Researchers seek to understand the mechanisms of the complex biological machinery that makes up a human with the aim of extending healthy life by reducing wear and tear. We shouldn't forget, however, that this machinery includes a large and significant bacterial component. "humans and some bacteria are known to have mutually beneficial relationships. People gain nutrients and energy with the aid of bacteria, and the microbes are provided with a buffered environment, carbohydrates, and other nutrients ... Since immune function is impaired with age, it might be expected that 'bacterial load' would increase or be otherwise altered as people grow older. Indeed, studies have found shifts in humans' intestinal bacteria with age and evidence that bacteria may blossom in the prostate and other organs of the elderly. To explore the consequences of such changes in bacteria with age in greater detail, the researchers looked to flies." You might recall that calorie restriction has an impact on bacteria in the body - as it seems to have an impact on almost everything that can be linked to aging.