How Much Do We Know about the Microbes in the Human Body?

Modern medical science can boast a lot of knowledge about the human body, but with those advances comes a realization that there is much more to learn. One prime example is the result of a DNA survey performed on blood that was carried out by Stanford scientists. Testing whether a patient's immune system was likely to reject an organ transplant by using DNA identification rather than a biopsy, the medical team was astonished to find an abundance of previously unknown microbes in the patient's body. Following more studies, the researchers learned that only 1 percent of the DNA fragments that were collected matched anything in the existing genetic database. Stanford Professor Stephen Quake, who led the investigating team, said the results showed the enormous diversity of the human microbiome. He added that the reason 99 percent of the microbes were previously unknown is that microbes are usually only identified when working on a person's stomach or skin. By examining blood, the team could look everywhere. “What this does is it arms infectious disease doctors with a whole set of new bugs to track and see if they’re associated with disease,” Quake said. “That’s going to be a whole other chapter of work for people to do.”

Don't let it bug you:

• While human adults have a huge amount of microbes living inside them, everyone is born free of bacteria.
• All adults carry approximately 3 pounds (1.4 kg) of microbes inside them.
• Despite their popularity, research indicates that store-bought probiotics offer very little benefit to people.