Type and number of bacteria living in the large intestine can play an important role in human health, writes Dick Ahlstrom.We share a symbiotic relationship with the bacteria; we give them somewhere to live and they help us to take nourishment from the foods we eat. There are useful and harmful bacteria present. The good ones break down certain starches and complex sugars which can then be absorbed by the intestine. The bad ones contribute nothing but can cause stomach upsets and diarrhoea.
Dr John Cummings of the UK Medical Research Council has argued that eating certain foods can enhance the good bacteria to the disadvantage of the bad. Eating "live" yoghurts is a traditional method to assist this but new studies also suggest that certain complex sugars can also help.