Health Benefits of Tuna
Your typical tuna salad sandwich just got more interesting. Not only is tuna packed with protein and essential vitamins, it is high in omega-3 fatty acids. Omega-3 fatty acids are a type of unsaturated fat and are essential fatty acids. Essential fatty acids cannot be synthesized by the body, so they must be obtained from the diet.
The three main types of omega-3 fatty acids are alpha-linolenic acid (ALA), docosahexaenoic acid (DHA) and eicosapenaenoic acid (EPA). Sources of ALA include canola oil, flaxseed, tofu, walnuts, and green leafy vegetables. ALA is eventually converted to DHA and EPA in the body, but the process requires many steps and enzymes to complete.
Tuna is high in DHA and EPA, which means that when you eat tuna, your body does not have to take the many steps normally needed to synthesize these essential fatty acids.
Thousands of studies over the last 3 decades have shown that the omega-3 fatty acids DHA and EPA have many heart health benefits. DHA and EPA accumulate in cell membranes and can lead to improved function of arteries, reduced blood pressure, decreased risk of abnormal heart beats and reduced formation of blood clots.
DHA and EPA can also lower triglycerides and suppress production of pro-inflammatory cytokines, which are implicated in the development of atherosclerosis.
The American Heart Association recommends eating oily fish at least two times (two servings) a week. Each serving is 3.5 ounces.
Tuna and Mercury
Children and pregnant women can safely eat up to 12 ounces (two average meals) of a variety of fish that are lower in mercury, including canned light tuna.
Since albacore (white) tuna has more mercury than canned light tuna, children and pregnant women can safely eat up to 6 ounces per week of canned albacore tuna or other fresh tuna.
Other Benefits
Tuna is also an excellent source of Vitamin B12 and selenium. Vitamin B12 is essential for the function of an enzyme that synthesizes the amino acid methionine from homocysteine. Inadequate function of this enzyme can lead to increased levels of homocysteine in the body, which may increase the risk of cardiovascular disease.
Vitamin B12 is also required for the function of an enzyme involved in producing energy from fats and proteins.
Selenium is a trace element that is required for the function of many selenium-dependent enzymes in the body called selenoproteins. Some selenoproteins also help regulate thyroid hormones and are essential for normal development, growth and metabolism.
Types of Tuna
Bluefin tuna – This type generally has more flavor than the other varieties and is the preferred variety when cooking fresh tuna. Its flesh is dark red in color and is similar in appearance to raw beef. Bluefin tuna are the largest and can grow up to 1,600 pounds! Most bluefin tuna are exported to Japan and sold for sashimi.
Yellowfin tuna – Also known as ahi tuna, yellowfin tuna is generally less expensive than bluefin and easier to find in supermarkets. Its flesh is pale- pink and it can also be canned.
Skipjack tuna – Also called bonito or aku, this variety has the strongest flavor and highest fat content. Skipjack is often canned. It is also the smallest variety, and rarely grows larger than 25 pounds.
Albacore tuna – This variety has the lightest flesh and mildest flavor. Albacore tuna is canned as white tuna.
Did You Know?
Tuna can swim up to 55 miles per hour in the ocean. To fuel their speed, the tuna eats up to ten percent of its body weight every day!
The tuna fish can weigh anywhere from 10 pounds to 600 pounds.
Many Ways to Enjoy Tuna
Canned tuna is a convenient way to eat your omega-3 fatty acids, but tuna tastes great when made from fresh! You can buy fresh filets and steaks of tuna in the fish section of your grocery store.
Fresh tuna season goes from late spring to early fall, but frozen tuna steaks are available all year. The flesh of fresh tuna can range in color from light pink to dark reddish brown, depending on the type.
Raw tuna steaks can closely resemble raw beef. The tuna steak may have an area that is darker brown. When choosing fresh tuna, avoid those with any dry or brown spots, other than the area that is naturally darker brown.
The fish should smell ocean-fresh and not extremely fishy, with no rainbow sheen. Once purchased, put the fresh tuna in the refrigerator as soon as possible. It is best to use fresh tuna the day you buy it.
If purchasing frozen tuna, thaw frozen tuna slowly in the refrigerator in a sealed zip-top back. You can also place the sealed bag in the sink or bowl of cold water. Do not use the microwave to thaw. Cooked fish can be kept three to four days in the refrigerator.
Ideally, fresh tuna should be cooked medium-rare. Sear the tuna very quickly over high heat, preferably on a grill. Make sure to not overcook the tuna; cook until the flesh changes color and is no longer translucent.
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