FUNCTIONAL FOOD-SCIENCE AND GASTROINTESTINAL PHYSIOLOGY AND FUNCTION

The gut is an obvious target for the development of functional foods, acting as it does as the interface between diet and the metabolic even ts which sustain life. The key recesses in digestive physiology which can be regulated by modifying diet are satiety, the rate and extent of macronutrient breakdown and absorption from the small bowel,sterol me tabolism, the colonic microflora, fermentation, mucosal function and b owel habit, and the gut immune system. The intestinal microflora is th e main; focus of many current functional foods. Probiotics are foods w hich contain live bacteria which are beneficial to health whilst prebi otics, such as certain nondigestible oligosaccharides which selectivel y stimulate-the growth of bifidobacteria in the colon, are already on the market. Their claimed benefits are to alleviate lactose maldigesti on, increase resistance to invasion by pathogenic species of bacteria in the gut, stimulate the immune system and possibly protect against c ancer. There are very few reports of well-designed human intervention studies with prebiotics as yet. Certain probiotic species have been sh own to shorten the duration of:rotavirus diarrhoea in children but muc h more work is needed on the mechanism of immunomodulation and of comp etitive exclusion and microflora modification. The development of func tional, foods for the gut is in its infancy and will be successful onl y if more fundamental research is done on digestive physiology, the gu t microflora, immune system and mucosal function.