Some call it one of the most powerful plant foods on the planet. There’s some evidence it may help reduce your risk of heart disease, cancer, stroke, and diabetes.
UsesFlax is grown both for its seeds and for its fibers. Various parts of the plant have been used to make fabric, dye, paper, medicines, fishing nets, hair gels, and soap. Flax seed is the source of linseed oil, which has uses as an edible oil, as a nutritional supplement and as an ingredient in many wood finishing products. It is also grown as an ornamental plant in gardens.
What's It Made Of
- Fiber (including soluble and insoluble)
- Protein -- approximately 20%
- Essential fatty acids (ALA) -- flaxseed is approximately 35% oil, of which 55% is ALA.
Recent studies have suggested that flaxseed may have a protective effect against cancer, particularly breast cancer, prostate cancer, and colon cancer. At least two of the components in flaxseed seem to contribute, says Kelley C. Fitzpatrick, MSc, director of health and nutrition with the Flax Council of Canada.
In animal studies, the plant omega-3 fatty acid found in flaxseed, called ALA, inhibited tumor incidence and growth.
Further, the lignans in flaxseed may provide some protection against cancers that are sensitive to hormones without interfering with the breast cancer drug tamoxifen. Some studies have suggested that exposure to lignans during adolescence helps reduce the risk of breast cancer and may also increase the survival of breast cancer patients, Thompson says.
Lignans may help protect against cancer by:
- Blocking enzymes that are involved in hormone metabolism.
- Interfering with the growth and spread of tumor cells.
Research suggests that plant omega-3s help the cardiovascular system via several different mechanisms, including anti-inflammatory action and normalizing the heartbeat, Fitzpatrick says. New research also suggests significant blood pressure-lowering effects of flaxseed, which may be due to both the omega-3 fatty acids as well as the amino acid groups found in flaxseed.
Several studies have suggested that diets rich in flaxseed omega-3s help prevent hardening of the arteries and keep plaque from being deposited in the arteries, partly by keeping white blood cells from sticking to the blood vessels’ inner linings.
"Lignans in flaxseed have been shown to reduce atherosclerotic plaque buildup by up to 75%," Fitzpatrick says.
Because plant omega-3s may also play a role in maintaining the heart’s natural rhythm, they may be useful in treating arrhythmia (irregular heartbeat) and heart failure, although more research is needed on this.
Eating flaxseed daily may help your cholesterol levels, too. Small particles of LDL or "bad" cholesterol in the bloodstream have been linked to an increased risk of heart disease, obesity, diabetes, and metabolic syndrome. A French-Canadian study in menopausal women reported a decrease in these small LDL particles after the women ate 4 tablespoons of ground flaxseed daily for a year. Fitzpatrick says the cholesterol-lowering effects of flaxseed are the result of the synergistic benefits of the omega-3 ALA, fiber, and lignans.
Preliminary research also suggests that daily intake of the lignans in flaxseed may modestly improve blood sugar (as measured by hemoglobin A1c blood tests in adults with Type 2 Diabetes).
Two components in flaxseed, ALA and lignans, may reduce the inflammation that accompanies certain illnesses (such as Parkinson's disease and asthma) by helping to block the release of certain pro-inflammatory agents, Fitzpatrick says.
The plant omega-3 ALA has been shown to decrease inflammatory reactions in humans. And studies in animals have found that lignans can decrease levels of several pro-inflammatory agents.
Reducing inflammatory reactions associated with plaque buildup in the arteries may be another way flaxseed helps prevent heart attack and strokes.
One preliminary study on menopausal women, published in 2007, reported that 2 tablespoons of ground flaxseed mixed into cereal, juice, or yogurt twice a day cut the women's hot flashes in half. And the intensity of their hot flashes dropped by 57%. The women noticed a difference after taking the daily flaxseed for just one week, and achieved the maximum benefit within two weeks.
But at the 2011 meeting of the American Society of Clinical Oncology, Mayo Clinic researchers reported there was no significant reduction in hot flashes between postmenopausal women and breast cancer patients eating a bar containing 410 milligrams of phytoestrogens from ground flaxseed and the group eating a placebo bar.
Other studies have shown that diets rich in the omega-3s from fish (DHA and EPA), which also naturally result in a lowered ratio of omega-6 to omega-3 fats, reduce bone loss. Researchers think this is most likely because omega-6 fats are converted into pro-inflammatory prostaglandins, while omega-3 fats are metabolized into anti-inflammatory prostaglandins. (Prostaglandins are hormone-like substances made in our bodies from fatty acids.)
In this study, 23 participants ate each of 3 diets for a 6-week period with a 3 week washout period in between diets. All 3 diets provided a similar amount of fat, but their ratio of omega-6 to omega-3 fats was quite different:
Diet 1 provided 34% total fat with omega-6 and omega-3 fats in amounts typically seen in the American diet: 9% polyunsaturated fats (PUFAs) of which 7.7% were omega-6 and only 0.8% omega-3 fats, resulting in a pro-inflammatory ratio of 9.6:1.
Diet 2, an omega-6-rich diet, provided 37% total fat containing 16% PUFAs of which 12% were omega-6 and 3.6% omega-3, a better but still pro-inflammatory ratio of 3.3:1.
Diet 3, which provided 38% in total fats, was an omega-3-rich diet, containing 17% PUFAs, of which 10.5% were omega-6 and 6.5% omega-3, resulting in an anti-inflammatory ratio of 1.6:1.
After each diet, subjects' blood levels of N-telopeptides, a marker of bone breakdown, were measured, and were found to be much lower following Diet 3, the omega-3-rich diet, than either of the other two.
The level of N-telopeptides seen in subjects' blood each diet also correlated with that of a marker of inflammation called tumor necrosis factor-alpha (TNF-alpha). Diets 1 and 2—the diets which had a significantly higher ratio of omega-6 to omega-3 fats—also had much higher levels of TNF-alpha than the Diet 3, which was high in omega-3 fats from walnuts and flaxseed. Practical Tip: Protect your bones' by making anti-inflammatory omega-3-rich flaxseed and walnuts, as well as cold water fish, frequent contributors to your healthy way of eating.
How to Take It
- Although studies have found that regular consumption of fish (which includes the omega-3 fatty acids EPA and DHA) may reduce the risk of macular degeneration, a recent study including two large groups of men and women found that diets rich in ALA may increase the risk of this disease. Ask your health care provider.
- Flaxseed may slow down the absorption of oral medications or other nutrients if taken at the same time. Therefore, flaxseed should be ingested several hours before, or after medicines or supplements. Talk to your health care provider before taking flaxseed if you regularly take any prescription or nonprescription medications, or dietary supplements.
- People with either diabetes or schizophrenia may lack the ability to convert ALA to EPA and DHA, the forms of omega-3 fatty acids that are generally made from ALA and are more readily used by the body. Therefore, people with these conditions should obtain their omega-3 fatty acids directly from dietary sources rich in EPA and DHA, such as cold water fish (including mackerel, salmon, or whitefish).
- Do not use flaxseed products or ALA if you have diabetes, prostate problems, breast cancer, or schizophrenia without the advice and supervision of a qualified health care provider.
Does ground flaxseed have more health benefits than whole flaxseed? http://www.mayoclinic.com/health/flaxseed/AN01258
Case: This Single Food Helps Your Cholesterol, Heart, and Weight
The Benefits of Flaxseed http://www.webmd.com/diet/features/benefits-of-flaxseed?page=3