Reply #6: Really!

[Richard D]

That's way too much tuna. I've eliminated (well just about) tuna from my diet because of mercury risk. It's not recommended to eat it more than once a week, and I'd personally say not at all for pregnant women.

Here's the FDA advisory on fish (not copyrighted):

The Mercury Content of Fish
Although fish is an excellent source of high quality protein, healthy Omega-3 fatty acids, and several vitamins and minerals, there are several species of fish which contain high mercury levels and should therefore be avoided. This is especially true regarding infants, young children, and pregnant women, since mercury can cause numerous developmental problems and birth defects. Adults are less susceptible, but mercury in high enough doses can still lead to numerous health problems.

There are two general categories of fish which contain large amounts of mercury – large fish which live a long time, and fish that come from polluted lakes.

The fish which have the highest levels of mercury are shark, swordfish, tilefish, and king mackerel (not the small mackerel which come in tins). These should always be avoided by pregnant women, children, and infants, and should probably not be eaten more than once a month by anyone else.

Marlin, snapper, bass, lake trout, white perch, orange roughy, and pickerel also have high levels and should also be avoided by pregnant women, children, and infants. Others should probably limit consumption to once or twice a month.

Tuna, halibut, and grouper have moderate amounts of mercury. Fresh tuna has higher levels than canned tuna. These fish can probably be eaten safely once a week or less by pregnant women and children, and everyone else can probably consume 3 or fewer servings a week safely. Infants and children younger than 4 should avoid fish from this category.

Salmon, canned light tuna, canned sardines, canned Atlantic mackerel, cod, haddock, flounder, pollock, whitefish, herring, ocean perch, and smelt have lower levels of mercury. Pregnant women and children can probably eat 2-3 servings a week safely, and everyone else can probably safely consume 3-6 servings a week. Remember, however, that if you eat from fish that have moderate or high amounts of mercury, you should cut back on those fish with lower amounts. Infants and children younger than 4 should probably avoid fish altogether, although eating fish with the low amounts of mercury once or twice a week is probably fine.

The above list of fish is by no means comprehensive – there are several types of fish which haven’t been tested yet, and other less commonly eaten species which I didn’t mention. At the end of the article I included a list of useful links which provide additional information on the mercury levels in different fish.

One last point I want to address is for all of you who go fishing. Unfortunately, many of the lakes in the United States are polluted with high concentrations of mercury. Therefore, it is wise to check with the local park officials before going fishing to see if the fish you caught are safe for consumption.