The Flax Plant

Flax (Linum usitatissimum L.) is an ancient oilseed plant with a variety of uses, every part of the plant is used for some purpose. The stem is a source of fiber for textile fabric (linen); the oil is an ingredient in paint, varnish, and soaps; the meal is an ingridient in animal feed. Whole flaxseed, also known as linseed, as ground (meal), powder and intact seed and oil capsule, is a source of essential fatty acids and fiber for humans. There is growing evidence that flax seed is beneficial for improving general health and preventing diseases.

Flaxseed Nutritional Value

Whole flax seed (ground meal, powder or intact seed) contains:

Flaxseed fat is mostly unsaturated fat (18% monosaturared fat, 73% polyunsaturated fat). The saturated fat is only about 9% of the total fat. More than 50% of the fat in flax seed is an essential omega-3 fatty acid called alpha-linolenic acid (ALA), which makes flax seed one of the richest plant source of dietary omega-3 fatty acids.

Flax seed is high in lignan, especially the hull. There is 30.9mg lignan /gram hull and 12.9mg lignan/gram of whole flaxseed. Unlike the ground meal and powder, flax seed oil contains no dietary fiber.

The protein in flaxseed is of high quality, meaning it has high digestibility and biological value.  It is mostly globulins, glutelins (gluten) but none of albumins. Among the amino acids, glumatic acid and arginine are the most abundant. Lysine, on the other hand, is the most limiting amino acid.

Flax seed is also a good source of other vitamines and minerals: vitamins E and B, calcium, iron, and potassium. It is also rich in phytosterols, antioxidants, such as lignans (also a phytosterogen) and other phenolic molecules.

Flaxseed contains to a small extent cyanogenic glucosides and linamarin, which breakdown to cyanide. They are more in the flaxseed variety grown for fiber (linen, textile) than the variety grown for flaxseed. Immature flaxseed contain more of it than mature seeds. It is estimated that whole flaxseed contains 250 - 500 mg cyanogenic glucosides per 100 gram seed.

More on nutritional profile of flax seed.

Benefits of Flaxseed in Human Health

Flax seed, with all the abundance of nutrients mentioned above, has beneficial effects on human health. The high dietary fiber, due to its high water-holding capacity and low digestibility, increases the bulkiness and gastric emptying of stool. This in effect helps relieve constipation and other irritable bowel syndrome. Lignans, which are antioxidants and phytoetrogens, may help reduce oxidative damage to cells and cellular molecules from free radicals. The alpha-linolenic acid (ALA) is associated with decreased blood pressure in patients with peripheral arterial disease.

Flax seed may lower blood glucose and improve insulin tolerance (diabetes). Whole flaxseed (powder and ground meal) may reduce blood total cholesterol and low-density lipoprotein cholesterol (LDL). Flaxseed can also reduce some markers of inflammation, and raise serum levels of the omega-3 fatty acids, ALA.

Studies suggest that consumption of ground flaxseed meal, at a dosage of 15 - 50 grams per day, can helpl ower serum total and LDL cholesterol with out meaningful change in HDL cholesterol and tryglyceride levels. No similar benefits are reported for flaxseed oil, though.

Flax Seed Diet

Flax seed can be consumed as a dietary supplement in various forms: whole seed, powder, ground (flax seed meal), or oil capsule. Flax seed taken as oil capsule lacks the fiber and lignan components. Flaxseed is used also as an ingredient in muffin, bread, or yogurt. Flaxseed meal can be prepared easily at home or bought in the market.

Side Effects of Flax Seed Oil

There are no recorded flax seed oil side effects on humans. Nevertheless, moderation is necessary. As the Dutch proverb goes “everything preceeded by the word ‘too’ is not good ”. Flaxseed may have side effects when consumed in large quantities, especially if it is uncooked. It contains cynogenic glycosides; and uncooked flaxseed intakes amounting to more than 10 tablespoons may elevate the cynide level to toxic levels. Large intakes of flaxseed may also upset hormonal balance. Studies on animals have reported birth defects. However, in humans, there is no reported danger of flaxseed on pregnancy or children. Most human studies on health benefits of flaxseed used 5 – 10 g/day dose.


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Bloedon, Leanne T., Szapary, Philippe O. 2004. Flaxseed and Cardiovascular Risk. Nutrition Reviews, 62(1): 18-27

Singh KK, Mridula D, Rehal J, Barnwal P. (2011). Flaxseed: a potential source of food, feed and fiber. Crit Rev Food Sci Nutr. 51(3):210-22.

Caligiuri SP, Aukema HM, Ravandi A, Guzman R, Dibrov E, Pierce GN. 2014. Flaxseed consumption reduces blood pressure in patients with hypertension by altering circulating oxylipins via an α-linolenic acid-induced inhibition of soluble epoxide hydrolase. Hypertension. 64(1):53-9.