EPA and DHA protect from PCBs


Risk factors for stroke (high blood pressure, high levels of cholesterol, atherosclerosis, and diabetes) have been associated with dietary intake of contaminants, including synthetic compounds such as polychlorinated biphenyls (PCBs). PCBs were marketed for nearly 50 years (from 1929 until the end of the 1970s, when they were banned in most parts of the world because of environmental concerns), being used in electrical equipment, surface coatings, inks, adhesives, flame-retardants, and paints. Once released into the environment, they accumulate and magnify in the food chain, degrade slowly, and are cycled and transported within the ecosystem. Nowadays, about 10% of the PCBs produced still remains in the environment.

Humans can absorb PCBs by eating contaminated food (particularly from animal origin), and, to a lesser extent by breathing contaminated air or through the skin (in certain jobs, via contact with equipment or materials made before their ban); but diet accounts for more than 95% of the total human exposure, and the highest exposure occurs via the consumption of contaminated fish. The highest concentrations of PCBs in the human body are found in the liver, fatty tissue, brain, and skin, but they are also present in the blood. PCBs can remain in the body’s adipose tissue from years to several decades, and mothers exposed may transmit them to their child (umbilical cord blood, placenta, and breast milk).

It is worthy of note that, while dietary PCBs exposure is associated with an increased risk of stroke, dietary supplementation with EPA and DHA has a protective effect in this respect.