this from an article from MSN:

"We know there's a huge difference in the diseases that different nations risk  broadly speaking, the Japanese tend to die of strokes, the Chinese of heart attacks  and we see those differences reflected in their urine," he added. "Of course they're different in terms of lifestyle  the Japanese tend to eat more fish than the Chinese as a whole do  but their gut bacteria are also very distinct as well."

Gut microbes help us get energy from our food.

"In your guts, you have about 1.5 kilograms (3.3 pounds) of 1,000 different species of bacteria," Nicholson explained. "If you include all the genes from bacteria along with your own, only about 1 to 2 percent of the genes in your body are human, with the rest from the gut microbes. And what bacteria you have can be quite different from person to person."

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I thought the folks here might get a kick out of these kinds of details. Imagine, only 1 to 2 percent of the DNA in our bodies are human. Ha. That should teach us not to get too arrogant in the future.