A glimpse inside older people's stomachs reveals how gut bacteria and diet might influence health.

Last year, Paul O'Toole at University College Cork in Ireland and his colleagues found that the collection of gut bacteria in adults over 65 varied considerably. "It was surprising because bacterial communities in the gut are broadly similar across young adults," says O'Toole.

To find out whether these differences affect people's health, O'Toole's team analysed the blood, faeces, urine, diet, physical strength and mental function of 178 people over 65 in Ireland. After adjusting for the effect of any medications, they found that the volunteers' gut bacteria varied depending on whether they were living at home or in a care home, and that the differences correlated with how long they had been in care for and their health.

After going into care, people's diets change within weeks but gut bacteria take about a year to alter, says O'Toole. The volunteers' health declined most at this time, suggesting that the bacteria and ultimately diet may be responsible.

O'Toole's team will now look at whether tweaking the diets of people in care can maintain gut bacteria that improve health.

Source: New Scientist

Journal reference: Nature, DOI: 10.1038/nature11319