The Fuss About Flaxseed Overlooks Important Distinctions

Several readers have sent us questions about flaxseed (a major source of alpha linolenic acid) and alpha lipoic acid, which they obviously think are the same thing. It’s easy to get confused by all these chemical names and even easier to get befuddled by the claims made for them by the supplement distributors of the world.

Flax is an ancient plant that has provided humans with clothing (linen fiber), food (whole flaxseed, flaxseed oil and flaxseed flour) and linseed oil (another name for flaxseed oil), which is found in paint, varnish and linoleum and is a fine oil for finishing wood.

So why, all of a sudden, are people touting flaxseed as a miracle food?

It is true that flaxseed and flaxseed oil are incredibly good sources of the essential fatty acid known as alpha linolenic acid. This is one of those substances that is necessary for life and must be consumed in foods because our bodies do not manufacture it. In this case, alpha linolenic acid is an omega-3 fatty acid, similar but not identical to that found in fish. Although we don’t know exactly why, consumption of fish (and fish oil) has been linked to a reduced risk of fatal heart disease. We do know that substituting unsaturated oils of almost any type for saturated fat may reduce blood cholesterol and thereby the risk of heart disease.

However, it turns out that alpha linolenic acid is not as beneficial as fish oil, and there is far less evidence that, in and of itself, it confers the same type of cardiac benefits. The studies that have shown some effect actually did not focus on flaxseed, but rather on canola oil, which also contains alpha linolenic acid. Other good sources include walnuts and soybean oil. Flaxseed is only one of several ways to get this essential fatty acid in the diet.

Aside from its alpha linolenic acid content, flaxseed also contains some important phytochemicals, most notably lignans, which are a type of phytoestrogen and also provide fiber. It is possible that they may have some antioxidant and anti-cancer properties as well. However, other plants also contain phytoestrogens, including soy, some herbs, whole grains and other seeds. Again, flaxseed is only one dietary source.

Although we don’t recommend taking the flaxseed capsules that are being heavily advertised and marketed, adding flaxseed to your diet is not difficult and certainly will not hurt you. Flaxseed flour can be combined with wheat flour when baking, and the seeds can be sprinkled on cereals or salads to provide a crunchy bonus.

A few words of caution, however. Unless you chew the seeds very thoroughly, they will simply pass through your body undigested, and because they are high in fiber, it’s good to increase your fluid intake at the same time. The seeds and the oil spoil easily, and need to be stored in dark bottles and refrigerated once they are opened.

Alpha lipoic acid is one of those supplements that might seem to be new because we are suddenly hearing so much about it, but actually it was discovered almost 50 years ago. This substance, which is required for normal energy production, is produced by the body in sufficient quantities to meet our basic needs. However, in the 1980s, it was shown to be a powerful antioxidant when there was more of it circulating in the body than needed.

Unfortunately, aside from yeast and liver, there is little alpha lipoic acid in foods, and the only way to produce such excesses is through supplements or injections.

What seems to make this a special antioxidant is that it helps to fight both water- and fat-soluble free radicals, protects DNA, and helps recycle vitamins C, E and other antioxidants to make them more effective in their work. The early research on alpha lipoic acid has been done primarily in animals, and the results have been somewhat inconsistent. At this point, it is not clear what dose might be effective in humans and what, if any, long-term effects there might be from something that seems to be this powerful.

Like all supplements sold in the United States, it is wholly unregulated. As a consumer, you have absolutely no guarantee of what’s inside the bottle even though it is being marketed as a preventive or treatment for such chronic conditions as heart disease, stroke, diabetes and cataracts. In Germany, where there is far more regulation of so-called nutritional supplements, it is sold only by prescription and is used to treat some of the complications of diabetes.

Alpha lipoic acid’s antioxidant potential may actually turn out to be important, but at the moment not enough is known about its effectiveness and safety. If you decide that you want to be a human guinea pig, you should discuss this with your physician, because it may, for instance, affect the dosage of other medications you might be taking.

Antioxidants are certainly recognized as important weapons in preventing (and maybe someday even treating) free radical damage and possibly the effects of aging. While some supplements (like vitamins E and C) are now recommended, not enough is known about many others like alpha lipoic acid.

Until the research is more fully developed, and the supplements flooding the marketplace are regulated in a way that protects the consumer, following the guidelines for increased consumption of fruits and vegetables is still the best and safest way to stay healthy.

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To submit questions, send e-mail to daogar@uclink4.berkeley.edu, fax (510) 642-2857, or write Dale Ogar, School of Public Health, UC Berkeley, Berkeley, CA 94720-7360. We regret that we cannot answer questions personally.