By Sara Altshul

Billions of one-celled beneficial bacteria call your blood, bones, and vital organs home. There they wage war against the harmful bacteria in your gut, mounting a constant defense to protect their turf and, coincidentally, your health. Called probiotics, these helpful bacteria play an essential role in many of the gut’s life-supporting metabolic functions.

Probiotics not only prevent harmful bacteria from multiplying and causing disease, they also enable the body to absorb and use such crucial minerals as calcium, zinc, and iron, and they help manufacture thiamin, riboflavin, and vitamins B6, B12, and K. Probiotics may also stimulate mucus formation, which enables helpful microbes to cling to and colonize the gut’s walls (primarily in the colon) and reinforce the barrier that keeps harmful invaders out.

Only about 1 percent of the bacteria we harbor potentially provoke disease. In a healthy body, the beneficial bacteria keep the dangerous ones in check by competing with them for food and muscling them out of spaces to occupy. In addition, some good bacteria produce a mild acetic acid solution—healthy for our guts but toxic to harmful bacteria.

This triumph of good over evil in our internal bacterial world enables us to enjoy vibrant health. But should something upset the system, dysbiosis can occur, allowing disease-causing bacteria to get a toehold and multiply.

Even subtle changes in the number of good bacteria in the gut can produce a host of common symptoms and result in an obvious lack of wellness, according to S.K. Dash, PhD, a probiotic researcher and author of A Consumer’s Guide to Probiotics (Freedom Press, 2005). The result: digestive problems, including diarrhea, irritable bowel syndrome (IBS), and indigestion. Other problems can include lowered immune function, frequent bouts of infectious disease, urinary tract infections, and prostatitis—even fertility problems and an increased risk of cancer, notes Dash.

Many holistic health practitioners see excellent results with probiotics therapy. Mitch Kennedy, ND, frequently prescribes them to his patients from his Avon, Connecticut clinic, Health With Nature. “I have successfully used probiotics to shorten the duration of common colds, viral respiratory infections, sinus infections, urinary, bladder, and prostate infections, and diarrhea—both viral and infectious ‘traveler’s’ types,” Kennedy reports.

When good bugs go AWOL
The balance of your internal bacterial population can tip in an unhealthy direction for many reasons—including stress, a poor diet, various drugs, and chemotherapy, says Sheryl Berman, PhD, dean of the School of Natural Health Sciences at Bastyr University in Kenmore, Washington.

According to many experts, antibiotics top the list for creating bacterial chaos. Although certainly life-saving at times, these drugs not only kill their intended target, harmful bacteria, they wipe out the beneficial ones, too. “Almost any antibiotic will change the bacterial balance in the intestines,” says Dash. It seems these “equal opportunity killers” severely disturb the gut’s floral ecology and create a vacuum that allows harmful bacteria to move in and take hold.

Sometimes, even a single dose of antibiotics can cause problems. With the good bacteria out of commission, harmful bacteria, such as Clostridium difficile, can multiply and produce a toxic substance that causes diarrhea—or an even more severe condition called pseudomembranous enterocolitis, the symptoms of which can include bloody diarrhea and body-bending cramps.

But antibiotic-related problems don’t just affect your gut. Berman says they can also cause an imbalance in the flora of the female genital tract, which can lead to yeast and bacterial infections. If you must take antibiotics, adding probiotics to your supplement regimen can help re-establish the proper balance of bacteria and work to stop these opportunistic infections before they start.

Mounting evidence for probiotics
Probiotic research has increased dramatically in the last several years. “The list of conditions in peer-reviewed literature that probiotics improves is quite long,” says Berman. “Probiotics have even proven effective in the treatment of acute bacterial and viral gastroenteritis.” Kennedy concurs: “Several recent studies have shown that daily probiotic supplementation decreases the number of days of work missed due to colds and flu, helps children grow, and decreases the duration and extent of IBS symptoms.”

Additionally, says Berman, studies link probiotics to improving food allergy symptoms, preventing and treating women’s urinary tract infections, treating eczema, decreasing outbreaks of Herpes Simplex I cold sores—
and even lowering blood cholesterol.

In one study, Belgian researchers reported a link between bacterial imbalance in the vagina with reproductive problems. They suggested that taking probiotics might be a safe way to re-establish normal conditions—and improve your chances of getting pregnant. (If you’re undergoing fertility treatments, check with your doctor first.)

Probiotic supplementation may also enhance overall immunity, according to a study reported in the British Medical Journal. More than 500 children at Finnish day care centers were given either milk fortified with Lactobacillus GG or plain milk. Those who drank the former had fewer and milder respiratory infections.

Using probiotics to maintain health isn’t a new concept. Back in 1905, Nobel laureate Elie Metchnikoff, PhD, then vice president of the Pasteur Institute, suggested that Bulgarian peasants lived long, healthy lives because they enjoyed fermented milk products. He noted, “Lactobacilli can displace toxin-producing bacteria, promoting health and prolonging life.” Now, more than 100 years later, we’re beginning to understand that this pioneering scientist’s theory was correct.

Fermented foods to the rescue
Although carefully chosen supplements are perhaps the best way to replenish beneficial bacteria, you can also include bacteria-friendly food in your diet for an additional boost. Yogurt and other fermented foods such as raw sauerkraut, kefir, and fermented soy foods like tempeh, miso, and natto contain probiotics. When buying yogurt, look for the words “live active cultures” on the label. Although the tart taste of plain yogurt may not suit you initially—it lacks the high sugar content of flavored commercial yogurts—it’s definitely your healthiest choice. Try adding your own fruit to plain yogurt. You’ll still avoid the refined sugar, and you’ll gain fiber and other valuable nutrients in the bargain.