Flaxseeds (Linum usitatissimum L.) are the tiny, brown seeds of the flax plant. The seeds produce a fixed oil known as linseed oil or flaxseed oil. Flaxseed’s therapeutic effects come from the fact that it’s high in fiber and omega-3 fatty acids, as well as phytochemicals called lignans. Flax has been shown to help prevent heart disease, reduce symptoms of inflammatory disorders, protect against cancer, and ease the effects of Type 2 diabetes.
Flaxseed Benefits and Studies
Flax contains disease-fighting compounds, primarily the omega-3 fatty acid, alpha linolenic acid (ALA), lignans and fiber. Flaxseed acts like a laxative because of its fiber content. Phytoestrogens (lignans), may help protect against some kinds of cancer. Other health effects of flaxseed, such as protection from heart disease and arthritis, are due to a high concentration of the omega-3 fatty acid ALA. Flaxseed contains 35% of its mass as oil, of which 55% is ALA. Other foods and oils contain ALA. However, at approximately 7 g per tablespoon, flaxseed oil is by far the richest source. Flax seed has been given in studies at doses from 15 to 50 g/day.
Flax is an excellent source of both soluble and insoluble fiber, providing 3 g of fiber per tablespoon. This helps keep the bowels regular. Flaxseed’s laxative effects come from the fiber and mucilage content in the seeds. Approximately 40% of flax seed is made up of fiber, about 10% soluble fiber and 30% insoluble fiber. Soluble fiber dissolves in water and forms a gel that travels through intestines. Insoluble fiber stays intact, travels through gut and helps pass food. If you are taking flax seed for constipation, consume 2 tbsp. Like other sources of fiber, flaxseed should be taken with plenty of fluids. In a clinical trial, 55 participants with chronic constipation caused by irritable bowel syndrome received either ground flaxseed or psyllium seed daily for three months. Those taking flaxseed had significantly fewer problems with constipation, abdominal pain. Commission E (Germany’s regulatory agency for herbs) authorizes the use of flaxseed for various digestive problems, such as chronic constipation, diverticulitis, irritable bowel syndrome, and general stomach discomfort.
A few studies have shown flaxseed to be as efficacious in treating hot flashes and night sweats as hormone replacement therapy. Flaxseed has been given in doses of 25 to 40 g/day in studies and demonstrated effect in postmenopausal women suffering hot flushes. A 2002 study in Obstetrics and Gynecology found that flax seed supplements were equally as effective as hormone replacement therapy in reducing menopausal symptoms. In a clinical trial, 28 women consumed four tablespoons of ground flaxseed daily—two in the morning, two at night. After 6 weeks, the frequency of their hot flashes dropped, on average, from 7.3 to 3.6 a day. In a study was conducted on 188 women in 2009 and found no statistically significant difference in mean hot flash scores between women taking flaxseed and those taking a placebo. Osteoporosis is characterised by low bone mass, which leads to an increase risk of fractures, particularly the hips, spine and wrists. Animal-based studies demonstrate that adding flaxseed oil to the diet could reduce the risk of osteoporosis in postmenopausal and women with diabetes, according to a report to be published in the International Journal of Food Safety, Nutrition and Public Health.
Flax contains lignans and ALA, both of which decrease inflammatory reactions. Lignans and ALA block the release of pro-inflammatory cytokines. Flax ALA has been shown to lower blood levels of a compound called (CRP) C-reactive protein. (Patients with elevated basal levels of CRP are at an increased risk for, hypertension, cardiovascular disease and diabetes. CRP levels of 0.3 mg/dL or greater are related with a higher risk of death in patients with acute coronary syndromes). Through these properties, flax consumption may help prevent and treat disorders characterized in part by an over-stimulated immune system. Such disorders include atherosclerosis, diabetes, rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis.
ALA in flaxseed enhances phospholipid ALA, DHA and EPA levels in mononuclear cells, neutrophils, lipoproteins, and platelets. This change in membrane phospholipid content results in reduced biosynthesis of arachidonic acid from linoleic acid and decreased production of the proinflammatory eicosanoids, LTB4 (leukotriene B4) and TXA2 (thromboxane A2). Lignans have been shown to decrease the production of tumor necrosis factor alpha and IL-6 in microglial cells of rats. In a clinical trial of 28 healthy men, consuming flax oil for four weeks resulted in a decrease in tumor necrosis factor alpha and IL-1ß production of approximately 30% in mononuclear cells. In the Nurses’ Health Study, the greater the ALA intake, the reduce the concentration of the inflammatory markers in the blood. These results indicate that ALA helps reduce inflammation and therefore lowers chronic disease risk.
Flaxseed decreases the production of major systemic markers of inflammatory activity, including eicosanoids, cytokines and platelet-activating factor. Flax is very high in the omega-3 fat ALA (alpha-linolenic acid). Two other omega-3 fats are DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). All of these omega-3 fatty acids help lessen inflammation, which is a trigger for heart disease, cancer, and arthritis. In a clinical trial, the ALA content of red blood cell membranes increased 225%, and their content of EPA increased 150%, in healthy men who ate a diet enriched with flax oil for twelve weeks.
The results of one large cohort study and two clinical trials indicate that flax and its essential omega-3 fat (ALA), decrease the blood levels of soluble cell adhesion molecules. Cell adhesion molecules are biomarkers of early events in the development of atherosclerosis or hardening of the arteries. Results from the Health Professionals Follow-up Study of 45,722 men showed that each one gram of ALA in the daily diet was associated with a 47% lower risk of heart disease among men with low intakes of DHA and EPA.
Populations with high intakes of ALA have a low risk of cardiovascular diseases such as CHD (coronary heart disease) and stroke. In a case-control study of 96 middle-aged men with incident stroke, found that a significant 0.06% increase in phospholipid ALA content was associated with a 28% decrease in the risk of stroke. A 0.13% increase in the serum level of ALA was linked with a 37% decrease in the risk of stroke. In the Lyon Diet Heart Study, ALA was associated with a reduction risk of recurrent fatal and nonfatal myocardial infarction, and a 73% decreased in risk of primary end points between the experimental and control groups. Some researches have showed 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. Regular use of flaxseed may influence the progression of atherosclerosis. Lignans in flaxseed have been shown to lessen atherosclerotic plaque buildup by up to 75%.
Arrhythmias usually precede a myocardial infarction and may ultimately cause death. Omega-3 fatty acids may protect against arrhythmia by helping heart muscle cells remain stable electrically and by preventing them from becoming hyperexcitable. In test tube studies of rat heart cells, omega-3 fats decreased the electrical excitability of the heart cells, making them less likely to develop abnormal heart rhythms. Pure preparations of ALA, DHA and EPA are equally good at protecting against fatal arrhythmias in dogs. In a study, pure solutions of ALA, EPA and DHA were infused separately. All three omega-3 fats reduced significantly the occurrence of ventricular fibrillation and protected a majority of dogs from fatal arrhythmias. According to a study; eating flaxseed was associated with reduced blood pressure in people with hypertension. A research team led by Dr. Grant Pierce, assessed 110 hypertensive patients with peripheral artery disease, which is strongly associated with high blood pressur. They sought to determine if adding 30 g of milled flaxseed each day for 6 months would lower blood pressure. In the placebo group, systolic blood pressure increased slightly while diastolic blood pressure remained steady. In the flaxseed group, systolic blood pressure dropped an average 15 mm Hg and diastolic blood pressure fell an average 8 mm Hg. “These anti-hypertensive effects of flax seed are amongst the most strong ever observed,” Dr. Grant Pierce said. “The change in blood pressure from flaxseed could result in about a 50% reduction of strokes and 30 % less heart attacks.”
Flax contains lignans which reduce the risk of prostate cancer in men and breast cancer in women. Flaxseed has been shown to affect intracellular signals within the body that may play a role in breast and prostate cancer growth. Lignans are estrogen-like chemical compounds with antioxidant effects able to scavenge free radicals in the body. Flaxseed is considered to be one of the most important sources of lignans. Flax contains up 75 to 800 times more lignans than other plant sources, such as whole grains and legumes. (When flaxseed is eaten, the lignans are activated by bacteria in the intestine. But, flaxseed oil does not contain the lignan).
Alpha-linolenic acid (ALA) in flax seed has shown promising results in reducing the risk of cancer because of its high concentration of lignans. These compounds interfere with the cancer-promoting effects of estrogen by binding to estrogen receptors. Flaxseed inhibits the growth and metastasis of human breast cancer, prostate cancer and melanoma in vitro and in mice. In a cell culture study, flaxseed lignans reduced stickiness and movement of breast cancer cells, both properties related to the cancer’s ability to spread or metastasize.
A 2004 article reported in the Nutrition Journal reports that eating flaxseed, along with plenty of fruits and vegetables, can help reduce risk of cancer. In a study, mice were injected with human cancer cells and then fed a typical laboratory chow diet for eight weeks. At eight weeks, rats were randomly assigned into a group that continued with the chow diet or to a 10% flaxseed diet. At the end of the study period, flax seed supplementation was shown to reduce the tumor growth rate and reduce metastasis by 45%. In another study reported in Molecular Nutrition & Food Research in 2010, flaxseed oil prevented breast tumors from growing in cancer patients.
Findings from a “Duke University Medical Center” small study on pre-surgical prostate cancer patients indicate “a flaxseed-supplemented, fat-restricted diet may affect prostate cancer biology and associated biomarkers”. In a clinical trial, ate a low-fat diet with 30 g of flaxseed daily lowered PSA (prostate specific antigen) levels in men with a precancerous prostate condition called prostatic intraepithelial neoplasia. In a study of 25 men with prostate cancer found that a low-fat diet along with flaxseed reduced serum testosterone, slowed the growth rate of cancer cells, and increased the death rate of cancer cells. One study presented at the 43rd annual meeting of the American Society of Clinical Oncology demonstrated that consuming flaxseed can stop prostate cancer tumors from growing. “Excited that this study showed that flaxseed is safe and associated with a protective effect on prostate cancer “ said Dr Wendy Demark-Wahnefried. After flax seed is consumed, its lignans are converted in the intestine into enterolactone, which then enter the bloodstream. New findings suggests that flaxseed may help avert prostate cancer by boosting blood levels of useful enterolactones. In a study that investigated blood enterolactone levels in men with prostate cancer versus healthy controls, men with the highest enterolactone levels were 82% less likely to have prostate cancer.