Dosing omega-3 fatty acids
Dr. Martinez’ and Dr. Marangell’s review on use of omega-3 fatty acids (Current Psychiatry, January 2004) was excellent.
Please clarify how these agents have been dosed. More specifically, when a study specifies a milligram dose amount of eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA), does that include only the “active” ingredient or the total milligrams of the capsule? In a commercial preparation, for example, a 2-gram fish oil capsule might contain 360 mg of EPA.
Robert L. Murdock, MD
Dr. Martinez responds
The studies that Dr. Lauren Marangell and I reviewed reported the total daily amount of either EPA or DHA (or both, if combination treatment was being studied) that a study participant would receive.
For example, in studies investigating 2 grams/d of EPA versus placebo, the treatment group received 2 grams/d total of EPA, with no DHA in the study compound. If the study drug contained 200 mg of EPA per capsule, patents would take 10 capsules per day.
Also, only studies looking at combination EPA/DHA treatment used study medications that contained both fatty acids. Again, these studies specified the total daily dosages of both the EPA and DHA portions.
James M. Martinez MD
Department of psychiatry
Baylor College of Medicine, Houston, TX