Gut Feeling: The Latest News Behind Probiotics & Prebiotics

Overwhelmed by the proliferation of news about probiotics? Here's what you need to know about them, and how you can take advantage of probiotics (and prebiotics) to improve digestion, fend off disease, and maximize nutrient absorption.
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For years, the thought of microorganisms living in your gut would have grossed you out. But by now, you’ve probably heard of the benefits of probiotics, the naturally occurring bacteria that are thought to promote a healthy digestive system as well as counteract the overuse of antibiotics (which destroy intestinal flora) and help prevent diseases such as inflammatory bowel disease.

“Probiotics are essential for optimal digestion of food and absorption of nutrients,” says Koya Webb, a Los Angeles–based holistic health and wellness expert. “They help your body produce vitamins, absorb minerals and aid in the elimination of toxins.”

"Pros" of Probiotics

Several studies are providing even more pros of probiotics. In August 2013, Pediatrics reported that babies whose mothers took probiotics during pregnancy and during the first year of the baby's life had a 12% lower risk of developing allergies. That follows an announcement from late 2012, when researchers at the American Heart Association’s Scientific Sessions presented evidence that a probiotic supplement taken in two 200-milligram doses each day for nine weeks lowered LDL (bad) cholesterol by 11.6% and total cholesterol by 9.1% in high- cholesterol patients.

The University of Medicine and Dentistry of New Jersey’s School of Health Related Professions studied nearly 200 college students and discovered that those who took probiotic supplements were less likely to suffer from the common cold. The study’s findings, shared in the October 2012 issue of the British Journal of Nutrition, also revealed that the probiotic-supplement takers experienced a shorter duration of colds, cold symptoms that were 34% less severe and fewer missed school days. Scientists attributed the relief to the anti-inflammatory qualities of probiotics. This anti-inflammatory effect can also help relieve psoriasis and chronic fatigue syndrome, found a study published in Gut Microbes in August 2013.

Pick Wisely

But not all probiotic supplements are the same, and some may even be misleading. While there are dozens of boxed probiotic supplements on drugstore shelves, Webb suggests trying probiotic-containing fermented foods (such as kimchi, kombucha, miso and coconut kefir) first. “Stay away from pasteurized versions of probiotics, as pasteurizations will destroy many of the naturally occurring probiotics,” she says. “Many probiotic yogurts also contain added sugars, high-fructose corn syrup, dyes or artificial sweeteners, all of which will only worsen your health.”

Be wary, too, of marketers promoting a specific amount of probiotics measured in colony-forming units (CFUs), as researchers haven’t yet been able to offer a specific and consistent recommendation. However, the International Scientific Association for Probiotics and Prebiotics points out that scientific literature has shown health benefits for products that contain anywhere from 50 million to more than 1 trillion CFUs per day.

See also How to Make Lacto-Fermented Root Vegetables.

What About Prebiotics?

Never heard of prebiotics? The sidekick of probiotics, these are indigestible food ingredients that help the trillions of microbes inside the gastrointestinal tract. Increasingly, scientists are discovering how important these prebiotics are for daily wellness. A systemic review published in The Cochrane Library found that infant formula fortified with prebiotic supplements may help prevent eczema. That finding is yet another indicator of the delicate bacterial balance required for optimal health.

“The gut, particularly the colon, is an immensely complex bacterial ecosystem that has a direct impact on health and well-being,” says Robert Rastall, PhD, head of the food and nutritional sciences department at the University of Reading in England and co-editor of Prebiotics and Probiotics Science and Technology (Springer, 2009). “Prebiotics allow us to manipulate the ecology to promote the more health-positive bacteria over the less desirable elements.”

See alsoDiversify Your Diet for Better Gut Health. 

At the 2012 National Meeting and Exposition of the American Chemical Society, Rastall cited how people with gastrointestinal diseases, type 2 diabetes, traveler’s diarrhea and inflammation may benefit from prebiotics. The challenge of prebiotics, however, is that they’re typically found in foods and plants we don’t eat large quantities of, such as onions, garlic and chicory (and wheat in small amounts). Rastall, as well as the United States Department of Agriculture’s Agricultural Research Service, advocate adding prebiotics to foods.
“One advantage of prebiotics over probiotics is that, because they are not alive, we don’t have to worry about killing them as we do with probiotics,” says Rastall. “This means that they can be formulated into a wide range of food products such as breakfast cereals, bread and juices.”

Like probiotics, the effective doses and daily requirements for prebiotics vary. In the US and northern Europe, the naturally occurring levels of prebiotics in the daily diet are quite low. “An intake of around 20 grams per day will have a measurable difference in most people, but some will have results with less, maybe 10 grams per day,” says Rastall. “Different people’s gut ecosystems tend to respond very differently to dietary changes, and there is a wide variation in what would be considered ‘normal’ levels of the various bacteria in the gut."

The good news is that the side effect of excess prebiotic ingestion is relatively benign. “The worst is gas production,” says Rastall. “If it does occur, then it usually eases after a few days as the bacterial ecosystem in the gut changes and adapts to the new diet.”

Foods with Fermented Probiotics:

Foods Rich in Prebiotics: