The fatty acid alpha-linolenic acid (ALA) is an essential nutrient. It is the 18-carbon polyunsaturated fatty acid (PUFA) in the omega-3 series found in unhydrogenated oils derived from plants. ALA is found primarily in margarines as well as in rapeseed (canola), flaxseed, and soybean oils.

ALA is a "parent" fatty acid. Our bodies convert it into the longer-chain omega-3 fatty acids (such as docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]), which are found primarily in fish oils. Scientists studying DHA and EPA have shown that omega-3 oils have several beneficial effects. Because these fatty acids are produced by ALA, this research can be applied to ALA as well.

The beneficial effects of omega-3 series oils include: lowering cholesterol and triglyceride levels, reducing the risk of heart disease, lowering blood pressure, improving rheumatoid arthritis, and protecting myelin formation and function. Omega-3 oils may also be helpful in treating multiple sclerosis and diabetes, and in preventing cancer.

ALA may help prevent coronary heart disease, and inhibit atherosclerosis. In one small study, 15 obese persons took 20 g of ALA from margarine products based on flaxseed oil daily. As a result, the subjects showed improvement in arterial compliance, and thus had a decreased risk of cardiovascular disease, despite a rise in LDL oxidizability. At the same time, insulin sensitivity and HDL cholesterol diminished. Another study found that ALA supplements from vegetable oil and EPA and DHA supplements from a fish source have largely parallel effects on hemostatic factors. Other research has indicated that ALA acts equivalently to n-6 fatty acids with respect to lipid and lipoprotein effects. However, very large amounts of ALA, which is plant-based, were needed to reduce triacylglycerol concentrations, which is the hallmark effect of the fish-based omega-3 fatty acids. The study concluded that plant-derived ALA is not equivalent to fish-based acids in its effect on lipoprotein metabolism. Scientists agree that the relationship among the fatty acids and the ratio of ALA to linoleic acid in the diet is an important area for further study.

Scientists are also investigating other uses for ALA. The anti-inflammatory and immunoregulatory effects of ALA, and its successor fatty acids, have been demonstrated. Successful treatment of migraines and alleviation of depression with ALA have been reported. Topical application of ALA inhibits melanin production and accelerates turnover of the stratum corneum, thus aiding in the removal of melanin pigment from the epidermis.

• Flaxseeds
• Flaxseed oil
• Linseed oil
• Canola (rapeseed) oil
• Soybean oil
• Margarine, if based on canola or soybean oil
• Pumpkin
• Walnuts

Alpha-linolenic acid is a long-chain polyunsaturated fatty acid with 18 carbon atoms. It is the parent fatty acid in the omega-3 series. It is converted to eicosapentaenoic acid (EPA), then to deocosahexaenoic acid (DHA), then to the prostaglandin E3 series (PGE3). Some fish products (e.g., mackerel and salmon) can introduce EPA and DHA directly into the body.

The essential fatty acids, including ALA, are known as vitamin F. The Food and Drug Administration prohibits the use of the term "vitamin F" in advertising, because foods like french fries could be advertised as being "vitamin enriched" because they were fried in oil containing these fatty acids.

ALA is commercially prepared in two ways.

• Cooking oils (canola oil, soybean oil, margarines made from these oils). Hydrogenated products are not preferred.
• Medicinal oil (flaxseed oil, gelatin capsules of flaxseed oil)

Several manufacturing methods can destroy the nutritional value of the products. Some preferred manufacturers use proprietary names for their packaging processes. Bio-Electron Process (Barlean's Organic Oils), Spectra-Vac (Spectrum Naturals), or Omegaflo (Omega Nutrition) are some examples. Generally, a high quality oil will be certified as organic by a reputable third party, is packaged in light-resistant containers, may be refrigerated, and will be dated.

The primary uses of ALA and other omega-3 oils include the following.

• Cardiovascular disease: reducing cholesterol levels and blood pressure
• Allergic and inflammatory conditions: e.g., for treatment of psoriasis and eczema
• Autoimmune diseases: e.g., for treatment of multiple sclerosis, lupus, and cancer

There is no recommended dietary allowance of ALA.

A healthy person eating a normal diet should consume fewer saturated fats and more polyunsaturated essential fatty acids.

N/A

Total fat intake should be considered.

The ratio of ALA to other essential fatty acids may be important in treating some conditions.

The addition of alpha-linolenic acid (40 µmol/L) to cultured human liver cells pretreated with lovastatin (10 µmol/L) prevented the increase in arachidonic acid-rich lipids that was associated with the drug (Hrboticky et al. 1996). More studies with ALA-supplemented diets are warranted to confirm these preliminary, in vitro findings. The combination of ALA and HMG-CoA reductase inhibitors may offer a cardioprotective benefit for patients on this therapy.

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