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Animal Nutrition. All animals must eat. Whether a herbivore, carnivore, or an omnivore the ingestion of nutrition and calories must satisfy the following needs: fuel -cellular need for energy (ATP) carbs 1st, fats 2nd, protein 3rd Organic molecules used for biosynthesis
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Animal Nutrition • All animals must eat. Whether a herbivore, carnivore, or an omnivore the ingestion of nutrition and calories must satisfy the following needs: • fuel -cellular need for energy (ATP) • carbs 1st, fats 2nd, protein 3rd • Organic molecules used for biosynthesis • Essential materials (vitamins and minerals) and raw material (essential amino acids) that an animal cannot make for themselves • malnourishment- a diet deficient in one or more essential mineral or compound
Essential materials • those amino acids that cannot be produced by an individual are considered to be essential • 9 essential AA in humans • Deficiency causes kwashiorkor - protein deficiency with adequate calories • meat is best source but can also obtain through food combining (whole grain +legume) • minerals - inorganic cofactors • Ca (bone & muscle fx), P (nucleic acid & ATP), Mg (enzymes that split ATP), Fe (cytochromes used in cellular resp. & in Hb), I (thyroid hormones - lack gives goiter), Zn, Na, K, Cl
Vitamins • vitamins -used as cofactors used in metabolic pathways • 13 are essential
Homeostatic Mechanisms • Glucose regulation • excess glucose is stored in the liver and muscles in the form of glycogen • stimulated by the hormone insulin • when stores are full, excess glucose ingested is stored as fat • release is promoted by hormone (glucagon) secretion • when caloric needs exceed ingestion of glucose, glycogen is removed from the liver 1st, muscles 2nd, and fat 3rd. • deamination of protein for energy occurs after glycogen and fat stores have been eliminated • gluconeogenesis • when blood sugar is raised after feeding, appetite decreases
Homeostatic Mechanisms • homeostatic mechanism for the maintenance of weight are located in the satiety center of the brain • hormones tell you when to start and stop eating • leptin - secreted by fat cells suppresses appetite as fat is stored • fat bulk decreases leptin and increases appetite • PYY - secreted by the small intestine to decrease appetite • ghrelin - secreted by the stomach at feeding times to increase appetite • insulin - secreted by the pancreas
Caloric Imbalances • Undernourishment • chronic energy imbalance created by the consumption of too few calories or essential calories • usually present in times of drought, war, or where disruption of the food supply occur (poverty) • after the glycogen and fat stores are used the body begins to eat protein from muscle tissue • may lead to protein imbalances in the brain • some of the damage may be irreversible even after recovery has occurred
Obesity • Obesity is considered an inherited condition • fat storage and the craving of fatty foods once served an evolutionary purpose as it would aid an animal in periods when food was scarce • created by the chronic over consumption of calories • over consumption of carbohydrates leads to hyper storage of fat • now recognized as a global health problem by the World Health Organization (WHO) • ~ 30% of Americans are severely obese (nearly doubled in the last decade) • ~35% are over weight • ~15% of children are obese • ~300,000 deaths/year associated with obesity • obesity is associated with an increase in breast and colon cancers, diabetes, and cardiovascular disease