Food and Nutrition
Health research tells us that Food and Nutrition make us active. When people eat food, they get the nutrients carbohydrate, protein, fat, minerals, vitamins and water. The Recommended Daily Allowance denoted as RDA lists amounts of nutrients healthy people should eat every day.
Carbohydrate Type Food
There are three types of carbohydrate—sugar, starch and fibre. Simple carbohydrates include fructose whereas complex carbohydrates include starches and fibre.
Sugar: These are monosaccharides like glucose , fructose , disaccharides like sucrose and lactose. Table sugar is made from sucrose which comes from sugar cane or beets. Starch: This is polysaccharide and is stored in plant roots, tubers or underground stems. Fibre: Fibre, containing non-nutrient cellulose, helps in the formation of the bulk of the waste of the digestive system. The Absence of dietary carbohydrate leads to (1) ketone body production and (2) an excessive degradation of body protein that provide carbon skeletons required for gluconeogenesis. The dietary protein requirement is influenced by the carbohydrate. When the intake is low, the synthesis of glucose for use as a fuel by the body. Therefore, carbohydrate is considered to be protein-sparing.
Functions. (i) Provides main source of energy;
- Helps the body use protein and fat efficiently;
- Supplies fibre for better digestion; (iv) Foods rich in carbohydrate supplies other nutrients too.
Sources. Carbohydrate mainly comes from the food groups of cereals (e.g., rice, wheat, maize), tubers, fruits, sweets, etc.
Proteins Type Food. Proteins are made of amino acids. These are known as essential amino acids. They are phenylalanine, histidine ,
leucine, methionine, valine, isoleucine, lysine, threonine and tryptophan. Some non-essential amino acids are arginine, asparagine acid, glutamic acid, proline, glycine and others. High quality, proteins provide the essential amino acids. All animal foods have high-quality protein whereas the proteins from plant sources typically have a lower biological value than that of animal protein.
Functions. (1) Helps build new cells and maintain or repair the injured ones; (ii) Used for energy when carbohydrates or fat are in short supply; (iii) Protein foods are vitamins and minerals; (iv) Take part in defence mechanism; (v) Produces enzymes and co-enzymes.
Sources: All animal foods (meat, fish, poultry, milk, etc.), nuts, dried peas and beans, lentils, and plant foods (wheat, corn, rice, etc.).
Fats Type Food
Fats or lipids are made of fatty acids (saturated, polyunsaturated, monounsaturated), triglycerides, phospholipids, glycolipids, etc. These are transported throughout the body in association with protein as a lipoprotein. The most important class of dietary fats from an energy perspective is triglycerides, constituting more than 90% of total dietary lipids. These compounds also supply the essential fatty acids required by the body but not produced by the body. Saturated fatty acids contain all the hydrogen they can hold whereas polyunsaturated fatty acids have less hydrogen. Triglycerides obtained from plants generally contain more unsaturated fatty acids than those obtained from animals . Coconut oil and palm oil are exceptions in that these vegetable oils are primarily saturated.