why does food have to be digested
Food constitutes of a mix of nutrients, which cannot be used unchanged from the organism to cover its special needs. Digestive system is designed to convert complex molecules (like carbohydrates and proteins) to simple ones (like glucose and amino acids), which can be used by cells in order to develop and be auto-repaired. Digestive system begins from the mouth, where the food is received, and ends up in the colon which is responsible for the elimination of waste material of the body. Digestion starts in the oral cavity, where salivary glands reside. Salivary glands are cells producing saliva, which contains digestion enzymes. These enzymesPare the first after chewingPto meet food and start degrading them. Food molecules are then delivered through the throat to the esofagus, and they end up in the stomach afterwardsPthrough a series of contractions.
The main digestion processing is happening there, because the pH of the stomach is acidic. That means that it contains acids (like hydrochloric acid) which have the ability to degrade food molecules, without destroying them. From there, food in a more liquid state is delivered to the small intestine, which is responsible both for the further cleavage of the food and for the absorption of nutrients in the blood circulation. As aforementioned, food molecules that are not transfered in the blood circulation are discharged by colon.
Why is digestion important? Digestion is important for breaking down food into nutrients, which the body uses for energy, growth, and cell repair. Food and drink must be changed into smaller molecules of nutrients before the blood absorbs them and carries them to cells throughout the body.
The body breaks down nutrients from food and drink into carbohydrates, protein, fats, and vitamins. CARBOHYDRATES Carbohydrates are the sugars, starches, and fiber found in many foods. Carbohydrates are called simple or complex, depending on their chemical structure. Simple carbohydrates include sugars found naturally in foods such as fruits, vegetables, milk, and milk products, as well as sugars added during food processing. Complex carbohydrates are starches and fiber found in whole-grain breads and cereals, starchy vegetables, and legumes. PROTEIN Foods such as meat, eggs, and beans consist of large molecules of protein that the body digests into smaller molecules called amino acids. The body absorbs amino acids through the small intestine into the blood, which then carries them throughout the body.
FATS Fat molecules are a rich source of energy for the body and help the body absorb vitamins. Oils, such as corn, canola, olive, safflower, soybean, and sunflower, are examples of healthy fats. Butter, shortening, and snack foods are examples of less healthy fats. During digestion, the body breaks down fat molecules into fatty acids and glycerol. VITAMINS Scientists classify vitamins by the fluid in which they dissolve. Water-soluble vitamins include all the B vitamins and vitamin C. Fat-soluble vitamins include vitamins A, D, E, and K. Each vitamin has a different role in the bodyвs growth and health. The body stores fat-soluble vitamins in the liver and fatty tissues, whereas the body does not easily store water-soluble vitamins and flushes out the extra in the urine.
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