It is recommended that you choose frozen, unless you know for certain that it is high-quality fresh fish. Most fish are flash frozen on the boat immediately after being caught. After thawing, it should still be of good quality.
On the other hand, "fresh" fish that was never frozen may have spent a few days sitting in a smelly ship's hold by the time you buy it. And some "fresh" fish may have been frozen and then thawed out behind the supermarket counter.
Many foods, from fruits and vegetables to dairy products and meat, can be tainted with chemicals and other unsavory items. Fish, too, can contain mercury and PCBs (a synthetic organic chemical compound of chlorine attached to biphenyl, which is a molecule composed of two benzene rings). But experts say the benefits are much more likely to outweigh the risks.
The benefits of regularly eating healthy fish keep piling up. It lowers blood pressure, cuts the risk of irregular heartbeats, and drops the risk of fatal heart disease by 36%.
It also seems to lower the risk of stroke and some cancers, improve your mood, and help with other conditions, such as rheumatoid arthritis.
Omega-3 fatty acids help our cells work. Because our bodies don't make enough of them, we have to get them in food. Fish that are high in omega-3 fatty acids include salmon, herring, mackerel, and sardines. Fish is a good source of protein and, unlike fatty meat products, it’s not high in saturated fat. Omega-3 fatty acids benefit the heart of healthy people, and those at high risk of — or who have — cardiovascular disease. Research has shown that omega-3 fatty acids decrease risk of arrhythmias (abnormal heartbeats), which can lead to sudden death. Omega-3 fatty acids also decrease triglyceride levels, slow growth rate of atherosclerotic plaque, and lower blood pressure (slightly).
Oysters have long been thought to have aphrodisiac properties, but very few studies have been conducted on the matter. One thing that brings credibility to the oyster myth is the fact that these slippery critters are full of zinc. Zinc controls progesterone levels, which have a positive effect on the libido. In theory, people who have very low levels of certain nutrients, like selenium, could feel friskier after eating more oysters. But that condition is rare.
The American Heart Association recommends at least two servings of fish per week, especially fatty fish high in omega-3 fatty acids. What's a serving? About 3.5 ounces -- a little bigger than the palm of a woman's hand.
Sushi lovers need not fret about the raw fish they consume, food scientists say, as long as the sushi has been prepared properly according to regulations. People preparing sushi themselves need to take extra care with both the raw fish and the rice. Raw fish poses several potential hazards for consumers besides parasites. Bacteria can develop in non-fresh fish and produce enzymes called histamines that may result in Scombroid poisoning. Certain tropical-water fish may also have a natural toxin called ciguatera which causes gastrointestinal and neurological symptoms. But the only sure way to avoid parasites and bacteria is to cook your fish. As for trying to make sushi with raw meat other than fish, best perish the thought.
Shellfish -- like crab, lobster, shrimp, scallops, and clams -- is quite low in fat. Compared to beef and chicken, shellfish tends to have higher levels of healthy fats and lower levels of unhealthy fats. Shellfish is a great source of protein, too.
Fish really might be brain food. Studies have found that eating baked or broiled fish once a week -- over the long term -- seems to help people keep their short-term memory sharp.
Eating fish also appears to lower your risk of Alzheimer's disease and mental decline.
It depends on the fish. Some fish, such as salmon, mackerel, herring, and trout, can be high in healthy omega-3s whether they're farmed or wild.
But a lot of farmed fish, especially tilapia, are fed a corn-based diet. As a result, they tend to have much lower levels of omega-3s.
Fresh seafood should have a mild smell or none at all. If it smells sour or fishy, it's past its prime. If it stinks up your kitchen every time you open the refrigerator door, throw it out.
Good fish should never be mushy either. It should be moist and springy when you touch it.
Stick with fish, not capsules. Most of the encouraging studies have looked at people eating fish, not taking a supplement. Extracted omega-3 fatty acids may not have the full benefits of what's naturally in fish.
Some recent studies of people at higher risk of heart disease did not find that omega-3 supplements helped. People with heart disease should talk to their doctor to see if omega-3 supplements might be a good idea.
Fish can carry some nasty parasites. One of the most revolting is the tapeworm. It can live in the human gut for years, growing up to a couple of yards long, causing severe pain, weight loss, and anemia.
But what is the good news? Cooking your fish so the internal temperature reaches 140 degrees Fahrenheit will kill any parasites.
Pregnant women should eat fish -- up to 12 ounces of seafood per week. Fish has nutrients that are important for a baby's brain development. Studies show that pregnant women who eat fish regularly have children that go on to score higher on intelligence tests.
However, pregnant women should avoid fish high in mercury, like shark, swordfish, tilefish, and king mackerel. Instead, choose varieties that are lower in mercury, like shrimp, canned light tuna, salmon, and catfish. Women who are pregnant or breastfeeding can eat white tuna (albacore), but only 6 ounces a week, because it's higher in mercury than light tuna.
Allergies to shellfish, like shrimp and lobster, are more likely to send people to the emergency room than any other food allergy. But people can also be allergic to finned fish, like haddock and trout.
Seafood allergies may develop suddenly in adulthood. Unfortunately, they don't tend to fade and can often be very serious. If you get a seafood allergy, you're probably stuck with it.
Fish is healthiest when it's baked or broiled. Unfortunately, fish's health benefits may disappear once it's deep-fried. Eating a lot of fried foods -- especially when cooked in saturated or trans fats -- is closely linked to heart disease and stroke. In one study of older women, a single serving of fried fish a week was associated with a 48% higher risk of heart failure.
Skip the fried fish. Choose baked or broiled instead.
Overall? Fish is one of the healthiest foods