Canola Council of Canada
Omega-3: Canola an Untapped Resource to Improved Health
Dr. Curtis Ellison
Chief, Section of Preventive Medicine and Epidemiology,
and Professor of Medicine and Public Health
Boston University School of Medicine
Certain plants (plankton, flaxseed, canola, soy) contain alpha-linolenic
acid (ALA), an omega-3 essential fatty acid. When fish eat plankton, ALA
is changed into "fish oils" (EPA and DHA). Humans get omega-3
fatty acids from fish or fish oils or from plant sources, especially from
the consumption of canola oil.
Many studies have shown that fish consumption decreases the leading
cause of death in the US and in the entire developed world: coronary
heart disease (CHD). Some, but not all, studies on fish oils have shown
similar protection against CHD, especially against the occurrence of
sudden death. There have been fewer studies on ALA, but they have shown
that ALA may be very protective against CHD, and has some potential
advantages over the use of fish oils.
While the initial approach for the dietary prevention of coronary heart
disease focused on decreasing saturated and total fats, such attempts had
very little success. Only when data from the Seven Counties Study were
carefully analyzed did scientists realize that the type of fat, not all
fat, was the important factor: monounsaturated and polyunsaturated fats,
especially the omega-3 series of polyunsaturated fats, proved to provide
the most protection against coronary heart disease. The particular site
in the Seven Countries Study with, by far, the lowest risk of heart
disease was Crete.
In the 1990's, Professor Serge Renaud tried to determine the key features
of the diet of the cohort in Crete that led to their protection against CHD
and total mortality and discovered that increased fruits and vegetables,
more fat (mainly from olive oil), and a high intake of ALA appeared to be
the most important. He developed a Mediterranean-type diet similar to that
of the subjects in Crete and tested it in the Lyon Diet Heart Study, comparing
it with the typical low-fat, low-cholesterol diet as advocated in the US by
the American Heart Association and the National Cholesterol Education Program
(NCEP). The single most important aspect of the diet was probably the use of
a canola oil-based margarine. The results were astounding! The risk of
subsequent heart problems or death among the subjects in the Lyon study on
the Mediterranean-type diet was about 75% lower than among subjects on the
low-fat, low-cholesterol diet.
A number of other studies have shown protection against CHD, especially against
sudden death, of omega-3 fatty acids in the form of fish oils, but few studies
have been done testing ALA. Those that have been done support a strong protection
against CHD and cardiovascular risk factors from dietary sources of ALA (mainly
canola oil in the US).
A Mediterranean-type diet with the use of olive oil, canola oil, and
especially a canola oil-based margarine, seems to be the preferable
dietary approach to advise for the prevention of heart disease, as
well as for the prevention of cancer and other chronic diseases. The
acceptability of such a diet among Americans will be described.
The key points of my presentation will be that (1) diet relates to
the risk of CHD and death, but saturated fat and cholesterol are
not the whole story; (2) the Mediterranean-type diet seems to be
the healthiest dietary approach, based on results from the Seven
Countries Study, the Lyon Diet-Heart Study, and other research,
and (3) ALA has many health benefits and research data now indicate
that canola oil should be considered as a key component of the
"Healthy Diet of 2004."
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