immune system is crucial in maintaining your healthso
its important to keep it in good order. But how do you
do that? People talk about boosting immunity as if it were a
task similar to building muscles or reducing blood cholesterol.
Hundreds of ads for supplements and other products promise to
boost immunity. But keeping your immune system in good shape
is a complicated task. "How do I boost immunity?"
is really the same question as "What can I do to stay well?"
does the immune system fight disease?
war is a handy metaphor for the human bodys reaction to
disease, science writers like to describe the immune system
in militaristic termsthe bodys department of defense.
But unlike the Armed Forces, the immune system has no headquarters
or commander-in-chief. And its operations are usually swifter
and more efficient than any armys could be.
than "making war," your immune system is really more
like an immigration service: a highly differentiated cellular
bureaucracy that supervises your biological commerce with the
outside world, sorts through billions of pieces of information
about incoming materials, and takes routine action as required.
Only occasionally does it declare an emergency.
immune systems basic task is to recognize "self"
(the bodys own cells) and "nonself" (an antigena
virus, fungus, bacterium, or any piece of foreign tissue, as
well as some toxins). To deal with nonself or antigens, the
system manufactures specialized cellswhite blood cellsto
recognize infiltrators and eliminate them. We all come into
the world with some innate immunity. As we interact with our
environment, the immune system becomes more adept at protecting
us. This is called acquired immunity.
are the parts of the system?
the primary components of the immune system are a variety of
white blood cells. These constitute a communications network
that helps organize the immune response.
people are surprised to learn that the skin, including the mucous
membranes, is among the most vital components of immunity. The
skin not only forms a wall against intruders, but actually alerts
the white blood cells if the wall is breached by invading organisms
(through a wound, for instance). The protection afforded by
the intact skin is why its nearly impossible to catch
a disease from a toilet seat, for example.
infectious agents get inside the body when we inhale them or
swallow them; a few can enter through the genitals. They make
their way into the blood and move rapidly through the body.
The immune system has its own circulatory system called lymphatic
vessels, which allow white blood cells to catch intruders. Other
important parts of the immune system include the tonsils and
adenoids, thymus, spleen, lymph nodes, appendix, certain areas
of the small intestine, and bone marrow.
do the white cells do?
mature white blood cells are highly specialized. The so-called
T lymphocytes (T stands for thymus-derived) have various functions,
among them switching on various aspects of the immune response,
and then (equally important) switching them off. Another lymphocyte,
the B cell, manufactures antibodies. A larger kind of white
cell, the scavenger called the phagocyte (most notably the macrophage),
eats up all sorts of debris in tissue and the bloodstream, and
alerts certain T cells to the presence of antigens.
addition, there are killer, suppressor, and helper T cells.
Killer T cells, stimulated by helper T cells, zero in on cells
infected by antigens, or turn against the bodys own cells
when, as in the case of cancer, they begin to proliferate abnormally.
Another class of lymphocyte killer cell is called "natural"
because, unlike T and B cells, it doesnt need to recognize
a specific antigen. Most healthy cells are of no interest to
natural killer cells, but cancer cells and cells invaded by
viruses may be vulnerable to their search-and-destroy missions.
makes a person immune to various diseases?
to the lymphocytes, the immune system possesses a memory, or
a sense of history. The lymphocytes manufacture antibodies (proteins
circulating in the blood) that attack intruders. Once you have
produced antibodies to a certain microbea specific flu
virus, for examplethat particular virus cannot make you
sick again, because you have cells that immediately recognize
it and produce the antibodies that destroy it. The immunity
may last for years, sometimes for life. This is "acquired
has also developed vaccines. It all began in the late eighteenth
century, when the English physician Edward Jenner observed that
people who caught a mild disease called cowpox never got smallpox,
which is related to it. Using a boy who had not had either disease,
Jenner tried inoculation: he scraped the childs skin and
applied secretions from cowpox sores, and the boy got cowpox.
When Jenner later inoculated him with smallpox matter, the boy
did not develop smallpox. (Such human experimentation would
land Dr. Jenner in court today.)
immunity by injecting healthy people with dead or altered disease-causing
microbes has prevented millions of deaths from measles, polio,
diphtheria, flu, smallpox, tetanus, yellow fever, and many other
diseases. Vaccines truly are immune-system boosters.
loss of sleep depress immunity?
can. But losing sleep for a few nights wont necessarily
make you ill. Many things boost or depress immunity temporarily.
The number of immune cells rises and falls naturally in healthy
foods boost immunity?
adequate diet helps maintain immunity and keeps you healthy.
The immune system needs such nutrients as protein, fatty acids,
vitamins, and minerals. Severely malnourished people are particularly
vulnerable to immune dysfunction, and they get sick more easily
than other people and stay sick longer. What most people want
to know, though, is whether one specific food or kind of food
will boost immunity in otherwise healthy people on an adequate
diet. The answer is generally no.
supplements boost it?
far theres no reason to believe that supplements will
boost immunity in healthy people, except in the malnourished
and many of the elderly. Though severe malnutrition is rare
in the U.S., some groups, particularly the elderly, may be deficient
in such nutrients as vitamin C, certain B vitamins, and zinc.
Studies suggest that raising nutrient intakes to adequate levels
can enhance immunity, and there is some evidence that elderly
people stay healthier if they take a multivitamin/mineral pill.
In contrast, other research suggests that megadoses of certain
nutrients can significantly suppress some immune responses.
zinc, for instance, found in meat and grains, and often promoted
as an ideal immune-system booster when taken as a supplement.
While some studies show that zinc supplements can boost immunity
and promote wound-healing in the elderly, high intakes can actually
suppress the immune response.
diet low in beta carotene can depress immunity, but its
not clear that beta carotene supplements can correct the situation,
or what levels of supplementation would be helpful. Among the
agents that have been shown to stimulate immunity in experiments
are bacteria such as those in yogurt, but its far from
certain that consuming yogurt (with or without live cultures)
will promote resistance to disease.
about vitamin C?
vitamin is necessary to good health and no doubt to immune function.
But numerous studies have shown that vitamin C supplements have
minimal or no effect on the immune response, unless you are
deficient in C.
exercise boost immunity?
research shows that sedentary people dont have as vigorous
an immune system as those who exercise. Moderate exercise (for
example, a moderate walking program undertaken by previously
sedentary people) seems to improve immune function. But there
is also evidence that overdoing exercise may depress the immune
system: high-intensity or prolonged endurance exercise steps
up the output of two so-called stress hormones, adrenaline and
cortisol, both of which can depress various components of the
and other highly trained athletes often report that after intense
competition and training they are more susceptible to colds.
Yet such news should not deter athletes from competing or exercisers
health benefits of exercise are clear. Regular aerobic exercise
is good for the heart. Weight-bearing exercise builds bone and
muscle. The idea that your immune cells might not show a response
to your exercise program should not deter you from exercising
or from beginning an exercise program if you are sedentary.
emotions affect the immune system?
of mind surely affect health, and extreme emotional stress may
damage immunity and bring on illness. But research into the
link between mind and immunity is in its early stages and has
produced very little solid evidence so farand not much
advice about how to protect the immune system from the ill effects
of emotional stress. An experiment may show that extreme grief
depresses human T cells, for instance, but we dont know
if the rest of the system is harmed, or whether the fluctuation
reports of increased illness and even death among the recently
bereaved are common. Cancer patients with a "fighting spirit"
seem to live longer than those who are despondent, but this
may or may not prove something about immune function. Good social
support is thought to improve immunity in people under stress.
cells and nerve cells do interact. For example, when fighting
an infection, immune cells are able to stimulate the brain to
transmit the impulses that produce fever. Receptors for many
of the chemicals released during stress, such as epinephrine
and norepinephrine, have been observed on the surface of lymphocytes
found near nerve terminals in the lymph nodes and spleen. This
suggests that what goes on in the brain can interact with the
immune system to suppress or, conversely, enhance it.
does smoking do to immunity?
of the reason smokers are at risk for lung cancer and respiratory
diseases may be that smoking suppresses immune cells. When smokers
quit, immune activity begins to improve within 30 days.
and why does the immune system malfunction?
immune system has so many built-in fail-safes that, in theory
at least, we should rarely fall ill. But, in fact, we do. Harmful
agents such as HIV can baffle our defenses. The system can simply
be overwhelmed by the number and toxicity of viruses, bacteria,
or other foreign cells and toxins.
the immune system defends us against cancer, it is subject to
cancer. Leukemia is a cancer of the white blood cells; multiple
myeloma affects certain lymphocytes that produce antibodies.
Cancers of the lymph system include lymphoma and Hodgkins
disease. Some of these cancers can now be successfully treated.
the gatekeepers of the system go crazy, mistaking a basically
inoffensive intruder such as pollen, dust, or a bit of bee venom
for an enemy and causing the body to go into the red alert known
as an allergic reaction. In addition, the immune system can
mistake the bodys own cells and tissues for "nonself"
and attack them, as in auto-immune diseases like rheumatoid
arthritis and systemic lupus.
immune system will also reject and kill potentially lifesaving
organ and tissue transplants, unless some way can be found to
circumvent the reaction. Though in theory a pregnant womans
immune system should attack the fetuswhich is nonselfit
doesnt. This is because the fetus itself produces a substance
that shields it from the maternal defense system.
how can I nurture my immune system?
the most direct action you can take is to consume a varied,
balanced diet of vegetables, fruits, whole and fortified grains,
and dairy products, with small amounts of fish and meat if you
wish. A basic daily multivitamin/mineral supplement is usually
a good idea for older people. Beware of any supplement, however,
that promises to boost immunity: protein supplements, enzyme
supplements, and the whole range of specific vitamins and minerals,
antioxidants, and nostrums that claim to boost immunity dont
moderate exercise is associated with good health and longevity
and will benefit your cardiovascular system, whether it boosts
immunity or not. Getting adequate sleep is also helpful. And,
of course, dont smoke.
Reference Source 98