People who regularly consume yogurt or buttermilk have a greater diversity of gut bacteria. Credit: © BillionPhotos.com / Fotolia
A large-scale study into the effect of food and medicine on the bacterial diversity in the human gut was led by RUG/UMCG geneticist Cisca Wijmenga. Researchers collected stool samples from more than 1100 people taking part in the LifeLines programme, which is monitoring the health of 165,000 residents of the Northern Netherlands. The samples were used to analyze the DNA of the bacteria and other organisms that live in the gut. In addition to stools, the study collected information on the participants’ diet, medicine-use and health.
This study is unique in that it focused on a group of normal people whereas previous research was frequently focused on patients with a specific illness. “Normally researchers only investigate one particular region of DNA in which different groups of bacteria can be distinguished,” Wijmenga explains. “We have mapped all the bacterial DNA to gain much more detailed information about bacteria types.”
This DNA analysis made it possible to examine which factors impact the diversity of the microbiome and that appears to be many. Eg People who regularly consume yogurt or buttermilk have a greater diversity of gut bacteria. Coffee and wine can increase the diversity as well, while whole milk or a high-calorie diet can decrease it. “In total we found 60 dietary factors that influence the diversity. What these mean exactly is still hard to say,” explains UMCG researcher Alexandra Zhernakova. “But there is a good correlation between diversity and health: greater diversity is better.”
Beyond diet, at least 19 different kinds of medicine have an impact on microbiome diversity. An earlier study by Groningen researchers has shown that antacids decrease this diversity, while antibiotics and the diabetes drug metformin also have an effect. Wijmenga stresses, “Disease often occurs as the result of many factors. Most of these factors, like your genes or your age, are not things you can change. But you can change the diversity of your microbiome through adapting your diet or medication. When we understand how this works, it will open up new possibilities.”
It is now possible to combat obesity through a ‘fecal transplantation’ in which the intestinal bacteria from a slender person are introduced into the gut of an obese patient. An appropriate diet or a specific medicine may produce the same effect on the microbiome.
Currently a lot of research is looking into the microbiome, but it often seems hard to reproduce. It is therefore striking that the results of a Belgian group published in the same issue of Science show about 80% agreement with those of the Groningen group. “The key is the way the research was done,” Wijmenga says. What was important was that the stool samples were frozen immediately by the participants themselves, and picked up by the researchers while still frozen. “When samples are sent in by post, as is often the case, you expose them to oxygen and high temperatures. These are conditions that some bacteria can’t survive in. These two Science articles have therefore set a new standard for future research in this field.”
http://www.eurekalert.org/pub_releases/2016-04/uog-lha042616.php
http://science.sciencemag.org/content/352/6285/565
http://science.sciencemag.org/content/352/6285/560
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