In what percentage, at most, one should expect to lower his triglycerides with a low-fat diet? And in what percentage with fibrates? Many thanks.

Diet intervention for high triglycerides (we are not talking cholesterol here) includes a restriction of total fat and saturated fat, simple sugars, and alcohol and an increase in fibers (particularly the soluble types). In addition, medications and infections can increase triglycerides and should be considered in the mix of things. Weight control and exercise also play a role.

Okay, that said, a recently reported study (see link below) suggested that good diet adherence could produce a 15% reduction in triglycerides at 3 months (n=48) and 49% reduction at 6 months in patients on protease inhibitor-based regimens. On non PI regimens diet adherence resulted in a 7% decrease in 3 months and 8% by 6 months.

Abstract of Diet Intervention Study

Fibrates are noted to decrease triglyceride levels at or above the 50% level. In one study of fibrate management with HAART suggested a slightly better than 40% reduction in triglycerides (see link below).

Fibrate Therapy for High Triglycerides

Hope that helps to answer your question for now!