From The May 1997 issue of Nutrition Science News
by Richard N. Podell, M.D.
More than half of all patients who visit general physicians
suffer from symptoms triggered or made worse by
stress--headaches, ulcers, fatigue or even emotional distress.
Two research studies demonstrated that essential fatty acid
nutritional supplements can increase resistance to stress--and
its debilitating and costly side effects.
The first study, published in the Journal of Clinical
Investigation in 1996, tested the anti- stress power of
docosahexaenoic acid (DHA), an omega-3 fatty acid most commonly
derived from fish oil but also found in algae. Eicosapentaenoic
acid (EPA), a close cousin of DHA, may be effective in reducing
heart disease risk and treating rheumatoid arthritis and
intestinal inflammations like Crohn's disease. DHA has different
beneficial properties and appears to be particularly important in
brain biochemistry. For instance, it is involved in the
maturation of brain cells during gestation and infancy.
The DHA study involved 41 healthy fourth-year medical students.
They took either fish-oil capsules containing 1.5 g to 1.8 g of
DHA daily or a placebo made mainly of soybean oil. They underwent
psychological testing, first during summer vacation, and again
three months later during final exams.
Not surprisingly, the control group showed increased feelings of
aggression during the exams compared to their scores during
summer vacation. However, the students taking DHA showed a modest
decrease in this negative emotion. The authors speculate that
reducing the tendency toward anger and hostility might be another
way that a diet high in fish and omega-3 fats could protect
against heart attacks.
The second study, published in the Journal of Human Hypertension
in 1989, found similar beneficial results from a different fat,
gamma linolenic acid (GLA). GLA is a component of borage oil,
primrose oil and black currant seed oil.
Thirty healthy Canadian university students volunteered to take
either nine borage oil capsules (containing 1.3 g per day of GLA)
or an olive oil placebo. Each student received a standard
psychological stress test known as the Stroop color-word conflict
test, both before and after 28 days of supplements.
The Stroop test consists of 200 words such as "red" or
"green," each printed in a color different from the one it
actually signifies. Thus, the word "red" might be printed in
green ink and the word "green" in red ink. Subjects proceed
through the list as rapidly as possible for two minutes, calling
out the color of the ink. The test's deliberately mixed message
typically stresses people and induces physical changes including
rapid heart rate, increased blood pressure and cold fingers due
to blood vessel spasms.
Students taking the placebo showed little change in their
vulnerability to stress. However, those taking high-GLA borage
oil showed reduced stress vulnerability after 28 days of
The Bottom Line
Both studies demonstrate that stress vulnerability is not "just"
psychological. How we eat affects our ability to resist stress.
If this is true for young, healthy students, how much more so
might it be for older or sick people?
It's unfortunate that neither study looked at subjects' red blood
cell fatty acid levels--a relatively inexpensive test offered by
several suppliers. Measuring people's fatty acid profiles might
make it possible to recommend fatty acid supplements that better
meet their needs.
These reports are scientifically important, but they also
illustrate changing attitudes toward nutrition. The borage oil
study appeared in the Journal of Human Hypertension, a respected
but little-read journal. No one since has bothered to repeat the
study to either confirm or refute it. And I never see the article
footnoted in the journals I read.
The DHA study was published in the Journal of Clinical
Investigation--JCI to those in academic medicine. While not well-
known to the public, no journal ranks higher in prestige within
the halls of academia.
Will the JCI's pedigree save the DHA article from obscurity?
Perhaps not. Few practicing physicians read the journal. But the
fact that the journal editors accepted a paper on DHA and
stress--and earmarked it for quick publication--shows how much
respect nutrition research has gained.
We still have much guesswork in our nutritional prescriptions,
but the scientific basis for our field is getting stronger every
month. In academic medicine, at least, the leaders are noticing.
Richard Podell, M.D., is clinical professor of family medicine
at the UMDNJ-Robert Wood Johnson Medical School in New Brunswick,
N.J. He is the author of Patient Power: How to Protect Yourself
Against Medical Error (Fireside, 1996).
Hamazaki, Tomohito, et al. "The effect of docosahexaenoic acid on
aggression in young adults: A placebo-controlled double-blind
study," Journal of Clinical Investigation, 97: 1129-34,1996.|
Mills, D., et al. "Dietary fatty acid supplementation alters
stress reactivity and performance in man," Journal of Human
Hypertension, j3: 111-16, 1989.|
Neuringer, M., et al. "Biochemical and functional effects of
prenatal and postnatal w3 fatty acid deficiency on retina and
brain in rhesus monkeys," Proceedings of the National Academy of
Science, 83: 4021-25, 1986.|
McLennan, P., et al. "Dietary fish oil prevents ventricular
fibrillation following coronary artery occlusion and
reperfusion," American Heart Journal, 116: 709-17, 1988.|
Mills, D, & Ward, R. "Effects of essential fatty acid
administration on cardiovascular responses to stress,"
Proceedings of the Society of Experimental Biology and Medicine
182: 127-31, 1986.
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