For many people, the idea of ingesting bacteria may sound crazy — since we usually try to steer clear of disease-causing germs. But not all bacteria are bad for us.

In fact, probiotics, bacteria available in supplement form, can balance and strengthen your health — and, in turn, boost your energy. Can probiotics help you? Yes, especially if you have gastrointestinal problems or immune problems (including susceptibility to colds)… are going into the hospital (they work preventively)… and even if you feel well, they can help maintain your health.

How do they work? Your digestive tract is home to more than 500 species of bacteria. Our bodies contain about 10 times more bacteria than human cells, with the bacteria accounting for several pounds of our weight. They feed on nutrients we consume and, in turn, help keep us healthy — as long as we give them some TLC.

Most bacteria in our digestive tract live in harmony, even though their “neighborhood” is crowded and diverse. But stress, poor eating habits, drinking chlorinated water, exposure to mercury and some medications (particularly antibiotics) can disrupt this bacterial neighborhood, leading to a microbial imbalance called dysbiosis. Consequences may include diarrhea, hormone imbalances, reduced immunity, infections, allergies and possibly increased cancer risk.

HOW PROBIOTICS CAN HELP YOU

Consuming just one or two types of probiotics can strengthen your gut’s entire bacterial environment… and taking more can yield even greater health benefits. Different probiotics increase the production of different immune compounds (such as immunoglobulin A and M) and release chemicals (such as lactic acid) that won’t hurt you but make life uncomfortable for disease-causing germs. Examples: Lactobacillus reuteri and L. casei GG are good all-purpose probiotics that help reestablish many species in the digestive tract. (Dosage varies among brands.)

Common conditions probiotics help prevent…

Weakened immunity. Some species of intestinal bacteria, such as Lactobacillus, play a fundamental role in the immune system, protecting us against infections and cancer. Researchers at the University of Cologne, Germany, discovered that destroying the intestinal bacteria of laboratory animals brought their immune systems to a screeching halt — and with probiotics, immune function was restored. The scientists also found that these bacteria secreted compounds called peptides that kept the immune system running at a low idle, ready to respond to disease-causing infections. More research has found that probiotics activate a wide range of immune compounds that fight harmful bacteria and viruses.

Good choice: L. rhamnosus.

Antibiotic-induced diarrhea. Oral antibiotics are like medical cluster bombs — they kill off disease-causing bacteria and wipe out beneficial bacteria at the same time. Opportunistic bacteria, such as Clostridium difficile, often quickly multiply, leading to a secondary infection and diarrhea. Use probiotics while taking antibiotics and for at least one month after.

Good choices: L. casei GG, Bifidobacterium lactis, Streptococcus thermophilus, Saccharomyces boulardii.

Infectious diarrhea. After analyzing nine studies, scientists at the University of Washington, Seattle, concluded that treatments with Lactobacillus cultures could lead to a faster recovery from infectious diarrhea. Probiotics secrete their own antibiotics, called bacteriocins and microcins, which fight pathogens.

Good choices: L. rhamnosus, B. bifidum.

Vaginal infections. Probiotic bacteria and a type of probiotic yeast, S. boulardii, often can resolve vaginitis, an inflammation of the vaginal tissues, as well as Candida infections. Live-culture yogurt, oral probiotic supplements and vaginal suppositories containing probiotics have been used successfully.

Good choices: L. acidophilus, L. rhamnosus, L. fermentum.

Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). When disease-causing bacteria find a home in your gut, they can trigger inflammation, damage the intestinal wall and set the stage for IBS and IBD. Probiotics can help resolve IBS (though I always consider the possibility of food allergies and antibiotics as precipitating causes).

Good choice: Bacillus coagulans.

Colon and breast cancers. The studies are preliminary but positive, demonstrating that Lactobacillus probiotics stimulated immune cells to fight these two types of cancer. Probiotics also may suppress bacteria that create cancer-causing compounds in the colon, as well as alter the inflammatory response so that it does not stimulate breast cancer cells. In addition, probiotics help break down potentially harmful estrogens as they pass through the digestive tract.

Good choices: L. lactis, any Lactobacillus formula.

PROBIOTIC FOODS AND SUPPLEMENTS

When it comes to probiotic foods, many people think only of yogurt, but there are many other interesting and tasty options. Japanese consume miso and tempeh (both include fermented soybeans)… Koreans eat kimchi (a spicy vegetable dish)… Germans eat sauerkraut… and Southeast Asian cuisine includes fermented fish sauces and pastes. Just about every cuisine includes some probiotic-rich food. Guidelines…

Best balance: Eat one probiotic food source at least every other day. Fortified beverages and yogurts are popular, but many contain added sugars. Or take probiotic supplements, which are at least five times as potent as yogurt. Choosing which ones to purchase can be confusing.

  • Consider the number of microorganisms listed on the label — such as 10 billion per capsule — but don’t be overly influenced by it. This is the number of probiotics on the day of manufacture, but bacteria die off over time, so this number will decrease. The species is more important than this number.
  • Buy the freshest product possible — indicated by the longest expiration date on the bottle.
  • Stick to formulas from reputable manufacturers — including Enzymatic Therapy, Jarrow and Nature’s Way. All are sold at health-food stores.

For general prevention, consider buying a blend of multiple species of probiotics, because diverse ingredients will likely have broader and more synergistic benefits. Important: Take probiotics at the end of a meal so that the food will buffer your stomach acid, which otherwise can kill most bacteria.

WHAT ABOUT PREBIOTICS?

Prebiotics are ingredients in foods that bacteria thrive on but that contain carbohydrate fibers that our bodies cannot fully digest. They bring many health benefits, likely by helping normal gut bacteria to flourish.

Food sources: Avocado, chicory root, Jerusalem artichoke, garlic, onion and jicama.

Supplements: Inulin (not insulin), fructooligosaccharides (FOS) and galactooligosaccharides (GOS).

Recent research showed that infants who were fed FOS and GOS in their formula had fewer upper respiratory infections than babies who did not get these supplements. At two years old, they continued to have fewer infections… and fewer allergies.

Prebiotics are safe, and some supplements contain both probiotics and prebiotics.