Alpha-linolenic acid is a kind of omega-3 fatty acid found in plants. It is similar to the omega-3 fatty acids that are in fish oil, called eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Your body can change alpha-linolenic acid into EPA and DHA. Alpha-linolenic acid is found in flaxseed oil, and in canola, soy, perilla, and walnut oils.
Omega-3 fatty acids -- especially EPA and DHA -- have been shown to reduce inflammation and may help prevent chronic diseases, such as heart disease and arthritis. They may be also important for brain health and development, as well as normal growth and development.
There is good evidence that fish oil containing EPA and DHA may help treat heart disease, prevent heart attack and stroke, and slightly reduce high blood pressure. Researchers have thought that the same may be true for alpha-linolenic acid. There is evidence that may be so, although it’s not as strong as it is for fish oil.
NOTE: Alpha-linolenic acid is not the same as alpha-lipoic acid, an antioxidant that helps the body turn glucose into energy. It can be confusing because both alpha-linolenic acid and alpha-lipoic acid are both sometimes abbreviated as ALA.
One of the best ways to help prevent and treat heart disease is to eat a diet that is low in saturated and trans fats, and rich in monounsaturated and polyunsaturated fats, particularly omega-3 fatty acids. The Mediterranean Diet, which emphasizes whole grains, root and green vegetables, daily servings of fruit, fish and poultry, olive and canola oils, and alpha-linolenic acid (found in flaxseed oil), is an example.
There’s some evidence that eating foods high in alpha-linolenic acid may help, too. One study suggests that people who eat a diet high in alpha-linolenic acid are less likely to have a fatal heart attack. In one study, women who ate high levels of alpha-linolenic acid (1.5 g per day) had a 46% lower risk of sudden cardiac death than those who ate the lowest amount of alpha-linolenic acid (about half a gram per day). Other population studies show that as people eat more foods with alpha-linolenic acid, heart disease deaths go down.
Researchers don’t know whether taking alpha-linolenic acid supplements would have the same effect as eating foods rich in alpha-linolenic acid.
People who follow a Mediterranean-style diet tend to have higher HDL ("good") cholesterol levels. In addition, walnuts -- which are rich in alpha-linolenic acid -- have been shown to lower cholesterol and triglycerides in people with high cholesterol. However, studies with flaxseed oil, which is high in alpha-linolenic acid, have been mixed -- some have found that it may help lower cholesterol, while others found it didn’t. Researchers don’t know whether alpha-linolenic acid supplements would have the same benefits as foods with alpha-linolenic acid.
High Blood Pressure
Several studies suggest that diets or supplements rich in omega-3 fatty acids lower blood pressure slightly in people with hypertension. One population study found that eating a diet rich in alpha-linolenic acid reduced the risk of high blood pressure by about 30%.
Preliminary research suggests that omega-3 fatty acid supplements (particularly perilla seed oil, which is rich in alpha-linolenic acid) may decrease inflammation and improve lung function in some people with asthma.
Dietary sources of alpha-linolenic acid include flaxseeds, flaxseed oil, canola (rapeseed) oil, soybeans and soybean oil, pumpkin seeds and pumpkin seed oil, perilla seed oil, tofu, walnuts, and walnut oil.
Alpha-linolenic oil is available on cooking oils, including canola oil and soybean oil, and in medicinal oils, including flaxseed oil and dietary supplements containing flaxseed oil.
Sometimes the active ingredients in products with alpha-linolenic acid can be destroyed by exposing them to air, heat, or light. Generally, look for oil bottled in light-resistant containers, refrigerated, and marked with an expiration date.
How to Take It
The recommended adequate intake of alpha-linolenic acid in the diet is listed below:
- Infants who are breastfed should get enough alpha-linolenic acid if the mother eats a healthy diet.
- Infant formula should contain alpha-linolenic acid.
- Children should not need supplements.
Amounts of alpha-linolenic acid in oils and foods vary. Flaxseeds have about 2.2 g per Tbsp.; canola oil, 1.3 g per Tbsp.; flaxseed oil, 8.5 g per Tbsp.; English walnuts, .7 g per Tbsp.
Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable health care provider.
Because of the risk of increased bleeding, you should stop taking omega-3 fatty acid supplements before surgery. Tell your surgeon that you have been taking the supplements.
People with diabetes or schizophrenia may not be able to convert alpha-linolenic acid to EPA and DHA, the forms the body uses more easily. They should get omega-3 fatty acids from foods rich in EPA and DHA.
Although studies have found that eating fish -- which includes omega-3 fatty acids -- regularly may reduce the risk of macular degeneration, one study of two large groups of men and women found that diets rich in ALA may increase the risk of macular degeneration. Until researchers know more, people with macular degeneration may want to get omega-3 fatty acids from sources of EPA and DHA, rather than alpha-linolenic acid.
In the same way, studies have found that fish and fish oil may protect against prostate cancer, but a few studies have seemed to show that alpha-linolenic acid was associated with an increased risk for prostate cancer. The evidence isn't clear, however. Other studies have found that flaxseed -- high in alpha-linolenic acid -- may benefit men at risk for prostate cancer. Until researchers know more, men with prostate cancer or who have a father or brother diagnosed with prostate cancer should ask their doctor before taking alpha-linolenic acid.
If you are being treated with any of the following medications, you should not use alpha-linolenic acid without first talking to your health care provider.
Blood-thinning Medications -- Omega-3 fatty acids may increase the blood-thinning effects of blood-thinning medications including warfarin (Coumadin), clopidogrel (Plavix), and aspirin, raising the risk of bleeding.
Cholesterol-lowering Medications -- Getting more omega-3 fatty acids in your diet may help a group of cholesterol-lowering medications known as statins work better. Statins include:
- Atorvastatin (Lipitor)
- Rosuvastatin (Crestor)
- Fluvastatin (Lescol)
- Lovastatin (Mevacor)
- Simvastatin (Zocor)
- Pravastatin (Pravachol)
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- Last Reviewed on 04/04/2011
- Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.
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