Monday, December 29, 2014

Is Aging Determined by our Gut Bacteria?

Carolyn Bohach, a microbiologist at the University of Idaho estimates that there are 10 times more bacterial cells in your body than human cells. Although smaller than human cells, and weigh only 1-3% of our body weight, the 500-1,000 species of bacteria that inhabit our body have evolved with us for millions of years.

Although bacteria are all over our body--inside and out--we see how it maintenance balance particularly in the human gut.  There are fewer physical changes in older adults' gastric system than any other system in the body. Although the stomach looses its elasticity and might be more prone to damage—primarily as a result of taking some medications—the small and large intestine, pancreas, liver, and gallbladder change minimally with age. So the changes that evolve inside our gut are argued to come from bacteria that inhabit this internal world.

In the gut there are 100 trillion microorganisms that engage in fermenting, killing off other harmful bacteria and viruses, enhancing our immune system and producing vitamins and hormones. This bacterial activity is so necessary to the body that their outcome, function as an independent organ--a virtual "forgotten" organ. Here, bacteria help extract energy and nutrients from our food. This sharing of benefits shows in experiments where bacteria-free rodents have to consume nearly a third more calories than normal rodents to maintain their body weight. Less well understood is the role of fungi and protozoa that are also part of the gut flora.

In 2012 Marcus Claesson and Ian Jeffery from University College Cork in Ireland and their colleagues, reported this gut flora changes among some older adults, and they correlated changes in the type of bacteria with frailty and mortality. They found that institutionalized older adults have a different gut flora than community older adults and younger people. And they related this flora—caused by a restricted diet—to diminished physical capacity.

But it was only in December 2014 that Martin Blaser from New York University and Glenn Webb from Vanderbilt University, Nashville, Tennessee, tried to explain how bacteria are designed to kill older adults. They argue that modern medical problems, such as inflammation-induced early cancer, resistance to infectious diseases and degenerative diseases are in response to bacterial change as we get older and this has an evolutionary cause. Using mathematical models the authors show how bacteria evolved because they contributed to the stability of early human populations: Enhancing the survivability of younger adults while increasing vulnerability of older adults. Such an evolutionary process has advantages, but in the modern world, bacteria's legacy is now a burden on human longevity. Although this mathematical model has many flaws—primarily the theory of antagonistic pleiotropy and that there are other factors other than bacteria responsible for specific diseases—it allows gerontologists to see aging as a balance, not an all or nothing event.

http://www.nih.govBacteria is necessary in balancing the biological activities in our human body. In one example scientists are using bacteria that cause botulism to eradicate tumors. While in another example, Linlin Guo and her colleagues from the Buck Institute for Research on Aging in California, have increased lifespan in flies by altering bacteria in their intestine.  It seems that bacteria form an important system in the body which might have repercussion on our longevity. Our body is a universe of organic activity and we are still learning about this miracle.

© USA Copyrighted 2014 Mario D. Garrett

No comments:

Post a Comment