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Flax
for Health
This
ancient grain is a good source of essential fat, dietary
fibre and lignans
By Artur Klimaszewski, MD
Source: Bioriginal Publishing
Date Published: March 2000
Ancient records
show that the human race has consumed flaxseed since
the beginning of civilization. Before 5,000 BC, Egyptians
carried flaxseed in their medicine bags. Much later
in history, Hippocrates wrote about using flax for the
relief of abdominal pains. In 8th century France, King
Charlemagne considered flax so important for the health
of his subjects that he passed laws and regulations
requiring its consumption.
Over the
centuries, the growing of flaxseed has spread across
Europe, Africa, and, finally, to North America. Flax
was the first oilseed to be widely grown in Western
Canada.1 Today, scientific findings are confirming the
nutritional benefits of flaxseed in a balanced diet.
Flaxseed offers:
* A high
content of Alpha Linolenic Acid (ALA). ALA is an essential
fatty acid that is converted in the body to EPA and
DHA, two compounds recognized for their benefits in
heart health, arthritis, thrombotic disease, and brain
function. ALA also has many benefits independent of
EPA and DHA. ALA is useful in heart disease, improving
immune function, cancer prevention, and male infertility.
* Large quantities
of soluble and insoluble dietary fibre, which helps
increase laxation.
* The highest
plant source of lignans, which are strong antioxidants
that could reduce the aging process and protect against
some environmental toxins. Lignans may help reduce the
risk of certain forms of cancer, particularly cancers
of the breast and colon.
Flaxseed
as a source of "good" fats
Flaxseed oil is a remarkably good source of Alpha Linolenic
Acid (ALA). ALA is an essential fatty acid and is one
of the essential nutrients that is necessary for life.
ALA must be obtained from the diet - the human body
is not able to manufacture it.
Approximately
20% of the ALA we consume is transformed in our bodies
into two other fatty acids: EPA and DHA (these are the
same beneficial compounds found in fish oil). The benefits
of EPA and DHA include: protection from fatal heart
attack, decreased inflammation and pain in arthritis,
and protecting from thrombotic disease.
As well,
DHA alone is noted for its effects on brain function,
mood and behaviour. DHA is one of the building blocks
for brain growth and development. Numerous animal studies
show that DHA improves learning, vision processes, memory,
and concentration.2 In a Rotterdam study with humans,
researchers found that elderly men who consumed more
DHA were able to better sustain their mental abilities
- including memory, concentration, and ability to communicate
verbally.3
In a Japanese
study, students who took supplemental DHA were able
to keep their aggression in much better control than
those in the placebo group. 4 Due to the benefits of
EPA and DHA produced from ALA in the diet, flaxseed
consumption may be particularly important for vegetarians
and people who prefer not to eat fish often.
In the past,
most research on ALA has related to its role in producing
EPA and DHA. Research in recent years, however, has
brought evidence that ALA has other beneficial functions
in the human body beyond its conversion to EPA and DHA
- ALA is useful in protecting against heart diseases,
improving immune function, cancer prevention, and improving
male infertility.
Heart
diseases
A growing body of research clearly shows that flaxseed
is a beneficial dietary supplement for people who want
to reduce their risk of heart attack and atherosclerosis
and maintain a healthy level of blood cholesterol.
Heart
attack: Population studies suggest that a diet rich
in ALA protects against heart attack. Animal studies
show that ALA can also reduce the occurrence of malignant
heart arrhythmia such as ventricular fibrillation or
ventricular tachycardia. Furthermore, dietary ALA can
prolong the lives of those who have already experienced
a heart attack. This was evidenced in a recent North
American study of more than 76,000 nurses whose dietary
habits were followed for more than 10 years.5
It was also
evident in a seven country study which showed the population
on the island of Crete had a longer life span and a
lower cardiovascular mortality rate than other populations.
Their good health was partly attributed to their diet,
which was high in ALA. A study in France found that
recent heart-attack victims that followed the Cretan
diet saw their mortality rate fall by more than 70%.6
Atherosclerosis:
Multiple studies have well documented the role of ALA
in the prevention of atherosclerosis, which is the underlying
cause of many cardiovascular diseases, including heart
attacks. It has been found that the addition of ALA
to the diets of hypertensive rats significantly extends
their life span due to the inhibition of the growth
of atherosclerotic plaque in their blood vessels.7
Cholesterol:
Researchers at the University of Toronto found that
total blood cholesterol levels dropped by 9% and LDL
decreased by 18% when a group of 9 healthy women added
flaxseed to their regular diets. The women ate 50 g
of milled flaxseed a day (as milled flaxseed or cooked
into bread) for four weeks.8 High total cholesterol
and LDL-cholesterol ("bad" cholesterol) levels are considered
to be risk factors for atherosclerosis.
In another
similar study, 10 young, healthy men and women ate flaxseed
muffins providing 50 g of flaxseed per day for four
weeks. Total plasma cholesterol was reduced 6% and LDL-cholesterol
was reduced up to 8%. Plasma HDL-cholesterol and triglycerides
did not change.8
Lastly, a
group of researchers conducted a three-month clinical
trial studying the effects of flaxseed consumption on
a group of 15 hyperlipemic men and women. The patients,
who were on long-term intake of vitamin E, added three
slices of flaxseed-containing bread and 15 g of ground
flaxseed to their daily diets. The result was a significant
reduction in cholesterol levels - total blood cholesterol
was reduced by 7% and LDL cholesterol levels were reduced
by 11%. HDL cholesterol levels did not change during
flax seed consumption.9
Improved
immune function
Immunity is the body's ability to defend itself successfully
against foreign substances. Flaxseed contains two components
that may improve immune function: Alpha Linolenic Acid
and lignans. Recent research suggests that ALA and lignans
in flaxseed modulate the immune response and may play
a beneficial role in the clinical management of autoimmune
diseases. 10,11
For example,
some researchers believe that flaxseed is a potential
treatment for lupus nephritis after the results of a
1995 study of 9 patients. Patients started with 15 g
of flaxseed daily for four weeks. The dosage was increased
to 30 g daily for the next four weeks and 45 g daily
for the last four weeks. The researchers concluded that
30 g flaxseed a day was well tolerated and conferred
benefit in terms of kidney function as well as inflammatory
and atherogenic mechanisms important in the pathogenesis
of lupus nephritis.12
Flaxseed
may also be useful in the nutritional management of
other disorders in which the immune system becomes overstimulated,
such as rheumatoid arthritis, psoriasis, and multiple
sclerosis.13
Cancer
prevention
Flaxseed contains abundant amounts of lignans and the
essential fat Alpha Linolenic Acid. These compounds
have been shown to have anticancer effects in animals.14,
15 Flaxseed appears to protect against certain cancers
in humans, particularly hormone-sensitive cancers such
as those of the breast, endometrium and prostate. 16,
17, 18,19 Long-term studies of the effects of flaxseed
in women with breast cancer are underway.
Male Infertility
Deficiency of DHA in sperm cells is one of the markers
of sub-fertility in men. A Belgian study demonstrated
that ALA can pass through the blood-testis barrier and
correct the deficiency of DHA in sub-fertile men. Interestingly,
fish oil supplementation did not achieve a similar effect,
showing again that ALA has its own unique properties
not matched by EPA and DHA from fish oil. 20
Relief
from constipation: flaxseed fibre
Flaxseed, like cereals and legumes, has the potential
to increase laxation because it provides dietary fibre.
There is about 30 g of dietary fibre in 100 g of dry
flaxseed. This can be especially important for the elderly,
who often have chronic difficulties with laxation due
to inactivity, low-fibre diets, and/or use of medication
for other conditions. In a study of seven subjects whose
average age was 78 years, the daily frequency of bowel
movements and the number of consecutive days with bowel
movements increased among subjects who complied with
the dietary regimen of eating 50 g of flaxseed daily.
The flaxseed was provided in muffins and consumed for
a period of four weeks.21
Flaxseed
as a source of lignans
Flaxseed is the richest plant source of lignans, which
are strong antioxidants that could reduce the aging
process and protect against some environmental toxins.
Several animal studies have shown that lignans from
flaxseed reduce cancer tumours. It is likely that lignans
also play a role in lowering blood cholesterol. Since
lignans are digested into estrogenic compounds, many
of the health benefits of lignans may be attributable
to their hormonal effects. Other benefits are derived
from their non-hormonal metabolic properties such as
influence on enzymes, protein synthesis or cellular
transport.
Adding
flax and flaxseed oil to your diet
Flaxseed comes in many forms. It is available whole,
milled, or as an oil in bottles or capsules. Whole and
milled flaxseeds may be used in cooking and baking,
while the oil is useful for daily supplementation. Whole
flaxseed cannot be very well digested - flaxseed are
hard to crack even with careful chewing - therefore
consumption of the whole flaxseed releases only a small
percentage of its available nutrients. One to two tablespoons
of milled flaxseed a day (approximately 30 g) may provide
adequate supplementation of ALA and lignans. Organic
flax oil contains some beneficial lignans while refined
flaxseed oil does not. The American recommendation for
adequate intake (AI) of dietary ALA for adults is 2.22
grams/day - approximately 4 grams of flaxseed oil.
References:
- Flax
Council of Canada, 1999.
- Okiniwa
Y. et al. A high linolenate and high alpha-linolenate
diet induced changes in learning behaviour of rats.
Effects of shift in diets and reversal of training
stimuli. Biological and Pharmaceutical Bulliten, 19(4):
536-40, 1996
- Kalmij
S. et al. Polyunsaturated Fatty Acids, Antioxidants,
and Cognitive Function in Very Old Men. American Journal
of Epidemiology Vol. 145. No 1 pp 33-41.
- Hamazaki
T et al. Administration of Docosahexaenoic Acid Infulences
Behaviour of Plasma Catecholamine Levels at Times
of Psychological Stress. Lipids, Vol. 34, Suppl. (1999)
- De Lorgeril
et al. Mediterranean alpha-linolenic acid-rich diet
in secondary prevention of coronary heart diseases.
Lancet, 1994, vol. 343, 1454-1459.
- Renaud
S, et al. Cretan Mediterranean diet for prevention
of coronary heart disease. American Society for Clinical
Nutrition. 1995, 61(Supplement) 1360S-7S.
- Jacob
R. et al. Prolongation of life span in hypertensive
rats by dietary interventions. Effects of garlic and
linseed oil. Basic Research in Cardiology 92(4):223-232,
1997
- Cunnane
SC, et al. Nutritional attributes of traditional flaxseed
in healthy young adults. American Journal of Clinical
Nutrition. 1995 January, 61(1):62-68.
- Bierenbaum
ML, et al. Reducing atherogenic risk in hyperlipemic
humans with flax seedsupplementation: a preliminary
report. Journal of the American College of Nutrition.
1993 October, 12(5):501-4.
- Blackburn
GL. Nutrition and inflammatory events: highly unsaturated
fatty acids (omega-3 vs omega-6) in surgical injury.
Proceedings of the Society for Experimental Biology
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- Parbtani
A and Clark WF. In: Flaxseed in Human Nutrition. Cunnane
SC and Thompson LU, eds. Champaign, IL: AOCS Press,
1995, pp. 244-260.
- Clark
WF, et al. Flaxseed: a Potential Treatment for Lupus
Nephritis. Kidney International. 1995 August, 48(2):475-80
- Calder
P. Immunoregulatory and anti-inflammatory effects
of n-3 polyunsaturated fatty acids. Brazillian journal
of Medical and Biological Research. 1998, vol 31(4),
467-90.
- Yan L.
et al. Dietary flaxseed supplementation and experimental
metastasis of melanoma cells in mice. Cancer Letters.
1998 124(2): 181-6.
- Onogi
N. et al. Suppressing effect of perilla oil on azoxymethane-induced
foci of colonic aberrant crypts in rats. Carcinogenesis,
17(6): 1291-6, 1996.
- Begin
ME et al. Selective killing of human cancer cells
by polyunsaturated fatty acids. Prostaglandins.1985,
vol 19, 177-186
- Begin
ME et al. Differential killing of human carcinoma
cells supplemented with n-3 and n-6 polyunsaturated
fatty acids. Journal of the National Cancer Institute.
1986, vol 77, 1053-1-61.
- Kokoglu
et al. Profiles of the fatty acids in the plasma membrane
of human brain tumors. Cancer Biochemistry Biophysics,
16(4):301-12 1998
- Thompson
LU. Flaxseed and its lignan and oil components reduce
mammary tumor growth at late stage of carcinogenesis.
Carcinogenesis, 17(6): 1373-6 1996.
- Christophe
A at al. Intake of Alpha Linolenic Acid, but not of
Docosahexaenoic Acid, correlates positively with DHA
content, and with parameters for fertilization potential
of human spermatozoa. Abstract for 90th AOCS Annual
Meeting, Orlando, Florida 1999
- Hamadeh
MJ, et al. Nutritional aspects of flaxseed in the
human diet. Proceedings of the Flax Institute. 1992,
4:48-53.
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