Most are supplied through foods. Vitamin D is made when your skin is exposed to sunlight. It is used to make muscles,tendons, ligaments, blood, enzymes, cell membranes, antibodies, and hormones. Proteins contain carbon, hydrogen, oxygen, nitrogen and sometimes sulfur and phosphorus. Many of these amino acids are constructed in the cells with materials provided by digestion.
Carbohydrates are organic nutrients that are the main source of energy for the body.
Starch, sugars, and cellulose are carbohydrates. Many of these amino acids are constructed in the cells in your body with materials provided by digestion. There are eight amino acids that cannot be made by the body and must be supplied by the food you eat. The eight amino acids are known as essential amino acids. Proteins are broken down into amino acids.