Do probiotics really do anything?

Probiotic Food Packaging

Seeking guidance on the label? When it comes to probiotics, you may not find what you're looking for.
Seeking guidance on the label? When it comes to probiotics, you may not find what you're looking for.
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To actually create some effect in your body, probiotics need first-class travel on the journey that is your digestive system. They have to be encased in something strong enough to survive the acid-filled stomach, but not so strong that they don't dissolve in the intestines, where they do their best work. The bacteria can be damaged by air and moisture, so extreme care has to be taken in creating food products with probiotics. These items may not have a particularly long shelf life.

Further complicating the problem is the fact that in some instances, scientists aren't sure of the exact dosage of bacteria that will confer health benefits, and because we're dealing with live bacteria here, it's hard to know how many you add to a product end up remaining viable in each serving. Additionally, the only way to determine how many probiotics actually made it through the gastrointestinal tract is to examine the fecal matter of those who consumed the probiotics, a research study that certainly doesn't sound appealing to this writer. And even that number would be circumspect, because while the feces would reveal how many bacteria made it down the tract, it wouldn't reveal how many probiotics actually did the job they were supposed to do in the gut.

N­ot that you'll find this information on the package; critics of probiotics food worry that labels don't always indicate which bacteria are present or how much of the ingredient is there. Some manufacturers may just slap the probiotic label on an item that doesn't have enough bacteria to make any sort of difference. For now, consumers won't get any help from the FDA, either. While the FDA has strict rules about marketing items that claim to cure disease, they don't have restrictions for items that talk in fairly general terms about bodily health, which is why you'll see Activia marketing its asset as an ability to regulate the digestive system, as opposed to being a cure for constipation [source: Warner].

Such vague claims may lead a consumer to believe that probiotics should be added to a regular, everyday diet. But are there health benefits for those that are already healthy? There are few studies on how probiotics affect the immune system of a healthy person [source: Senok et al.]. The effects of probiotics are temporary, though, which means you have to keep consuming them, and if you're going to add a daily step to your routine, it may be more advantageous to consider measures with proven benefits, such as diet and exercise. Already nutritionists worry that consumers will add these products to their diet, rather than substituting them for something else, potentially leading to an excess of calories.

But what if you just love the taste of Activia, or you're already devoted to your probiotic supplement? Though there may be no definitive proof of the health benefits yet, there's also little evidence that you're doing harm to your body, either. Flatulence and abdominal discomfort are the only real side effects that have been reported [source: Kligher, Cohrssen]. However, one important exception exists: In a study group of nearly 300 patients with pancreatitis, the patients who received probiotics rather than a placebo were more likely to require intensive care and surgical intervention, even though the severity of illness was roughly the same before the study [source: Bakalar]. In the group taking probiotics, 24 people died, more than twice the number of deaths in the placebo group [source: Bakalar].

So do probiotics really do anything? Right now, the answer seems to be a big, fat maybe. But with consumers interested in natural health and manufacturers eager to cash in on the functional food fad, we can hope for more studies that will shed a light on the subject. For health-related subjects we already know a fair bit about, head on over to the next page and see the links there.

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  • Agrawal, Renu. "Probiotics: An emerging food supplement with health benefits." Food Biotechnology. 2005.
  • Bakalar, Nicholas. "Diet Supplement Seen as Risky for Some Users." New York Times. Feb. 19, 2008. (Nov. 18, 2008)
  • Bee, Peta. "Probiotics, not so friendly after all?" The Times. Nov. 10, 2008. (Nov. 18, 2008)
  • Brody, Jane E. "Putting Good Bacteria to Work." New York Times. Sept. 14, 2004. (Nov. 18, 2008)
  • Farnsworth, Edward R. "The Evidence to Support Health Claims for Probiotics." The Journal of Nutrition. June 2008.
  • "Getting to Know 'Friendly Bacteria'." CAM at the NIH: Focus on Complementary and Alternative Medicine. Summer 2006. (Nov. 18, 2008)
  • Kligler, Benjamin and Andreas Cohrssen. "Probiotics." American Family Physician. Nov. 1, 2008.
  • Martin, Andrew. "In Live Bacteria, Food Makers See a Bonanza." New York Times. Jan. 22, 2007. (Nov. 18, 2008)
  • Reid, Gregor and Jo-Anne Hammond. "Probiotics: Some evidence of their effectiveness." Canadian Family Physician. November 2005.
  • Sanders, Mary Ellen. "Considerations for Use of Probiotic Bacteria to Modulate Human Health." The Journal of Nutrition. 2000.
  • Senok, A.C., A.Y. Ismaeel and G.A. Botta. "Probiotics: facts and myths." Clinical Microbiology and Infection. December 2005.
  • Squires, Sally. "Mainstream Food Firms Get Proactive About Probiotics." Washington Post. April 15, 2008.
  • Warner, Melanie. "Eating Your Way to Health; Companies are Marketing Fortified Foods to the Drug-Wary." New York Times. Dec. 28, 2005. (Nov. 18, 2008)
  • Zied, Elisa. "Probiotics: More hype than help?" MSNBC. Oct. 31, 2008. (Nov. 18, 2008)