Chapter 18 Nutrition and Metabolism Nutrients – Macronutrients Micronutrients vitamins minerals Essential Nutrients synthesize certain amino acids 18-2

Carbohydrates Sources starches glycogen in meats RDA is g Excesses lead to dental nutritional deficits Deficiencies lead to metabolic acidosis 18-3

Utilization of Carbohydrates production of certain molecules (ribose, deoxyribose) stored as glycogen converted to fats and stored in adipose tissue 18-4

Utilization of Carbohydrates 18-5

Lipids Sources eggs lard plant oils RDA is g Excesses lead to increased serum cholesterol Deficiencies lead to skin lesions hormonal imbalances 18-6

Utilization of Lipids production of triglycerides, phospholipids, lipoproteins, and cholesterol glycerol may be used to synthesize glycerol 18-7

Utilization of Lipids The liver uses fatty acids to synthesize a variety of lipids. 18-9

Proteins Sources cheeses legumes RDA is 0.8g/kg body weight or 10% of diet Excesses lead to obesity Deficiencies lead to muscle wasting anemia growth retardation 18-10

Utilization of Proteins enzymes transport of oxygen regulation of water balance control of pH formation of antibodies can be converted to carbohydrates or fats may be broken down and oxidized for energy 18-11

Nitrogen Balance amount of nitrogen taken in is equal to amount excreted negative nitrogen balance develops from starvation positive nitrogen balance develops in growing children, pregnant women, or an athlete in training 18-14

Energy Values of Food Carbohydrates 4.1 calories per gram Lipids 9.5 calories per gram Proteins 4.1 calories per gram Calorie – 18-15

Energy Requirements Basal metabolic rate primarily reflects energy needed to support activities of organs varies with gender, body size, body temperature, and endocrine function Energy needed to support muscular activity to maintain body temperature for growth in children and pregnant women 18-16

Energy Balance positive energy balance leads to weight gain overweight is defined as exceeding desirable weight by 10% - 20% obesity occurs when person is 20% above desired weight due to excess adipose tissue 18-17

Fat Soluble Vitamins Vitamin A synthesized from carotenes stored in liver necessary for visual pigments necessary for bone and teeth development necessary for maintenance of epithelial cells excesses lead to nausea, headache, dizziness, hair loss, birth defects deficiencies lead to night blindness and degeneration of epithelial tissues Vitamin D group of steroids stored in liver, brain, skin, spleen, and bone promotes absorption of calcium and phosphorus necessary for bone and teeth development excesses lead to diarrhea, calcification of soft tissues, and renal damage deficiencies lead to bone weakening 18-18

Fat-Soluble Vitamins Vitamin E stored in muscles and adipose tissue prevents oxidation of vitamin A and some fatty acids may help stability of cell membranes excesses lead to hypertension Vitamin K stored in liver necessary for prothrombin synthesis deficiencies lead to bruising and bleeding 18-19

Sources of Fat-Soluble Vitamins Vitamin A liver fish milk leafy green vegetables yellow and orange vegetables and fruits Vitamin D skin egg yolk milk fish liver oils Vitamin E cereal seed oils salad oils margarine shortening fruits nuts vegetables Vitamin K liver soy oil egg yolk leafy green vegetables tomatoes cauliflower 18-20

Water-Soluble Vitamins Vitamin B 1 thiamine coenzyme for carbohydrate oxidation meats liver leafy green vegetables eggs cereals legumes deficiencies lead to Beriberi, muscular weakness, enlargement of heart Vitamin B 2 riboflavin parts of enzymes and coenzymes (FAD) milk leafy green vegetables meats deficiencies lead to dermatitis and blurred vision 18-21

Water-Soluble Vitamins Niacin parts of coenzymes (NAD) liver meats peanuts legumes deficiencies lead to pellagra, dermatitis, diarrhea, or mental disorders Pantothenic Acid part of coenzyme A meats cereals legumes milk vegetables deficiencies lead to mental depression and muscle spasms 18-22

Water-Soluble Vitamins Vitamin B 6 part of coenzymes needed for synthesis of proteins meats cereals peanuts milk bananas avocados deficiencies lead to vomiting and convulsions Vitamin B 12 part of coenzyme needed for nucleic acid synthesis plays role in myelin sheath formation needed for RBC formation meats milk liver cheese eggs deficiencies lead to anemia 18-23

Water-Soluble Vitamins Folic Acid coenzyme required for amino acid and nucleic acid metabolism needed for normal RBC production cereals legumes milk leafy green vegetables deficiencies lead to anemia Biotin coenzyme required for metabolism of amino acids, fatty acids, and nucleic acids egg yolk liver legumes nuts mushrooms deficiencies lead to elevated blood cholesterol, fatigue, nausea, and anorexia 18-24

Water-Soluble Vitamins Vitamin C ascorbic acid needed for collagen production and metabolism of some amino acids promotes absorption of iron and synthesis of hormones from cholesterol citrus fruits tomatoes potatoes leafy green vegetables deficiencies lead to scurvy, lowered resistance, and slow wound healing 18-25

Minerals Major Minerals calcium phosphorus potassium sulfur sodium chlorine magnesium Trace Elements iron manganese copper iodine cobalt zinc fluorine selenium chromium 18-26

Major Minerals Calcium mostly in bones and teeth needed for bone structure essential for nerve impulse conduction essential for muscle fiber contraction essential for blood coagulation increases permeability of cell membranes activates certain enzymes excesses lead to kidney stones deficiencies lead to stunted growth and fragile bones 18-27

Major Minerals Phosphorus mostly in bones and teeth needed for structure of bones and teeth component in nearly all metabolic processes constituent of ATP, nucleic acids, many proteins, enzymes, and some vitamins deficiency leads to stunted growth Potassium widely distributed maintains intracellular osmotic pressure and pH promotes metabolism required for muscle contraction and nerve impulse conduction deficiency leads to muscular weakness, cardiac abnormalities, and edema 18-28

Major Minerals Sulfur widely distributed abundant in skin, nails, and hair component of certain amino acids, thiamine, biotin, and mucopolysaccharides Sodium widely distributed maintains osmotic pressure of extracellular fluids regulates water movement in and out of cells required for nerve impulse conduction and contraction of muscle fibers excesses lead to edema and hypertension deficiency leads to muscle cramps and convulsions 18-29

Major Minerals Chlorine most concentrated in cerebrospinal fluid and gastric juice helps maintain osmotic pressure of extracellular fluids regulates pH essential for formation of hydrochloric acid aids in transport of carbon dioxide deficiency leads to muscle cramps Magnesium abundant in bones required in metabolic reactions for ATP production helps breakdown of ATP to ADP excess leads to diarrhea deficiency leads to neuromuscular disturbances 18-30

Trace Elements Iron part of hemoglobin catalyzes formation of vitamin A incorporated into some enzymes Manganese occurs in enzymes required for fatty acid and cholesterol synthesis, formation of urea, and functioning of the nervous system Copper essential for hemoglobin synthesis, bone development, melanin production and myelin formation 18-31

Trace Elements Iodine component of thyroid hormone Cobalt required for synthesis of several enzymes Zinc component of many enzymes necessary for wound healing and maintaining integrity of skin 18-32

Trace Elements Fluorine component of tooth structure Selenium occurs in enzymes Chromium essential for use of carbohydrates 18-33

Food Pyramid 18-34

Malnutrition poor nutrition undernutrition – overnutrition – primary malnutrition – malnutrition from diet alone secondary malnutrition – diet is sufficient but nutrients cannot be absorbed 18-35

Starvation person can survive days without food symptoms include low blood pressure, slow pulse, chills, dry skin, hair loss, and poor immunity Anorexia nervosa – Bulimia – 18-36

Life-Span Changes BMR rises in early childhood and peaks in adolescence BMR declines in adulthood change in nutrition often reflects effects of medical conditions and social and economic circumstances 18-37