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Can gut bacteria improve your health?

Initial research suggests certain bacteria in your gut can prevent and treat many common diseases.

Image: newannyart/Thinkstock

In many ways, your gut bacteria are as vast and mysterious as the Milky Way. About 100 trillion bacteria, both good and bad, live inside your digestive system. Collectively, they’re known as the gut microbiota.

Science has begun to look more closely at how this enormous system of organisms influences—and even improves—health conditions, from heart disease to arthritis to cancer. But understanding how the gut microbiota works, and how you may benefit, can be daunting.

“This is a new frontier of medicine, and many are looking at the gut microbiota as an additional organ system,” says Dr. Elizabeth Hohmann of the infectious diseases division at Harvard-affiliated Massachusetts General Hospital. “It’s most important to the health of our gastrointestinal system, but may have even more far-reaching effects on our well-being.”

The gut microbiota in action

Within those trillions of gut bacteria are about 1,000 different species, represented by some 5,000 distinct bacterial strains. Everyone’s gut microbiota is unique, but there are certain combinations and collections of bacteria that are found in healthy individuals.

The main factors that affect your personal microbial mix are age, diet, environment, genes, and medications (particularly exposure to antibiotics, which can deplete gut bacteria). Your gut microbiota plays many roles. It metabolizes nutrients from food and certain medications, serves as a protective barrier against intestinal infections, and produces vitamin K, which helps make blood-clotting proteins.

But the gut microbiota may do much more. Most research has involved only preliminary animal studies; however, initial findings suggest gut bacteria may be the key to preventing or treating some diseases.

Since the gut microbiota is so complex, it is difficult to pinpoint certain bacteria as the most beneficial. “It would be great if we could identify 10 or so bacteria and say these are the ones you need most, but it doesn’t work that way, and there is no magic bullet,” says Dr. Hohmann. “There may be a community dynamic at play as well as good mixtures of communities.”

Here’s a summary of the latest findings:

Rheumatoid arthritis. Two studies from the Mayo Clinic suggest gut bacteria may predict susceptibility to rheumatoid arthritis (RA) as well as offer a possible treatment. A study published online April 21, 2016, by Genome Medicine looked for a biomarker of the disease. Researchers were able to isolate certain bacteria that are high in RA patients, but low in healthy individuals. The other study, published online June 23, 2016, by Arthritis & Rheumatology, found that mice treated with the bacterium Prevotella histicola had less severe and less frequent symptoms and fewer inflammatory conditions associated with RA.

Cancer. A study published online April 13, 2016, by PLOS ONE offered some evidence that a particular strain of the bacterium Lactobacillus johnsonii may protect against some cancers. Scientists gave mice a mutation that is associated with a high incidence of leukemia, lymphomas, and other cancers. When treated with the bacterium, the mice developed lymphoma only half as quickly compared with a control group.

Heart disease. Research in the February 2016 Journal of Applied Microbiology found the bacterial strain Akkermansia muciniphila could prevent inflammation that contributes to fatty plaque buildup in arteries. Scientists believe the effect was due to a protein that blocks communication between cells in the inner lining of the gut. As a result, fewer toxins from a poor diet could pass into the bloodstream, which in turn reduced inflammation.

Immune system. In a study published online Nov. 5, 2015, by Science, University of Chicago researchers found that introducing a particular bacterial strain into the digestive tracts of mice with melanoma prompted their immune systems to attack tumor cells. The gains were comparable to treatment with anti-cancer drugs called checkpoint inhibitors.

Gut check time

What does all this mean? Should you even be concerned about your gut microbiota? “A healthy gut microbiota is still important for health,” says Dr. Hohmann. “Anything that can feed good bacteria and keep them plentiful is good for overall health. When the gut is happy, you are happy.” Here are some suggestions on how to do that:

FermentedFoods probiotics gut bacteriaDo not overuse antibiotics. Again, overusing antibiotics can deplete good gut bacteria. “In general, older people are more susceptible to infections and have more medical problems, so they are more likely to be prescribed antibiotics,” says Dr. Hohmann. “These are important lifesaving drugs, but they need to be used judiciously.”

Don’t be so quick to ask for antibiotics to fight viral ailments like the common cold, she says. Also, if your doctor prescribes one, ask if you really need it, what is the shortest treatment course, and whether there are alternative methods.

Eat more fermented foods. Bacteria are living organisms that need to eat. “A healthy, varied, balanced, high-fiber diet with complex carbohydrates is good for the bacteria living in your gut and encourages a diverse ecosystem,” says Dr. Hohmann.

Other helpful dietary choices include naturally fermented foods containing probiotics (live bacteria), such as sauerkraut, pickles, miso, certain types of yogurt, and kefir (a yogurt-based drink).

Probiotic supplements are another option. They are also touted as a remedy for common digestive problems like irritable bowel syndrome, inflammatory bowel disease, and infectious diarrhea. However, the science is still cloudy about their overall effectiveness for these and other related conditions.

“Some people say they feel better after taking probiotics, which is great, but they can be expensive,” says Dr. Hohmann. “Plus, many probiotics disappear from the gut once you stop taking them regularly.”

People with depressed immune function from late-stage cancer or chemotherapy should not take probiotics. Also, not all probiotic preparations are the same, so discuss the options with your doctor before you take one.

A new way to fight gut infection

Fecal transplantation? Yes, it’s real, and yes, it might help you fight a recurring type of gut infection.

A fecal transplant involves inserting stool from a healthy donor into a person’s gastrointestinal tract to treat recurrent colitis from Clostridium difficile infection, which causes inflammation in the colon and leads to diarrhea, cramping, and fever.

People with C. difficile colitis are first given antibiotics. However, in about 25% to 30% of cases, the infection returns days or weeks after therapy ends. “The more episodes of C. difficile colitis a patient experiences, the more likely it is that further relapses are going to occur,” says Dr. Elizabeth Hohmann of the infectious diseases division at Harvard-affiliated Massachusetts General Hospital.

This is when fecal transplants are considered. Their job is to replenish good bacteria that have been killed by antibiotics. “When healthy, normal flora is absent, it is easier for infections to take hold or persist,” says Dr. Hohmann. Fecal matter is not something people would normally consider “healthy,” but human stool contains a variety of helpful bacteria, viruses, fungi, and other organisms.

For the procedure, fecal matter is collected from a tested donor, mixed with saline, strained, and then placed into the colon by colonoscopy, endoscopy, sigmoidoscopy, or enema. The longer the patient holds the transplanted stool, the more healthy bacteria are absorbed. A fecal transplant can also be administered in capsule form, or by a tubes going down the nose and into the stomach or small intestine.

A review of existing research in the July 12, 2016, PLOS Biology suggests fecal transplants cure about 90% to 95% of cases of stubborn C. difficile colitis. Fecal transplants are not covered by most insurance, although the colonoscopy or other transplant procedure might be cov-ered on its own.

Image: marekuliasz/Thinkstock

Posted by: Dr.Health

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