The ratio of the essential fatty acids, ω3:ω6, has
drifted from about the 2:1 found in populations suffering few degenerative
diseases such as the Japanese and traditional-living Eskimos to 20:1 or worse
with the industrialization of food production.
We eat way too many ω6 fatty acids from vegetable oils, way too few
ω3 fatty acids from fish.
Even the American Heart Association
acknowledges that ω6 fatty acids in refined vegetable oils promotes
inflammation and the tendency of the blood to clot, and increases risk of both cardiovascular
disease and cancer. Yet their
“heart-healthy” advice is to eat more
ω6-rich polyunsaturated oils to lower cholesterol, which worsens the ω3:ω6 ratio. Perhaps their lowering of the vegetable oil
prescription from 22% to 10% to the current level of 7% is an implicit
acknowledgement that this is bad advice.
One adverse effect of a high intake
of vegetable oils is cancer. In the Veterans
Administration trial, a group of institutionalized men ate soybean oil in
place of saturated fat. While their
incidence of heart disease decreased by a small amount relative to the control
group, a 15% larger number of the treatment group succumbed to cancer, more
than canceling out any benefit.
Interestingly, depressed people
were found to have lower than normal ω3:ω6 ratios.
My book, Food for Vitality
(Bantam UK, 1992), goes into detail about how this works. Briefly, the enzymes which process the
essential fatty acids produce largely anti-inflammatory prostaglandins from the
ω3 oils and mostly inflammatory prostaglandins from the ω6 oils. If the ratio between the oils is healthful,
there is little inflammation in the system.
Importantly, the body’s system for processing the fatty acids requires
specific vitamins and minerals, and is inhibited by several factors. When we eat ώ6 (from vegetable oil, say)
and ώ3 fatty acids from (walnuts or flax seed oil), they compete for the
processing enzymes, which is why the ratio between them is so important. These enzymes elaborate them to become
valuable locally-acting prostaglandin E1 and prostacyclin, which are anti-inflammatory
artery relaxers and anti-clotting factors made from w6 and w3s
respectively. Or, if there’s too much
w6, the enzymes make much more undesirable thromboxane and leukotrienes, which
are inflammatory. Clearly, we want
plenty of w3 to inhibit inflammation, and to make into EPA and DHA for brain,
artery and nerve production and repair.
However, the enzymes are compromised
by viral infections, obesity, diabetes and aging. trans-fats, excess saturated fats, cholesterol and insulin
(consequent on too much sugar) all inhibit their activity. And they also cannot work without the
minerals magnesium, selenium and zinc, and the vitamins B3, B6, C and E, which
are all in short supply in the American diet.
Imagine the body trying to conduct its business with too much
inflammation, and without the raw materials for repair of brain, arteries and
nerves. Well, this is business as usual
on the American diet!
Correcting the ω3:ω6 ratio
in the Lyon
Heart Study reduced heart attacks among a very high-risk population who’d
already had a heart attacks by 47% compared to the control group on the “heart
healthy” American Heart Association diet, a finding so extraordinary that the study
was stopped to avail the control group of this life-saving strategy.
To restore this ratio, I believe it’s
important to replace all
polyunsaturated oils with minimally-processed olive oil, and eat plenty of fish
or take “molecularly distilled” fish oil
supplements. The process of molecular
distillation removes toxic heavy metals such as mercury which ocean fish are
all too likely to be contaminated with.