Beginning in the United States, obesity has become a world-wide problem. There are many causes of obesity including, let's be honest, overeating, but Washington University (St. Louis) researchers in the USA have found the strongest evidence yet that bacteria in the small intestine and colon causes chronic weight problems.
Identical Twins with Different Gut Bacteria Gain Weight Differently
Dr. Jeffrey Gordon, director of the Center for Genome Sciences and Systems Biology at Washington University in St. Louis, led a research team that recruited four sets of identical twin women at locations around the world. One twin of each pair was thin, the other obese. The doctors then collected stool samples and transferred the bacteria, protozoans, and viruses the samples contain to mice that had been raised in a sterile environment.
The difference between the two kinds of gut bacteria turned out to be their ability to digest sugars from fiber. The bacteria from women who were obese broke down various kinds of fiber into sugars. Some of the sugars find their way into the bloodstream of the mouse, or human, that hosts them. The bacteria from the women who were thin fed on the many of the same nutrients as their human or mouse hosts, and allowed fiber in food to pass undigested out the digestive tract.
Antibiotics Not the Solution for Weight Gain Caused By Bacteria
"It appears that certain bugs drive obesity," microbiologist Sarkin Mazmanian told the LA Times. If scientists could identify the single strain of bacteria most responsible for obesity, they could develop an antibiotic to kill it.
Or, as Mazmanian and many other scientists point out, it may be that antibiotics fed to farm animals and prescribed too often in disease treatment are the basic problem. As antibiotics have been used over more and more of the world to help cows gain weight in feedlots or to keep chickens from catching infections while they live out their short lives in crowded cages, people over more and more of the world have been getting fatter and fatter.
There are many causes of obesity, but it may be that antibiotics have been killing the "good bugs" that have been keeping the "obesity bugs" in check. So what is an ordinary person to do with this information?
Bacterial Problem, Bacterial Rescue
Although most news accounts don't mention it, the researchers in Dr. Gordon's study didn't just find that "bad bacteria" caused weight gain. They also found that mice given bacteria from the thin women started to reverse weight gain.
And earlier research has found that the bacteria that drive weight gain don't just break down fiber into sugars that provide extra calories. They cause inflammation that causes swelling. Up to 30% of the mass of fat around your waist or on your hips, and even more of the extra weight on your thighs, can be fluid and white blood cells generated by inflammation.
The good bacteria that can help you fight the obesity-causing bacteria are in the genus Bacteroides. These bacteria aren't added to most brands of yogurt, or at least they aren't yet. Your best bet for getting the healthy strains of Bacteroides is to eat brands of yogurt that are also available in Europe, such as Muller, distributed in the US by Quaker, Oikos, and FAGE.