The Pros and Cons of Probiotics



WHAT’S GOOD FOR THE GUT might also be good for reducing stress, anxiety and anger.  So-called probiotics — good bacteria — might also improve problem-solving abilities as well as mood and might help with weight loss.

While these possibilities are enticing, the evidence is not yet completely in for good microbes doing much more than their traditional uses: to offset the side-effects of taking antibiotics or “for symptoms that are digestive in nature or urinary tract-based,” says local clinical nutritionist Kelly Dorfman, who works with other medical professionals to help people cope with complex symptoms.

Based on studies (mostly at Yale) that suggest probiotics boost immune function and help prevent illness, Dorfman says, “I often use probiotics when people get sick frequently.”

The digestive tract can be viewed as a second or small brain. Along the walls of the 30-or-so-foot tube — composed of the stomach and small and large intestines — are trillions of microbes, including many good bacteria that control the smaller amounts of bad bacteria, which in large numbers can make you sick. The best good gut bacteria are probably specific strains of Lactobacillus and Bifidobacterium, according to Shekhar Challa, a Topeka, Kansas, gastroenterologist and author of “Probiotics for Dummies.”  When taking antibiotics knocks out these good bacteria, nasty bugs can cause digestive problems, and a particularly nasty one called Clostridium difficile can cause potentially serious diarrhea and fever, explains Joel Mason, nutrition scientist at Tufts School of Medicine.

While it has been known for years that hormones related to high stress can increase the virulence of bad gut bacteria, leading to stomach pains and diarrhea, recent evidence suggests the reverse might also be true: A rise in good bacteria can, for example, raise the levels of tryptophan, a precursor of the feel-good neurotransmitters serotonin and dopamine. Also in a French study of moderately anxious people, taking a daily probiotic supplement decreased anger and depression. And an Irish study on stressed mice showed that daily doses of good bacteria changed the way the mice reacted to a maze, which typically causes high anxiety.

In addition, studies on overweight mice found that there was a higher percentage of one type of the bad bacteria in their guts, and when those bacteria were put into germ-free thinner mice, they became fat. too. Research on the Old Order Amish sect (whose members eat similar diets and are genetically similar) found 26 species of bacteria present in different amounts in obese people compared with thinner family members and neighbors, according to researchers at the University of Maryland Medical School in Baltimore. Jane Foster, PhD, an associate professor in psychiatry and behavioral neurosciences at McMaster University in Ontario, suggests that “people struggling with weight try a probiotic supplement.”

On the other hand, there is a story with the opposite outcome: A chemist took antibiotics for travelers’ diarrhea and suddenly began began losing the weight he’d struggled with for a long time. The theory is that some “good” gut bacteria are more efficient at breaking down food, which enables the body to absorb more calories — so after the chemist began taking antibiotics, he wiped out some “good” bacteria so his body absorbed fewer calories and he lost weight. In that case, forget the probiotics: Reducing “good” bacteria would be the key to weight loss.

Determining the best levels of good and bad bacteria, however, is not simple.

According to Dorfman, the prescription depends on an individual’s symptoms, sensitivities and diet, but exactly how this works is not well understood. The National Institutes of Health is now compiling information for its “Human Microbiome Project,” which hopefully will clarify these issues.  Although Dorfman sometimes takes a stool sample to assess an individual’s situation, she says that “for many situations, you throw in a bunch of species [of bacteria] and hope one sticks.”

Among foods that contain probiotics are kefir and cheese; fermented foods such as sauerkraut and kimchi (Korean fermented cabbage); and pickles fermented in briny water, not vinegar.  Local classes in “Fermenting Fundamentals” or “Crazy for Kefir and Kombucha” are taught by Gina Rieg, certified Health Coach at Holistic Maryland in Columbia.

Also yogurt, if it has been refrigerated and the label says “live” or “active.” In a study comparing Dannon’s Activia, which contains a strain of bifidobacterium, with yogurt that does not, food passed more quickly through subjects who ate Activia — which may reduce the discomfort of constipation, according to Robynne Chutkan, founder of the Digestive Center for Women in Chevy Chase and Associate Professor of Medicine at Georgetown University Medical Center.

Foods that operate as prebiotics, to stimulate the growth and activity of good bacteria already living in the intesting, include oats, chicory, bananas, wheat, garlic and onions, flaxseed, artichokes, barley, legumes and raw dandelion greens, and honey, contain prebiotics that stimulate the growth and activity of good bacteria already living in the intestine.

If you don’t love yogurt, kimchi and pickles, improving your store of the good bacteria could be as easy as taking one pill a day –- but do not drink anything hot for an hour afterward because heat destroys bacteria en route to the stomach.

More magazine author of “A Surprising Way to Beat Stress” Dianne Lange suggests Align. (My totally unscientific sampling of Align saw a decline in post-meal symptoms, including occasional stomach pains and gas.) But Joel Mason at Tufts warns that the “good” bacteria you’re swallowing can lead to infections, albeit in rare situations. And Dorfman cautions that unrefrigerated supplements can be ineffective; she recommends checking Consumer Lab for product evaluations.

 Finally, a related treatment involves “fecal transplants” — from a healthy person into someone who is sick, specifically with C. diff., usually caused by antibiotics and often found in hospitals.  A recent study conducted in the Netherlands supports the experience of gastroenterologists around the United States that fecal transplants have saved the lives of patients with C.diff.  Use of these transplants will hopefully be obviated as the Human Microbiome Project pinpoints which bacteria work best in different situations.

–Mary Carpenter

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