Myths about Seafood and Fish – Debunked by Dietitians

Written By: Gloria Tsang, RD

Title: Founding Registered Dietitian

Alumni: University of British Columbia

Last Updated on:

Top Myths about Seafood – debunked by Dietitians

Avoid seafood to lower blood cholesterol

This is definitely the number one myth about seafood. Seafood in general contains a high level of cholesterol; however it is low in saturated fats. Cholesterol found in seafood and other meats has little effect on blood cholesterol in most people. Saturated fats and trans fatty acids are the most important factors that raise blood cholesterol, not dietary cholesterol! Saturated fats are usually found in meat products and packaged foods. Trans fats, on the other hand, are also found in packaged snack foods, deep-fried foods or firm margarine containing hydrogenated oil.

Limit fish intake because it contains mercury

Everywhere I go, people often ask me which fish to eat and which fish to avoid. Obviously, they have read the FDA’s 2004 seafood advisory. However please note that this advisory was directed to warn pregnant and nursing women as well as young children only who are most prone to mercury toxicity; it was not supposed to be for the general public. There is really no need to be fear of fish. In the Harvard Center for Risk Analysis study published in November 2005, it was estimated that an additional 8000 deaths from heart attacks and stroke would be resulted per year if all Americans cut their fish intake by 1/6 of the current amount. Don’t stay away from all fish if you are still leery of mercury, only stay away from high-mercury fish (shark, swordfish, king mackerel, and tilefish)

The fattier the fish, the better they are

It is true that fatty fish such as mackerel, salmon, sardines and herring contain high amounts of the heart-protecting omega 3 fatty acids; most fish eaters I have spoken to routinely look for fattier fillets when choosing fish. However it is important to note that although some fish in general contain more fat and therefore more omega 3 fatty acids, some fattier fish such as farmed salmon contain higher levels of PCBs – harmful chemicals which was banned in 1977. Therefore, instead of choosing a fattier fillet, look for wild fish which still offers a good source of omega 3 fatty acids. Note: Canned salmon are usually made with wild salmon.

Fish oil supplements are good for health

The American Heart Association recommends people with documented heart disease take fish oil supplements with their doctor’s consent. However, many people including children take them unnecessarily. In addition, not all fish oil supplements are the same. Cod liver oil, for instance, contains high levels of Vitamin A and D. According to UC Berkeley, as little as 6,000 IU of vitamin A daily can interfere with bone growth and promote fractures in children. In addition, they also warned that since the liver acts as a filter, cod liver oil is more likely to be contaminated with toxins such as PCBs than other fish-oil supplements. If you are concerned about your cod liver oil, discuss it with your doctor.

Bottom Line

Fish and seafood are an excellent substitute for meat products. They provide a rich source of protein and omega 3 fatty acids; and they are also low in saturated fats. In 2002, the American Heart Association recommended eating at least 2 servings of fish a week, particularly fatty fish. With increasing public concerns over farmed fish, choose wild fish.


debunked, diet myths, seafood


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