Fish oil can reduce triglyceride levels in HIV patients

Fish oil can significantly reduce triglyceride levels in HIV-positive people taking antiretroviral therapy, according to a small US study published in the November 15^th edition of Clinical Infectious Diseases. An accompanying editorial calls the study “important” and states, “fish oil therapy looks like it is as good as other possible therapies.”

However, the investigators did find that as triglyceride levels fell in patients taking fish oil, their LDL cholesterol increased.

“Hypertriglyceridaemia is the hallmark of HIV-associated dyslipidaemia”, write the investigators and although antiretroviral therapy has brought a longer, healthier life to many HIV-positive individuals, lowering lipids and reducing the risk of cardiovascular disease are becoming “a common component of the management of HIV disease.”

Omega-3 fatty acids (usually called fish oil) have been shown to lower triglyceride levels and reduce the risk of cardiovascular disease in HIV-negative individuals. However, its effectiveness and safety in HIV-positive people taking antiretroviral therapy has not been assessed. Therefore investigators in North Carolina designed an open-label, randomised controlled trial involving 52 HIV-positive patients taking antiretroviral therapy who had fasting triglyceride levels above 200mg/dl.

Patients were randomised into one of two study arms. Both arms received counselling about diet and exercise to control triglycerides. In addition to the counselling, the fish oil arm received a 16 week course of omega-3 fatty supplementation consisting of 1750mg of eicosapentaenoic acid and 1150mg of docosahexaemoic acid daily (about ten times the level found in a normal cod liver oil tablet). The daily pill burden was not specified.

Triglyceride levels were monitored at weeks four and 16, as were changes in total cholesterol, HDL and LDL cholesterol, and lipoprotein A.

After four weeks, there was a statistically significant decrease in fasting triglyceride levels in the fish oil arm (mean reduction, 25%), compared to a mean increase in triglyceride levels of 3% in the counselling only arm. This difference was statistically significant (p = 0.007) and remained so after controlling for baseline levels.

Absolute levels of triglycerides were also lower at week four in the fish oil arm (mean 306mg/dl) than the counselling only arm (mean 503mg/dl) at week four and the percentage of patients achieving a triglyceride level below 200mg/dl was 40% in the fish oil arm compared to only 10% in the counselling arm, a statistically significant difference (p = 0.04).

At week 16, the mean reduction in triglyceride levels for patients in the fish oil arm was 20% compared to a mean reduction of 6% for the counselling only arm. The difference between the two study arms was not statistically significant. There was a trend for patients taking fish oil to have lower mean triglyceride levels (304mg/dl) compared to patients who did not take the supplement (mean 503mg/dl, difference p = 0.09). Although a higher proportion of patients taking fish oil achieved a triglyceride level below 200mg/dl (32%) compared to patients who only received counselling (22%), the difference was not statistically significant.

No changes were noted in total cholesterol, HDL cholesterol or lipoprotein A throughout the study. However, the investigators did observe a significant increase in the level of LDL cholesterol in the fish oil arm (16% increase from baseline by week four and 22% increase by week 16), but not in the counselling only arm.

One patient withdrew from the fish oil arm because of the taste of fish oil and one because of nausea and vomiting.

“Among HIV-infected patients with elevated triglyceride levels who were receiving antiretroviral therapy, administration of omega-3 fatty acids in conjunction with a diet and exercise program…led to significant decreases from baseline in fasting triglyceride levels”, write the investigators. They add, “it is notable that fish oil supplementation was able to produce durable reductions in fasting triglyceride levels despite ongoing treatment with antiretroviral therapy.”

Regarding the increase in levels of LDL cholesterol observed in patients taking fish oil, the investigators comment “fibrates may also increase LDL cholesterol level in hypertriglyceridemic HIV-infected patients.”

The accompanying editorial comments on the “nice reductions” in triglyceride levels which fish oil treatment achieved and calls for further studies double blinded studies into the efficacy of the treatment.