Chapter 12

Nutrients at Work for You

Nutrients at Work for You

• Nutrients are chemical substances from food, which the body uses to function properly.

• After your body digests food, your bloodstream absorbs nutrients from the digestive tract and carries them to body cells.

• Nutrition is the science of how nutrients support the body.

Nutrients at Work for You

• Nutrition is the science of how nutrients support the body.

• The nutrients that keep your body working properly are divided into six major classes:

• Carbohydrates• Proteins• Fats• Minerals• Vitamins• Water

Carbohydrates

• Carbohydrates are the major sources of energy in your diet.

• There are three kinds of carbohydrates: sugars, starches, and fiber.

• Your body can change both sugars and starches into energy.

• Sugars are simple carbohydrates found in foods such as milk, fruits, candy and cookies.

Carbohydrates-2

• Starches are often called complex carbohydrates.

• Cereals, bread, rice, pasta, and starchy vegetables are good sources of starch.

• Like starch, fiber is a complex carbohydrate.• When you eat more carbohydrates than your

body can use, some of them are changed to glycogen.

Carbohydrates-3

• Glycogen is stored in your body for times when you need quick energy, such as when you run to catch a bus.

• Your body maintains only a small amount of glycogen.

• Excess carbohydrates that are not stored as glycogen are changed to fat for storage in the body.

Proteins

• Proteins are a nutrient found in every cell in your body.

• They are needed for growth, maintenance, and repair of body tissues.

• Proteins are made up of amino acids, which are building blocks for your cells.

• Your body uses proteins to produce enzymes and hormones.

• These help the body maintain its chemical balance and build antibodies to fight infections.

Proteins

• There are two classes of proteins----complete proteins and incomplete proteins.

• Complete proteins supply all the amino acids your body needs.

• Incomplete protein sources contain some, but not all, of the amino acids your body needs.

• When incomplete proteins are combined with complete proteins in a meal, all the needed amino acids are provided.

Fats

• Fats are concentrated sources of food energy.• They provide slightly more than twice as much

energy per unit of weight as carbohydrates and proteins.

• Fats are divided into two classes.• Saturated fats are solid at room temperature.• Unsaturated fats are most often liquid at

room temperature.

Fats-1

• Sometimes manufacturers process unsaturated fats to make them solid.

• This process is called hydrogenation.• Cholesterol is a fatty substance found in every body

cell.• The body uses cholesterol to make a number of

important materials, including sex hormones and vitamin D.

• Your body manufactures all the cholesterol you need.

Minerals

• Minerals are inorganic substances needed for building tissues and regulating body functions.

• They are essential part of bones, teeth, and red blood cells.

• Minerals also aid in the proper functioning of muscles and nerves and in the clotting of blood.

• Your body can absorb minerals directly from the foods you have eaten.

Calcium and Phosphorus

• Calcium and phosphorus are the most abundant minerals in the body.

• Reserves are stored in the bones• Calcium and phosphorus are also found in

teeth, soft tissues, and body fluids.• Calcium also helps the nervous system function.• However, a low calcium intake over a long

period could lead to osteoporosis.

Minerals-2

• Fluorine• Fluorine is needed for the proper development of bones and

teeth.• Iodine

• Iodine is present in very small amounts in the body.• Iron

• Iron is another essential mineral.• Hemoglobin is a substance in the blood that carries oxygen

from the lungs to cells throughout the body.• A diet that is constantly low in iron results in a condition

known as iron-deficiency anemia.

Minerals-3

• Sodium• Sodium works with other minerals to help

maintain the balance of fluids in the body.• It also plays a role in transmitting nerve

impulses to the brain.• The main sources of dietary sodium are table

salt and processed foods, which often contain a lot of salt.

Minerals-4

• Zinc• It is important for normal growth and development.• It helps the immune system work properly.• Zinc also helps wounds heal.• Too little zinc in children's diets can stunt their growth.• Meat, fish, poultry, whole grains, and some legumes

are good sources of zinc.• Legumes are seeds that grow in pods of some

vegetable plants.

Vitamins

• Vitamins are organic substances needed in small amounts for normal growth and the maintenance of good health.

• Vitamins are regulators of body process.• Like minerals, they do not directly supply

energy.• Vitamins are necessary to enable the other

nutrients to do their work.

Fat-Soluble Vitamins

• Vitamins can be divided into two groups.

• The first group is fat-soluble vitamins.

• These are vitamins that can be stored in your body in fatty tissues and in the liver.

• The fat-soluble vitamins are A,D,E, and K.

Vitamin A

• Vitamin A is needed for good vision, normal growth, and healthy skin.

• A deficiency of vitamin A can cause night blindness and drying of the eyes and skin.

• Night blindness occurs when the eyes cannot adjust from bright to dim light.

• Excesses of vitamin A from food are not common.

Vitamin A-1

• Good sources of vitamin A are liver, whole and fortified milk products, and fish oils.

• Carotene is an orange pigment the body can convert to vitamin A.

• Carotene is present in orange fruits and vegetables, like apricots, carrots, and sweet potatoes.

• It is also present in dark green vegetables, like spinach and broccoli.

Vitamin D

• Vitamin D helps your body absorb calcium and phosphorus and deposit them into cells.

• Vitamin D works with calcium and phosphorus to form and maintain bones and teeth.

• Extreme shortages can result in a condition called rickets.

• Vitamin D is often called the “sunshine vitamin,”• However, foods such as eggs, butter, fish liver

oils, and fortified milk are more reliable sources.

Vitamin E

• The main function of vitamin E in the human body is to act as an antioxidant.

• Vitamin E protects blood cells and cells in the lungs from oxygen damage.

• Vitamin E is found in vegetable oils, whole grain cereals, liver, and green leafy vegetables.

Vitamin K

• Vitamin K is needed for proper blood clotting.• A severe deficiency could cause bleeding, but

deficiencies are rare.• Bacteria in the human digestive tract make

about half of the body’s needed vitamin K.• The rest of vitamin K needs must be met by

food sources such as spinach, cabbage, eggs, and liver.

Water-Soluble Vitamins

• These vitamins are not stored in the body to a great extent.

• The B vitamins and vitamin C are water-soluble vitamins.

• These vitamins can be lost during cooking.• After cooking, do not throw away cooking

liquid.• Instead, save it for use in a sauce or soup.

B Vitamins

• Thiamin, riboflavin, and niacin may be the most well known B vitamins.

• Folate and vitamin B12 are also members of this vitamin group.

• Thiamin helps you obtain energy from the foods you eat.

• A severe deficiency can lead to a disease called beriberi.

• Good sources of thiamin include pork, legumes, and whole grain and enriched grain products.

B Vitamins-2

• Riboflavin is also needed by your body to obtain energy.

• It is needed for healthy skin and normal vision.• A deficiency of riboflavin can cause cracked

lips, a skin rash, and extremely sensitive eyes.• The best sources of riboflavin are dairy

products, meats, and leafy green vegetables.

B Vitamins-3

• Niacin, like thiamin and riboflavin, is needed to help you obtain energy from foods.

• It is also needed for healthy skin, good digestion, and proper functioning of the nervous system.

• A deficiency of niacin can cause pellagra, which affects the skin and digestive system.

• Good sources of niacin include meat, poultry, fish, nuts, dried beans, and whole grain and enriched grain products.

B Vitamins-4

• The body uses folate to make all new cells.• This function has a special significance for pregnant

women.• The spine and brain of a baby growing in its

mother’s womb may not develop properly if the mother’s diet lacks folate.

• Damage to the spine and brain can occur in the first few weeks of pregnancy.

• Fresh fruits and vegetables, leafy green vegetables, are good sources of folate.

B Vitamins-5

• Vitamin B12 helps the body make red blook cells.

• This vitamin also protects nerves.• A vitamin B12 deficiency can result in anemia

and nerve damage.• Vitamin B12 naturally occurs only in foods of

animal origin, such as meat, fish, poultry, eggs, and dairy products.