Nutrients are chemical substances essential for maintaining the life, growth, development, and health of an organism. They are obtained from food and perform various functions, including providing energy, maintaining cell structure, participating in metabolic processes, and regulating physiological functions.

Nutrients are categorized into several main groups:

1. Macronutrients: Substances required by the body in larger amounts.
   • Proteins: The building blocks of cells and tissues, involved in the regulation of enzymes and hormones.
   • Fats: Sources of energy, components of cell membranes, and participants in hormone synthesis.
   • Carbohydrates: The primary energy source, especially for the brain and muscles.
   • Water: Essential for all biochemical reactions, temperature regulation, and the elimination of waste products.
2. Micronutrients: Substances needed in smaller amounts but play a crucial role in maintaining health.
   • Vitamins: Organic compounds necessary for various biochemical processes, including energy production, immune function, and DNA synthesis.
   • Minerals: Inorganic elements like calcium, iron, and magnesium, important for bone health, nervous system function, and other body processes.

A deficiency or excess of nutrients can lead to various diseases and conditions, making it crucial to maintain a balanced diet.