Intestinal Health

Did you know that your body hosts a veritable bacterial zoo?

Billions live on your skin and hair, and an estimated 200 types reside comfortably in your intestines. Friendly tenants, these organisms—called probiotics, which include a popular type found in acidophilus supplements—offer a more proactive defense than antibiotic drugs, which poison disease bacteria. Instead, probiotics crowd out the bad bugs and strengthen the mucosal lining of the intestines, so that unwanted organisms and allergens won't pass through.

They also assist in the manufacture of essential vitamins, such as the B vitamins, niacin, folic acid, pyridoxine, and biotin, and in the manufacture of substances that prevent the growth of microorganisms that might otherwise make you sick.

Recent research supports the practice of administering probiotics to children with diarrhea as well as to adults who develop "traveler's" diarrhea.

Probiotics are also recommended to women with vaginitis or recurring urinary tract infections.

Because supplements contain large numbers of the probiotic species, it is likely that enough pass through the digestive process intact to ward off interlopers (often, Candida) that contribute to disease.

While these "bacterial buddies" occur naturally in your gut, at times their populations could use a little coddling, specifically, when you—their "host" have been taking antibiotics. Antibiotics tend to kill a broad scope of internal bacteria, the "good" types along with the bad. This diminishes your defenses against the more malevolent microbes

Fortunately, you can increase your best bugs with probiotic supplements, and nourish them with "prebiotic" foods, such as the plant-based complex carbohydrate, fructooligosaccharide, which encourage their growth.

Survival of the Fittest, or Death to Interlopers

What are these bacteria doing in your intestines in the first place? First and foremost, they're propagating—to your benefit.

As part of your intestinal flora, they strengthen your defenses by attaching to cells that line the intestine, preventing their attachment to disease-causing microbes. In addition, they also produce a few beneficial chemicals:

Butyric acid, which may curtail cancer caused by dietary nitrosamines; lactic acid; and short chain fatty acids (both of which lower the mucosal pH, creating an intestinal environment that's too acidic for many a would-be disease-causing resident). Hydrogen peroxide competes with "bad" bacteria and yeasts in the intestines, crowding them out.

Probiotics also produce bacteriocins, compounds that kill major pathogens including staphylococcus, salmonella, and pseudomonas bacteria. One probiotic in particular—L. acidophilus—may trigger the release of immunoglubulin secretory IgA, which prevents infection in the intestinal lining as well as on other mucosal surfaces.

Practical Uses:

Urinary-genital and gastrointestinal infection. Lactobacillus, inserted in the vagina, may reduce UTI recurrence and may suppress H. pylori and recurrent diarrhea.

Lactose intolerance. In studies, yogurt with active lactic acid bacteria improved lactose absorption in lactose intolerant persons.

Vaginal infections. The daily ingestion of eight ounces of yogurt enriched with live L. acidophilus may prevent recurring bacterial vaginosis and candida infection, according to a study published in the Annals of Internal Medicine. Supplements may also be effective.

AIDS. L. acidophilus may help reduce candida overgrowth in AIDS patients, who may also benefit from immune enhancement stimulated by probiotic activity.

Antibiotic-induced diarrhea. Research has shown that probiotics help prevent ampicillin-induced diarrhea. They also help repopulate the gut with beneficial bacteria, reducing the likelihood that you'll get an infection when you stop taking your prescription.

The Antibiotic-Yogurt Connection

If you're taking antibiotics, or giving them to your kids, you may already know that yogurt may discourage the vaginal yeast infections that threaten to follow antibiotic therapy. But did you know that yogurt may also help prevent diaper rashes and thrush in your ear-infection prone toddler?

It may also help to repopulate the gut with the bacteria it needs to fend off your child's illness in the first place.

That's because yogurt is cultured with the types of bacteria that normally live in your (and your child's) gut, where it naturally protects against the growth of candida and other organisms—including those that contribute to otitis media— that can proliferate on mucosal surfaces, where they can develop into sticky, itchy, swollen, and smelly forms of infectious goo.

The most beneficial bacteria added to yogurt cultures are Lactobacillus acidophilus, L. casei, L. reuteri, and Bifidobacterium bifidum. And whether you and your children get them through yogurt or through supplements, they have been shown to reduce risks for intestinal and vaginal illnesses, diarrhea, and candida yeast overgrowth, and may support immune function.

Additional Considerations

Preliminary research, mostly on L. acidophilus, suggests that probiotics positively affect many conditions in addition to the ones listed above. They alter cholesterol so that it's not easily absorbed, which may help to reduce serum cholesterol levels.

And when leukemia patients increased their bifido bacteria levels, their yeast infection incidence decreased. While scientific proof is lacking, probiotics may also improve skin health, treat herpes infections, and relieve symptoms of irritable bowel syndrome.

 References De Roos NM, Katan MB. Effects of probiotic bacteria on diarrhea, lipid metabolism, and carcinogenesis: a review of papers published between 1988 and 1998. Am J Clin Nutri 71(2):405-11 2000 Feb. Donnet-Hughes A, et al. Modulation of nonspecific mechanisms of defense by lactic acid bacteria: effective dose. J Dairy Sci May 1999; 82(5):863-869. Gmeiner M, Kneifel W, Kulbe K, et al. Influence of a synbiotic mixture consisting of Lactobacillus acidophilus 74-2 and a fructooligosaccharide preparation on the microbial ecology sustained in a simulation of the human intestinal microbial ecosystem (SHIME reactor). Appl Microbio Biotechnol 53 (2):219-23 2000 Feb. Gotz V, et al. Prophylaxis against ampicillin-associated diarrhea with a lactobacillus preparation. Am J Hosp Pharm Jun 1979; 36(6): 754-757. Guandalini S, Pensabene L, Zikri M, et al. Lactobacillus GG administered in oral rehydration solution to children with acute diarrhea: a multicenter European trial. J Pediatr Gastroeneterol Nutr 30 (1):54-60 2000 Jan. Hilton E, et al. Ingestion of yogurt containing Lactobacillus acidophilus as prophylaxis for candidal vaginitis. Ann Intern Med Mar 1 1992;116(5): 353-357. Hoyos AB. Reduced incidence of necrotizing enterocolitis associated with enteral administration of Lactobacillus acidophilus and Bifidobacterium infantis to neonates in an intensive care unit. Int J Inf 3(4): 197-202 1999 Summer. McIntosh GH, Royle PJ, Playne MJ. A probiotic straine of L. acidophilus reduces DMS-induced large intestinal tumors in male Sprague-Dawley rats. Nutr Cancer 35 (2):153-9 1999. McLean NW, Rosenstein IJ, Characterisation and selection of a Lactobacillus species to recolonise the vagina of women with recurrent bacterial vaginosis. J Med Microbiol 49 (6): 543-52 2000 Jan. Nobaek S, et al. Alteration of intestinal microflora is associated with reduction in abdominal bloating and pain in patients with irritable bowel syndrome. Am J Gastroenterol, 95(5):1231-8 2000 May. Tihole F. Possible treatment of AIDS patients with live lactobacteria. Med Hypothesis May 1988; 26(1): 85-88.