But did you know that many of these micro-organisms work equally hard to protect your health?

The Pros

Humans have approximately three and a half pounds of bacteria living in the intestinal tract, so it’s important to maintain plenty of beneficial microflora, commonly known as probiotics (literally “for life”), to balance out harmful bacteria. According to the Food and Agriculture Organization and the World Health Organization, probiotics are “live organisms that, when administered in adequate amounts, confer a health benefit” to the person ingesting them.

Friendly flora increase the nutritional value of foods by improving digestion and increasing absorption of vitamins and minerals. “The presence of probiotic bacteria may also provide a low-level stimulation of the gut-associated immune system,” says Rosemary J. Young, RN, MS, a specialist in pediatric gastroenterology.

Most important, beneficial bacteria compete with pathogens (disease-causing bacteria, fungi, viruses, and yeasts), lessening their chances of causing illness. No wonder that probiotics have been found to fight autoimmune, chronic, and other conditions including acid reflux, allergies, heart disease, diarrhea, food poisoning, fungal infections (like candida), irritable bowel syndrome (IBS), lactose intolerance, and liver disease.

Stay Balanced

Aging, formula feeding, dietary changes, drugs (especially antibiotics that kill all bacteria, not just the harmful ones), environment (such as daycare or school), pollution, stress, and travel can all deplete stores of beneficial bacteria, skewing the internal balance away from health. Fortunately, it’s relatively easy to restock your body’s supply of beneficial bacteria.

Simply eating yogurt with live, active cultures improves intestinal and immune health. “Yogurt can also be used by people with lactose intolerance because of lactase enzyme deficiency,” says integrative physician Elson M. Haas, MD. “The bacteria change or ferment the lactose sugar and produce lactic acid.” Or select acidophilus milk (often labeled “lactose free”) and probiotic supplements (products that guarantee millions or billions of beneficial bacteria).

Healthy Cultures

“Actually, acidophilus itself acts as a mild antibiotic,” Dr. Haas adds, “that is, it has antibacterial activity. With regular use, it may even replace harmful bacteria.” These bacteria, as well as bifidus cultures (prevalent in infants), synthesize B vitamins in the body while inhibiting coliform and possibly salmonella bacteria.

Lactobacillus GG and L. reuteri have been found to shorten the duration of viral diarrhea in children as much as one day. Not to be confused with Streptococcus feacalis (a potential pathogen), Streptococcus feacium is another strain of bacteria that’s subject to recent research. Particularly helpful in diarrhea, this culture helps produce needed enzymes and combats other, more harmful bacteria.

To Feed Probiotics

Prebiotics, or food for beneficial bacteria, add bulk in the digestive tract while helping to support immune function, fight diarrhea, and protect against inflammatory conditions, science has discovered. A new study in the Journal of Nutrition shows that healthy, full-term babies given prebiotics in their first six months were less likely to develop allergic manifestations (itching or wheezing) or infections (including fever and upper respiratory tract ailments) than those given a placebo.

“As gastrointestinal disorders are prevalent in terms of human health, both probiotics and prebiotics serve an important role,” reports a recent British study. Products that contain both, or synbiotics, “also protect probiotics like bifidobacteria from destruction in the stomach and increases the survival of lactobacillus in the human gut,” explains nutritionist Marcia Zimmerman, MEd, CN. Look for the prebiotic inulin in artichoke (added to healthy bacteria in some yogurts) or fructooligosaccharides to boost the protective benefits of probiotics.

Functional Foods

Increasingly, you’ll find a number of foods that contain probiotics (and often prebiotics), so read labels on the following carefully:

• Cereals and grains (bulgur wheat, cornflakes, couscous, brown rice)
• Cottage cheese, kefir, liquid yogurt
• Drinks (almond, dairy, rice, soy milks)
• Infant formula and baby food (specifically look for Bifidobacterium infantis)
• Protein shakes and smoothies.

Never heat these foods or probiotics if you want to enjoy their many benefits; they’re best tepid. Temperatures higher than 120 degrees and acidic ingredients (citrus, tomatoes, or vinegar) kill the friendly bacteria.