Diet and Disease: Introduction

DIET AND DISEASE

INTRODUCTION

Nutrition is concerned with food and how the body uses it. All nutrients mustbe ingested, and most of them digested, before they can be assimilated and used by the body. Carbohydrates, lipids and proteins are nutrients that are required in comparatively large amounts. Others, such as vitamins, minerals and trace elements, are also necessary but are required in much smaller quantities. Water is also necessary to support life. Nutrients have a variety of metabolic roles and are needed for normal growth, development and the maintenance of health. The body can make some nutrients from others that must be supplied in the diet; the former are nonessential, the latter essentialnutrients. Specific daily nutritional requirements are determined by a numberof factors and, indeed, vary throughout the life of any individual. The major factors concerned include the age, sex, physical activity and the general well-being of the person concerned and, in the case of females, menstruation, pregnancy and lactation. Good nutrition is essential for health and the prevention of diseases. Nutritional disorders may arise from a deficiency or, in some cases, an excess of some component of the diet.