Q: Should I take evening primrose oil daily? I was told years ago to take it to regain my health and now take it periodically through the month.
– Paula from New York

A: Both evening primrose oil and borage oil are sources of a type of fat called gamma linolenic acid (GLA). This fat is manufactured by our bodies and is useful in the manufacture of hormone-like compounds called prostaglandins, which regulate blood clotting, cholesterol synthesis, and inflammation. There have been numerous studies on GLA on its effectiveness for breast pain and eczema, premenstrual syndrome, psoriasis, high cholesterol levels, rheumatoid arthritis, asthma, and nerve damage. However, there are few well-designed studies that show any definite benefits from taking GLA or its oils, and none that show its usefulness long-term. On the other hand, there is no evidence these oils are toxic, although some borage oil capsules have been found to contain liver toxins. The bottom line? It’s an expensive supplement with questionable benefits, but also appears to at least have few side effects. -Elizabeth Somer