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ise.aspx

Probiotics Show Digestive Promise
7/28/2009 7:33:00 AM

As yogurt ads shift from hearty centenarian Soviet peasants to
Hollywood stars with tummy troubles, so has the public’s—and science’s—
notion of probiotic cultures.

WHO’s your favorite bug

The World Health Organization (WHO) defines probiotics as
microorganisms that, when administered in adequate amounts, confer a
health benefit on the host (ftp.fao.org/es/esn/food/wgreport2.pdf,
2002). Many of these involve one of the bugs’ preferred homes, the
human digestive tract.

The large intestine’s natural beneficial microbial flora help digest
food components not previously digested in the small intestine, such
as digestion-resist fibers, plus produce substances with other
beneficial effects, such as short-chain fatty acids that can suppress
“bad bugs” and the production of carcinogenic compounds. Research
indicates probiotics might be useful in addressing a range of
digestive problems, such as constipation, diarrhea, Helicobacter
pylori (the microorganism linked to ulcers), irritable bowel syndrome,
inflammatory bowel disease and lactose intolerance.

Studies strongly suggest that probiotics are effective in treating and
possibly preventing diarrhea caused by antibiotics or certain
infections, such as those caused by rotavirus, particularly strains of
Lactobacillus and Saccharomyces boulardii. WHO suggests probiotics
potentially provide an important means to reduce problems caused by
infectious diarrhea, which is responsible for several million deaths
globally each year.

Digestive disease fighters

In a 2008 presentation on “Probiotics and Inflammatory Bowel Disease,”
for the American College of Nutrition 49th Annual meeting, Dr. Stefano
Guandalini, professor of Pediatrics, University of Chicago, Comer
Children’s Hospital, Chicago, suggests that probiotics would be
helpful for those suffering from maladies such as Crohn’s disease and
ulcerative colitis for several reasons: “Essentially probiotics are
known to interfere with bacterial pathogens by reducing their bonding
to the enteral sites, producing antibacterial substances and even
competing for receptor sites. They also enhance innate immunity by
decreasing the production of inflammatory cytokines and increasing the
production of anti-inflammatory cytokines. They finally improve the
intestinal health by increasing the barrier integrity and survival.”

Guandalini went on to say that these proposed mechanisms supported the
theory that probiotics have a role in balancing inflammation in these
diseases, which is supported by research in animal models. Research in
humans indicates additional studies are needed to support the
hypotheses that probiotics (Lactobaccillus, in particular) might
induce and maintain remission of Crohn’s disease and ulcerative
colitis, however. The current, limited body of human research has not
found probiotic consumption results in significant improvement in
Crohn’s disease, but it has found a more-positive correlation in
helping ulcerative colitis, particularly in children, and a positive
effect on a condition called “pouchitis,” an inflammatory complication
in patients that have had colon-removal surgery.

Using the good guys

Different strains of the same species can have markedly different
effects, according to another presentation at the American College of
Nutrition meeting, “The Potential Uses of Probiotics in Human Health,”
by Mary Ellen Sanders, Ph.D., consultant, Dairy and Food Culture
Technologies, Centennial, CO. She notes that clinical support to
substantiate claims must be obtained for each strain or blend, which
“makes it very difficult in terms of communications on probiotics,
because it’s so much easier to talk in generalities than to talk about
specifics.”

Most experts recommend daily dosage levels ranging from 5 to 20
billion CFUs of the live cultures to achieve benefits.  However, it’s
not possible to come up with a single number as a “minimum dose” for
probiotics, according to Sanders. “Sometimes I’ve seen the number one
billion kicked around—109 live cells is a minimum dose for probiotics.
But, in fact, what I would argue is that’s a very scientifically
unsubstantiated statement,” because the products, strains levels and
clinical endpoints differ. She strongly recommends the levels used in
products should be based on levels found to be efficacious in human
studies for a particular effect.

WHO has issued a comprehensive paper on probiotic evaluation
guidelines that can be found at who.int/foodsafety/fs_management/en/
probiotic_guidelines.pdf.