lecture 10 nutrition and metabolism

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Copyright 2010, John Wiley & Sons, Inc. Chapter 20 Nutrition and Metabolism

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Lecture 10 nutrition and metabolism

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Page 1: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Chapter 20

Nutrition and Metabolism

Page 2: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Nutrients Nutrients are chemicals the body uses for

growth, maintenance, and repair Essential nutrients: ones needed in the diet

because the body cannot make sufficient amounts to meet body needs.

There are six major types of nutrients: carbohydrates, lipids, proteins, minerals, vitamins, and water.

Page 3: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Healthy Eating 4 Cal/ gram for protein or carbohydrate 9 Cal/gram for lipids Experted-suggested dietary calories:

50-60% Calories from carbohydrate Should be <15% monosaccharides

<30% from fats (mostly triglycerides) Should be < 10% from saturated fats

12-15% from protein

Page 4: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Guidelines for Healthy Eating Eat a variety of foods Maintain a healthy weight Choose foods low in fat, saturated fat, and

cholesterol Eat plenty of fruits, vegetables, and grains Use sugars in moderation Use sodium in moderation: < 2.3 grams/day Use alcoholic beverages in moderation only:

1 drink/day for women; 2 drinks/day for men

Page 5: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

My Pyramid Introduced in 2005 by USDA Web: http://www.mypyramid.gov/ Personalized approach to healthy food

choices Based on gender, age, and activity Food from each of 6 bands needed each day Example: healthy, moderately active 18-year-old

Female requires about 2000 Calories/day Male requires about 2800 Calories/day

Steps a reminder of daily activity needed

Page 6: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

My Pyramid

Page 7: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Categories of Nutrients Carbohydrates, proteins, lipids

Calories for energy + building materials. Water Minerals

Ca, P, K, S, Na, Cl, Fl, Mg, Fe, Cr, I, Mn, Co, Cu, Zn, Se. Table 21.1

Vitamins: essential or dietary provitamins Lipid-soluble: A, D, E, K Water-soluble: B vitamins and C Functions: Table 20.2

Page 8: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Categories of Nutrients: Six Carbohydrates, proteins, lipids

Give calories for energy + building materials. Minerals: inorganic (Table 20.1)

Ca, P, K, S, Na, Cl, Fl, Mg, Fe, I, Mn, Co, Cu, Zn, Se, Cr

Electrolytes, components of skeleton, enzymes Vitamins: organic (Table 20.2)

Lipid soluble: A, D, E, K Water soluble: B group, C Many function as coenzymes

Page 9: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Metabolism Facilitated by enzymes and coenzymes

NAD+ from B vitamin niacin FAD from riboflavin (B2)

Sequence of enzymatic steps is a pathway Two categories

Anabolism: synthesis of more complex chemicals Catabolism: breakdown with energy release

40% cellular functions (ATP) 60% heat

Page 10: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Metabolism

Page 11: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

MetabolismInteractions Animation

Introduction to Metabolism

You must be connected to the internet to run this animation.

Page 12: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Metabolism

Page 13: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Carbohydrate Metabolism Glucose: the body’s preferred source for ATP

production Possible uses of glucose

Used immediately for ATP production Stored as glycogen in liver or skeletal muscle Leftover: forms triglycerides in adipose tissue

Enters cells by facilitated diffusion Insulin increases rate of transport

Page 14: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Glucose Catabolism Overall catabolism of glucose

Glucose + 6 O2 36-38 ATP + 6 CO2 + 6 H2O 1. Glycolysis (in cytosol)

Glucose pyruvate + ATP + NADH + H+

Anaerobic cellular respiration2. Transition step (in mitochondria):

Pyruvate acetyl CoA + CO2 + NADH + H+ 3. Krebs cycle (in mitochondria): aerobic

CO2 + ATP + NADH + H+ + FADH2 4. Electron transport chain (in mitochondria): aerobic

NADH + H+ + FADH2 + O2 ATP + H2O

Page 15: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Glucose Anabolism and Regulation of Blood Glucose Levels When blood glucose is high

Glucose + ATP glycogen (in liver, muscle) Effect: blood glucose level is lowered

When blood glucose is low Hormones glucagon and epinephrine stimulate

Glycogen breakdown to glucose Hormones: glucagon and cortisol stimulate

Gluconeogenesis in liver cells by Glycerol (from fat) glucose Some amino acids glucose

Page 16: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Glucose Anabolism and Regulation of Blood Glucose Levels

Page 17: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Lipid Metabolism Lipolysis (catabolism): triglycerides

glycerol + fatty acids Glycerol glycolysis or gluconeogenesis Fatty acids acetyl-CoA (2-carbon) Krebs

cyle ATP Liver converts some acetyl-CoA ketone bodies Diabetics can form excessive ketone bodies acetone

(causes sweet breath) + acidosis (with possible coma and death)

Lipogenesis (anabolism) Excess fats, carbohydrates, or proteins fats

Page 18: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Lipid Metabolism

Page 19: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Lipid Transport in Blood Lipids are not water soluble so need

protein coating lipoproteins Types of lipoproteins

Chylomicrons: carry dietary fat to adipose Very low-density lipoproteins (VLDL)

Made in liver; transport fat to adipose tissue Converted to LDLs

Low-density lipoproteins (LDL): “bad” Carry 75% of cholesterol to cells for use there

High-density lipoproteins (HDL): “good” Remove excess cholesterol and transport to liver for

disposal

Page 20: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Protein Metabolism Catabolism: protein breakdown

Deamination in liver to remove NH2 NH3

Liver converts toxic NH3 urea urine Rest of amino acid Krebs cycle ATP

Anabolism: protein synthesis to form many different proteins in the body Essential amino acids (10): must come in diet Nonessential amino acids (10): can be made in

the body by modifications of essential amino acids

Page 21: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Metabolism and Body Heat Gain Heat is one form of energy Measured in calories

1 calorie (cal) = energy needed to raise 1 g of water 1oC

For foods use kilocalories (1000 cal) = Calorie Heat is produced (gained) from catabolism

Rate of production = metabolic rate Basal metabolic rate (BMR) = heat produced from

catabolism when resting and fasting BMR for adult :1200-1800 Cal/day

Page 22: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Metabolism and Body Heat Metabolic rate is affected by the following

Exercise: rate can increase 15-20 times Hormones: thyroid is primary Nervous System: ANS can increase Body temperature: warming increases Ingestion of food: gives 10-20% increase Age: metabolic rate of child higher than adult’s Gender, pregnancy, climate, sleep, malnutrition

Page 23: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Body Heat Loss Must be continuous as catabolism constantly

produces heat Routes of heat loss

Radiation: loss of body heat to air Conduction: loss of body heat to surface, such as

cold metal seat Convection

Loss of body heat to air moving from a fan or from breeze outside shower curtain

Evaporation Conversion of water to vapor as in sweating; helps

prevent overheating with exercise

Page 24: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

Control of Body Temperature Balance regulated by hypothalamus

Detects changes in temperature (“thermostat”) Warming mechanisms

Sympathetic vasoconstriction heat loss Epinephrine metabolism Increased muscle tone metabolism

Can lead to shivering heat from muscles TSH thyroid gland thyroid hormone in

blood metabolism Cooling mechanisms

The reverse + sympathetic-stimulated sweating

Page 25: Lecture 10 nutrition and metabolism

Copyright 2010, John Wiley & Sons, Inc.

End of Chapter 20

Copyright 2010 John Wiley & Sons, Inc.All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publishers assumes no responsibility for errors, omissions, or damages caused by the use of theses programs or from the use of the information herein.