Tuesday, August 15, 2006

A Fascinating New Angle on Obesity

It's rare, but occasionally an article comes along that completely flips my way of thinking upside down. Today, I read one of those pieces. It's a feature from the New York Times titled, "Fat Factors," and it investigates the possible link between microbes in the human body and obesity.

Microbes inside me? But I don't feel sick.
According to the Times article, the human body contains trillions of cells, "at least 10 times as many cells… as there are stars in the Milky Way." Astonishingly, 90 percent of these cells are microbes like bacteria, fungi, protozoa and archaea. "Because there are so many trillions of microbes in the gut, the vast majority of the genes that a person carries around are more microbial than human," read the Times article. In total, there are between 395 to 500 different species of microbe in your body right now.

Of course, not all microbes make you sick, or otherwise do harm. In fact, the community of microbes in your body, known as the microflora, does a lot of good. According to the Times feature, "It helps create the capillaries that line and nourish the intestines. It produces vitamins, in particular thiamine, pyroxidine and vitamin K. It provides the enzymes necessary to metabolize cholesterol and bile acid. It digests complex plant polysaccharides, the fiber found in grains, fruits and vegetables that would otherwise be indigestible."

The symbiotic relationship between microbe and man is perfectly natural and lasts from before the cradle until after you're in the grave.

"Microbes colonize our body surfaces from the moment of our birth… they are with us throughout our lives, and at the moment of our death they consume us,” Jeffrey Gordoon of the Center for Genome Sciences at Washington University, told the Times.

The majority of microbes, reported the Times, are in our guts. The thriving culture of microbes in your gut (all 10 to 100 trillion) are called the gut microflora.

So what's the link to obesity?
The gut microflora, according to the Times, "helps extract calories from the food we eat and helps store those calories in fat cells for later use -- which gives them, in effect, a role in determining whether our diets will make us fat or thin."

In theory, the role the microflora play is largely determined by the balance between species of microbes that help you burn calories and microbes that help you store calories. For example, if your gut is thriving with microbes that help you extract lots of calories from food, you're more likely to gain wait.

Does this mean that some people get more calories from, say, a piece of bread, than others? It's possible. Two people with different gut microflora could sit down to a meal of 1000 calories, and one could absorb 750 while the other absorbs 975.

In one experiment described by the Times, mice that were raised in "sterile isolators," and had no microbes, had 60 percent less fat than typical ones despite eating 30 percent more food. When microbes were added to these mice, "they were just as fat as ordinary mice" within two weeks.

Someday, by manipulating the microbes in our body, we may be able to alter the way that we process calories and ultimately store fat. We could take antimicrobial medications to kill a specific type of microbe that makes our body extract more calories from food. After wiping these guys out, voila! We'll all look handsome and gorgeous as movie stars.

But that won't be for a long time. For today, "whatever the reason for any one individual’s tendency to gain weight, the only way to lose the weight is to eat less and exercise more," read the Times column.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.