More than several hundreds of millions of people will be diabetic and obese over the next decades because their actual therapeutic approaches aim at treating the consequences rather than causes of the impaired metabolism. The wide analysis of the genome cannot predict more than 10–20% of the disease, whereas changes in feeding and social behaviour have certainly a major impact. Several health-related effects associated with the intake of probiotics and prebiotics, including alleviation of lactose intolerance and reducing the risk of diabetes and obesity. Probiotics are live non pathogenic bacterial components that are helpful in the prevention and treatment of metabolic syndrome or diseases. The probiotic bacteria used in commercial products today are mainly members of the genera Lactobacillus and Bifidobacterium. Additionally, oligosaccharides are the best known â€•prebiotics, â€•a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers health benefits to the host. The isolated carbohydrates and carbohydrate-containing foods, including galactooligosaccharides (GOS), transgalactooligosaccharides (TOS), polydextrose, wheat dextrin, acacia gum, psyllium, banana, whole grain wheat, and whole grain corn also have prebiotic effects. Overall, a number of factors influence the composition of the microflora. These include changes in physiological conditions of the host (e.g., age stress, health status), composition of the diet, and environmental circumstances (e.g., antibiotic therapy, hygiene with antiseptics, etc.). Recognition of the health-promoting properties of certain gut microorganisms has encouraged dietary-based modulation of the human intestinal microflora towards a more beneficial composition and metabolism. The other potential functional effects of prebiotics are on the bioavailability of minerals, and on lipid metabolism. Potential health benefits may include reduction of the risk of intestinal infectious diseases, cardiovascular disease, non-insulin-dependant diabetes, obesity, osteoporosis and cancer.