Since the early 1970’s, “healthy diet” messages have pervaded the United States as a public health measure to reduce the risk of cardiovascular disease. The message was strong: decrease saturated fat intake and replace it with healthy polyunsaturated fats. But
there is now a growing appreciation for the balance
of the two major kinds of polyunsaturated fats, the
omega-6 and omega-3 varieties, and their potentially
vastly different effects on health.
Because of our current food preferences massively favor high amounts of the omega-6 fatty acids, the ratio of omega-6 to omega-3 fats in our diet is now around 25 to 1. Arachidonic acid, a physiologically significant omega 6 fatty acid, is the precursor for prostaglandins and other physiologically active inflammatory molecules. Research has suggested that excessive levels of omega-6 fatty acids, relative to omega-3 fatty acids, may increase the probability of many disease states. Modern Western diets typically contain an omega-6 to omega-3 ratio greater than 30:1. Again the optimal ratio should be approximately a 1:1 ratio. Observational
studies have demonstrated that diets high in
Omega-3s and low in Omega-6s confer significant
health benefits. The Greenland Eskimos,
for instance, have a ratio of omega-6 to omega-3
fatty acids approximating 1 to 1, which is associated
with an extremely low rate of heart attacks and
very low rates of diseases involving inflammation
such as psoriasis, asthma and arthritis. Similarly,
the traditional Japanese diet, high in omega-3
fat intake, correlates with low rates of heart
disease and rheumatoid arthritis.
These epidemiological observations have driven
research on the effects of fish oil on other
diseases involving inflammation. Rheumatoid
arthritis is one such disorder and the central
symptomatic issue in rheumatoid arthritis is
chronic and excessive inflammation of the joints.
Could such a devastating and disabling chronic
illness benefit from increased Omega-3 intake? Twelve
(12) double-blind, placebo-controlled dietary
intervention studies with omega-3 fatty acids,
in the form of fish oil capsules, demonstrated
a significant degree of clinical benefit
in rheumatoid arthritis. Durations of these
studies varied from 12 to 52 weeks and the
amount of omega-3 fatty acids ingested varied
from 1 to 7.1grams. Among these clinical trials, at least two of the following outcome measures improved in each study: number of tender joints, number of swollen joints, duration of morning stiffness, grip strength, as well as patient and physician global health assessment. Also,
fish oil intake led to decreased anti-inflammatory
drug use in three of the eleven studies
in which it was measured. One significant
feature of these omega-3 fish oil studies
is that they were conducted in a double-blind,
placebo-controlled manner. Randomizing
some patients to take fish oil, and
others to take a “placebo” oil, with neither patient nor investigator knowing which oil is being taken, allows for the most accurate level of scientific measurement and effect. This
important aspect of the fish oil
studies is a requirement for any
sound study of experimental treatments. Although
research regarding the use of
omega-3 fatty acid supplements
for inflammatory joint conditions
has focused almost entirely on
rheumatoid arthritis, relatively
recent research also suggests
that diets rich in omega-3 fatty
acids (and low in omega-6 fatty
acids) may benefit people with
other inflammatory disorders,
such as Osteoarthritis (OA). In
fact, several laboratory studies
of cartilage-containing cells
have found that omega-3 fatty
acids decrease inflammation and
reduce the activity of enzymes
that break down cartilage. Additionally, a study by Curtis et al in 2002 demonstrated that supplementation with Omega 3 fatty acids, but not omega 6 fatty acids, caused a decrease in both the degradative and inflammatory aspects of cartilage metabolism. The Curtis et al study provides evidence supporting the assertion that dietary supplementation of omega 3 fatty acids may have a beneficial effect of slowing and reducing inflammation in the pathogenesis of degenerative joint diseases in man. Another study by Caterson et al 2006 revealed that pathologic indicators manifested in human osteoarthritis cartilage can be significantly altered by exposure of the cartilage to omega-3 fatty acids, but not to other classes of fatty acids.
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