Consuming probiotics–live “friendly bacteria and yeasts” that are added to foods or taken as a supplement–is another way to bolster your gut’s population of healthy microbes. For probiotics to work, however, there must be a sufficient number of live bacteria present, and they must survive the hostile environment of the stomach, including its acidity, and reach the large intestine. The presence of the prebiotics, which act as food to nourish friendly bacteria in the large intestine, will ensure their growth and colonization.
Friendly bacteria unlock powerful nutrients. Unlike people, bacteria have the digestive enzymes needed to break down fiber for energy. In the process, the helpful bacteria produce gases and various acids that benefit the intestine and other body systems. The acids reduce the pH of the colon, making the environment less suitable for the pathogenic bacteria.
One of the acid byproducts, butyric acid, may help prevent colon cancer by feeding the cells that line the colon and helping them to grow into healthy cells, explains Gastroenterologist Dr. Satish Rao. And another acid turns off a key enzyme in cholesterol synthesis, thus lowering blood cholesterol and decreasing the risk of cardiovascular disease. Better glucose control may be another benefit.
Bacteria in the gut also release trapped phytochemicals–health-protective compounds in plants–that otherwise would be unavailable to affect disease pathways. For example, the phytochemicals may be bound to fiber, or require metabolism by the bacteria to convert to an active compound.
Compounds in broccoli, cabbage and other cruciferous vegetables, for instance, seem to have anti-inflammatory effects and decrease the risk of several cancers. These vegetables contain glucosinolates which must be activated into the biologically active form called isothiocyanates either by chewing the raw vegetable, or if cooked, through the action of the intestinal bacteria, explains Johanna W. Lampe, Ph.D., R.D., a nutrition scientist and Associate Division Director, Public Health Sciences Division at the Fred Hutchinson Cancer Research Center, Seattle, WA.
Isoflavones in soy may also exert anti-cancer effects. They’re mostly in an inactive form when they enter the colon, but the gut bacteria convert them to an active form.
“Then the bacteria can also metabolize the isoflavone to additional bioactive compounds that we would never be exposed to if it weren’t for our bacteria,” adds Lampe. The interaction of the intestinal bacteria and the human body is anything but simple. Scientists have much more to learn.
Some studies suggest that exposure to soy foods in childhood may offer cancer protection in adulthood. One theory that requires additional research is that interactions between the intestinal microbes and isoflavones in the developing gut could affect development of the immune system and the long-term microbiotic environment of the individual.
– Jill Weisenberger, M.S., R.D., C.D.E., Environmental Nutrition
Reprinted with permission from Environmental Nutrition, a monthly publication of Belvoir Media Group, LLC. 800-829-5384.www.EnvironmentalNutrition.com. (c) 2012 BELVOIR MEDIA GROUP DISTRIBUTED BY TRIBUNE MEDIA SERVICES, INC.