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ANTIOXIDANTS
Key Concepts in Antioxidant Research:
- Antioxidants help protect the body from chronic degenerative diseases, such as heart disease and cancer, combat premature aging, and support a healthy immune system.
- An intake of antioxidants in excess of the Recommended Dietary Allowances (RDAs) is probably necessary for optimal health protection.
- A combination of antioxidants may be more effective than single
antioxidants.
The role of free radicals (unruly molecules that damage the body) as
instigators
of disease is now an accepted fact in most scientific quarters. However,
continuing research in the antioxidant field clarifies the role of
antioxidants
in disease and uncovers antioxidant links to new health conditions.
SOLID HEART PROTECTION
It was almost a year ago that vitamin E gained new respect for guarding
against
heart disease. The Cambridge Heart Antioxidant Study (CHAOS) assigned
2,002
men and women diagnosed with atherosclerosis to take vitamin E
supplements
(containing either 400 I.U. or 800 I.U.) or a placebo daily. After 17
months
of using the supplements, the risk of non-fatal heart attack was reduced
by 77%. The risk of fatal heart attacks was also significantly reduced.
(Stephens, N.G., Lancet, 1996;347:781-786.)
Researchers from the University of Minnesota School of Public Health
assessed
the diets of 34,486 women and followed their health for 7 years. When
intakes
of vitamin E were compared to mortality, it was found that the risk of
dying
from heart disease decreased as dietary vitamin E intakes increased. The
women in the highest vitamin E group had a 58% lower risk compared to
women
in the lowest group. (Kushi, L., et al., New England Journal of
Medicine,
1996;334:1156-1162.)
Clearly, lifelong high levels of antioxidant nutrients protect against
the
development of heart disease, but it may never be too late for heart
disease
patients to benefit from antioxidants. High doses of antioxidants
(vitamins
A, C, and E, and beta-carotene) in the month following an acute heart
attack
can significantly reduce the number of deaths, as well as the extent of
cardiac
damage in non-fatal cases. (Singh, R.B., et al., American Journal of
Cardiology,
February 1, 1996;77:232-236.)
CANCER EVIDENCE SHAKEN
Antioxidants' reputation has taken a beating in the press lately Some
studies
show no effect of antioxidants on cancer, and other studies -- such as a
study of beta-carotene in smokers -- actually show a detrimental effect.
Researchers at the Center for Vitamins and Cancer Research at the
University
of Colorado Health Sciences Center may have an explanation for the
apparent
inconsistencies of antioxidants and cancer risk.
It appears that combinations of antioxidant vitamins are the most
effective
in inhibiting tumor growth, and "in the absence of knowledge of doses
and
the effect of potential interaction, cancer prevention trials among
high-risk
populations or cancer treatment trials can be ineffective. Therefore the
current clinical trials on cancer prevention in which one or two
arbitrarily
selected vitamins at arbitrarily selected doses are used are likely to
yield
inconsistent results." (Prasad, K.N., et al., Nutrition and Cancer,
1996;26:11-19.)
ANTIOXIDANTS AND LONGEVITY
A group of researchers from Italy recently compared the antioxidant
blood
levels, free radical activity, and state of health of 100 healthy and 62
disabled 80+ year old adults with 91 middle-aged adults. Those over 80
years
old showed greater systemic oxidative stress and lower levels of
antioxidants,
such as vitamin C and vitamin E. Within the elderly group, those who
were
unhealthy (that is aging unsuccessfully compared to those who were aging
successfully) showed the greatest systemic oxidant load. (Mezzetti, A.,
Journal
of the American Geriatrics Society, 1996;44:823-827.)
When crucial strands of protein in the cells of the brain and immune
system
deteriorate with age, they send a signal to the body that the cell is
old
and should be destroyed. This protein, called band 3 protein, is a sign
of
immune system and neurological aging. Vitamin E has been found to
prevent,
or at least delay, this indication of aging and prolong the life of
cells
in the laboratory. (Kay, M.B., et al., Proceedings of the National
Academy
of Sciences, May 1996;93:5600-5603.)
ANTIOXIDANTS EASE
OSTEOARTHRITIS
High doses of antioxidant vitamins can slow the progression of
osteoarthritis
of the knee, says Timothy E. McAlindon, D.M., and colleagues in
Arthritis
& Rheumatism (1996;39(4):648-656). High intake of vitamin C may slow
the progression of osteoarthritis by as much as three-fold; the benefits
of betacarotene and vitamin E were not as strong.
VITAMIN E PRESERVES FERTILITY
Male smokers may have dangerously high levels of sperm damage, compared
to
non-smokers, which could "lead to cancer, birth defects, and genetic
diseases
in [their] offspring," says a study in Mutation Research
(1996;351:199-203).
One marker of sperm DNA damage was 50% higher and vitamin E levels were
32%
lower in smokers. The antioxidant activity of vitamin E and other
antioxidants
could reduce smoking-related sperm damage.
UPPING VITAMIN C
RECOMMENDATIONS
Dr. Mark Levine at the National Institutes of Health claims that the RDA
for vitamin C should triple to about 200 mg. daily. Dr. Levine's study
examined
vitamin C absorption and excretion in only seven men, but the conditions
of the study were rigorously controlled.
Daily intakes of vitamin C at the highest level tested (2,500 mg.)
caused
no adverse effects. In contrast, even a marginal deficiency of vitamin C
resulted in feelings of fatigue and irritability. (Levine, M.,
Proceedings
of the National Academy of Sciences, 1996;93:3704-3709.)
NEW ANTIOXIDANTS JOIN IN
Most antioxidants are limited in where they work in the body. That is,
they
either protect the watery areas, such as the bloodstream, or the fatty
areas,
such as cell membranes. A new antioxidant, alpha-lipoic acid, has the
unique
ability to fight free radicals in both water-soluble and fat-soluble
areas.
Dr. Lester Packer, an expert on this antioxidant, believes that "the
therapeutic
potential of alpha-lipoic acid is just beginning to be explored, but
this
compound holds great promise." (Packer, L., et al., Free Radical Biology
& Medicine, 1996;20(4):625-626.)
Several flavonoids are recognized for their antioxidant and anti-viral
activity.
For example, researchers at the University of Arizona investigated the
potential
of Pycnogenol (a pine bark extract source of flavonoids) to fight
infections,
in particular HIV infection. This study determined that Pycnogenol
restored
the production of interleukin (cells that help the immune system
communicate)
and also restored the activity of natural killer cells, which go on
"seek
and destroy missions" for virus-infected cells. This is especially
beneficial
because depressed natural killer cell activity often leads to a rapid
progression
from HIV to full-blown AIDS. (Watson R.R., et al., Life Sciences,
1996;58(5):87-96).
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