Selenium is an element that rarely occurs in nature but can be found in certain foods and taken as a supplement. Selenium that is in the body makes enzymes that perform important functions to maintain the body’s health. It also protects the body from the harmful effects of mercury exposure by bonding with the mercury and neutralizing its effects. Since a high intake of mercury can both interfere with the metabolic activities of selenium and cause mercury toxicity, it is important to make sure that you are getting adequate selenium in your diet to produce the enzymes that perform important health functions.
Ocean fish are one of the richest sources of dietary selenium. They can also be a high source of mercury. When mercury outnumbers selenium, the selenium cannot perform its necessary function because it bonds to the mercury. While mercury in ocean fish can be harmful, the negative effects can also be offset if the fish is rich in selenium. In cases where selenium is higher than the mercury, the food is quite beneficial.
Recent studies have shown that every animal species intake selenium which as a guard against mercury toxicity, and this selenium intake is far more important that previously admitted. Current mercury intake guidelines were based on the results of a study of food intake of the peoples of the Seychelles and Faroe Islands which did not consider selenium intake. The people of the Faroe Islands ate large quantities of Pilot Whale meat, which is much higher in mercury than selenium. The result was a negative effect on the unborn children of pregnant women. The Seychelles study found no effects on the children who were born to mothers who ate fish. They typically ate fish in amounts of up to 20 times of that of the US consumer.
Since selenium is a highly important diet supplement, it is best that the consumer gets this from natural sources of ocean fish that have selenium levels that exceed mercury levels such as chunk light and albacore tuna. A recent study published in the Lancet, England's most prestigious medical journal found that pregnant women who eat less than ? pound of seafood per week put their babies at risk. Due to mercury fears, many people and pregnant women stop eating fish altogether. The benefits of fish intake exceed the negatives, and as long as your fish has selenium levels that exceed mercury levels, it is a healthy eating choice.