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.
Uses
Flax 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.
Flax seed
Flax seeds come in two basic varieties: (1) brown; and (2) yellow or golden. Most types have similar nutritional characteristics and equal amounts of short-chain omega-3 fatty acids. The exception is a type of yellow flax called solin (trade name Linola), which has a completely different oil profile and is very low in omega-3 FAs. Although brown flax can be consumed as readily as yellow, and has been for thousands of years, it is better known as an ingredient in paints, fiber and cattle feed. Flax seeds produce a vegetable oil known as flaxseed or linseed oil, which is one of the oldest commercial oils, and solvent-processed flax seed oil has been used for centuries as a drying oil in painting and varnishing.What's It Made Of
Flaxseed contains several phyto (plant) compounds that may be beneficial in humans, including:
- Fiber (including soluble and insoluble)
- Protein -- approximately 20%
- Lignans
- Essential fatty acids (ALA) -- flaxseed is approximately 35% oil, of which 55% is ALA.
Health Benefits
Flaxseeds are rich in alpha linolenic acid (ALA), an omega-3 fat that is a precursor to the form of omega-3 found in fish oils called eicosapentaenoic acid or EPA. Since the fats are found in their isolated form in flaxseed oil, it is a more concentrated source of ALA than the seeds themselves (although it doesn't have the other nutrients that the seeds do). ALA, in addition to providing several beneficial effects of its own, can be converted in the body to EPA, thus providing EPA's beneficial effects. For this conversion to readily take place, however, depends on the presence and activity of an enzyme called delta-6-destaurase, which, in some individuals, is less available or less active than in others. In addition, delta-6-desaturase function is inhibited in diabetes and by the consumption of saturated fat and alcohol. For these reasons, higher amounts of ALA-rich flaxseeds or its oil must be consumed to provide the same benefits as the omega-3 fats found in the oil of cold-water fish.
Yet research indicates that for those who do not eat fish or wish to
take fish oil supplements, flaxseed oil does provide a good alternative.
A study published in the Journal of Nutrition found that
flaxseed oil capsules providing 3 grams of alpha-linolenic acid daily
for 12 weeks—an amount that would be provided by 3 tablespoons of
flaxseed oil a day—increased blood levels of EPA by 60% in a
predominantly African-American population with chronic illness.
A recent MedLine check (MedLine provides access to the published
peer-reviewed medical literature) revealed 1,677 research articles on
linolenic acid, investigating its effects on numerous physiological
processes and health conditions.Cancer
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.
Cardiovascular Disease
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.
High cholesterol
People
who follow a Mediterranean diet tend to have higher HDL ("good")
cholesterol levels. The Mediterranean diet consists of a healthy balance
between omega-3, omega-6, and omega-9 (found in olive oil) fatty acids.
It emphasizes whole grains, root and green vegetables, daily intake of
fruit, fish and poultry, olive and canola oils, and ALA (from flaxseed,
flaxseed oil, and walnuts), along with discouragement of ingestion of
red meat and not much use of butter and cream.
Flaxseed
and flaxseed oil have been reported to possess cholesterol-lowering
properties in laboratory studies. Human studies have used flaxseed
products and measured effects on cholesterol, with mixed results. A
human study found that dietary flaxseed significantly improved lipid
(cholesterol) profile in patients with high cholesterol, and may
favorably modify cardiovascular risk factors.
Diabetes
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).
Inflammation
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.
Hot Flashes
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.
Omega-3-rich Flaxseeds Protect Bone Health
Alpha linolenic acid, the omega-3 fat found in flaxseed and walnuts,
promotes bone health by helping to prevent excessive bone turnover—when
consumption of foods rich in this omega-3 fat results in a lower ratio
of omega-6 to omega-3 fats in the diet.(Griel AE, Kris-Etherton PM, et
al. Nutrition Journal)
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.
Other uses
Although
further research is needed, preliminary evidence suggests that omega-3
fatty acids may help protect against certain infections and treating a
variety of conditions, including ulcers, migraine headaches, attention
deficit/hyperactivity disorder, addiction, eating disorders, preterm
labor, emphysema, psoriasis, glaucoma, Lyme disease, lupus, and panic
attacks.
Available Forms:
Flaxseed
oil should be refrigerated. Use whole flaxseeds within 24 hours of
grinding, otherwise the ingredients lose their activity. Flaxseeds are
also available ground in a special mylar package so that the components
in the flaxseeds stay active. Ripe seeds, linseed cakes, powder,
capsules, and flaxseed oil are all available at health food and grocery
stores.
How to Take It
Pediatric
Flaxseed
oil may be added to a child's diet to help balance fatty acids. If an
infant is breastfed, the mother may ingest oil or fresh ground seed to
increase fat content in breast milk. See adult dosage below.
Children (2 - 12 years): 1 teaspoonful (tsp) daily of ground flaxseeds, or 1 tsp of fresh flaxseed oil for constipation.
Adult
Flaxseed:
Take 1 tablespoonful (tbsp), 2 - 3 times daily or 2 - 4 tbsp, 1 time
daily. Grind before eating and take with lots of water.
Flaxseed
oil: Take 1 - 2 tablespoonfuls daily, or 1 - 2 capsules daily. Flaxseed
oil is often used in a liquid form, which contains approximately 7 g of
ALA per 15 mL tbsp, and contains approximately 130 calories.
As a substitute for fish oil, a dose of 7.2 grams of flaxseed is approximately equivalent to 1 gram of fish oil.
Precautions
The
use of herbs is a time-honored approach to strengthening the body and
treating disease. Herbs, however, contain components that can trigger
side effects and interact with other herbs, supplements, or medications.
For these reasons, herbs should be taken with care, under the
supervision of a health care provider qualified in the field of
botanical medicine.
- 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.
Possible Interactions
Flaxseed
supplements may alter the effects of some prescription and
nonprescription medications. If you are currently being treated with any
of the following medications, you should not use flaxseed without first
talking to your health care provider:
Blood-Thinning Medications --
Omega-3 fatty acids may increase the effects of blood-thinning
medications, including aspirin and warfarin. While the combination of
aspirin and omega-3 fatty acids may be helpful under certain
circumstances (such as heart disease), they should only be taken
together under the guidance and supervision of a qualified health care
provider.
Diabetic Medications --
If you are taking medicines for diabetes, including insulin, you should
only use flaxseed (ALA) under the supervision of a qualified health
care provider.
Oral Contraceptives or Hormonal replacement therapy (HRT) --
Flaxseed may alter hormonal levels and alter the effects of oral
contraceptives or HRT. Only use flaxseed under the supervision of a
qualified health care provider if you are taking hormonal altering
medications such as oral contraceptives or HRT.
Other --
Avoid taking flaxseed at the same time of day as medications and other
supplements, as it may slow down the absorption of oral medications or
other nutrients if taken at the same time. Take the flaxseed either 1
hour before or 2 hours after taking any prescription or nonprescription
medicine or dietary supplement.
Sources:
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
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