Chapter 1: Nutrition and Diet.

Diet and nutrition are fundamental in maintaining the general and oral health of populations. Diet refers to the total amount of food consumed by individuals; whereas nutrition is the process of utilising food for growth, metabolism and repair of tissues. The relationship between diet and nutrition and health is 2-way; health status can be affected by nutrient deficiency and vice versa. Dietary guidelines have been developed to provide evidence-based food and beverage recommendations for populations; aiming to promote a diet that meets the nutrient requirement, and to prevent diet-related diseases such as dental caries and obesity. Based on the amount required by the human body for normal metabolism, growth and physical well-being, nutrients are divided into 2 categories: macronutrients consisting of proteins, carbohydrates and fat; and micronutrients consisting of vitamins and minerals. Fats are the most energy-dense macronutrient; whereas carbohydrates are quantitatively the most important dietary energy source for most populations. Proteins are vital structural and functional components within every cell of the body and are essential for growth and repair and maintenance of health. Vitamins and minerals, which are found in small amounts in most foods, are essential for normal metabolic function. This chapter provides an overview of the impact of nutrients on general and oral health, with an emphasis on macronutrients.