As we age, disease worms its way into our lives. Arthritis, cardiovascular problems,
longer-lasting colds, even cancer—they seem to sneak up on us at a certain age, doing
their best to ruin the quality of our lives, just when we should be enjoying a bountiful
In the past, people accepted this as one of the evils of growing old; in other words,
that age beget disease. Today, we know that this is not true, and that many of the health
problems traditionally associated with aging have more to do with the immune system than
Writing in the June, 1996, issue of The American Journal of Clinical Nutrition,
authors Kelley and Bendich note that ". . .several recent, well controlled human intervention
studies found that clinically important immune responses were improved when amounts of
vitamin C, vitamin E, or beta carotene higher than the recommended dietary allowance
(RDA) were consumed in healthy populations."
Beta carotene has long been known to be an immune booster, and recent studies
support this contention. The same authors as quoted above go on to say that, "Beta carotene
supplementation appears to be beneficial for individuals with compromised immune systems,
and does not overstimulate the immune responses of healthy adults . . ."
Beta carotene may be particular helpful for the immune system of the elderly. According to
Richard Passwater, Ph.D., in his book, Beta Carotene and Other Carotenoids, beta
carotene supplementation has been shown to enhance some, but not all, aspects of cell-mediated
immunity in healthy older men.
Michelle Santos, et al, writing in the November 1996 issue of The American Journal
of Clinical Nutrition, notes that beta carotene may increase the activity of natural killer
cells. This is an important point, as natural killer (NK) cell activity has been postulated to be
an immunologic link between beta carotene and cancer prevention.
The article states that, "Our results show that long-term beta carotene supplementation enhances
NK cell activity in elderly men, which may be beneficial for viral and tumoral surveillance."
The link between Beta Carotene and Cancer
Last year, Harvard Medical School released research that indicates that beta carotene can
sharply reduce the risk of prostate cancer in men with low beta carotene blood levels.
(Cancer Weekly Plus, June 9, 1997). In this research, the diets, lifestyles, and health of
more than 22,000 male doctors were observed. Half of the doctors were given 50 mg (80,000 IU)
of beta carotene every other day. The findings indicated that physicians with low levels of beta
carotene were one-third more likely to develop prostate cancer. The doctors who supplemented
with beta carotene were 36 percent less likely to develop prostate cancer than those who ate few
beta carotene-rich fruits and vegetables and did not take beta carotene supplements.
The link between cancer and beta carotene is also mentioned in more recent research. An
article in the American Journal of Clinical Nutrition (August 1997) notes that epidemiological
studies reveal that people with high intakes of beta carotene or high blood concentrations of this
nutrient have a reduced risk of various diseases, including cancer and heart disease. The authors
note that this is a credible hypothesis, because
1) increased consumption of beta carotene is strongly associated with reduced risk of cancer;
2) beta carotene is a dietary antioxidant and antioxidants inhibit early stages of carcinogenesis,
3) beta carotene reduces cancer in experimental animal models.
It appears that this hypothesis is on the right track, as doctors may have discovered why beta
carotene fights cancer. Apparently, beta carotene stimulates a molecule that helps the immune
system target and destroy cancer cells. It increases the number of receptors on white blood cells
for a molecule known as major histocompatibility complex II (MHC II). MHC II is integral in helping
monocytes, a type of white blood cell, direct killer T cells to cancerous cells (Cancer Weekly
Plus, Jan 6, 1997). In other words, beta carotene is integral in directing the immune system to
kill cancer cells.
The link between Beta Carotene and Rheumatoid arthritis
Rheumatoid arthritis (RA) is another problem linked to aging, and it occurs when the immune
system turns on itself. This results in inflammation, which in turn triggers the release of chemicals
into the joint lining. This in turn results in joint damage that makes it hard to manipulate areas
such as the knuckles and knees.
Arthritis experts have known for years that free radicals (harmful renegade molecules) are
present in the fluid of the joint lining, and that they increase in joints inflamed by RA. Related
research has shown that patients with RA have lower blood levels of beta carotene than patients
Now, The Tufts University Health & Nutrition Letter, (Sep. 1997, Vol. 15 No. 7)
reports that a Johns Hopkins University study suggests that a low level of beta carotene in the blood
may actually increase a person’s risk of developing RA. Surveys show that among those without this
condition, the pre-disease beta-carotene blood levels were 29 percent higher.
What does all this mean? Beta carotene is important for all of us to get, especially the elderly.
Studies have shown that pollen extracts reduce prostate inflammation, which in turn reduces