CONTINUE CLASSIFICATION OF NUTRIENTS

>Vitamins:
Organic nutrients needed in small quantities for growth, regulating body functions, and preventing some diseases are called vitamins. For instance, your bone cells need vitamin D to use calcium, and your blood needs vitamin K in order to clot. Most foods supply some vitamins, but no food has them all. Some people feel that taking extra vitamins is helpful, while others feel that eating a well-balanced diet usually gives your body
all the vitamins it needs. Vitamins are classified into two groups,Some vitamins dissolve easily in water and are called watersoluble vitamins. They are not stored by your body so you have to take them daily. Other vitamins dissolve only in fat and are called fat-soluble vitamins. These vitamins are stored by your body. Although you eat or drink most vitamins, some are made by your body. Vitamin D is made when your skin is exposed to sunlight. Some vitamin K and two of the B vitamins are made
with the help of bacteria that live in your large intestine.



>Minerals:
Inorganic nutrients—nutrients that lack carbon and regulate many chemical reactions in your body—are called minerals. Your body uses about 14 minerals.Minerals build cells, take part in chemical reactions in cells, send nerve impulses throughout your body, and carry oxygen to body cells.
In Figure, you can see how minerals can get from the soil into your body.

Of the 14 minerals, calcium and phosphorus are used in the largest amounts for a variety of body functions. One of these functions is the formation and maintenance of bone. Some minerals, called trace minerals, are required only in small amounts. Copper and iodine usually are listed as trace minerals. Several minerals, what they do, and some food sources for them are listed in Table

>Water:

Water is important for your body.Next to oxygen, water is the most important factor for survival. Different organisms need different amounts of water to survive.You could live for a few weeks without food but for only a few days without water because your cells need water to carry out their work. Most of the nutrients you have studied in this chapter can’t be used by your body unless they are carried in a solution. This means that they have to be dissolved in water. In cells, chemical reactions take place in solutions. The human body is about 60 percent water by weight. About two thirds of your body water is located in your body cells.Water also is found around cells and in body fluids such as blood. your body loses water as perspiration.When you exhale, water leaves your body as water vapor.Water also is lost every day when your body gets rid of wastes. To replace water lost each day, you need to drink about 2 L of liquids. However, drinking liquids isn’t the only way to supply cells with water. Most foods have more water than you realize. An apple is about 80 percent water, and many meats are 90 percent water.