Diet-microbiota-health interactions in older subjects: implications for healthy aging.

With modern medicine and an awareness of healthy lifestyle practices, people are living longer and generally healthier lives than their ancestors. These successes of modern medicine have resulted in an increasing proportion of elderly in society. Research groups around the world have investigated the contribution of gut microbial communities to human health and well-being. It was established that the microbiota composition of the human gut is modulated by lifestyle factors, especially diet. The microbiota composition and function, acting in concert with direct and indirect effects of habitual diet, is of great importance in remaining healthy and active. This is not a new concept, but until now the scale of the potential microbiota contribution was not appreciated. There are an estimated ten times more bacteria in an individual than human cells. The bacterial population is relatively stable in adults, but the age-related changes that occur later in life can have a negative impact on host health. This loss of the adult-associated microbiota correlates with measures of markers of inflammation, frailty, co-morbidity and nutritional status. This effect may be greater than that of diet or in some cases genetics alone. Collectively, the recent studies show the importance of the microbiota and associated metabolites in healthy aging and the importance of diet in its modulation.