Home > Total Nutrition > Supplements for Health and Healing

Supplement Savvy for Cancer: Omega-3 Fatty Acids

By Jill Place, MA, RD

What They Are . . .

Omega-3 fatty acids are a type of good dietary fat that might prevent cancer. One of the best places to get Omega-3's is in fatty fish. If you don't like fish and want to get Omega-3s from food, alternatives include flaxseed meal and purslane, an herb that can also be used as a salad green. If none of these foods seem appetizing to you, you may want to take fish oils as a supplement.

What They Do . . .

Research has shown that Omega-3s, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may slow the spread of cancer and stop formation of blood vessels that feed tumors. Omega-3s might also regulate prostaglandins, very important substances that help in many body processes. One way Omega-3s may stop tumors from happening is by making less of one type of prostaglandin and making more of another. Because of their effect on prostaglandins, EPA and DHA might also reduce inflammation and protect your heart. In cancer treatment, EPA and DHA may increase the potency of some chemotherapies, including doxorubicin, mitomycin, cisplatin, and vincristine. EPA and DHA might also keep you from losing weight, losing muscle, and being malnourished.

What To Do . . .

First, you might want to think about eating more fish. And the more fat(ty acids) in your fish the better. Fatty fish best bets include salmon (approximately 1.5 to 2.0 grams of Omega-3s per four ounces cooked fish), herring (approximately 2.5 grams), tuna (approximately 1.0 grams), trout (approximately 1.0 grams), oysters (approximately 1.5 grams), and whitefish and sablefish (approximately 2.0 grams).

Flaxseed oil also has a lot of Omega-3s in the form of alpha-linolenic acid (ALA). But flaxseed oil isn't very stable and may not be converted well to EPA, the most cancer-fighting Omega-3. You might want to try using flaxseed oil with a sulfur-containing protein such as yogurt or cottage cheese so that your body can use it better. Flaxseed meal may be a better dietary bet, but the lignans in flaxseed meal have a weak estrogen-like effect and therefore may not be good in large amounts for those with hormone-related cancers such as breast cancer. Stick to about one tablespoon of the meal, or about 1 to 2 grams a day, if you have these types of cancers.

We Americans also eat a ton of Omega-6 fatty acids in vegetable oils and products like margarine. These fats help make that other kind of prostaglandin that may help cancer grow. You might want to change your oil to Omega-9 olive oil, which has no effect on cancer growth, or to use a smattering of butter on your bread. Or, better yet, skip those fries more often and do other things to lower your total fat intake.

There's no substitute for a good diet that has all the things we've talked about, but cancer treatment may make it impossible to eat perfectly. And your body may demand more Omega-3s during this time. So if you're not eating at least 12 to 16 ounces of fatty fish a week in treatment or for prevention, you might want to invest in a fish oil supplement.

What To Watch Out For . . .

Fish oils and ALA make cell membranes more fluid and cause less blood clotting. So they're not appropriate for hemophiliacs, those taking wayfarin (coumadin), or pre- and post-surgery patients. Also, children, pregnant women, and diabetics should be monitored by a physician when taking these supplements. Rare interactions may happen between fish oils, ALA, and aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) and herbs such as Garlic and Gingko Biloba. Side effects may include mild nausea and diarrhea, bad breath, a general fishy smell, possible nosebleeds, and easy bruising. You also want to take fish oil supplements with a small amount of vitamin E to keep them from oxidizing and lessen their possible unpredictable effect upon the immune system.

© Copyright 2002 Jill Place, MA, RD