A recent study using mice, and following them for 4 generations, has implications for Americans who typically eat a low-fiber diet (average of 15 grams daily). Note that current dietary guidelines recommend that women should eat around 25 grams and men 38 grams daily of fiber. The researchers found that low-fiber diets not only deplete the complex microbial ecosystems residing in the gut, but can cause an irreversible loss of diversity within those ecosystems in as few as three or four generations.
This is because fiber feeds the millions of microbes in the gut - and so a fiber-rich diet can nourish a wide variety of gut microbes, but a low-fiber diet can only sustain a narrower community. As the generations went by, the rodents’ guts became progressively less diverse, as more and more species were extinguished. If the fourth-generation mice switched to high-fiber meals, some of the missing microbes rebounded, but most did not. It took a fecal transplant (mice style) to get back the missing microbes. From Science Daily:
Low-fiber diet may cause irreversible depletion of gut bacteria over generations
A study by Stanford University School of Medicine investigators raises concerns that the lower-fiber diets typical in industrialized societies may produce internal deficiencies that get passed along to future generations. The study, conducted in mice, indicates that low-fiber diets not only deplete the complex microbial ecosystems residing in every mammalian gut, but can cause an irreversible loss of diversity within those ecosystems in as few as three or four generations.
Once an entire population has experienced the extinction of key bacterial species, simply "eating right" may no longer be enough to restore these lost species to the guts of individuals in that population, the study suggests. Those of us who live in advanced industrial societies may already be heading down that path.
There is a new procedure in which microbiota (the microbes) from a healthy individual are introduced into the gastrointestinal system of a diseased individual via a fecal transplant. The purpose of the fecal transplant is to replace good bacteria which has been suppressed or killed (usually by antibiotics) , and which has caused bad bacteria, such as Clostridium difficile, to overpopulate the gut. This is having amazing success rates. It has been used the most for Clostridium difficile (C. difficile) infections, which sickens about half a million Americans annually. This infection can be so debilitating and so resistant to all antibiotics that about 14,000 Americans die each year from it. Even though not that many have been done, fecal transplants are gaining in popularity (some even being done by do-it-yourselfers using fecal enemas at home) because fecal transplants can have a 95 to 98% success rate.
New research is starting to see if the fecal transplant can be made even easier (via a "poop pill"), and also if fecal transplants will work for Inflammatory Bowel Diseases (IBD). This would mean the future treatment possibility of transplanting microbiota from healthy individuals to individuals sick with IBD. From the October 4, 2013 Science Daily:
Fecal Transplant Pill Knocks out Recurrent C. Diff Infection
C. diff infection can occur after people take antibiotics, wiping out the good bacteria in the gastrointestinal (GI) system, allowing C. diff to flourish and leading to severe diarrhea. In some patients, infection continues to recur despite standard treatment with antibiotics. For patients trapped in that cycle, doctors have transplanted feces from healthy donors into their GI system to rebalance the bacteria and stop infections from recurring.
University of Calgary researchers reported a 100 percent success rate -- none of the 27 patients who took the tablet-sized pills had a recurrence of C. diff, even though all of them previously had had at least four bouts of the infection. Patients ingested between 24 and 34 capsules containing fecal bacteria, often donated by family members.
There is even the site The Power of Poop which calls itself a "patient information resource dedicated to promoting safe accessible Fecal Microbiota Transplant (FMT) and to raising awareness of the role of the human microbiome in digestive illness." http://thepowerofpoop.com