Gut microbes help the body extract more calories from food

ScienceDaily (Sep. 12, 2012) — You may think you have your food all to yourself, but you're actually sharing it with a vast community of microbes waiting within your digestive tract. A new study from the University of North Carolina School of Medicine reveals some gut microbes increase the absorption of dietary fats, allowing the host organism to extract more calories from the same amount of food.

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"This study is the first to demonstrate that microbes can promote the absorption of dietary fats in the intestine and their subsequent metabolism in the body," said senior study author John Rawls, PhD, associate professor in the Department of Cell and Molecular Physiology at UNC. "The results underscore the complex relationship between microbes, diet and host physiology."

Previous studies showed gut microbes aid in the breakdown of complex carbohydrates, but their role in dietary fat metabolism remained a mystery, until now. The research was published in the Sept 13, 2012 issue of the journal Cell Host & Microbe.

The study was carried out in zebrafish, which are optically transparent when young. By feeding the fish fatty acids tagged with fluorescent dye, the researchers were able to directly observe the absorption and transport of fats in the presence or absence of gut microbes.

The researchers pinpointed one group of bacteria -- Firmicutes -- as instrumental in increasing fat absorption. They also found the abundance of Firmicutes in the gut was influenced by diet: fish fed normally had more Firmicutes bacteria compared to fish that were denied food for several days. Other studies have linked a higher relative abundance of Firmicutes in the gut with obesity in humans.

"Our findings indicate that the gut microbiota can increase the host's ability to harvest calories from the diet by stimulating fat absorption," said the study's lead researcher, Ivana Semova, PhD, who was a graduate student at UNC at the time the study was conducted. "Another implication is that diet history could impact fat absorption by changing the abundance of certain microbes, such as Firmicutes, that promote fat absorption."

Although the study involved only fish, not humans, the researchers say it offers insights that could help inform new approaches to treating obesity and other disorders. For example, said Rawls, "If we can understand how specific gut bacteria are able to stimulate absorption of dietary fat, we may be able to use that information to develop new ways to reduce fat absorption in the context of obesity and associated metabolic diseases, and to enhance fat absorption in the context of malnutrition."

Study co-authors include Lantz Mackey of UNC, Juliana Carten and Steven Farber of the Carnegie Institution for Science, and Jesse Stombaugh and Rob Knight of the University of Colorado at Boulder.

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Grape Seed Extract Lowers Blood Pressure

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Turmeric extract may protect heart after surgery: study

Reuters – 9 hrs ago (Reuters) - Extracts from turmeric spice, known for their antioxidant and anti-inflammatory properties, may help ward off heart attacks in people who have had recent bypass surgery, according to a study from Thailand.

During bypass surgery the heart muscle can be damaged by prolonged lack of blood flow, increasing the patient's risk of heart attack. But the new findings, published in the peer-reviewed American Journal of Cardiology, suggest that curcumins - the yellow pigment in turmeric - may ease those risks when added to traditional drug treatment.

The conclusions are based on a relatively small group of subjects and needs to be confirmed in larger studies, said researchers led by Wanwarang Wongcharoen from Chiang Mai University. Turmeric extracts have long been used in traditional Chinese and Indian medicine.

Research has suggested inflammation plays an important role in the development of a range of diseases, including heart disease, and curcumins could have an effect on those pathways, said Bharat Aggarwal, who studies the use of curcumins in cancer therapy at the MD Anderson Cancer Center in Houston, Texas.

"It's very, very encouraging," said Aggarwal of the study, which he did not take part in.

The researchers studied 121 patients who had non-emergency bypass surgery at their hospital between 2009 and 2011.

Half of those patients were given one-gram curcumin capsules to take four times a day, starting three days before their surgery and continuing for five days afterwards. The other half took the same number of drug-free placebo capsules.

The researchers found that during their post-bypass hospital stays, 13 percent of patients who'd been taking curcumins had a heart attack, compared to 30 percent in the placebo group.

After accounting for any initial pre-surgery differences, Wongcharoen and his colleagues calculated that people on curcumins had a 65 percent lower chance of heart attack.

Researchers said it's likely that the antioxidant and anti-inflammatory properties of curcumins may have helped limit heart damage in the patients.

"Curcumin has for many years now been shown to reduce inflammation and to reduce oxygen toxicity or damage caused by free radicals in a number of experimental settings," said Jawahar Mehta, a cardiologist at the University of Arkansas for Medical Sciences in Little Rock, who didn't work on the study.

"But that doesn't mean that this is a substitute for medication," he said, noting that drugs like aspirin, statins and beta blockers have been proven to help heart patients and people in the current study were taking those as well.

One limitation was that the study was relatively small. Another is that while curcumins are thought to be safe, there could be side effects at very large doses.

"Taken in moderation or used in cooking, (curcumins) are quite useful. But I wouldn't go to a health food store and start taking four grams of curcumin a day, as was done in this study," Mehta said. SOURCE: http://bit.ly/HEnC5f

(Reporting from New York by Genevra Pittman at Reuters Health; editing by Elaine Lies and Jeremy Laurence)

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