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Ingredient Information

Tuna

seared slices of fresh tuna on a bed of lettuce

There are a number of different species of tuna but the most common found in the fresh fish market will be yellowfin, bluefin and albacore (or white).

The flesh of bluefin tuna turns a darker red as the tuna grows older and the flavor intensifies. Many are worried about the bluefin being overfished. These tuna mature slowly and many are caught when still young and the result has been depletion of the fisheries. Choose bluefin that is dark red with an even color to the flesh.

Yellowfin tuna is a paler color than bluefin and the flavor is milder. You might see this listed on a menu or in the market as "ahi" tuna. Yellowfin are found in the tropical waters of all oceans on the planet and are not farmed fish. Yellowfin tuna should not be confused with the fish "yellowtail," which is a species of amberjack.

Albacore has a higher fat fish and a lighter flesh. It is not often available fresh but is one of the main sources of canned tuna. The label on the can will generally say "white" or "albacore" or come combination of the two words. When choosing fresh ablacore look for an ivory appearance to the flesh.

Bonitos are members of the tuna family but are often marketed without being designated as tuna. They are more strongly flavored than other species with a medium to high fat content. The Japanese dry bonito into flakes and use them as a seasoning for many dishes.

As with all fresh fish, pick tuna that has very little aroma to it. The flesh should be firm and not spongy and the color bright and shiny. Don’t hesitate to ask about whether the fish has been frozen or fresh or how long it has been in the market itself. In smaller towns you will likely be better off with fish that has been previously frozen.

What of mercury in tuna? This is an issue and most guidelines now recommend not eating tuna more than three times each month. Because the tuna sits higher up the food chain and lives longer, the concentrations of mercury are higher than in many other fish. I generally limit myself to once a month (See my Dr. Tim Says article on mercury in fish). I will, however, admit to eating a great deal of canned tuna during medical school and residency (I actually almost never eat canned tuna for this reason, having had quite my fill of it!).

That said, tuna is quite high in Omega-3 fats and very good for you. The risk from mercury is clearly outweighed by the health benefits.

I love serving tuna at dinner parties. It cooks quickly and you can sauce it at the last minute making it look as if you have spent hours in the kitchen.

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