It has become generally known that fish is good for you. It has long been referred to as “brain food” as eating fish regularly contributes to the development and function of the brain and retina, to say nothing of the benefits of Omega-3 fatty acids that help with the health of our central nervous system. Fish oils have anti-inflammatory properties that benefit our immune system, and lower the incidents of heart disease and cancer. Fish are a good source of protein, usually between 15% and 25%, A and B vitamins, minerals, amino acids, iodine and calcium. Fish contain phosphorous, potassium and iron. Ocean fish are particularly valuable, as they reside in very cold temperatures and consume tiny oceanic phytoplankton, from which their Omega-3 fatty acids are derived. Freshwater fish do not has access to phytoplankton, thus they have negligible amounts of Omega-3s. However as all fish are low in saturated fats, whenever fish replaces meat in the diet, they lower blood cholesterol and the risk for heart disease. Some of us eat fish roe like shad roe or caviar, and it contains thiamine and riboflavin. A caution, however, as not all fish roes, are edible and if the wrong kind is consumed, like roe from the sculpin family of fish, it can make you very sick.
As mentioned last week, the key to good fish is how it has been harvested, and handled after harvest before it reaches your fishmonger’s. Oceanic fish, due to the really cold water it lives in, must be packed in ice or frozen, immediately after harvest. As these deep-water fish live in such a cold environment, their fats and cell membranes must remain fluid and operational at temperatures approaching 32 degrees. Failure to maintain an icy environment will result in these fats and oils becoming rancid, stale smelling, and the flesh to deteriorate. Just keeping your fish in the refrigerator is not cold enough to maintain fish freshness, so plan on cooking it the same day you purchase it.
Remember, every pollutant on our planet has a tendency to leach through the ground, run off the land, and find its way into our rivers and oceans. These pollutants end up in our fish as evident by the widespread contamination of certain species with polychlorinated biphenyls (PCBs), mercury, lead and other heavy metals, carbon containing pollutants, and toxins. Some species of fish contain so much mercury that the FDA recommends that children and pregnant mothers avoid swordfish, shark, tilefish and king mackerel, or limit their consumption to 12 oz or less a week. Even tuna, one of the most popular fish in the US, is best if eaten on a limited basis. Fish that don’t accumulate mercury and other poisons are small, shorter lived fish like Pacific salmon and soles, talapia, catfish, mackerel, trout and stripped bass, many of which are raised on fish farms where the water is filtered.
Next week we’ll learn more about mollusks, cephalopods and crustaceans, some of my personal favorites.