DHA: The Good Fat

Focuses on the health benefits of docosahexanoic acid (DHA), an omega-three fatty acid. Protection against heart disease without negative side effects; Role of DHA in the brain; Food sources.

By PT Staff, published on March 01, 1999

Not all fat is created equal. While diets high in triglycerides may be badfor your health, those with omega-3 essential fatty acids are clearly good for your heart.

In a recent four-month study conducted by the U.S. Agricultural Research Service, scientists found that DHA (docosahexanoic acid), an omega-3 fatty acid, can protect against heart disease without negative side effects. Previous studies of omega-3s showed many of the same encouraging outcomes; there were also, however, some corresponding negative side effects, such as increased bleeding time or slower-than-normal blood clotting.

Volunteers in the ARS study who ate a DHA-enriched diet decreased their triglyceride levels by 26%. At the same time, their levels of HDL, the good cholesterol, rose by 9%, and concentrations of apoprotein-E (the compound that carries cholesterol from tissue back to the liver so that it can be broken down and excreted) increased by 69%.

DHA is also an essential building block of the brain, helping its billions of cells transmit electrical signals to all parts of the body. Indeed, experts say, 60% of the brain is made up of fat, 25% of which is DHA. This hardworking omega-3 fatty acid is also essential in maintaining vision by protecting the retina.

Low levels of DHA have been linked with visual disorders as well as other mental conditions, including dementia and depression. One intriguing study, published in the American Journal of Clinical Nutrition, noted that depression in North America increased signifcantly at the same time that consumption of DHA dwindled.

How to Take It: Since the body does not produce omega-3 essential fatty acids, they must be consumed, either in foods or supplements. While most commonly found in oily fish, such as mackerel, bluefish and salmon, omega-3s are also present in in flaxseed, leafy green vegetables, canola oil and nuts. Taking a DHA supplement is also a good way of getting more DHA into your system. Currently, American scientists are debating whether DHA should be added to infant formulas as is done in Europe and Japan.