|
Disorders of the Immune System:
Allergy
The most common types of allergic reactions-hay
fever, some kinds of asthma, and hives-are produced when the immune
system responds to a false alarm. In a susceptible person, a normally
harmless substance-grass pollen or house dust, for example-is
perceived as a threat and is attacked.
Such allergic reactions are related to the
antibody known as immunoglobulin E. Like other antibodies, each IgE
antibody is specific; one reacts against oak pollen, another against
ragweed. The role of IgE in the natural order is not known, although
some scientists suspect that it developed as a defense against
infection by parasitic worms.
The first time an allergy-prone person is
exposed to an allergen, he or she makes large amounts of the
corresponding IgE antibody. These IgE molecules attach to the surfaces
of mast cells (in tissue) or basophils (in the circulation). Mast
cells are plentiful in the lungs, skin, tongue, and linings of the
nose and intestinal tract.
When an IgE antibody sitting on a mast cell or
basophil encounters its specific allergen, the IgE antibody signals
the mast cell or basophil to release the powerful chemicals stored
within its granules. These chemicals include histamine, heparin, and
substances that activate blood platelets and attract secondary cells
such as eosinophils and neutrophils. The activated mast cell or
basophil also synthesizes new mediators, including prostaglandins and
leukotrienes, on the spot.
It is such chemical mediators that cause the
symptoms of allergy, including wheezing, sneezing, runny eyes and
itching. They can also produce anaphylactic
shock, a life-threatening allergic reaction characterized by
swelling of body tissues, including the throat, and a sudden fall in
blood pressure.
Natural Treatments:
For the best allergy-alleviating action,
some doctors suggest adding these nutrients to a healthy balanced
diet.
NUTRIENTS, DAILY AMOUNTS, and APPLICATIONS
- Magnesium: 400 milligrams
- Vitamin C: 1,000-2,000 milligrams (ester-C or calcium
ascorbate), taken as 2 divided doses
Plus a multivitamin/mineral supplement
MEDICAL ALERT!
If you have heart disease or kidney problems, definitely check with
your doctor before taking magnesium supplements. Some people may
experience diarrhea when taking more than 1,200 milligrams of vitamin
C a day.
Why Your Nose Runs
Histamine is usually stored in granules inside mast cells. When a mast
cell is exposed to a substance that triggers an allergic reaction,
however, the cell releases its histamine into surrounding tissues.
Histamine plays an important role in certain types of allergic
reactions, it causes small blood vessels to widen and become more
permeable to fluid, allowing fluid to pass from the bloodstream into
surrounding tissues, causing nasal congestion, runny eyes and nose and
sometimes hives.
Histamine makes the smooth muscles in the walls of the lungs, blood
vessels, stomach, intestines and bladder contract. That contraction
brings on a wide range of symptoms. In the lungs, for example,
histamine may cause wheezing. Histamine release also indirectly
stimulates the production of thick, sticky mucus.
You can blame Mom and Dad for the fact you're allergic; the tendency
is inherited. But some doctors believe a healthy diet and certain
nutritional supplements can balance your immune system, keeping it
strong but not overreactive.
To crack the underlying problem, you really need a healthy nutritional
foundation that's based on diet, if you continue to eat poorly and
simply take a few supplements, you aren't going to see much of a
benefit.
With that in mind, here are particulars on the nutrients that may be
helpful in fighting allergies.
Vitamin C Stops Histamine
There's no doubt that vitamin C can help tame allergic reactions, at
least under laboratory conditions. Several studies have shown that
high levels of vitamin C help reduce histamine release from mast cells
and also make histamine break down faster once it is released. Not
only that, but studies have also shown that vitamin C deficiency can
send blood levels of histamine through the roof.
Only two studies have been done in humans, however. One small study,
by researchers at Methodist Hospital in Brooklyn, New York, found that
people who took 1,000 milligrams of vitamin C every day for three days
had significant reductions in blood levels of histamine.
In another study, Italian researchers found that people with hay fever
were better able to maintain the volume of air they could exhale if
they were taking 2,000 milligrams of vitamin C a day. (In many
allergic reactions, air passages narrow and restrict the flow of air
into the body.)
Other studies have shown that vitamin C may also help dampen some of
the inflammation associated with chronic allergies.
Vitamin C has not been proved to help much if it's taken once symptoms
begin, but if you take it before you're exposed to whatever is causing
your allergies and allow it to get into your bloodstream, it is
helpful, although it doesn't work as dramatically as do standard
anti-asthma drugs.
We recommend taking the slow-release form of vitamin C--ester-C or
calcium ascorbate--in 500- to 1,000-milligram doses twice a day. (If
you take regular vitamin C, you'll see the best results if you take
several hundred milligrams three or four times a day, he notes.)
Although the Daily Value for vitamin C is only 60 milligrams, these
higher doses are considered safe for most people. Some people
experience diarrhea with doses as low as 1,200 milligrams, however. If
you experience any discomfort, you might want to cut back.
Extra Help from Bioflavonoids
Some vitamin C supplements contain added ingredients called
bioflavonoids. These chemical compounds, which are closely related to
vitamin C, have intrigued allergy researchers for decades. The
chemical structure of bioflavonoids is similar to that of a drug
called cromolyn, used in inhalers to reduce asthma-related
inflammation.
Bioflavonoids may help reduce the body's release of symptom-producing
histamine.
Unfortunately, experience with one of the common bioflavonoids,
quercetin, suggests that it isn't readily absorbed, so its effect on
allergic reactions in people is still to be clarified.
Researchers are still investigating the role of bioflavonoids in
allergy prevention. For now, experts say, save your money on
supplements and instead chow down on bioflavonoid-rich foods: citrus
fruits, cherries, dark grapes, broccoli, red and green peppers and
herb teas (stinging nettle is specifically recommended for allergies).
You'll be getting a host of other helpful nutrients as well.
Magnesium May Ease Breathing
Some doctors who treat people with allergies recommend that their
patients get the Daily Value of magnesium, which is 400 milligrams.
That's because this essential mineral is known to help relieve
bronchospasm, or constricted airways in the lungs. Magnesium has been
used intravenously to help relieve the symptoms of life-threatening,
drug-resistant asthma attacks. Doctors who recommend it for simple
nasal allergies are inferring that it may also help these symptoms.
One study, by researchers at Brigham Young University in Provo, Utah,
found that laboratory animals severely deficient in magnesium had much
higher blood levels of histamine when exposed to substances that
trigger allergies than animals getting sufficient magnesium.
The flow of calcium into and out of a cell helps regulate some cell
function. So it's possible that a magnesium deficiency changes the
permeability of mast cell membranes, allowing calcium to more easily
enter cells. When that happens, histamine is released.
Magnesium deficiency definitely accentuates the allergic situation.
In animals, magnesium deficiency causes the release of substances that
can act on immune cells such as mast cells and basophils and make them
hyperactive--more likely to release histamine. Magnesium deficiency
also causes other immune responses in the body that can lead to
redness, swelling and pain.
You don't need to load up on magnesium to tame your sneeze and wheeze.
If you do, you'll soon find your maximum tolerable dose: You'll end up
with diarrhea. (That's why milk of magnesia is such a good laxative!)
Doctors suggest getting the Daily Value of magnesium, which is 400
milligrams. Studies show that women get only about half of that
amount, while men generally fall short by about 100 milligrams. The
very best sources of magnesium are nuts, beans and whole grains. Green
vegetables are another good source, as are bananas. Most processed
foods contain very little of this essential mineral. (If you have
heart disease or kidney problems, definitely check with your doctor
before taking magnesium supplements.)
Nutrients to Protect Mucous Membranes
Vitamin A (or its precursor, beta-carotene), selenium and zinc. That's
because these nutrients play important roles in the health of mucous
membranes, your body's internal skin.
"If you have healthy mucous membranes, your chances of having
significant allergy problems will be less. The mucous membrane is a
layer of cells that secrete the slimy substance we all know and should
love, because it contains an array of infection-fighting biochemicals.
Mucus also shields cells from direct contact with pollen and other
allergens, substances that trigger allergies.
"This mucus layer protects cells from the damaging effects of air
pollution. Studies show that people who are exposed to both air
pollution and allergens are more likely to have severe allergic
reactions than those exposed only to allergens.
The allergic reaction itself also causes the generation of unstable
molecules called free radicals, which injure your body's healthy
molecules by stealing electrons to balance themselves. In the process,
free radicals injure mast cells and may make them even more twitchy
and prone to histamine release. Vitamins C and
E, beta-carotene,
selenium and other antioxidants all help to neutralize free radicals
by offering their own electrons and so protect healthy molecules from
harm.
Some doctors recommend taking a multivitamin/mineral supplement that
covers all of the bases. For some people with allergies, avoiding
certain foods can be dramatically helpful for all of their symptoms.
Some of the most serious allergic reactions--including deadly
shock--can involve food. People with serious allergies usually find
out through tests which foods they need to avoid. Components of
certain foods may also help trigger allergies. Here's what you need to
know.
Pinpoint your problem foods. If you suspect food is the
culprit, see a specialist who can help you determine which foods are
aggravating your symptoms, experts suggest. Peanuts, nuts, eggs, milk,
soy and fish and other seafood have all been implicated in allergic
reactions. And gluten, a protein found in wheat, rye, barley and oats,
can cause allergy-related intestinal problems in some people.
Watch out for cross-reactions. Some people with inhalant
allergies develop allergies to foods that contain similar substances.
Someone who reacts to birch pollen, for instance, may get itching or
swelling of the lips, tongue, throat or roof of the mouth if he eats
apples. People allergic to ragweed, on the other hand, may react to
melons.
The foods most likely to cause reactions confined to the mouth:
uncooked fruits, nuts and vegetables.
|
|
|
The
Whole Story