Allergies

Nutrients That Ease the Sneeze

Allergies are versatile. They can show up just about anywhere in your body and create an incredible variety of symptoms. They can affect your nose, eyes, throat, lungs, stomach, skin and nervous system. They can make you itch, wheeze and sneeze, make your nose run and your eyes weep, give you a headache or a bellyache and even bring on fatigue and depression.

So with all of these possible symptoms, what is it that makes an allergy an allergy? To put it another way, what exactly is going on in your body when you have an allergy?

Allergy symptoms occur when your body's immune system overreacts to substances in your environment. Most people can live with a little cat dander, dust or pollen, for example. (Some folks can live with a lot!) But people with allergies have immune systems that can react to just about anything that comes along. "It fights these foreign substances just as it would bacteria or viruses," explains Jeremy Kaslow, M.D., a Garden Grove, California, allergy specialist and associate professor of medicine at the University of California, Irvine.

The main causes of run-of-the-mill allergy symptoms are histamine and leukotrienes, biochemicals that your immune system releases. Your immune system is an incredibly complex system of several different kinds of cells working in tandem. The overly sensitive cells involved in allergies are mainly mast cells and basophils. Mast cells are found in tissues such as your skin, lungs, throat, stomach and intestines, while basophils hang out in your blood vessels. As you can see, these cells cover nearly every part of the body.

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," Dr. Kaslow explains. "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 that 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," says Dr. Kaslow. "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, 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 who had 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, the 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.

"My experience is that vitamin C can have modest beneficial effects for inhalant allergies and asthma if it's taken on a regular basis," says Richard Podell, M.D., clinical professor of family medicine at the University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School in Piscataway and author of When Your Doctor Doesn't Know Best: Errors That Even the Best Doctors Make and How to Protect Yourself.

Vitamin C has not been proved to help much if it's taken once symptoms begin, Dr. Podell says. "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," he adds.

He recommends 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, explains Elliott Middleton, Jr., M.D., professor of medicine and pediatrics at the State University of New York at Buffalo.

"Unfortunately, experience with one of the common bioflavonoids, quercetin, suggests that it isn't readily absorbed," Dr. Middleton explains. "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, don't spend money on supplements; instead chow down on bioflavonoid-rich foods such as 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," Dr. Podell explains.

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," explains Kay Franz, Ph.D., one the study's authors. "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," says Terry M. Phillips, D.Sc., Ph.D., director of the immunogenetics and immunochemistry laboratory at George Washington University Medical Center in Washington, D.C., and author of Winning the War Within.

"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," he says. 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

Dr. Kaslow also recommends other nutrients: 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," Dr. Kaslow says. 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," Dr. Kaslow says. "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, Dr. Kaslow adds. 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.

Dr. Kaslow suggests nixing junk foods and eating more unprocessed foods to get an adequate supply of all of these nutrients. Some doctors recommend taking a multivitamin/mineral supplement that covers all the bases. For some people with allergies, avoiding certain foods can be dramatically helpful for all of their symptoms.