A Provider Primer on Omega-3

Research increasingly indicates that omega-3 fatty acids have beneficial effects. This has some primary care physicians wondering how to advise patients about over-the-counter fish oil supplements and more potent prescriptions for omega-3.

Fish oil is primarily known for lowering the risk of sudden cardiac death, and it potentially could lower patients' risk of stroke, nonfatal heart attack, heart failure, atrial fibrillation, and dementia, says Dariush Mozaffarian, MD, DrPH, an assistant professor of medicine and epidemiology at Harvard Medical School and Harvard School of Public Health in Boston. But these other correlations are less well established and require further investigation before researchers can draw firm conclusions, cautions Mozaffarian, who has led several studies on fatty acids, fish intake, and cardiovascular health.^1–6

There's no doubt, however, says Mozaffarian, that “for cardiovascular health, the most important single food in the food supply is fish or omega-3, and high doses are not required.”

He encourages patients to eat seafood once or twice a week, preferably oilier fish such as salmon, herring, anchovies, and tuna. “For patients who don't eat fish, or want to be sure they get omega-3, a low-dose supplement should be considered,” he adds.

FIRST STEP: RISK PROFILE

Before recommending omega-3 or other supplementation, physicians typically will work up a patient's risk profile. They'll compile information on blood lipids, levels of glycated hemoglobin (A1C), and possible inflammatory markers, as well as measures of body mass index (BMI) and blood pressure, says Linda Van Horn, PhD, RD, chair-elect of the American Heart Association's nutrition committee and a professor of preventive medicine at Northwestern University's Steinberg School of Medicine in Chicago.^7,8

A patient's cardiovascular history also should factor into a physician's decision to recommend omega-3 supplementation, says Lisa Jackson, MD, MPH, an assistant professor of cardiovascular medicine at University of Michigan Medical School in Ann Arbor.

“Someone with high triglycerides and low HDL cholesterol, but no history of heart attack, might benefit from omega-3 supplements in the form of flaxseed or fish oil,” Jackson says.

However, Jackson's recommendation differs for patients who have had heart attacks. For them she advises “secondary prevention” of another such event with 1–2 g of fish oil in capsules or cold-water fish twice a week.

“The evidence is especially strong related to the prevention of sudden death brought on by sudden heart rhythm disturbances,” Jackson explains. “Although the exact mechanism for the benefit of omega-3 fatty acids is not completely clear, it may relate to the role of omega-3 in cell-membrane stability.”

OTC OR OMACOR?

Omega-3 is available over the counter (OTC) or in a more concentrated prescription form known as Omacor (omega-3-acid ethyl esters), which comes in the form of a 1-g soft-gel capsule manufactured by New Jersey-based Reliant Pharmaceuticals, Inc. The recommended daily dose is 4 g for patients with triglyceride levels >500 mg/dl. Omacor contains the essential omega-3 fatty acid components, eicosapentaenoic acid (465 mg) and docosahexaenoic acid (375 mg).

When supplementing a proper diet, Omacor is intended to lower very high triglyceride levels (≥500 mg/dl). The Food and Drug Administration advises caution in prescribing Omacor for patients with fish allergies.

A 5-year trial begun in 2004 named Outcome Reduction with an Initial Glargine Intervention (ORIGIN) will evaluate Omacor and glargine insulin treatment in patients with early type 2 diabetes or pre-diabetes at high risk for cardiovascular events. The study is tracking 10,000 patients across 600 sites in ≥35 countries. Past research has shown that—when administered as 4 g daily to patients with high blood lipids—Omacor reduced levels of median LDL and triglycerides and raised median HDL levels.^9,10

Fish oils sold OTC are just as beneficial as Omacor, but Omacor can ease compliance because patients don't need to take as many pills to achieve the same benefits, says Robert H. Eckel, MD, past president of the American Heart Association and director of the lipid clinic at University of Colorado Health Sciences Center in Denver.

“If the drug is reimbursed by the insurance and the co-pay is low, I would go with Omacor,” Eckel says. If the drug is not reimbursed, he advises using OTC supplements. ▪