, I prefer to eat the fish a couple times a week rather than take handfuls of pills. This gives you lean protein and omega 3’s at the same time. (It tastes good and is more economical, besides). Every day I also take an essential oil blend containing flaxseed oil, which is the richest source of omega 3 – even richer than fish.

It would be wise to pay attention to the FDA and EPA warnings and guidelines, but moderation in all things is good advice in this situation, rather than total paranoia. When I’m eating out, I’ll occasionally have swordfish, fresh tuna steak, or sushi and I don’t give any thought to whether it’s contaminated - I just enjoy it. Like you said, you would have to stop eating (and breathing!) to completely avoid exposure to every possible toxin... and the people who live in fear of disease are usually the ones who get it.