2006-02-17 10:53:00
Richard Harkness - Knight Ridder Newspapers

Q: I'm thinking of taking omega-3 fatty acids (as in fish oil) to reduce my cholesterol. How large a dose can be safely taken and what are the side effects? Also, are omega-3-6 fatty acids something different?

A: Fish oil supplements contain the omega-3 fatty acids EPA and DHA.

Fish oils from supplements or dietary sources can reduce triglycerides by 20-50 percent, as well as provide other heart-healthy benefits.

Studies have used triglycerides-lowering doses of 1 to 4 grams (1,000 mg to 4,000 mg) daily.

You mentioned cholesterol, but fish oil has little effect on LDL cholesterol (the bad kind), other than perhaps pushing it up a bit if you have high triglycerides to begin with, though this effect seems to be temporary.

A possible benefit is that long-term intake of fish oil might nudge up your HDL cholesterol (the good kind).

Fish oil supplements are generally safe and well-tolerated at doses of 3 grams or less daily.

Nausea, heartburn, or loose stools occasionally occur. Taking the capsules with meals may help.

There's some concern that fish oil at higher doses (e.g., more than 3 grams daily) might blunt the immune response. That could be a problem for elderly individuals and those with suppressed immune function related to medications or diseases such as HIV infection.

Doses greater than 3 grams daily can thin the blood. Combining fish oil supplements with other blood-thinning drugs or supplements merits caution due to the potential risk of excessive bleeding.

Such drugs include aspirin, NSAIDs (e.g., ibuprofen, naproxen), clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), and warfarin (Coumadin).

Supplements include angelica, clove, danshen, garlic, ginger, ginkgo, Panax ginseng, red clover, turmeric, willow, flaxseed oil, phosphatidylserine, policosanol, and high-dose vitamin E.

One sign of abnormal bleeding is unusual bruising. Other signs are nosebleeds, coughed up blood that resembles coffee grounds, and black or tarry stools.

As to your other question: "Omega-3-6" fatty acids likely refers to flaxseed oil supplements, which contain both an omega-3 fatty acid (alpha-linolenic acid) and an omega-6 fatty acid (linoleic acid).

The body can convert the omega-3 fatty acid in flaxseed oil to EPA and DHA (as in fish oil) in limited amounts.

Keep in mind that flaxseed oil does not appear to lower triglycerides, so it's not a substitute for fish oil in this respect.