Do probiotics really solve digestive problems?
September 29, 2015 MVP Blog comments
You may have heard that foods and supplements made with probiotics can help your digestion and prevent infections. Probiotics are very much like some microorganisms that already live in your body: “good” bacteria and yeasts that can help balance out “bad” bacteria that appear when your system is thrown off by illness or antibiotics. Manufacturers are adding probiotics to all sorts of products, from trail mix to chocolate bars.
One in 5 Americans with digestive problems seeks out probiotics, according to market research. They can be found in the supplements aisle as well as the dairy case. (Fermented foods — notably, yogurt — can contain naturally occurring and added probiotics.) But do they work?
That depends. Some studies that tout their benefits have been small, poorly designed or sponsored by those with a vested interest in the outcome. “The quality of the research has probably not been as good as it should have been over the years,” notes Patricia Hibberd, a professor at the Harvard Medical School. But there’s some evidence that probiotics might shorten a bout of diarrhea caused by antibiotics, a virus or contaminated food, and studies suggest that they help manage irritable bowel syndrome. An analysis of 23 clinical trials found that taking probiotics with antibiotics can substantially cut the risk of diarrhea caused by Clostridium difficile, a serious infection. Consumer Reports’ advice: Consider probiotics if you’re on antibiotics for more than a few days, if you’re taking two simultaneously or if you’ve switched from one to another.
How much might be helpful? It takes billions of colony-forming units, or CFUs, for probiotics to have any impact. When Consumer Reports tested yogurts several years ago, it found that they were probiotic powerhouses, with an average of 90 billion to 500 billion CFUs per serving. Probiotic dietary supplements that were tested contained fewer — from just under a billion to 20 billion CFUs per capsule.
You might be tempted to buy probiotic snacks, but some appear to have much lower CFU levels than yogurt (Consumer Reports didn’t test them), and the labels show lots of sugar and fat. For example, Attune says its probiotic dark-chocolate bars contain 6.1 billion CFUs, 80 calories and six grams each of fat and sugar in a 20-gram bar. A quarter-cup of Gold Emblem Abound Sweet & Nutty Probiotic Trail Mix has about 250 million CFUs but 190 calories, 11 grams of fat and 19 grams of sugar.
The bottom line. Probiotic products may have some benefit, but scientists are still sorting out the evidence. Don’t count on probiotics to help with allergies, asthma, celiac disease, constipation, Crohn’s disease, eczema and respiratory and urinary tract infections. Probiotics are generally safe, but they may have negative effects on those with compromised immunity or serious medical conditions.
If you decide to try them:
– Be aware that makers of dietary supplements containing probiotics generally don’t have to prove that their products are safe or effective. What’s more, the Food and Drug Administration doesn’t preapprove food or supplement labels, and many don’t specify which strain is being used, though you might be more likely to find that info on supplement packages than on foods. Consumer Reports’ experts advise that you:
– Pick the right type. Research suggests that the most effective probiotics are combinations of L. acidophilus, L. casei, L. rhamnosus and S. boulardii.
Know your dose. To reduce the risk of diarrhea caused by C. diff, the most effective dose is thought to be more than 10 billion CFUs per day.
– Look for the right logo. The National Yogurt Association’s Live and Active Cultures seal tells you that the yogurt contained at least 100 million live cultures per gram at the time of manufacture.
Check the dates. Note expiration dates, sell-by dates and use-by dates.
– Store them correctly. Some probiotic products need refrigeration.
For more information about infections and the overuse of antibiotics, go to www.consumerreports.org/superbugs.