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FLAX FACTS FLAX A SMART…
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Created: Thu Sep 14 19:13:12 2006
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FLAX FACTS
FLAX A SMART CHOICE
by Dr. Diane H. Morris
Humans have been eating flax for thousands of (see Figure 1). Most of the fatty acids in flax are
years. Flax is a founding crop, being one of the first polyunsaturated. Flax is particularly rich in alpha-
domesticated plants. Its cultivation likely began in the linolenic acid (ALA), the essential omega-3 fatty
fertile valleys of the so-called Fertile Crescent in acid. As little as one tbsp of ground flax provides
Mesopotamia about 8,000 to 10,000 years ago. Flax 1.8 g ALA, more than enough to meet the daily
was valued in Ancient and Early Modern times as both recommended intake for this nutrient.5
a food and medicine.1 FIGURE 1
Today, consumers turn to flax for its pleasant, nutty Fatty Acid Composition of Flax Oil
flavour and many health benefits. Clinical and
large-scale population studies show that flax improves
laxation, lowers blood cholesterol, aids in blood
glucose control, and blocks inflammation.2 Because
it has an anti-inflammatory effect,3,4 eating flax Saturated
fatty acids
regularly may help prevent and treat chronic diseases 9%
in which inflammation plays a role chronic diseases
like heart disease, stroke, diabetes, cancer, obesity, Polyunsaturated fatty acids Monounsaturated
Omega-3s fatty acids
the metabolic syndrome, and Alzheimer disease. Here
57 % Polyunsaturated fatty acids 18 %
are good reasons to eat flax. Omega-6s
16 %
Major Nutritional Components
of Flax A Low Omega-6/Omega-3 Fatty
The major nutritional components of flax are oil Acid Ratio
(fat), protein, and dietary fibre, as shown in Table 1. Because of its high ALA content, flax has an
Milled flax provides about 36 kcal/tbsp. Flax oil omega-6/omega-3 fatty acid ratio of 0.3:1. Consuming
provides about 124 kcal/tbsp. Ground flax is very flax, flax products, and omega-3 enriched eggs derived
low in carbohydrates (sugars and starches), providing from hens fed flax or other similarly enhanced foods
only 0.1 g/tbsp one reason why flax is popular with increases the omega-3 fatty acid content of the diet
people following a high-protein, low-carbohydrate and improves the dietary omega-6/omega-3 fatty acid
weight-loss diet.2 ratio. Consumers are advised to increase their omega-3
fat intake because the typical Western-type diet is high
TABLE 1
in omega-6 fats and low in omega-3 fats compared
Composition of Flax As a Food
with the Paleolithic diet on which humans evolved.6
Fata 41%
Eating less omega-6 fats and more omega-3 fats may
help lower the risk of chronic diseases like heart
Total dietary fibre 28%
disease, stroke, and cancer.
Protein 20%
Moisture 7% Essential Fatty Acids
Ash 4% Flax contains two essential fatty acids (EFAs)
a
Analysed by the American Oil Chemists' Society's (AOCS) Official Method
alpha-linolenic acid (ALA), the parent fatty acid of the
Am 2-93, which is based on the Federation of Oils, Seeds and Fats Associations omega-3 family, and linoleic acid (LA), the parent fatty
Ltd. (FOSFA) Official Method. The American Organization of Analytical Chemists acid of the omega-6 family. EFAs are required for
(AOAC) Method 996.06 will produce a lower fat content.
maintaining the structure of cell membranes and the
health of the skin, and they are involved in cholesterol
Additional information about the nutrient content of flax, transport and metabolism. EFAs can be converted to
including its vitamin and mineral content and amino acid compounds called eicosanoids, which play a role in
profile, can be found in the Flax Council of Canada's book,
inflammatory reactions.2
Flax A Health and Nutrition Primer. The book is available
in PDF format on the Council's website at www.flaxcouncil.ca
Lignans
Lignans are both antioxidants and phytoestrogens.
A Unique Mix of Fatty Acids Antioxidants are compounds that work to keep oxygen
Flax is naturally low in saturated fat and has a from reacting with and damaging proteins, fats and
moderate amount of monounsaturated fat other compounds in our tissues. Phytoestrogens are
compounds found in plants that can have weak cancers of the GI tract and the lung. A protective effect
estrogen activity in animals and humans. of fibre-rich diets for cancers of the breast and prostate
The main lignan in flax is secoisolariciresinol has not been established conclusively. Even so, diets
diglycoside (SDG). The SDG found in flax and other rich in fibre from fruits, vegetables, and whole grains are
foods is converted by bacteria in the gut to the lignans less likely to promote obesity itself a risk factor for
found in humans and other mammals enterodiol cancer because these foods tend to be low in fat.13,26
and enterolactone.
The level of enterodiol and enterolactone in blood It Tastes Good, Too!
and urine reflects the lignan content of the diet. In one Flax is rich in ALA, the essential omega-3 fat;
study of nine healthy young women, for example, lignans, which are phytoestrogens and antioxidants;
eating milled flax for seven days produced significant and dietary fibre, which helps maintain bowel
increases in the plasma and urinary concentrations of function. Just as important as its nutrient content is
enterolactone and enterodiol.7 its taste flax has a mild, nutty flavour. It can be
Lignans protect against cancer by blocking certain mixed into salads, soups, stews, chilies, hamburgers,
enzymes involved in hormone metabolism and vinaigrettes, hot and cold cereals, fruit smoothies,
interfering with the growth and spread (metastasis) of cookies, muffins and bread dough. Indeed, it can be
tumour cells.8,9 Indeed, populations with high intakes added to just about any recipe!
of lignans, antioxidants and phytoestrogens from fruits,
vegetables, nuts and whole grains have low rates of
References
cancer of the ovaries10,11 and the Gastrointestinal (GI)
tract including cancer of the mouth, esophagus, 1. Vaisey-Genser M, Morris DH. In: Flax--The Genus Linum.
stomach, colon and rectum12-18 compared with those Muir AD, Westcott ND, eds. New York: Routledge, 2003,
who have low intakes of these foods.19 pp. 1-21.
In addition to having anticancer effects, a new study 2. Flax Council of Canada. Flax--A Health and Nutrition
suggests that postmenopausal women who have a high Primer. Winnipeg, MB, 2003.
intake of lignans perform better on tests of memory than 3. Lopez-Garcia E, et al. J Nutr. 2004;134:1806-1811.
women with low intakes. The intake of lignans, but not 4. Zhao G, et al. J Nutr. 2004;134:2991-2997.
isoflavones (found in soy products, beans, peas, nuts), 5. Institute of Medicine. Dietary Reference Intakes, Part I.
was related to better cognitive function in this study.20 Washington, DC: National Academies Press, 2002, pp.
8-1 8-97.
6. Simopoulos AP. Prostaglandins Leuko Essent Fatty Acids.
Other Phytochemicals
1999;60:421-429.
Flax contains several phytochemicals. ("Phyto" means 7. Nesbitt PD, et al. Am J Clin Nutr. 1999;69:549-555.
"plant.") In addition to the lignans, which are abundant 8. Brooks JD, Thompson LU. J Steroid Biochem Mol Biol.
in flax, flax contains phenolic acids, cinnamic acids, 2005;94:461-467.
flavonoids, and lignins. These compounds are 9. Thompson LU, et al. Clin Cancer Res. 2005;11:3828-3835.
antioxidants and affect cell growth and viability 10. Pelucchi C, et al. Eur J Cancer. 2001;37:2235-2239.
actions that may increase their potential use as agents 11. McCann SE, et al. J Nutr. 2003;133:1937-1942.
which protect against cancer and heart disease.21,22 12. Kushi LH, et al. Am J Clin Nutr. 1999;70(suppl):451S-458S.
13. Greenwald P, et al. Eur J Cancer. 2001;37:948-965.
Dietary Fibre 14. Levi F, et al. Eur J Cancer. 2001;37:2091-2096.
Flax is a source of dietary fibre, providing about 15. Bingham SA, et al. Lancet. 2003;361:1496-1501.
2.2 g/tbsp of ground flax. It contains both insoluble 16. Peters U, et al. Lancet. 2003;361:1491-1495.
and soluble fibre. Insoluble fibre helps improve 17. Johnson IT. Mutation Res. 2004;551:9-28.
laxation and prevent constipation, mainly by increasing 18. Slattery ML, et al. Am J Clin Nutr. 2004;79:274-281.
fecal bulk and reducing bowel transit time.13 In a 19. Rose DP. Annu Rev Publ Health. 1993;14:1-17.
recent study of elderly residents in a long-term care 20. Franco OH, et al. J Nutr. 2005;135:1190-1195.
facility, adding 1 tbsp of milled flax to the daily diet 21. Arts ICW, Hollman PCH. Am J Clin Nutr.
resulted in a 32% increase in bowel frequency by the 2005;81(suppl):317S-325S.
end of the 4-month intervention. The use of 22. Lambert JD, et al. Am J Clin Nutr. 2005;81(suppl):284S-291S.
suppositories decreased 50% in this population over 23. Hill C, et al. Investigating the use of ground flaxseed to
the course of the study.23 improve bowel regularity in older adults living in a long term
The water-soluble fibre fraction of flax makes up care setting. Report to the Flax Council of Canada, 2005.
about one-third of total dietary fibre. The main soluble 24. Health Canada. Canada's Food Guide to Healthy Eating.
fibre in flax is mucilage gum. Water-soluble fibre helps Available at www.hc-sc.gc.ca/fn-an/index_e.html.
maintain blood glucose levels and lower blood 25. U.S. Department of Health and Human Services, U.S.
cholesterol levels.2 Department of Agriculture. Dietary Guidelines for Americans,
North Americans are advised to eat more fibre-rich 2005. Available at www.healthierus.gov/dietaryguidelines.
foods,24,25 as diets rich in fibre appear to protect against 26. Key TJ, et al. Lancet. 2002;360:861-868.
Flax Council of Canada, 465167 Lombard Ave., Winnipeg, MB, Canada R3B 0T6, E-mail: flax@flaxcouncil.ca Website: www.flaxcouncil.ca 10.05PD09.06
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