Saturday, October 18, 2014

Circadian Rhythms of Gut Microbes Tied to Obesity

Psych Central | Oct 17, 2014 | Rick Nauert PhD

© Psych Central
A new study suggests that messing with the biorhythms of our gut bacteria can cause obesity.

Researchers studied gut microbes in mice and humans and discovered the bacteria have circadian rhythms controlled by the biological clock of the host in which they live.

Investigators believe study results show that disruption of the circadian clock in the host alters the rhythms and composition of the microbial community. This interference causes changes in the composition of the bacteria favoring the growth of bacteria that have been linked to obesity and metabolic disease.

The study is published in the journal Cell Press.

“These findings provide an explanation for a long-standing and mysterious observation, namely that people with chronically disturbed day-night cycles due to repetitive jet lag or shift work have a tendency to develop obesity and other metabolic complications,” said senior study author Eran Elinav, Ph.D., of Israel’s Weizmann Institute of Science.

“These surprising findings may enable us to devise preventive treatments for these people to lower their risk for these complications.”

Disruption of the circadian clock in humans is a hallmark of relatively recent lifestyle changes involving chronic shift work or frequent flights across time zones.

These widespread behavioral patterns have been linked to a wide range of diseases, including obesity, diabetes, cancer, and cardiovascular disease.

But, until now, it has not been clear how changes in circadian rhythms increase the risk for these diseases.

In the new study, Elinav and his team set out to determine whether gut microbes could be the missing link.

An analysis of microbes found in fecal samples collected from mice and humans at different times of day revealed rhythmic fluctuations in the abundance of microbes and their biological activities.

The host’s circadian clock and normal feeding habits were required for the generation of these rhythmic fluctuations in the gut microbes.

When mice were exposed to changing light-dark schedules and abnormal 24-hour feeding habits, the microbial community lost its rhythmic fluctuations and changed in composition.

Moreover, a high-fat diet caused these jet-lagged mice to gain weight and develop metabolic problems associated with diabetes.

Comment:The "high-fat," reference is misleading and does not designate a meaning. An example would be saturated fat which is quite beneficial and reduces weight. A more accurate reference might be a "high-sugar," diet. There are also trans-fats which are actually quite unhealthy. The reader may want to understand various aspects of referencing and chemical concoctions derived into food substances.

New Science Destroys the Saturated Fat Myth
The four biggest dietary lies that need to be corrected
'Fat is good': the message from a man who swapped sugar for bacon and eggs
Why Are Trans Fats Bad For You? The Disturbing Truth
How Food Marketers Made Butter the Enemy

Similarly, jet lag in two humans who had traveled from the United States to Israel changed the composition of gut microbes, favoring the growth of bacteria that have been linked to obesity and metabolic disease.

“Our findings highlight a new therapeutic target that may be exploited in future studies to normalize the microbiota in those people whose lifestyle involves frequent alterations in sleep patterns, such as shift workers and very frequent fliers,” Elinav said.

“Targeting the harmful changes in the microbiota in these large human populations with probiotic or antimicrobial therapies may reduce or even prevent their risk of developing obesity and its complications.”

Source: Cell Press

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