Flaxseed & Flaxseed Oils for Omega-3 and EFAs
http://www.countcarbs.com/advice/LCT_flax_omega3_EFAs.htm
Flaxseed and flaxseed oil are currently recognized as appropriate sources
of omega-3 fatty acids by several US government agencies, including
USDA and NIH. These agencies have held conferences and workshops on
the importance of omega-3 fat , which have included recommendations
for consuming flaxseed.1
There are, however, present-day challengers on the Internet to the
use of flax as food. The Now Age Press website is a typical example.
Critics take issue with any statement made in recent years that refers
to flaxseed as having a history as a “staple” food in any
culture. These critics will admit only to the use of flaxseed as food
in times of famine. In addition to their challenge to the notion of
the use of flaxseed or flaxseed oil as food in antiquity, as well as
to aspects of safety related to the presence of lignans and various
anti-nutrients such as cyanogenic glycosides in flaxseed, the writers
for these websites make substantive mistakes about composition, stating,
for example, that hemp oil has levels of omega-3 fatty acids as high
as flax oil. Actually, flax oil contains about 60 percent of total fatty
acids as omega-3 fatty acids, compared to about 20 percent for hemp
oil.2
When we search out historical documents written a century ago, however,
we are presented with another view. The 1911 edition of the Encyclopaedia
Britannica reported that “Linseed [flaxseed] formed an article
of food among the Greeks and Romans, and it is said that the Abyssinians
at the present day eat it roasted. The oil is to some extent used as
food in Russia and in parts of Poland and Hungary.”
The article also describes concern voiced over “. . . direct
adulterations. . . [by]. . . admixture of cheaper and inferior oil-seeds.
. . .” In 1864, a union of traders of linseed oil was formed in
England to prevent this adulteration by monitoring all imported oil.3
The more recent Cambridge World History of Food records the use of
flaxseed oil for cooking in Russia in the 19th Century and the use of
seeds for making tea.4
A recent text on flaxseed, edited by researchers at the University
of Toronto, contains discussions of historical uses as a food, both
directly and indirectly. In the introduction, we learn that the edible
flaxseed was the one predominantly grown in India, that flaxseed is
consumed in the diet as oil in China, that it is consumed in Ethiopia
in a stew (wat), as a porridge (gufmo), and as a drink (chilka), and
has been part of the traditional foods in Egypt since the time of the
Pharaohs.5
In the US, the earliest record in Food and Drug Administration (FDA)
writings raises the question of GRAS status for flaxseed use in foods.
This appears in correspondence to the FDA in 1948 when the food industry
initiated an inquiry about the use of flax in cereal foods. The FDA
originally declined the GRAS status request because the use of flax,
as (or in) food prior to 1958, was in other countries and not in the
US. In addition, the FDA indicated concern about untreated flaxseed
being a source of toxic hydrocyanic acid and posted an import alert
in 1978; this decision was abandoned in 1982 when the import alert was
canceled and flaxseed was permitted in bread in levels of 10-12 percent.
The agency stated that there was no concern that there would be “.
. . any more exposure to hydrogen cyanide than from other foods such
as lima beans, fava beans, chickpeas, cassava, yams, cashews or almonds.
. . ”6
Researchers from two universities evaluated flaxseed powder consumption
in women and reported that the lignans, which they considered as protective
against certain cancers, were normally metabolized by the microflora
in the gut. These researchers reported that the possible cyanide exposure
from 60 grams of raw flaxseed in healthy individuals is not hazardous;
further they indicated that raw flaxseed is traditionally consumed in
10-gram amounts (approximately 1 tablespoon).7
So how much flaxseed, or flaxseed oil is appropriate and unquestionably
safe? The recommendation from the US government agencies is usually
2 tablespoons of flaxseed per day to supply omega-3 fatty acids for
a 2000 kcal diet. (The flaxseed needs to be ground in order for the
proper digestion of the seeds to take place.) Two tablespoons of flaxseed
is about 20 grams of seed and since there is about 40 percent oil in
the seeds and about 50-60 percent omega-3 in the oil, 20 grams of seed
could provide about 8 grams of flaxseed oil and about 4 grams alpha-linolenic
acid, the basic omega-3 fatty acid. Four grams of omega-3 fatty acids
is about 36 calories, which is slightly more than the usual recommendation
of 1.5 percent of calories for a 2000 calorie intake. The amount of
flaxseed oil needed to provide this much omega-3 is about 1.5 to 2 tsp
per day.8 If you are getting omega-3 fatty acids from other sources
in your diet, then the recommended amount of flaxseed oil would be less.