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  1. 1. Chapter 30: Nutrition K. Dunlap Chem 104
  2. 2. Nutrition the study of food and how the body uses it Function of Nutrients: 1) supply energy 2) supply materials for building and replacing body tissues 3) supply other substances needed for various life processes
  3. 3. Nutrition • Nutrients:Nutrients: the components of food and drink that provide growth, replacement, and energy: 1. Carbohydrates 2. Lipids 3. Proteins 4. Vitamins 5. Minerals 6. Water • DigestionDigestion: the hydrolysis of starches, fats, and proteins into smaller units that can be absorbed and metabolized.
  4. 4. Elemental Composition of the Human Body
  5. 5. Digestive Tract • breakdown of food is done through a series of enzyme-catalyzed reactions • CHO start breaking down into maltose and disaccharides in the mouth by salivary amylase • pepsin begins the breakdown of protein into polypeptides • acids are neutralized • CHO to monosaccharides and absorbed • polypeptides to amino acids and absorbed • triglycerides to FAs and glycerol
  6. 6. Digestion Continued… • Bile acids are like soaps. They have a polar and nonpolar groups that aid water soluble lipase and the incorporation of fats into chylomicrons for transport. They are synthesized in the liver and stored in the gallblader • Lipase cleaves triglycerides to fatty acids and glycerol • Fatty acids, glycerol, amino acids, monosaccharides are absorbed in the small intestine and travel through the blood stream to the liver for further modification
  7. 7. Proteins • Different enzymes catalyze the hydrolysis of peptide chains at different specific sites.
  8. 8. Carbohydrates Proteins Fats Mouth Salivary amylase Disaccharides Maltose Stomach Pepsin Polypeptides Small Intestine Pancreatic enzymes Simples sugars Glucose Pancreatic enzymes Amino acids Lipase Bile salts Glycerol FAs Bloodstream Liver Glycogen Body proteins Body fats
  9. 9. Calorimeter • Food energy is measured in Calories (capital C) 1 Cal = 1 kcal = 1000 cal = 4180 joules • a Calorie is defined as the amount of energy required to raise 1 kg of water 1°C •Measured in a bomb calorimeter
  10. 10. Calculating the Caloric Value of Food Carbohydrate = 4 Cal per gram Proteins = 4 Cal per gram Fats = 9 Cal per gram
  11. 11. Determining Fat Content of Foods
  12. 12. Recommended Dietary Needs
  13. 13. Recommended Daily Intake: Adults: 0.8 g per kg of body weight Children and Pregnancy: 1.5-2.0 g per kg body weight Complete Protein - contains all essential amino acids -meat, eggs, dairy, fish Incomplete Protein - missing one or more essential amino acids -legumes and grains combined make a complete protein Proteins
  14. 14. Proteins – Gelatin, which is denatured collagen, is an incomplete protein because it lacks Trp, and is low in Ile and Met. – Corn protein is low in Lys and Trp. – Rice is low in Lys and Thr. – Wheat protein is low in Lys. – Legumes are low in Met and Cys. – Soy protein is very low in Met. Protein complementation:Protein complementation: a diet in which two or more proteins complementation each other’s deficiencies; for example: – grains + legumes (rice + beans)
  15. 15. Fats • recommended 30% of diet -10% monounsaturated -10% saturated -10% unsaturated Essential Fatty acids: Omega-3 EPA, DHA, linoleic Omega-6 Arachidonic acid, α-linolenic • EPA, DHA, AA are 20 carbon hormone-like fatty acids that play an important part in the immune function
  16. 16. Percentage of Calories in Common Foods
  17. 17. Energy Needs Woman 2000 Cal Men 2200 Cal -physical activity and lifestage affects energy needs -need to burn 3500 Cal to lose 1 pound Basal Caloric Requirements -the requirements for a resting body
  18. 18. Vitamins -Organic compounds required in small amounts for normal metabolism and good health - not a source of energy Water soluble - C and Bs -must be replenished everyday -Difficult to overdose Fat soluble - A, D, E, K -does not need to be replenished everyday -can cause toxicity
  19. 19. Fat Soluble Vitamins
  20. 20. Water Soluble Vitamins
  21. 21. Recommended Daily Allowances (RDA)
  22. 22. Vitamin Absorption and Storage • All absorption takes place in the small intestine • Fat-soluble vitamins – Are absorbed in the duodenum – Storage • Vitamin A is mainly stored in the liver • Vitamins K and E are partially stored in the liver • Vitamin D is mainly stored in the fat and muscle tissue • Can build up in body to point of toxicity
  23. 23. Vitamin Absorption and Storage • Water-soluble vitamins – Absorbed with water and enter directly into the blood stream – Most absorbed in the duodenum and jejunum – Most are not stored in the body – Excess intake excreted through the urine – Important to consume adequate amounts daily – Dietary excesses can be harmful
  24. 24. Digesting and Absorbing Water-Soluble Vitamins Figure 10.1
  25. 25. Water-Soluble Vitamins Fat-Soluble Vitamins Absorbed in the Small Intestine Small Intestine Hydrophobic or Hydrophilic Hydrophilic Hydrophobic Absorbed into the Blood Lymph Stored in the body Not Generally Yes Can build up and become toxic Not Generally Yes Need to consume daily Yes No
  26. 26. Bioavailability • Varies based on – Amount in food – Preparation – Efficiency of digestion and absorption of food – Individual nutritional status – Natural or synthetic • Fat-soluble vitamins are generally less bioavailable than water-soluble vitamins • Vitamins from animal foods are generally more bioavailable than those in plant foods
  27. 27. 32 vitamin D • A prohormone synthesized from cholesterol • Vitamin D3 = cholecalciferol • Found in animal products • Vitamin D2 = egocalciferol • Found in plants and fortified foods
  28. 28. Vitamin D3 and D2
  29. 29. • Time spent outdoors • Amount of skin exposed • Skin color • Clothing • Body fat • Latitude • Season and time of day What affects your vitamin D level?
  30. 30. Vitamin D Synthesis and Latitude Vitamin D Synthesis and Latitude
  31. 31. Childhood rickets • Epidemic with industrialization in 19-20th centuries • With discovery of vitamin D and fortification, rickets was almost entirely eliminated • Until now…
  32. 32. London 1889 Idaho 1989
  33. 33. • 40-90% of US community dwelling elderly • 50% of premenopausal women • 50% of Hispanic and black adolescents • 48% of French preteens • 30-50 % of adults in Saudi Arabia and UAE • 73 % of pregnant women taking prenatal vitamins …are DEFICIENT
  34. 34. How to get vitamin D... • 100 IU/d raises level by about 1 ng/mL • Sunlight 3000 IU/10 minutes • Oily fish 300 IU/3 oz – Salmon, sardines, mackerel, tuna • Mushrooms 100 IU/3 oz • Fortified drinks 100 IU/8 oz – Milk, orange juice, yogurt, cereals
  35. 35. Updated Recommendations In Process • Studies suggest that the daily vitamin D intakes should be much higher than 400 IU/d. • Daily intakes in the range of 800 to 1000 IU/d should be strongly considered. • Although there are concerns regarding vitamin D toxicity, side effects at intakes exceeding the current upper limit of 2000 IU/d have not been reported to date. • Assessment of vitamin D status with serum measurements of 25(OH) vitamin D levels for a broader range of patients should be encouraged.
  36. 36. Vitamin Deficiency Scurvy - vitamin C (ascorbic acid) deficiency -bleeding gums, vomiting, weight loss, anemia, poor wound healing Beri beri - vitamin B1 (thiamine) deficiency -stiffness of limbs, heart disease, mental disorders, paralysis of limbs Pellagra - vitamin B3 (niacin) deficiency -reddening and drying of skin, gastrointestinal and nervous system disorders
  37. 37. blindness - vitamin A (retinol) deficiency -night blindness, scaly and hard skin, eye degeneration -retinol is required for the generation of rhodopsin, a photosensitive material Rickets and Osteomalacia - vitamin D (calciferol) deficiency -required for the absorption of Ca and P -skeletal problems, knock knees, protruding forehead -Rickets in children -Osteomalacia in adults Vitamin Deficiency cont….
  38. 38. Minerals -defined as those elements, other than carbon, oxygen, hydrogen, and nitrogen that are needed for normal growth and maintenance Major or Macrominerals - those required in amounts of 1 gram or more Ca, P, K, Na, Cl, Mg, Trace or micromineral - those required in amounts less than 1 gram Cu, Co, Z, Fe, I, F, Se
  39. 39. Minerals Phosphorus Balancing calcium in diet 800-1200 mg Potassium Sodium Calcium Chloride ion Povides membrane potential O smotic pressure Bone formation; hormonal function; blood coagulation; muscle contraction O s motic pressure Mineral Function Magnesium Iron Zinc Copper Manganese Chromium Molybdenum Cobalt Selenium Iodine Fluorine Cofactor in enzymes O xidative phosphorylation; hemoglobin Cofactor in enzymes; insulin O xidative enzymes cofactor Bone formation G lucose metabolism Protein synthesis Component of vitamin B12 Fat metabolism Thyroid glands Enamel formation 3500 mg 2000-2400 mg 800-1200 mg 1700-5100 mg 280-350 mg 15 mg 12-15 mg 1.5-3.0 mg 2.0-5.0 mg 0.05 - 0.2 mg 0.075-0.250 mg 0.05 mg 0.05-0.07 mg 150-170 µg 1.5-4.0 mg RD A
  40. 40. Source and function of common Vitamins and Minerals
  41. 41. Fiber - indigestible carbohydrates -lowers risk of cardiovascular disease, diabetes, colon cancer, diverticulitis and obesity • absorbs water and promotes frequent bowl movements • fermented in the Large intestine by microbes • lowers LDL cholesterol 1) Soluble 2) Insoluble • slows gastric emptying • causes satiety • adds fecal bulk
  42. 42. Problems with Processed Food • nutrients are lost in processing • some but not all nutrients are added back (Enriched) • Fortified is when other ingredients are added that were not originally the food • are lower in fiber • processed foods are digested more quickly and lend to weight gain
  43. 43. Nutritional Diseases Kwashiorkor - protein deficiency -often provides enough calories -common b/w the ages of 1-4 b/c of premature weaning
  44. 44. Nutritional Diseases marasmus - protein and calorie deficiency -more serious condition
  45. 45. Nutritional Diseases Anorexia Nervosa- a psychological disorder characterized by low body weight and poor body image Bulimia Nervosa- psychological disorder characterized by periods of binging and purging -often eat over 20,000 Cal
  46. 46. Nutritional Diseases Obesity - excessive weight gain that is associated with heath concerns and increased risk of mortality -characterized by a BMI of greater than 30 BMI (body mass index) = weight in kg divided by the square of the height in m -25% of Americans are obese -60% of Americans are overweight (BMI 25- 29.9)
  47. 47. Nutritional Diseases Diabetes - condition in which body is unable to utilize glucose in a normal way Type I - an auto immune disease that results in the permanent destruction of insulin producing beta cells in the pancreas Type II - metabolic disorder that is usually characterized by insulin resistance, insulin deficiency and hyperglycemia -associated with obesity -Increased prevalence
  48. 48. Food Supplements - vitamins, minerals, herbal remedies, etc… -$60 billion a year industry -Balanced diet provides adequate needs -Elderly, dieters, alcoholics, pregnant, lactation may require supplementation - often supplements are not in a form that is as available as it is in food
  49. 49. Supplement Label
  50. 50. Nutrition Labels
  51. 51. Food Additives -added to prevent spoilage, sweeten, enhance flavor, color, appearance, emulsify
  52. 52. Food Preservatives -mostly used to prevent food spoilage Antimicrobial: Nitrites -clostridium botulism - identified as cancer-causing Sulfites -wine and dried fruit -can cause allergic rxn Others -Na, K, Ca salts, benzoic acid, propionic acid, sorbic acid
  53. 53. Food Preservatives cont…. Antioxidants: added to slow the oxidative process -usually phenols Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) -Prevent oxidation of fats by combining with free radicals Natural Antioxidants -Vitamin E, Vitamin C, carotenoids, other polyphenols -also stop oxidation by combining with free radicals
  54. 54. Chemical Structures of Flavorings -largest class of food additive -natural and synthetic -Mostly aldehydes and esters -Many synthetics have not been thoroughly tested
  55. 55. Chemical Structures of Artificial Sweeteners -growing market for dieters and diabetics NutriSweet Sucralose Splenda
  56. 56. Sweetness of Sweeteners
  57. 57. Phytonutrients
  58. 58. What are functional foods? • International food information council “those foods that provide health benefits beyond basic nutrition” Bioactive Nutraceutical • Considered non-essential for growth and development • Decrease risk of chronic diseases
  59. 59. dietary supplements • Regulated as foods • Safety of supplement regulated by FDA only after they have entered the market • DSHEA states that a dietary supplement is “adulterated” only if it presents a “significant or unreasonable risk of illness or injury”
  60. 60. Dietary supplement health & education act of 1994 Definition of a supplement: “Is a product (other than tobacco) that is intended to supplement the diet that bears or contains one or more of the following dietary ingredients: a vitamin, a mineral, an herb or other botanical, an amino acid, a dietary substance for use by man to supplement the diet by increasing the total daily intake, or a concentrate, metabolite, constituent, extract, or combinations of these ingredients.” •Is intended for ingestion in pill capsule, tablet, or liquid form •Is not represented for use as a conventional food or as the soled item of a meal or diet •Is labeled as a “dietary supplement” •Includes products such as an approved new drug, certified antibiotic, or licensed biologic that was marketed as a dietary supplements or food before approval, certification, or license (unless the Secretary of Health and Human Services waives this
  61. 61. the challenge of assessing dietary supplements • Need surrogate endpoints! • Example assessment of risk of cancer, inflammation • Bioactive components decrease inflammation via multiple mechanisms, i.e. activation of transcription factor and other epigenetic regulations • Act as antioxidant etc.
  62. 62. secondary metabolites• phytonutrients content vary by location, harvest & storage • Sometimes phytonutrient cocktail is better than isolated nutrient –
  63. 63. carotenoids • Yellow and orange fruits, dark green leafy vegetables • α and β-carotene and β cryptoxantin – precursor to Vitamin A • lycopene, lutein, and zeaxantin – not precursors to vit A • Foods rich in carenoids may be safer than purified supplements • Typical western diet contains about 6 mg/day of carotenoids, 60% from animal
  64. 64. lycopenes • accumulates in certain tissues, such as prostate • Lycopene commonly in plasma associated with LDLs • Lutein and zeaxantin have high binding affinity to HDLs – accumulate in macula lutea of retina, act as photoreceptors
  65. 65. the benefits of salmo astaxanthin
  66. 66. Plant sterols & stanols• Most abundant Sterols = β- sitosterol, stigmasterol, campesterol • Inhibit growth of various forms of lung, stomach, ovarian and breast cancer. •Stanols = sitostanol, campestanol • Sterols essential component cell membrane • Have sterol ring – differ in side chain. • Stanols are saturated form of sterol
  67. 67. Sterols and stanols cont…• Cholesterol lowing effect by lowering absorption • FDA authorized health claims – must contain at least 0.65 g of plant sterols or 1.70 g stanol esters (esters have higher lipid solubility and are more easily incorporated into foods) • Typical diet  .15 - .4 g/day of sterols and stanols • To achieve 1.5
  68. 68. Polyphenols • 1) flavanoids, 2) phenolic acids • Secondary metabolites – more than 8000 • Hydroxyl groups might provide reducing power or antioxidant potential (ROS) • Usually lots of conjugated double bonds • Usually in free form or Ο- glycosides
  69. 69. Phytoestrogens • Majority phytoestrogens belong to 4 subclasses: isoflavanoid, coumestans, isoflavones, lignans, stilbenes • Composed of a planar aromatic ring system with one or more hyroxyl • Phytoestrogens proposed to mimic estrogen and act as weak agonist, promoting estrogen • favorably affect hormone-dependent cancers, menopausal symptoms, glycemic control and weight maintenance, decrease thrombus and platelet aggregation, lower TGL, LDL. • Recommended as alt to hormone replacement therapy. • No safety info
  70. 70. ESTRADIOL Estrogens function in growth, reproduction, and maintenance and integrity of skeleton and CNS.
  71. 71. Phytoestrogens cont… • Founds in licorice, kudzu, soy, red clover, saw palmetto • Wine, grapes and peanuts good source of resveratrol • Flax seed, whole grain products, vegies, tea good source of lignans. • FDA approved health claim of 25 g or more
  72. 72. Indole-3-carbinol • A chemically, mechanistically, and phylogenetically separate phytoestrogen is indole-3- carbinol • does not mimic estrogen, but alters alters estrogen metabolism via a different mechanism. • Acid condensate of I-3-C binds to aryl hydrocarbon receptor which is capable
  73. 73. Organosulfurs • Contains a derivative of cysteine called alliin, released when allium vegetables are crushed. • the enzyme allinase produces a lipid-soluble, unstable intermediate called allicin that decomposes to produce allyl sulfides, including diallyl sulfide (DAS, DAD and DATS) • Onions, leaks, chives, scallions, garlic (richest source)
  74. 74. Polyols • Sugar alcohols are used as sweeteners – Xylitol, Sorbitol, Mannitol • Fewer calories (1.5 – 3 kcal/g) and lower glycemic index due to reduced absorption by intestine • Excessive consumption of sugar alcohols lead to osmotic diarrhea – >50g of
  75. 75. Stevia • A natural zero calorie South American herb • Steviol contains two hydroxyl groups • Sugar residues are esterified to one or both of the –OH groups to form glycosides which are 200 – 450 times sweeter than sucrose. • Microflora in intestine release sugars and steviol • May lower blood pressure
  76. 76. Food Pyramid
  77. 77. The Food Guide Pyramid
  78. 78. 2005 Food Pyramid
  79. 79. 2011 My Plate
  80. 80. 1. How does the body store energy? 2. How many Cal of energy are released 180 grams of glucose are converted to CO2 and H2O? 3. There are 2 fatty acids that the body needs but cannot synthesize. What are they? 4. What is meant by a complete protein?
  81. 81. 5. Are vitamins organic or inorganic? 6. Identify each vitamin. a) tocopherol b) calciferol c) ascorbic acid d) cobalamin e) retinol 7. What are the fat soluble vitamins? 8. What is kwashiorkor?