Posted by Brigham and Women's Hospital July 17, 2013
Not all bacteria are bad or dangerous. In fact, your large intestine (colon) is home to trillions of bacterial microoganisms, known as microflora. There are over 1,000 species or subspecies of these bacteria that have lived within each of us since birth. They form a mini-ecosystem sometimes called the colonic microbiome.
Probiotics are useful or “friendly” microorganisms that, if eaten in adequate quantity, are beneficial to our health. Some fermented foods are rich in probiotics, such as yogurt, kefir, tempeh, miso and sauerkraut. They have been eaten for centuries and touted by many as a way to promote good health.
We are just beginning to understand how these helpful bacteria work. For example, it is believed that healthy intestinal microflora, aided by probiotics, help to:
- Maintain proper balance of microorganisms in our intestines, helping to control the growth of “bad” or dangerous bacteria.
- Maintain the intestinal barrier so that bad bacteria and inflammatory proteins do not “leak” into the body.
- Strengthen and regulate our immune system, helping us fight off disease and control processes that lead to allergic, autoimmune, and inflammatory conditions.
- Produce substances in the colon that help control intestinal spasm, diarrhea, constipation, and perception of pain.
- Manufacture important substances within our bodies, such as vitamin K, folate, and short-chain fatty acids, and help mediate the breakdown of dietary carcinogens.
There are several things you can do to nurture the helpful microflora in your body:
- Add fermented foods to your diet (see above).
- Avoid eating refined carbohydrates and simple sugars and taking unnecessary antibiotics. These actions can disrupt the balance of good to bad bacteria in your body.
- Consider consuming prebiotics, substances that stimulate the growth of the helpful microflora. Examples of prebiotics include FOS (fructo-oligosaccharide), a non-digestible form of fructose that is found in artichokes, leeks, asparagus, onions, and bananas.
It also may make sense to take a mix of probiotics in the form of a nutritional supplement, but it is not clear what should go in that mix and at what doses. Keep in mind that there is no one specific probiotic species or mixture that will be universally effective in maintaining healthy intestinal microflora. There is evidence that certain species and mixtures are reasonable choices for specific health conditions, such as constipation, irritable bowel syndrome, inflammatory bowel disease, diarrhea, and some allergic conditions, such as eczema. To determine how to use probiotics most effectively, it’s best to consult with a health care provider who has an interest in this emerging field.
For more tips about healthy living, read the Osher Center’s Healthy 850 enewsletter.