Animal based diet quickly alters bacteria to lead to IBD

Kathleen Blanchard's picture
Could eliminating meat treat Crohn's disease and colitis?
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Eating meat could alter bacteria in the gut that leads to IBD, say researchers. According to a Harvard investigation it doesn't take long to alter the trillions of microbes in the intestines to lead to Crohn's disease, ulcerative colitis or other forms of IBD that are still poorly understood. The changes happen in just one day. The finding supports the notion that food can be used as a treatment for inflammatory bowel disease and that meat greatly contributes to inflammatory bowel disease.

Meat and plants have different effects on intestinal flora

For their study, published in the journal Nature, the researchers studied 11 people. The participants ate their normal diet over a period of four days, documented their food intake and submitted stool (fecal) specimens for testing. Over the next four days they ate what the researchers provided and again had fecal testing. The investigators then watched the participants for the next six days as a control.

Eating a plant based diet that was low fat and low protein had little effect on the gut bacteria. Conversely, eating an animal based diet that was low in fiber significantly changed microbes in the gut that can cause inflammation.

Lawrence David, one of the Harvard researchers and now an assistant professor at Duke University’s Molecular Genetics & Microbiology and Institute for Genome Sciences & Policy said in a press release: “We’re getting an increasing appreciation of how flexible and responsive the microbiome is, even on a very short time scale.”

Previous studies showed the same results in mice, but this is the first time it has been replicated in humans, David said.

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It's all about the host

Thousands of bacteria live in the intestines and on our skin and how they interact with humans who are the host has been poorly understood. Why some bacteria become invasive is a complex issue that seems to depend on balance.

One of the bacterium that increased from eating meat and found in this study was Bilophila wadsworthia, which is known to cause colitis in mice.

The authors also found" eating meat increased other microorganisms that are "bile tolerant", including Alistipes, Bilophila and Bacteroides, in addition to decreasing levels of Firmicutes that metabolize dietary plant polysaccharides - Roseburia, Eubacterium rectale and Ruminococcus bromii.

Eating a high fat diet has previously been linked to changes in intestinal bacteria that can lead to obesity, type 2 diabetes and a variety of other chronic illnesses. People with lower levels of Firmicutes are generally obese and have higher fat intake, but questions have remained whether obesity or diet are responsible for changes in the gut flora.

A study conducted on Zebrafish also showed more fat is extracted from the diet when Firmicutes bacteria is more rampant, supporting the notion that what lives in our intestines has an influence on obesity and other types of inflammatory conditions.

“Perhaps in prehistoric groups, when there was a lot more volatility in terms of what you can forage or hunt for, this could have been very useful,” David said. “It creates a way of buffering nutritional changes and may have enabled ancient humans to be a little more flexible with their diet. Eating meat also altered the way some of the bacteria expressed genes.

Understanding how an animal based diet can lead to changes in intestinal bacteria that cause IBD means switching to primarily plant based foods and lowering met intake that is generally high in fat could be a valuable intervention for treating Crohn's disease and colitis.

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Comments

...and more hungry people could be fed with the grain we feed the cattle than we could feed from the meat of the cattle.
True Jim - so true.