Ingestion of food may affect oral-dental health by both systemic and local mechanisms. Nutritional effects are mediated systematically and the dietary effects are mediated locally in the oral cavity. The systemic effects result from the absorption and circulation of nutrients to all cells and tissues and may be mediated through influences on development of teeth, the quality and quantity of salivary secretion, improved host resistance and improved function. Dietary constituents exert their local effects by influencing the metabolism of the oral flora and by modifying salivary flow rates and, in-directly, the qualitative aspect of salivary secretions. Also important is the manner in which food items affect taste perception and condition dietary preferences and patterns of eating.