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Known as linseed in Europe, flaxseed is prized by health-conscious eaters everywhere due to its abundant omega-3 fatty acid content. Small, oval-shaped flaxseeds come from the flax plant, which is grown in European countries, including France, Belgium, Russia, and Germany. In the United States, flaxseeds are primarily produced in Montana, Minnesota, Texas, and the Dakotas.
Flaxseeds are sold whole or ground. You can ground whole flaxseeds at home in a coffee grinder.
Flaxseeds should be ground before using, for better digestion. In addition to sprinkling them on cereals, salads, casseroles, and desserts, ground flax can be used in baking to boost nutritional content. Flaxseeds combined with water in a blender become quite viscous and can be used to replace eggs in many recipes. Flax oil is used as a salad oil or can be drizzled over cooked foods. Flax oil is unstable at high temperatures and should not be used as a cooking oil.
Flaxseeds, 1 Tbsp
Calories: 59
Protein: 2.3g
Carbohydrate: 4.1g
Total Fat: 4.1g
Fiber: 3.3g
*Good source of: Magnesium (43.4mg)
*Foods that are a “good source” of a particular nutrient provide between 10 and 20% of the Recommended Daily Value.
Alpha-linolenic acid is a fatty acid found in many foods. Most, but not all, studies have found that high dietary or blood levels of alpha-linolenic acid correlate with an increased risk of prostate cancer. Concentrations of alpha-linolenic acid are high in almonds, Brazil nuts, cashews, flaxseeds, hazelnuts, macadamia nuts, peanuts, pecans, pine nuts, pistachios, and walnuts.
Flaxseed is a bulk-forming laxative. It has a high fiber and mucilage content that expands when it comes in contact with water. As the volume in the bowel increases, a reflex muscular contraction occurs, stimulating a bowel movement. This mild laxative is best suited for long-term use in people with constipation.
Flaxseed, like other good sources of soluble fiber, has been reported to lower cholesterol. A recent trial found that partially defatted flaxseed containing 20 grams of fiber per day significantly lowered LDL cholesterol, suggesting that at least one of the cholesterol-lowering components in flaxseed is likely to be the fiber in this product (as opposed to the oil removed from it). In a preliminary trial, young women who had normal cholesterol levels took 50g (approximately 1–3/4 oz.) of raw flaxseed per day for a month, either as flour or baked into bread, which resulted in a 9% decrease in total cholesterol and an 18% decrease in LDL (“bad”) cholesterol.
Doctors and researchers are interested in alpha-linolenic acid (ALA)–the special omega-3 fatty acid found in large amounts in flaxseeds and flaxseed oil. ALA is a precursor to EPA, a fatty acid (obtained in nature from fish oil) that is believed to protect against heart disease. To a limited extent, ALA converts to EPA in the body. However, unlike EPA, ALA does not lower triglyceride levels (a risk factor for heart disease). Preliminary research on the effects of ALA from flaxseed has produced conflicting results. For example, ALA has improved parameters of blood vessel health that should protect people from heart disease, yet ALA may cause damage to LDL cholesterol. Such damage is believed to be a precursor to heart disease.
Foods high in omega-3 fatty acids, such flaxseed, may decrease lupus-induced inflammation. In one trial, nine people with kidney damage due to SLE were fed increasing amounts of flaxseed for a total of 12 weeks. After examining the results, researchers concluded that 30 grams per day was the optimal intake for improving kidney function, decreasing inflammation, and reducing development of atherosclerosis. Flaxseeds also contain antioxidants, potentially helpful to those with lupus.
Soybeans contain compounds called phytoestrogens that are related in structure to estrogen, though the estrogenic activity of soy is quite weak according to some reports. Soy is known to affect the menstrual cycle in premenopausal women. Researchers have linked societies with high consumption of soy products to a low incidence of hot flashes during menopause. In one double-blind trial, 60 grams of soy protein caused a 33% decrease in the number of hot flashes after four weeks and a 45% reduction after 12 weeks. However, in further analysis of the data in this trial, researchers now believe constituents in soybeans other than phytoestrogens must have been responsible for the therapeutic effect. In one randomized trial, high intake of phytoestrogens from soy and flaxseed reduced both hot flashes and vaginal dryness, but much (though not all) of the benefit was also seen in the group not taking the supplements. As a result of these studies, doctors often recommend that women experiencing menopausal symptoms eat tofu, soy milk, tempeh, roasted soy nuts, and other soy-based sources of phytoestrogens. Soy sauce contains very little phytoestrogen, and many processed foods made from soybean concentrates have similarly low levels of phytoestrogens. Flaxseed (as opposed to flaxseed oil) is also a good source of phytoestrogens.
Health benefits and
concerns for nuts and seeds
Many health benefits and concerns associated with this food are applicable to other nuts and
seeds. Read about health benefits and concerns
for nuts and seeds for a full description.
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The information presented in Foodnotes is for informational purposes only and was created by a team of U.S. registered dietitians and food experts. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements, making dietary changes, or before making any changes in prescribed medications. Information expires March 2005.