Chapter 18 Overview of Nutrition and Metabolism (Nutrition PDF)

Chapter 18 Overview of Nutrition and Metabolism Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 1 18.1 Overview of Nutrition and Metabolism Nutrition: Study of n...

Chapter 18 Overview of Nutrition and Metabolism Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 1 18.1 Overview of Nutrition and Metabolism Nutrition: Study of nutrients and how body uses them Nutrients: Chemicals from the environment that organisms need for survival Used to supply energy to fuel metabolic processes, and for building blocks for producing the molecules the body needs 2 major nutrient classes: Macronutrients: Required in large quantities, such as carbohydrates, lipids, proteins; provide energy Micronutrients: Required in small amounts, such as vitamins and minerals; help extract energy from macronutrients Essential nutrients: Nutrients that the body cannot synthesize or cannot synthesize in sufficient quantity Must be obtained from the diet Calories: Units of heat used to express amount of energy in foods Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 2 Carbohydrates: Organic compounds, such as sugars and starches Energy held in their chemical bonds is used to power cellular processes Carbohydrate sources: Polysaccharides: Complex carbohydrates, such as starch from plant foods and glycogen from meats Disaccharides (double sugars): milk sugar, cane sugar, beet sugar, molasses Monosaccharides (single sugars) from honey and fruits Digestion breaks complex carbohydrates into monosaccharides that are small enough to be absorbed Cellulose is a complex carbohydrate abundant in our food; not digested, but provides fiber Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 3  Nerve cells use Glucose as primary energy  source Different monosaccharides are absorbed from digestive tract: fructose, galactose, and glucose Glucose is broken down into CO2, H2O, and energy when needed Excess glucose is converted into glycogen by glycogenesis, and stored in liver and muscle cells Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 4 Conversion of Other Monosaccharides into Glucose Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 5 Figure 18.2 Carbohydrate Digestion and Use Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 6 Lipids:  Organic compounds that include fats, oils, phospholipids, and cholesterol Supply energy for cellular processes Serve as building blocks for structures such as cell membranes Triglycerides: Glycerol and 3 fatty acids Most common dietary lipids Also called “fats” Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 7 Lipids: Lipids in foods include phospholipids, cholesterol, and most commonly, fats/triglycerides Functions of lipids: Mainly supply energy Contain more than twice as much chemical energy per gram as carbohydrates or proteins Glycerol and fatty acids can be used to synthesize storage fats in adipose tissue Excess glucose or amino acids can also be converted into fat molecules Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 8 Figure 18.4 Fatty Acid Usage by Liver Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 9 Proteins: Consist of chains of amino acids Have many functions, including building new proteins (structural proteins, enzymes, hormones, antibodies, clotting factors, and other plasma proteins) Proteins also supply energy: First broken down into amino acids Amino groups (-NH2) are removed through deamination; they react to form urea, which is excreted in urine Deaminated portions of amino acids are decomposed in various pathways that produce ATP, such as the citric acid cycle Excess amino acids can also be converted into glucose or fats Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 10 Protein Sources  Foods that contain proteins: Meats, fish, poultry, cheese, nuts, milk, eggs are high in protein Legumes (beans and peas) contain less protein Body needs 20 types of amino acids to synthesize proteins: 12 can be synthesized by the body; called non- essential amino acids 8 cannot be synthesized; called essential amino acids Essential amino acids are not stored in the body Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 11 Complete proteins (high-quality proteins) contain adequate amounts of the essential amino acids for good health; found in meat, milk, and eggs Incomplete proteins (low-quality proteins) do not contain adequate amounts of essential amino acids; found in many plant proteins Certain combinations of plant proteins (such as beans and rice) provide adequate diversity of the dietary amino acids Isoleucine (e) Phenylalanine (e) Leucine (e) Threonine (e) Lysine (e) Tryptophan (e) Methionine (e) Valine (e) Eight essential amino acids (e) cannot be synthesized by human cells and must be provided in the diet. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 12 18.5 Energy Expenditures  Energy Values of Foods: Calorie: the amount of potential energy a food contains Calories are actually units of heat One kilocalorie (1 kcal or 1000 calories) is the amount of heat (energy) needed to raise the temperature of one kg of water by one degree Celsius (°C). Caloric content of foods can be measured by a bomb calorimeter Caloric content of various types of nutrients: Carbohydrates: 4.1 Calories/gram Proteins: 4.1 Calories/gram Lipids: 9.5 Calories/gram Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 13 Table 18.3 Calories Used During Various Activities Activity Calories (per Hour) Walking up stairs 1,100 The first column shows activity and the Running second(jogging) 570 column shows calories (per hour). Swimming 500 Vigorous exercise 450 Slow walking 200 Dressing and undressing 118 Sitting at rest 100 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 14 Basal metabolic rate (BMR): Rate at which body expends energy under basal conditions (awake and at rest, after overnight fasting, in comfortable environment) BMR varies with gender, body size, body temperature, thyroid hormone activity Maintaining BMR requires body’s greatest energy expenditure Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 15 Energy Balance  Exists when caloric intake from food equals caloric output from BMR and muscular activities Body weight remains constant Positive energy balance: Caloric intake exceeds output Tissues store excess nutrients Leads to weight gain Negative energy balance: Caloric expenditure exceeds intake Tissues are broken down for energy Leads to weight loss Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 16   Body Mass Index (BMI) is used today to assess weight, taking height into consideration A person is classified with BMI as either underweight, normal weight, overweight, or obese: Normal is defined as a BMI between 18.5 and 24.9 Overweight is defined as exceeding desirable weight by 10% to 20%, or a BMI of 25 and 30 Obesity is defined as exceeding desirable weight by >20%, or with a BMI over 30 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 17  Obesity Almost 1/3 of adults in the United States are obese (20% above desirable weight, having extra pounds of fat in the body) Obesity increases risk for type 2 diabetes, digestive disorders, heart disease, kidney failure, hypertension, stroke, certain cancers Both heredity and environment can contribute to obesity Treatments: Diet and exercise (losing 1 lb. requires burning of 3,500 calories) Drug therapy (can be effective, but many drugs are harmful) Surgery: 3 types of bariatric surgery are used to treat obesity Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 18 Weight Loss Surgery Weight Loss Medications - Semaglutide (Wegovy) Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 19 Minerals and Vitamins Minerals Inorganic elements that plants extract from soil or water and introduce into the food web Vitamins Small dietary organic compounds that are necessary for metabolism Neither is used as fuel Both are essential to our ability to use other nutrients Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. Vitamins: Organic compounds that are required in small amounts for normal metabolic processes Essential nutrients; cannot be synthesized by body cells in adequate amounts. Classified on the basis of solubility: Fat- soluble vitamins: A, D, E, and K Water-soluble vitamins: B vitamins and vitamin C B vitamins are essential for normal cellular metabolism B vitamins are usually found in the same foods, so together, they are known as the vitamin B complex Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 22  Table 18.7 Fat-Soluble Vitamins Vitamin Characteristics Functions Sources and RDA* Conditions Conditions for Adults Associated Associated with with Excess Deficiencies Vitamin A Exists in several forms; An antioxidant necessary Liver, fish, whole milk, Nausea, Night synthesized from for synthesis of visual butter, eggs, leafy green headache, blindness, carotenes; stored in liver; pigments, mucoproteins, vegetables, yellow and dizziness, hair degeneration of stable in heat, acids, and and mucopolysaccharides; orange vegetables and loss, birth epithelial bases; unstable in light for normal development of fruits 600 IU** defects tissues The first column shows vitamin, the second column bones and teeth; and for maintenance of epithelial cells shows characteristics, the third column shows Vitamin D A groupfunctions, of steroids; thePromotes fourthabsorption column of shows Producedsources in skin and RDA Diarrhea, Rickets, bone resistant to heat, oxidation, calcium and phosphorus; exposed to ultraviolet calcification of decalcification forbases; acids, and adults, stored inthepromotes liver, skin, brain, spleen, fifth column development of teeth and bones shows conditions light; in milk, egg yolk, fish liver oils, fortified soft tissues, renal damage and weakening and bonesassociated with excesses, and the sixth column foods 400 IU Vitamin E A groupshows of compounds;conditions associated An antioxidant; prevents with deficiencies. Oils from cereal seeds, Nausea, Rare, uncertain resistant to heat and visible oxidation of vitamin A and salad oils, margarine, headache, effects light; unstable in presence polyunsaturated fatty acids; shortenings, fruits, nuts, fatigue, easy of oxygen and ultraviolet may help maintain stability and vegetables 30 IU bruising and light; stored in muscles and of cell membranes bleeding adipose tissue Vitamin K Exists in several forms; Required for synthesis of Leafy green vegetables, Jaundice in Prolonged resistant to heat but prothrombin, which egg yolk, pork liver, soy formula-fed clotting time destroyed by acids, bases, functions in blood clotting oil, tomatoes, cauliflower newborns and light; stored in liver 55 to 70 µg *RDA – Recommended daily allowance. **IU – International unit. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 23   Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.   Vitamin C deficiency Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.   Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.   Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. Folic Acid needed for neural tube development Deficit  Spina Bifida Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Vitamin K Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. Mineral - Iron  Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 18.10 Life-Span Changes Dietary requirements remain about the same throughout life BMR rises in early childhood, peaks in adolescence, and declines in adulthood Change in nutrition often reflects the effects of medical conditions, and social and economic circumstances: Depression Tooth decay, periodontal disease, diabetes mellitus Deficiency of vitamin A may take a long time to show up Calcium deficiency may not show symptoms as bones lose mineral content Vitamin D deficiency may develop in absence of sun exposure Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 34 Table 18.12 Energy Requirements Decline with Age CAL/DAY CAL/DAY Age Female Male The first column shows age and the 23 to 50 2,000 second 2,700 for column shows CAL/DAY female and male. 51 to 74 1,800 2,400 75+ 1,600 2,050 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 35