NURITION I.ppt
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The document discusses the fundamentals of nutrition, focusing on macronutrients and micronutrients, their roles in diet, and their contributions to energy metabolism. It explains concepts such as basal metabolic rate (BMR), specific dynamic action (SDA), and the importance of proteins, including their nutritional indices and the impact of nitrogen balance on protein intake. The content emphasizes the significance of understanding nutrient interactions and their implications for health and dietary planning.
NURITION I.ppt
- 1. NUTRITION BI 8.1 TO 8.5 Dr. Vishnu Kumar Professor & Head, Department of Biochemistry, MPTMC, Siddharthnagar vkawasthi@hotmail.com madhwapur1976@gmail.com
- 2. Learning Objectives • Introduction • Proximate Principles of nutrition Respiratory quotient Basal Metabolic Rate Specific Dynamic action • Nutritive indices of proteins • Nutritional Importance of Protein
- 3. Nutrition is the science of food and the nutrients and other substances contained in food. It is the study of their actions, interactions and balance in relation to health and disease.
- 4. There are five classes of nutrients that contribute to an adequate diet. Each plays a special role. These may be divided into : • Macronutrients • Micronutreints
- 5. Macronutrients • Carbohydrates • Fat • Protein Micronutrients • Vitamins • Mineral elements Macrominerals Microminerals
- 6. Food- provide energy (calories) & body building materials. Calorie- heat required to raise temp. of 1g of water through 1°C.(kCal=1000cal) Calorific value (kCal/g) Carbohydrate 4 Fat 9 Protein 4.2 Alcohol 7
- 7. • Protein ,fats & carbohydrates are some times referred as proximate principle. They form the main bulk of food. • They are oxidized in body to yield energy, which the body needs. • Though the protein provides energy their primary function is to provide essential and nonessential amino acids for building of proteins. • Fats, concentrated form of energy, provide essential fatty acids.
- 8. In Indian dietary intake, they contribute to total energy in the following proportion- Proteins 7 to 15% Fats 35 to 45% Carbohydrates 50 to 70%
- 9. Respiratory Quotient (RQ) Defined as the ratio of volume of CO2 produced to the oxygen consumed. RQ = CO2 produced O2 consumed Carbohydrates = 1 Fat = 0.7 Protein = 0.8
- 10. Factors affecting energy expenditure: • Basal metabolic rate • Thermogenic effect (specific dynamic actions) of food • Physical activity • Environmental temperature
- 11. Basal metabolic rate (BMR) Energy required by the person who is a) At complete physical and mental rest. b) Awaken state. c) Post-absorptive condition. d) Ideal room temp (26°C). e) Stress free environment. Men (34-37 kCal/m²body surface area / hr) Women (30-35 kCal/m²body surface area / hr)
- 12. • BMR is the energy required by an awake individual during physical, emotional and digestive rest. • It is the minimum amount of energy required to maintain life or sustain vital functions like the working of the heart, circulation, respiration etc.
- 13. Measurment of Basal Metabolism Basal metabolism can be measured by: • Calorimeter directly by measuring the heat dissipated under basal condition or • Indirectly by measuring oxygen consumption and carbon dioxide evolved per unit time.
- 14. BMR measurement
- 15. Factors affecting BMR 1.Age (Children > adults ) 2. Sex ( Male > female ) 3. Body surface area (Built > lean ) 4. Temperature (Cold > hot) 5. Ethnic ( Western > asian) 6 .Exercise ↑ 7. Starvation ↓ 8. Fever ↑ 9. Hormone Thyroid ↑
- 16. KNOW YOUR BMR Women: BMR = 655 + ( 9.6 x w ) + ( 1.8 x h ) - ( 4.7 x a) Men: BMR = 66 + ( 13.7 x w) + ( 5 x h ) - ( 6.8 x a) Unit: kcal/day w = weight in kg h = height in cm a = age in years.
- 17. Specific Dynamic Action (SDA) • This is the energy expended in the digestion , absorption, storage and subsequent processing of food. • This is called the thermogenic effect of food as these process require energy and generate heat. • SDA can be considered as the activation energy needed for a chemical reaction. This energy has to be supplied initially.
- 18. • The consumption of protein produces the greatest increase in energy loss compared to fat or carbohydrate. • Proteins 30% • Fat 15% • Carbohydrates 5% • Mixed diet 10% In some people a high degree of diet induced thermogenesis may be a factor which allows them to maintain a normal body weight even after overeating.
- 19. Physical Activity • Represents 20 – 40% of the total energy expenditure. • Because of great variation in amount of physical activity among individuals , this component of energy expenditure is the most important reason for the difference in caloric intake required to maintain energy balance.
- 20. Environmental Temperature • Temp. will affect the metabolic rate. • Low temp. increases energy expenditure by inducing shivering and nonshivering thermogenesis. • Shivering provides a regulated means of producing heat by increasing muscle activity in response to cold stress. • Nonshivering thermogenesis can also produce heat in response to cold stress. The site is brown adipose tissues.
- 21. Nutritional importance of proteins • Proteins are vital to any living organism • Important constituents of tissues and cells • Supply the body building material & make good the loss that occur due to wear and tear. • Forms the defense system of body
- 22. Nitrogen Balance Catabolism of amino acids leads to a net loss of nitrogen from the body. This loss must be compensated by diet in order to maintain a constant amount of body protein. Nitrogen balance studies evaluate the relationship between the nitrogen intake and nitrogen excretion.
- 23. Intake of nitrogen = excretion of nitrogen (Healthy) Intake of nitrogen > excretion of nitrogen (+NB) Intake of nitrogen < excretion of nitrogen (- NB) Proteins are major source of nitrogen (16%) Positive Nitrogen Balance Negative nitrogen balance • growing period, starvation • pregnancy acute & chronic illness • convalescence protein deficiency
- 24. Nutritional indices of proteins • Biological value of proteins (BV) • Net protein utilization (NPU) • Net dietary protein value (NDPV) • Protein efficiency ratio (PER) • Chemical score.
- 25. Biological value of proteins (BV) Defined as the percentage of absorbed nitrogen retained by the body and is calculated by- BV = Retained nitrogen X 100 Absorbed nitrogen Egg BV = 97 very good protein Milk 84 Meat 80 Fish 85 Rice 64 Groundnut 54
- 26. Net protein utilization (NPU) NPU = Retained nitrogen X 100 Intake of nitrogen • Better index than BV to denote nutritional quality of proteins. Milk 75 Meat 76 Fish 72 Rice 57 Groundnut 45
- 27. • Biological measures of NPU gives a more complete expression (both absorption and retention) of protein quality than chemical score. • In calculating protein quality , 1g of protein is assumed to be equivalent to 6.26g of nitrogen. • Protein requirement varies with the NPU of dietary protein. If NPU is low the protein requirement is high and vice versa. • The NPU of the protein of Indian diet varies between 50-60.
- 28. NDPV & PER NDPV - Intake of nitrogen x 6.25 x NPU Protein Efficiency Ratio – The nutritive value of food protein can be determined with lab animals like rat. Gain in weight in gm / Protein ingested in gm
- 29. Chemical Score is a measure of the conc. of each EAA in the test protein expressed as a percentage of that amino acid in the reference protein. This mode of assessment does not take into account the digestibility of dietary protein. The chemical score for starches is between 50- 60 and for animal food is 70 -80. Chemical score - mg of EAA / gm of protein mg of amino acid / 1g of protein X 100 mg of amino acid / 1g of egg protein
- 30. Nutritive value of food proteins Protein BV NPU PER Chemical score Egg 90 91 4.5 100 Milk 84 75 3.0 65 Fish 85 72 3.0 60 Meat 80 76 2.8 70 Rice 64 57 2.0 60 Wheat 58 47 1.7 42 Bengal gram 58 47 1.7 44 Groundnut 54 45 1.7 44 Soya bean 64 54 2.0 57
- 31. Limiting amino acid • One or more essential amino acids which is deficient in the protein which limits the weight gain. • Problem can be solved by mutual supplementation of proteins in the diet.
- 32. Protein limiting Amino acid Mutual supplied protein Rice Lysine, threonine pulse proteins Wheat Lysine, threonine pulse proteins Gelatin Tryptophan milk protein Zein Tryptophan, Lysine fish protein Tapioca Phenylalanine fish protein Bengal gram Cysteine, methionine cereals
- 33. EAT TO LIVE AND NOT LIVE TO EAT THANK YOU