The human body contains billions of bacteria and other microorganisms. Some are ‘bad guys’, disease causing pathogens, but many bacteria are beneficial and play an important role in keeping us healthy.
The bacteria naturally found on and in the human body are called ‘normal micribiota’ or ‘normal flora.’ These bacteria provide us with many valuable services; aiding our digestion, producing vitamin K and protecting us against the invasion of harmful microbes.
Probiotics and Normal Flora
Probiotics are the same types of bacteria as some of the normal microbes that live in our digestive tract, and as such, may provide similar health benefits. Although probiotics can be added to the diet through supplements, they can also be found in foods, primarily yogurt and kefir, as well as a few other dairy, soy and fruit products. Once ingested, these probiotic bacteria thrive and reproduce in the digestive tract, colonizing the intestines and replenishing our population of beneficial gastrointestinal microbes.
Probiotics and Pasteurization
Many food products are disinfected before being brought to market, often through the process of pasteurization, a sterilizing procedure named after the French chemist and microbiologist Louis Pasteur. Pasteurization uses heat to destroy all microbes that naturally occur in foods. Therefore, probiotic foods that have been subjected to pasteurization must have good bacteria reintroduced into the food after the sterilization process.
What Are the Benefits of Probiotics?
Though there are many claims regarding the beneficial effects of consuming probiotics, only a few of these claims have been supported by scientific evidence.
Probiotics after Antibiotics
Most beneficial effects of probiotics relate to replenishing normal microbiotic populations after a person takes antibiotics. Antibiotics are drugs that we take to kill bacteria that are making us sick. But many antibiotics are broad-spectrum and don’t discriminate between the bad and the good bacteria. Although antibiotics help us recover from illness by killing bacterial pathogens, they also often wipe out some of the normal flora that naturally exists in our body.
Many of our good bacteria help to crowd out pathogens, maintaining a healthy microbial balance in our body. When the populations of normal flora are depleted, health problems can result. For example, because of the short female urethra and its proximity to the anus, women are particularly prone to urinary tract infections (UTI). After taking antibiotics to combat the bacteria causing a UTI, it is common for women to then develop a yeast infection. This happens because the protective bacteria of the vagina have been eliminated by the antibiotics, allowing the yeast population to grow out of control. Introduction of probiotic bacteria into the vagina can help combat the overgrowth of yeast.
Probiotics to Control Diarrhea and IBS
Lactobacillus, one of the types of bacteria commonly added to yogurt cultures, can reduce symptoms of antibiotic induced diarrhea and diarrhea in children that results from rotavirus.
Several brands of yogurt are now being marketed as potential relief for those with irritable bowel syndrome (IBS), a digestive disorder distinguished by abdominal pain, cramping, bloating, gas, diarrhea and or constipation. Research supporting the use of probiotics to treat IBS has shown conflicting results, but some bacteria, such as Bifidobacterium infantis has been shown to relieve symptoms.
More Information
To learn more about healthy diet and taking care of your GI tract, see the Mayo Clinic Digestive System Center.
Sources
Bauman, R. W., 2003. Microbiology. Pearson Benjamin Cummings.
Friedrich, M.J. 2000. A bit of culture for Children: Probiotics may improve health and fight disease. Journal of the American Medical Association, 248 (11).
University of Michigan data presented at the annual American College of Gastroenterology (ACG) conference in Philadelphia, PA.
Please note: The information in this article is not to be followed as medical advice, diagnosis or treatment. Please consult with your physician or primary health practitioner for information regarding your own personal health and necessary treatments.
