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Ch. 6: Human Organism and the Importance of Nutrition

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1 Ch. 6: Human Organism and the Importance of Nutrition
Processing Nutrition: Digestive System: eat food that gets absorbed and transformed into nutrients for cellular use. Respiratory System: require oxygen to use the nutrients we eat. Cardiovascular System: blood circulates nutrients and oxygen to cells. Urinary System: waste is discarded in blood and filtered out in liquid form.

2 You Are What You Eat! Food: substance to be ingested sustaining life. Supplies body with nutrients. Nutrient: substance found in food that is used by the body for various purposes. 6 nutrients: Carbohydrates Fats/Lipids Protein Vitamins Minerals Water

3 Adolescent girl: 1800 Cal (7200kJ)-2400 Cal (9600kJ)
Energy: Is the ability to do work measured in joules (J). For food the common unit of measure for energy is dietary calorie. Calorie (Cal): 1 Cal is equal to 4000 J or 4 kJ. Adolescent girl: 1800 Cal (7200kJ)-2400 Cal (9600kJ) Adolescent boy: 2200 Cal (8800kJ)-3200 Cal ( kJ) 3 factors to measure calorie output: basal metabolic rate (BMR), physical activity, and the digestion of food.

4 Measuring Calorie Output:
BMR: is the amount of energy required by the body to carry on its vital processes while at rest. Ex: respiration, circulation, cellular metabolism and maintaining body temperature. Physical activity: the energy required for physical activity is a function of the type of activity, the duration of the activity, and the size of the individual. Food digestion: the active process of breaking down, absorption, and assimilation of food.

5 Calorie Input and Output
Energy balance reflects the relationship between incoming and outgoing calories. Three relationships are possible: input = output; body weight maintained input > output; body weight increase input < output; body weight decrease

6 4 sources of calories: protein, fat, carbohydrates, and alcohol.
Fibre: is cellulose, comes from cell wall of plants. It can’t be digested by the human body. It helps prevent constipation, helps to absorb water, stimulates contraction of the intestine. Carbohydrates, fats, and proteins are complex molecules that need to be broken down into smaller molecules. Main function: provide energy for cells. Cellular respiration: Glucose + Oxygen Energy + Carbon dioxide + Water C6H12O6 + O ATP + CO2 + H2O

7 Carbohydrates consist mainly of sugars (polysaccharides, disaccharides or monosaccharides). Are broken down into glucose. Found in: fruits, breads, pasta, rice, some vegetables, honey, juice, candy, grains, flour, legumes and tubers (beets, potatoes, turnips) Function: Provides main source of energy Provides energy: 4 Cal/g (17 kJ/g). Energy can be used rapidly

8 Fats/Lipids Found in: oils from plants and animals Ex: dairy products, eggs, margarine, nuts, meat, chips, fish Fat is broken down into fatty acids and glycerol. Function: Energy usually stored by the body; available over longer periods of time. Building blocks of hormones, cell membrane and protects organs, insulator. Source of energy; 9 cal/g (38 kJ/g) Stored in fat (adipose) cells.

9 Proteins Large molecules consisting of long chains of amino acids.
Found mainly in meat, poultry, fish, meat substitutes: nuts, legumes, eggs, tofu and milk products. Proteins are broken down into amino acids. Function: Allows the body to build and repair tissues (bones, muscle and skin) Body’s last choice for energy. Are the basic building blocks for cells Provides energy: 4 Cal/g (17 kJ/g).

10 Vitamins, minerals and water are simple molecules that can be used directly by the cells (Don’t need to be broken down).

11 Vitamins vital to all the body’s functions
13 types including: A, B, C, D, E and K. Found in:fruits, vegetables (esp. dark green and orange veggies), eggs, meat substitutes, milk, grains, and nuts Function: for proper growth and repair, regulation of metabolism (regulate chemical reactions in the body), helps fight infections by strengthening immune system. Fat Soluble Vitamins: are absorbed through the intestinal tract with the help of lipids (fats). They are more likely to accumulate in the body. (A, D, E and K) Water Soluble Vitamins: dissolve easily in water, and in general, are readily excreted from the body. Consistent daily intake is important. Many types of water-soluble vitamins are synthesized by bacteria. (8 B vitamins and vitamin C).

12 Minerals Are simple chemical elements
Include: calcium (Ca), potassium (K), sodium (Na), phosphorus (P) and iron (Fe). Found in: fruits, vegetables, legumes, meat, milk and fish. Only need a small amount of minerals. Function: play a role in the makeup of various tissues (cartilage, teeth, bones and nerves), regulation of metabolism and are essential to nervous system and muscle contractions, transport oxygen.

13 Water A pure substance that makes up about 70% of the human body.
Found in most food; mostly in beverages, fruits and vegetables. Body needs ~2-3 L per day. Function: Important in chemical reactions, regulate body temperature, transports nutrients and waste products.

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