Alpha-linolenic acid (ALA) is an essential fatty acid that comes from plants. It is considered an essential nutrient, which means that your body requires it.

ALA is used as a source of energy by the body. It also serves as the parent substance to omega-3 fatty acids, compounds that regulate blood pressure, blood clotting, heart rate, blood vessel dilation, the immune response, and breakdown of fats. Essential fatty acids are also used to make brain and nervous tissue. Only certain plant products provide ALA. Primarily, they are canola (rapeseed), flaxseed (linseed), and soybean oil. Some fish (for example, mackerel and salmon) contain omega-3 fatty acids. Corn, safflower, cottonseed, sesame, and sunflower oils are rich in fats called omega-6 fatty acids. These two families of fats have very important, but different, roles in the body. It is important to have a balance of omega-6 and omega-3 fatty acids in the diet. Excessive intake of either type of fat can cause health problems.

American diets are typically high in omega-6 fatty acids and low in omega-3 fatty acids. Americans' high consumption of omega-6 oils (corn, safflower, sunflower oils), low intake of fish, and focus on decreasing overall fat in the diet are the primary reasons for inadequate or imbalanced levels of omega-3 fatty acids in the diet. Taking in more omega-6 than omega-3 fatty acids may encourage your body to produce substances that cause inflammation and negatively affect your body's response to disease. These imbalances may make you more susceptible to heart disease, inflammatory conditions such as arthritis and psoriasis, and infections, and can lower your immunity. You may gain significant health benefits by increasing the level of omega-3 fatty acids in your diet. This is especially true if you take in large amounts of omega-6 fatty acids.

Omega-3 fatty acids have several proven benefits. They are especially good for your heart, they can provide relief from rheumatoid arthritis, they may be helpful in treating multiple sclerosis and some cases of diabetes, and they may help prevent cancer. Recently, omega-3 fatty acids were shown to help treat migraines and depression. ALA may be useful in treating skin cancer.

ALA and other omega-3 oils are used to help treat the following:

• Heart disease: ALA may reduce the risk of heart disease by improving the arteries that carry blood throughout the body and to the brain, and by lowering cholesterol and triglyceride levels.
• Hypertension (high blood pressure)
• Allergic and inflammatory conditions such as psoriasis and eczema
• Autoimmune diseases, such as multiple sclerosis, lupus, and cancer

The following foods are good sources of ALA: flax seeds, flaxseed oil, canola (rapeseed) oil, soybean oil, margarine, if made from canola or soybean oil, pumpkin, and walnuts.

There are two types of commercial preparations. Cooking oils (canola oil, soybean oil, margarines made from these oils), and medicinal oils (flaxseed oil, gelatin capsules of flaxseed oil).

Several manufacturing methods can destroy the nutrient value of products that contain ALA. Preferred methods are "modified atmospheric packing methods." Generally, high-quality oil will be certified as organic by a reputable company, bottled in light-resistant containers, refrigerated, and marked with an expiration date.

There is no recommended dietary allowance (RDA) for ALA.

A healthy diet should include less saturated fats and more polyunsaturated essential fatty acids. Discuss your total fat intake with your health care provider if you are thinking about taking ALA supplements.

You should talk with your health care provider about your regular diet. Your health care provider can help you decide if you should take supplements, and what kind of supplements may be best for you. Remember that ALA supplements are fats, and are high in calories. Avoid products containing hydrogenated fats.

In a laboratory study, the combination of alpha-linolenic acid (ALA) and lovastatin may offer benefits to patients on lovastatin therapy. However, additional studies in humans are needed to confirm these findings. You should consult with your healthcare provider before taking ALA if you are currently taking lovastatin.

Ando H, Ryu A, Hashimot A, Oka M, Ichihashi M. Linoleic acid and alpha-linolenic acid lightens ultraviolet-induced hyperpigmentation of the skin. Arch Dermatol Res. 1998;290:375–381.

Billeaud C, Bougle D, Sarda P, et al.. Effects of preterm infant formula supplementation with alpha-linolenic acid with a linoleate/alpha-linoleate ration of 6. Eur J Clin Nutr. August 1997;51:520–527.

Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, Ore: Eclectic Medical; 1998:71-72.

De Smet PAGM, et al, eds. Adverse Effects of Herb Drugs 2. Berlin, Germany: Springer-Verlag, 1993.

DeDeckere EA, Korver O, Verschuren PM, Katan MB. Health aspects of fish and n-3 polyunsaturated fatty acids from plant and marine origin. Eur J Clin Nutr. 1998;52:749–753.

Denis L, Morton MS, Griffiths K. Diet and its preventive role in prostatic disease. Eur Urol. 1999;35(5–6):377–387.

Edwards R, Peet M, Shay J, Horrobin D. Omega-3 polyunsaturated fatty acid levels in the diet and in red blood cell membranes of depressed patients. J Affect Disord. 1998;48:149–155.

Ensminger AH, Ensminger ME, Konlande JE, Robson JRK. Foods & Nutrition Encyclopedia. 2nd ed. Baton Rouge, Fla: CRC Press, Inc; 1994:1:684–708.

Ferretti A, Flanagan VP. Antithromboxane activity of dietary alpha-linolenic acid. Prostaglandins Leukot Essent Fatty Acids. 1996;54:451–455.

Freese R, Mutanen M. Alpha-linolenic acid and marine long-chain n-3 fatty acids differ only slightly in their effects on hemostatic factors in healthy subjects. Am J Clin Nutr. 1997;66:591–598.

Garrison Jr RH, Somer E. The Nutrition Desk Reference. 3rd ed. New Canaan, Conn: Keats Publishing, Inc; 1995:23–64.

Haas EM. Staying Healthy with Nutrition. Berkley, Calif: Celestial Arts Publishing; 1992:65–79.

Haggans CJ, Hutchins AM, Olson BA, et al. Effect of flaxseed consumption on urinary estrogen metabolites in postmenopausal women. Nutr Cancer. 1999;33(2):188–195.

Harris WS. N-3 fatty acids and serum lipoproteins: human studies. Am J Clin Nutr. 1997;65:1645S (10).

Hrboticky N, Zimmer B, Weber PC. Alpha-Linolenic acid reduces the lovastatin-induced rise in arachidonic acid and elevates cellular and lipoprotein eicosapentaenoic and docosahexaenoic acid levels in Hep G2 cells. J Nutr Biochem. 1996;7:465-471.

McGuffin M, Hobbs C, Upton R, et al, eds. Botanical Safety Handbook. Boca Raton, Fla: CRC Press; 1997.

Prasad K. Dietary flaxseed in prevention of hypercholesterolemic atherosclerosis. Atherosclerosis. 1997;132(1):69–76.

Rozanova IA, Pogozheva AV, Miagkova MA. Effect of antiatherosclerotic diet with polyunsaturated fatty acids omega-3 from linseed oil on dynamics of natural antibodies to bradykinin and angiotensin II in blood serum of patients with cardiovascular diseases [in Russia]. Savitskaia IuA Vopr Pitan. 1998;2:32–34.

Talom RT, Judd SA, McIntosh DD, et al. High flaxseed (linseed) diet restores endothelial function in the mesenteric arterial bed of spontaneously hypertensive rats. Life Sci. 1999;16:1415–1425.

Wichtl M, ed. Herbal Drugs and Phytopharmaceuticals. Boca Raton, Fla: CRC Press; 1994.

de Lorgeril M, Renaud S, Mamelle N, et al. Mediterranean alpha-linolenic acid-rich diet in secondary prevention of coronary heart disease. Lancet. 1994;343:1454–1459.

Mantzioris E., James MJ, Gibson RA, Cleland LG. Dietary subsitutions with an alpha-linolenic acid-rich vegetable oil increases eicosapentaenoic acid concentrations in tissues. Am J Clin Nutr. 1994;59:1304–1309.

Murray MT. Encyclopedia of Nutritional Supplements. Rocklin, Calif: Prima Publishing; 1996:239–278.

Nestel PJ, Pomeroy SE, Sasahara T, et al. Arterial compliance in obese subjects is improved with dietary plant n-3 fatty acid from flaxseed oil despite increased LDL oxidizability. Arterioscler Thromb Vasc Biol. 1997;17:1163–1170.

Newstrom H. Nutrients Catalog. Jefferson, NC: McFarland & Co, Inc; 1993:103–105.

Simon JA, Fong J, Bernert JT Jr, Browner WS. Serum fatty acids and the risk of stroke. Stroke. 1995;26:778–782.

Shils ME, Olson JA, Shike M, Ross AC. Modern Nutrition in Health and Disease. 9th ed. Baltimore, Md: Williams & Wilkins; 1999:90–92, 1377–1378.

Voskuil DW, Feskens EJM, Katan MB, Kromhout D. Intake and sources of alpha-linolenic acid in Dutch elderly men. Eur J Clin Nutr. 1996;50:784–787.

Wapnir RA. Copper absorption and bioavailability. Am J Clin Nutr. 1998;67:1054s.

Wagner W, Nootbaar-Wagner U. Prophylactic treatment of migraine with gamma-linolenic and alpha-linolenic acids. Cephalalgia. April 1997;17:127–130.

Werbach MR. Nutritional Influences on Illness. 2nd ed. Tarzana, Calif: Third Line Press; 1993:13–22; 655–671.

Yehuda S, Rabinovitz S, Carasso RL, Mostofsky DI. Fatty acids and brain peptides. Peptides. 1998;19:407–419.