Nutrition is the science that infers the interaction of nutrients and other substances in food in relation to preservation, growth, reproduction, health and disease of an organism. It comprises food intake, absorption, assimilation, biosynthesis, catabolism and excretion. The nutrition of an organism is what it eats, which is largely determined by the availability and palatability of foods. For humans, a healthy diet comprises preparation of food and storage techniques that preserve nutrients from oxidation, heat or leaching, and that diminishes hazard of foodborne illnesses.