Developing allergies and food sensitivities isn’t necessarily a product of geography, the season of the year, or even of aging.

While allergies may have many causes, consider the possibility that systemic yeast overgrowth may be an underlying factor.

It may sound far-fetched for those of us who think of yeast infections as those annoying itchy vaginal problems, but extensive research shows that yeast overgrowth can weaken the immune system and open the door to food sensitivities, allergies, asthma, and other seemingly unrelated health problems.

How can this be?

In his recently published book, The Yeast Connection and Women’s Health, the late Dr. William Crook described a process known as the "leaky gut syndrome."

You can upset the balance of friendly bacteria in your digestive tract. This usually happens if you take antibiotics, even for a short time or eat a diet high in processed foods, or you take birth control pills.

Having fewer friendly bacteria in your gut allows the normal small colonies of yeast to begin growing out of control, compromising that part of your immune system located in the digestive tract.

The yeast changes from buds to mycelia that actually cause tiny perforations in your intestines, which allows yeast and other toxins to spill into your bloodstream, triggering allergic responses.

In addition, the failure of your immune system to function perfectly sometimes triggers over-response (known as a histaminic response) to some substances that were not formerly problematic.

Some doctors think the term "allergy" should be limited to those conditions in which an immunological response can be demonstrated using skin tests or more sophisticated laboratory tests.

But some doctors expand that definition to include hypersensitivity to foods and environmental toxins.

The most common food allergies are wheat, corn, milk, and eggs, although many people have dozens of food allergy triggers. These food sensitivities may not cause the obvious symptoms: sneezing, runny nose, coughing, hives, and itching.

In fact, as Dr. Crook explained, some of your favorite foods could be the ones feeding your problems, especially if they are high in yeast and sugar. And they may have been causing you trouble for years without your knowledge.

Environmental toxins, ranging from tobacco smoke to perfumes to household cleaning products, can cause similar symptoms. And they may be caused by yeast overgrowth resulting in the release of toxins into your bloodstream.

These toxins can trigger everything from depression to fatigue to endometriosis to headaches.

If you’ve gotten unsatisfactory results from decongestants, anti-histamines and nasal sprays, perhaps it is time to consider the possibility that systemic yeast overgrowth is causing your problem.

Many of Dr. Crook’s patients and readers of his books found relief from food sensitivities, allergies, and allergy-triggered asthma when they adopted an anti-yeast plan that includes changes in diet, supplements, non-prescription antifungal medications, and sometimes prescription antifungal medications. You’ll find more information at: yeastconnection.com/getting.html

The first method of treatment for allergies starts with avoiding the substance that is triggering your problems. That’s fine if you know you’re allergic to eggs or cat hair or ragweed.

But what if you don’t know what you’re allergic to?

For food allergies and sensitivities, the easiest way is to self-diagnose with what Dr. Crook called The Elimination Diet. You'll find a helpful symptom diary at: yeastconnection.com/pdf/DailySymptomChart.pdf

Before you begin the elimination diet start a symptom diary. Continue to keep the diary throughout your three-week elimination diet.

• milk
• sugar in all forms (including fruit and high fructose corn syrup)
• all wheat products (read labels carefully!)
• processed and packaged foods
• all food colors and dyes
• corn
• eggs
• chocolate
• condiments like vinegar, catsup, soy sauce and all fermented foods

You'll probably notice that your symptoms will begin to diminish over the first week or so. Keep careful note of this in your diary.

You'll probably also notice that sugar cravings will disappear after two or three days.

While the purpose of this diet is not to lose weight, you may drop a few pounds--a pleasant side effect of this diet.

What you can eat on this diet:

• lots of fresh vegetables
• lean meats
• fish
• nuts and seeds
• unprocessed oils

• dried beans and other legumes
• plain yogurt
• whole grains like brown rice, barley, oats
• grain alternatives like amaranth, buckwheat, and quinoa

After three weeks, you'll enter what is known as the Challenge Phase.

During this time, you'll introduce the most common allergy-causing foods, one at a time, and watch the effects carefully.

Most people with wheat allergies, for example, will notice that congestion returns if they eat even half a slice of bread.

Many people with yeast-related allergies and food sensitivities have problems with sugar, which is doubly problematic because it actually feeds the yeast that is already overgrown in their systems. Once you have identified your allergy triggers, you can avoid these foods or eat them only on rare occasions.

You'll find more details on the anti-Candida diet plus recipes, an online support group, supplements especially designed for this condition, and lots more information at www.yeastconnection.com.

Environmental triggers for your allergies are usually easier to identify. You know if your head fills up when you're around cats or if you can't bear the smell of cigarette smoke. Allergies to specific pollens, household cleaning products, fabrics and other common substances around us are sometimes more difficult to identify. These types of allergies can be fairly easily identified through a skin prick allergy test.

A 1999 Mayo Clinic study concluded that some allergy sufferers have a systemic response to yeast rather than bacterial infection as an underlying cause of chronic sinusitis, which is a common complication of allergies.

Treatment of yeast overgrowth with non-prescription and prescription antifungal medications provides relief for many people who have suffered with allergies for years.

Whether your allergies are food- or environmentally triggered, natural anti-fungal medications may give you relief.

Probiotics are usually the first line of defense. These capsules containing friendly bacteria help to restore the natural balance of bacteria and yeast in your digestive system. Although probiotics are unlikely to completely take care of your problem, they will begin the job.

Olive leaf extract is a potent antimicrobial that inhibits the growth of many microorganisms ranging from yeast to viruses, bacteria, and protozoa.

Caprylic acid, derived from castor oil, is a naturally occurring fatty acid that is readily absorbed in the entire digestive tract by using an enteric-coated form. Some research suggests it interferes with the growth and reproductive processes of yeast organisms.

Garlic has been widely used for medicinal purposes for centuries. Garlic extract has been scientifically proven to strengthen the immune system by helping white blood cells engulf and destroy enemy germs, including Candida albicans yeast.

Citrus seed or grapefruit seed extract has been shown to discourage the growth of yeast in the intestinal tract. Some doctors say this extract is as effective as prescription medications in treating Candida-related yeast problems.

These products are available at your local health food store and offered along with an anti-Candida program, books, diet, and supplements at yeastconnection.com.

If your yeast overgrowth has been long-established, it's likely you'll need to take prescription antifungal medications for several months or even more.

Diflucan is common for the short-term treatment of vaginitis and is the drug of choice for many physicians treating yeast overgrowth on a long-term basis. It works throughout the system to penetrate tissues infested with yeast organisms. Your liver function should be monitored if you take Diflucan on a long-term basis, since rare cases of liver toxicity have been reported.

Nystatin has been in use longer than Diflucan and similar drugs. It works in a unique way to help re-establish the strength of the intestinal walls, eliminating the leaky gut syndrome.

There are numerous other prescription antifungals. Discuss them with your doctor. But remember that following an anti-Candida diet and taking probiotics will enhance the success of prescription anti-fungal drugs.