Except for nutrients, food contains small amounts of so called bioactive compounds. These compounds add value beyond nutrition, directly affecting physiological functions in our body by acting on cellular pathways. Epidemiologic studies, where the effects of a diet in different populations are observed, indicate that those who eat fruits, vegetables, whole grains and fish are likely to lead a long and healthy life. We know very little of which compounds that generate health effects and the mechanisms involved. We believe that the combination of compounds is important, and therefore a more positive health effect is expected from the ingestion of fish and whole grain products compared with isolated fish oil and separated bran fraction. Nutrition is the science that interprets the interaction of nutrients and other substances in food (e.g. phytonutrients, anthocyanins, tannins, etc.) in relation to maintenance, growth, reproduction, health and disease of an organism. It includes food intake, absorption, assimilation, biosynthesis, catabolism and excretion. The diet of an organism is what it eats, which is largely determined by the availability, processing and palatability of foods. A healthy diet includes preparation of food and storage methods that preserve nutrients from oxidation, heat or leaching, and that reduce risk of food-borne illnesses. A poor diet may have an injurious impact on health, causing deficiency diseases such as blindness, anaemia, scurvy, preterm birth, stillbirth and cretinism; health-threatening conditions like obesity and metabolic syndrome; and such common chronic systemic diseases as cardiovascular disease, diabetes, and osteoporosis.
Various specialists working in different areas of food science for which food chemistry is relevant. It is worthy to mention such areas as: bioactive food components and chemistry behind their health-promoting action, analytics and monitoring of food components upon processing, biotransformation and bioavailability of food components, design of functional foods based on the knowledge of chemical and biological properties of bioactive ingredients
Soya protein is a major component of the diet of food-producing animals and is increasingly important in the human diet. However, soy protein is not an ideal protein because it is deficient in the essential amino acid methionine. Methionine supplementation benefits soy infant formulas, but apparently not food intended for adults with an adequate nitrogen intake. Soya protein content of another essential amino acid, lysine, although higher than that of wheat proteins, is still lower than that of the milk protein casein. Adverse nutritional and other effects following consumption of raw soybean meal have been attributed to the presence of endogenous inhibitors of digestive enzymes and lectins and to poor digestibility.