(16-11-07) DHA Reduces Triglycerides in Statin-Treated Patients with Persistent Hypertriglyceridemia

Recent results from the JELIS study confirmed the ability of long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFAs) to reduce cardiovascular risk even in patients taking statin medication. In that study, the addition of 1.8 g of eicosapentaenoic acid (EPA)/day to the statin treatment significantly reduced the likelihood of any major coronary event and of unstable angina by 19% and 24%, respectively, in patients with high cardiovascular risk. The question is, does docosahexaenoic acid (DHA), the other key n-3 LC-PUFA, do the same in hyperlipidemic patients? DHA is thought to be somewhat more potent than EPA in reducing cardiovascular risk factors, but in practice, the two fatty acids are usually consumed together and each may have distinct and complementary functions in protecting against cardiovascular disease.

To determine the effects of DHA in statin-treated patients, Barbara Meyer and colleagues at the University of Wollongong in Australia conducted a randomized placebo-controlled trial in 45 hyperlipidemic patients who had persistent high triglycerides (>1.6 mmol/L) despite taking statins for at least 3 months. They were randomly assigned to consume 1 of 3 treatments: 4 g/day of DHA-rich tuna oil containing 7% EPA and 27% DHA, 8 g/day of DHA-rich tuna oil, or olive oil at either 4 or 8 g/day. These amounts of tuna oil are equivalent to 1.1 and 2.2 g of DHA/day and 0.3 and 0.6 g/day of EPA. The amount of monounsaturated fat in either of the placebo groups was dwarfed by the dietary intake of monounsaturates. Participants maintained their usual statin therapy and consumed the study oils for 6 months. They provided fasting blood samples at the commencement of the trial and after 3 and 6 months. Forty patients completed the trial.

Patients who consumed 2.2 g of DHA/day experienced a significant (27%) drop in their plasma triglyceride levels as early as 3 months after treatment (Figure). At the end of 6 months, triglycerides showed no further decrease. Consumption of 1.1 g of DHA/day had no significant effect on triglyceride levels, although triglycerides tended to decrease. There was no difference in the two placebo groups and so their results were combined. There were no significant effects of DHA treatment on total, HDL- and LDL-cholesterol levels or on blood pressure.

This trial provides evidence that, just as in the JELIS study using EPA, moderately large amounts of DHA (over 2 g/day) from tuna oil in the presence of a quarter as much EPA are associated with significant reductions in plasma triglycerides in patients with elevated cholesterol levels and persistent high triglycerides. Current medical practice relies on statins to reduce cholesterol with the addition of either fibrates or niacin to lower triglycerides. Both of these adjuncts may have undesirable side effects and be poorly tolerated. In contrast, fish oils rich in either DHA, such as tuna oil, or EPA are well tolerated, although some patients may experience belching or "fishiness." In addition to reducing triglyceride levels, fish oils confer other cardioprotective benefits such as more stable heart rhythms, anti-coagulation, reduced inflammation, lower heart rate and heart rate variability and possibly greater plaque stability. These attributes suggest that fish oils may be the adjunct treatment of choice in managing patients with hyperlipidemia.


Meyer BJ, Hammervold T, Rustan AC, Howe PRC. Dose-dependent effects of docosahexaenoic acid supplementation on blood lipids in statin-treated hyperlipidaemic subjects. Lipids 2007;42:335-344.

Source: Cardiovascular Health September 2007

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