Nutrients Chapter 10, pages

Definitions Nutrition – The process by which the body takes in and uses food. Nutrients – the substances in food that your body needs to grow, to repair itself, and to supply you with energy. Calories (kilocalories) – units of heat that measure the energy used by the body and the energy that foods supply to the body.

Hunger vs. Appetite Its important to understand the difference between your physical need for food (hunger), and your psychological desire for food (appetite).

Hunger vs. Appetite Hunger is an unlearned, inborn response to protect you from starving. It is the natural physical drive to eat, prompted by your body’s need for food. When your stomach is empty, it’s walls contract, stimulating nerve endings, which signal your brain that your body needs food. When you eat, the walls of the stomach are stretched and the nerve endings are no longer stimulated.

Hunger vs. Appetite Appetite is the psychological desire for food. An example, is when you eat something “just to be social,” or respond to a familiar sensation (aroma, sight) of food.

Influences of Food Choices

Environmental factors 1.Family, cultural and ethnic background If your family eats most meals at home, this will influence what you eat. You may prefer certain foods because of your family’s cultural or ethnic background 2. Friends and Peers You might try new foods with friends from other cultures.

Environmental factors 3.Convenience & Cost People with busy schedules may choose foods that are quick and easy to prepare. Cost can also be a factor (i.e., you may not eat expensive steaks very often). 4. Advertising Advertisers try to influence your decisions about food.

Emotions Sometimes people eat in response to an emotional need, like when they feel stressed, frustrated, lonely, or sad. Some people snack out of boredom or use food as a reward. Some people snack continuously while absorbed in another activity.

Nutrients (Macronutrients)

Carbohydrates Starches and sugars found in foods, which provide your body’s main energy source. Each gram of carbohydrates provides 4 calories of energy. Most nutrition experts recommend getting 45%- 65% of your daily calories from carbohydrates.

Carbohydrates There are three different kinds of carbohydrates a)Simple Carbohydrates (sugars) Fructose found in fruit Lactose found in dairy products Sucrose found in plants and refined to make table sugar.

Carbohydrates b. Complex Carbohydrates (starches) Whole grains Seeds Nuts Beans Tubers (root vegetables)  Complex carbohydrates must be broken down into simple carbohydrates before your body can use them for energy.  Your body converts all carbohydrates into glucose. Glucose can be stored in your liver and muscles in the form of glycogen, which can be converted back into glucose or stored as body fat.

Carbohydrates c. Fiber A tough complex carbohydrate that you body cannot digest. It is found in the tough, stringy parts of vegetables, fruits and whole grains. It is useful to help move waste through the digestive system Sources include fruits and vegetables with edible skins and whole grain products such as bran cereals, oatmeal, and brown rice. Experts recommend 20 to 35 grams of fiber per day.

Proteins Vital nutrients that help build and maintain body cells and tissues. The role of proteins includes building new cells and tissues to replace damaged and worn-out cells, and the production of enzymes, hormones, and antibodies. They also supply the body with energy. Excess protein is converted to body fat.

Proteins Proteins are made up of 20 different amino acids. Your body can manufacture all but 9 of the 20 amino acids. These are referred to as essential amino acids and have to come from the food that is eaten.

Proteins Each gram of protein provides 4 calories of energy. Teen boys ages should consume about 52 grams of protein per day, and teen girls ages need 46 grams per day. Between 10 to 15 percent of your total daily calories should come from protein

Proteins 1.Complete Proteins These contain adequate amounts of all nine essential amino acids. Sources include animal products (fish, meat, poultry, eggs, milk, cheese, and yogurt) and soybean products

Proteins 2.Incomplete Proteins These lack one or more of the essential amino acids. Sources include beans, peas, nuts, and whole grain. Eating a combination of incomplete proteins over the course of a day is equivalent to consuming a complete protein.

Fats (Lipids) A fatty substance that does not dissolve in water. Fats provide more than twice the energy of carbohydrates or proteins and some fat in your diet is needed for good health. Each gram of fat provides 9 calories of energy.

Fats (Lipids) The role of fats is to provide a concentrated form of energy Help transport vitamins A, D, E and K in your blood Serve as a source of linoleic acid, an essential fatty acid needed for growth and healthy skin.

Fats (Lipids) Fats also add flavor and texture to food and help satisfy hunger longer than other nutrients do. Food high in fats also tends to be high in calories, and consuming excess amounts of fat increases your risk of unhealthy weight gain and obesity.

Fats (Lipids) Nutrition experts recommend that teens consume less than 25 to 35 percent of their daily calories from fat. Choose healthful unsaturated fats & limit your intake of saturated fats, including trans fats, to less than 10 percent of your total calories.

Fats (Lipids) The building blocks of fats are called fatty acids and the fatty acids your body cannot produce are called essential fatty acids. Fatty acids include: – Saturated fatty acids – Unsaturated fatty acids – Trans fatty acids

Fats (Lipids) 1.Saturated Fatty Acids – fats high in saturated fat, which are usually solid at room temperature Examples of animal fats and tropical oils (palm, palm kernel, and coconut oils) A high intake of saturated fats is associated with an increased risk of heart disease

Fats (Lipids) 2. Unsaturated Fatty Acids – can be either mono- unsaturated fatty acids, which are usually liquid at room temperature but tend to solidify when refrigerated, or poly- unsaturated fatty acids, which are liquid both at room temperature and in the refrigerator. Example include vegetable oils (olive, canola, soybean, corn, safflower and cottonseed oils)

Fats (Lipids) 3. Trans Fatty Acids – formed by a process called hydrogenation, which causes vegetable oil to harden. As it hardens, the fat becomes more saturated. It can be found in stick margarine, snack foods, and packaged baked goods such as cookies & crackers Trans fat can raise your total blood cholesterol level, increasing your risk for heart disease.

Cholesterol A waxy, lipid-like substance that circulates in blood. Your body uses the small amount it manufactures in the liver to make cell membranes and nerve tissue, and to produce many hormones, vitamin D and bile (which helps digest fat). Excess cholesterol is deposited in arteries and increases the risk for heart disease and stroke.

Cholesterol High cholesterol may be hereditary, and levels tend to rise as people age. A high intake of saturated fats is linked to increased cholesterol production. Dietary cholesterol is found only in animal products such as egg yolks, meats (esp. organ meats), and high-fat milk products. Losing excess weight can also lower cholesterol levels.

Nutrients (Micronutrients)

Vitamins Compounds found in foods that help regulate many vital body processes, including digestion, absorption, and metabolism of other nutrients

Vitamins 1.Water-soluble vitamins – (C, B1, B2, Niacin, B6, Folic Acid, B12, and Pantothenic Acid). They dissolve easily in water and pass easily into the blood during digestion. The body doesn’t store these vitamins, so you have to replenish them regularly through the foods you eat.

Vitamins 2. Fat-Soluble Vitamins – (A, D, E, and K) They are absorbed, stored, and transported in fat. Your body stores these vitamins in your fatty tissue, liver and kidneys. An excess buildup of these vitamins in your body can become harmful.

Minerals Substances found in foods that the body cannot manufacture but that are needed for forming healthy bones and teeth, and for regulating many vital body functions.

Water Water is essential for most body functions. All the body cells contain water. Teen girls need about 9 cups of fluids a day, and teen boys need about 13 cups each day. About 20% of your total daily water intake comes from foods you eat, since all foods contain some water

Water If you are very active, or during hot weather, you will need to drink even more water to replace what your body loses when you sweat. Limit your consumption of coffee, tea, and soft drinks that contain caffeine. Caffeine is a substance that eliminates water from your body and can actually make you dehydrated.

Water Waters functions include: – Moving food through the digestive system – Digesting carbohydrates & protein, and aiding other chemical reactions in the body. – Transporting nutrients & eliminating wastes. – Storing & releasing heat – Cooling the body during perspiration. – Cushioning the eyes, brain and spinal cord. – Lubricating the joints.