Health Benefits of Flaxseed
Flaxseed is a type of whole grain that contains several major components associated with numerous health benefits. This includes the short-chain omega-3 fatty acids, certain phytochemicals and dietary fiber. Flaxseed comes from the flax plant (Linum usitatissimum), which is cultivated in moderate climates. The plants are grown for their seeds and are also used to produce fiber for fabric.
The edible seeds are usually added or sprinkled onto other foods. Many processed foods, like cereals or breads, are fortified with flaxseed. People are advised to consume ground, rather than whole flaxseed, because whole seeds may pass through the digestive tract without being absorbed.
Furthermore, flaxseed is cold-pressed to produce linseed (flaxseed) oil that is often sold as a nutritional supplement but also used in industrial applications. However, oil offers fewer health benefits than the seeds because it contains no fiber or lignans, though sometimes lignans may be added back. Some of the healthful flaxseed components are fragile. Therefore, flaxseed should be stored in airtight containers away from heat and should not be used for cooking.
Consumers are advised to obtain nutrients and other beneficial substances from foods, such as flaxseed, rather than supplements. This is because plant foods contain a number of other healthful substances like various vitamins and minerals, phytochemicals, fiber and fatty acids that are not necessarily contained in a supplement. In addition, supplements may contain harmful impurities and additives.
Potential Health Effects of Flaxseed Components
Although the scientific evidence regarding health benefits of flaxseed is not conclusive, at least three components are believed to benefit human health, including:
Alpha-linolenic acid (ALA). An omega-3 fatty acid, which is a polyunsaturated fat that has been shown to reduce the risk of cardiovascular disease. Flaxseed is the richest dietary source of alpha-linolenic acid, although it can be also found in other foods such as canola oil, fish oil, walnuts, soybeans or leafy green vegetables. Plant-based alpha-linolenic acid is the least potent of the three types of omega-3 fatty acids and is converted in the body into the other two types – docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). DHA and EPA are types of omega-3s found in fish oil, but not in flaxseed.
Lignans. A type of phytochemical known as a phytoestrogen because it mimics the female sex hormone estrogen and may inhibit its action. Therefore, lignans are often associated with certain estrogenic and anti-estrogen effects in the body. Lignans may also act as antioxidants and thus may help decrease the risk of cancer. They can be found in many foods such as sesame seeds and other seeds and nuts, whole grains, bran, kale, broccoli or apricots, but their highest concentrations are found in flaxseed.
Dietary fiber. Fiber has a laxative effect and helps promote digestive system function and relieve constipation. Flaxseed contains both types of fiber – soluble and insoluble fiber. Consumption of soluble fiber, in particular, is linked to reduced cholesterol levels. It was also found to slow the liver’s production of cholesterol and change the particles of “bad” cholesterol to make them less damaging. Moreover, diets high in fiber have been shown to reduce the risk of some types of cancer.
Dietary Recommendations for Flaxseed
There is no recommended daily allowance for flaxseed but there are RDAs for some of its major components. When it comes to alpha-linolenic acid (ALA), it is recommended that adults consume between 1.1 grams (women) and 1.6 grams (men) of ALA per day. Regarding fiber, the RDA is 25 grams for women and 38 grams for men per day. There is no RDA for lignans, another important component of flaxseed. To put it into perspective, one tablespoon (15 millilitres) of ground flaxseed contains approximately 1.75 grams of alpha-linolenic acid and a total of 2.2 grams of dietary fiber. One tablespoon of flaxseed oil provides about 7.5 grams of alpha-linolenic acid but no fiber.
Possible Risks Associated with Flaxseed Consumption
When taken moderately, flaxseed rarely causes side effects. However, when consuming foods high in fiber, including flaxseed, it is necessary to drink ample amounts of liquids to prevent constipation. Moreover, the fiber in flaxseed may interfere with the body’s absorption of certain drugs, therefore, avoid taking flaxseed and medications at the same time. Flaxseed may also not be suitable for people in certain circumstances, such as:
- People with allergies to flaxseed or any members of the Linum genus plant family.
- Those who experience a narrowing of the esophagus or intestines, bowel obstruction or ileus.
- People who may be harmed by the laxative or bulking effects of fiber in flaxseed, e.g., those with diarrhea, irritable bowel syndrome, inflammatory bowel disease or diverticulitis.
- Individuals who may be harmed by increased bleeding, for example those on anticoagulant medications or people with a history of bleeding disorders.
- Women with hormone-sensitive conditions such as endometriosis, uterine fibroids, polycystic ovary syndrome or cancers of the breast, ovary or uterus.
- Pregnant and breastfeeding women
Where to Get More Information: HealthyFlax.org