The Benefits of Probiotics
Last reviewed by Faculty of Harvard Medical School on January 16, 2013
By Audrey Young, M.S., R.D., L.D.N.
In a society of anti-bacterial warfare, who would have thought that anyone would tout the benefits of bacteria? Living microorganisms found in yogurt and other cultured foods may help improve your body's bacterial environment inside and out. They're called probiotics, a name that means "for life."
More and more people are using probiotic products to treat or improve illnesses or to maintain overall well-being. In fact, the amount that Americans spent on probiotic supplements between 1994 and 2003 nearly tripled.
In 1907, Russian microbiologist Elie Metchnikoff (1845-1916) was the first to associate the large amounts of fermented dairy products with the good health and longevity of Bulgarians. He proposed that the acid-producing organisms in fermented dairy products could prevent what he called "fouling" in the large intestine. He believed if eaten regularly, these foods could lead to a longer, healthier life. One version of the Old Testament even attributes Abraham's long life 175 years to the "consumption of sour milk." Fermented milk products may have also been used to treat illnesses of the digestive tract during Roman times.
Our bodies are home to a mix of good and bad bacteria. They're pretty much everywhere the mouth, gut and skin. Probiotics may help
Under normal or "balanced" conditions, friendly bacteria in the gut outnumber the unfriendly ones. Probiotics can act as gut-beneficial bacteria that create a physical barrier against unfriendly bacteria.
Probiotics can also help offset the bacterial imbalance caused by taking antibiotics. Antibiotics kill good bacteria along with the harmful ones, often leading to gas, cramping or diarrhea.
Probiotics may help breakdown protein and fat in the digestive tract a valuable benefit to help infants, toddlers or patients who need to build strength throughout and after an illness.
Not all probiotics are the same. Different strains of the bacteria have different effects. For example, one strain may fight against cavity-causing organisms in our mouths and don't need to survive a trip through our guts.
Research has been promising for these friendly critters. Potential benefits have been seen in the treatment or prevention of
Fermented or cultured dairy products are a major source of probiotics. Other sources include miso, tempeh, soy beverages, buttermilk and fermented milk. The bacteria either occur naturally in these foods or have been added during preparation. Probiotics are also available as dietary supplements in capsule, tablet or powder-form.
Here are the most common strains of probiotics:
Bifidus regularis, a name created for marketing purposes by Dannon, is also known as Bifidobacterium animalis DN-173 010. This strain of probiotics is used exclusively in Dannon's popular Activia products, which Dannon claims promote regularity.
Keep in mind that in order for a yogurt to be considered probiotic, it must contain one of the strains listed above. All yogurts are required to be treated with the strains Lactobacillus bulgaricus and Streptococcus thermophilus.
Food marketers have found a new niche with probiotic-containing foods. Probiotic cereal, granola bars, soy milk, cottage cheese, sour cream and infant formula are available. However, their claims may be based only on preliminary scientific findings.
More research is needed to see whether probiotic bacterias' beneficial effects are the same when they're treated or added to food products. Dried probiotics may survive a trip through the intestines if prepared and stored properly. Heat often kills live active cultures.
The scientific community agrees that there are potential health benefits to eating foods with probiotics. However, more research is needed to solidify the claims. The best we can say right now is they won't hurt and may help.
Remember that dietary supplements are not tested by the U.S. Food and Drug Administration like medications. And the probiotic strains in the supplements may not be specific for the condition you're looking to treat. You may want to consult with a practitioner, like a registered dietitian, who is familiar with probiotics. Always tell your physician what you are doing that may affect your health.
Audrey Young, M.S., R.D., L.D.N. is a senior nutritionist at Brigham and Women's Hospital. She holds a Bachelor of Science degree in nutritional sciences from the University of Connecticut and a master's degree in nutrition communication from Tufts University. She completed her dietetic internship at Brigham and Women's Hospital.