Lecture 7b- 28 February 2019 Vitamins in metabolism and regulation Most of this lecture taken from Chapters 7,10,11 of Rolfes et al(Understanding Normal and Clinical Nutrition (Nutrition 2104/2105 text)

Outline of lectures 7a,b Vitamins     Definition of vitamins     Overview     Bioavailability     Precursors     Organic nature     Solubility         Water soluble vitamins         Fat soluble vitamins     Toxicity     Class exercise

Outline of lectures 7a,b Water Soluble vitamins     B vitamins and C     Found in what foods    

Outline of lectures 7a,b B class-roles in metabolism and regulation of metabolism         Thiamine         Riboflavin         Niacin         Biotin         Pantothenic acid         B6         folate         B12         Class exercise

Outline of lectures 7a,b Fat soluble vitamins     Found in what foods     Fat soluble vitamins class-roles in metabolism and regulation of metabolism         A         D         E         K     Class exercise

More detailed comments

Water Soluble vitamins     B vitamins and C     Found in what foods         Thiamine-whole grains         Riboflavin-milk products or whole grains         Niacin-meat, eggs, fish, poultry, whole grains         Biotin-widespread in foods, organ meats, egg yolks, soybeans, fish, whole grains, GI bacteria        

Water Soluble vitamins     B vitamins and C     Found in what foods            Pantothenic acid-widespread in foods, organ meats, broccoli, whole grains         B6-meat, fish, poultry, legumes, fortified cereals         folate-fortified grains, leafy green vegetables, legumes         B12-animal products, fortified cereals

B class-roles in metabolism and regulation of metabolism Thiamine-part of thiamine pyrophosphate (TPP)-a coenzyme-small organic molecule that associates closely with certain  enzymes                                                                                 -TPP removes carbon from pyruvate to make acetyl CoA                                                                                 TPP participates in Krebs cycle        

B class-roles in metabolism and regulation of metabolism Riboflavin-part of co-enzymes FMN(flavin mononucleotide) and FAD(flavin adenine dinucleotide) (used in energy metabolism)                        -used in energy metabolism        

B class-roles in metabolism and regulation of metabolism Niacin-part of co-enzymes NAD(nicotinamide adenine dinucleotide) and NADP(its phosphate form)-used in energy metabolism Biotin-part of coenzyme used in energy metabolism, fat synthesis, amino acid metabolism and glycogen synthesis Pantothenic acid-part of co-enzyme A-used in energy metabolism

B class-roles in metabolism and regulation of metabolism B6-part of coenzymes PLP(pyroxidal phosphate) and PMP(pyridoxamine phosphate) used in amino acid and fatty acid metabolism; helps convert tryptophan to niacin and serotonin folate-part of THF(tetrahydrofolate) and DHF(dihydrofolate) used in DNA synthesis        

B class-roles in metabolism and regulation of metabolism B12-part of coenzymes methylcobalamin and deoxyadenosylcobalamin used in new cells synthesis(THF metabolism)       -reforms folate coenzyme       -assists in catabolism of some fatty acids and amino acids -figure 10-13        

Figure 10.13: Animated! Metabolic Pathways Involving B Vitamins. These metabolic pathways were introduced in Chapter 7 and are presented here to highlight the many coenzymes that facilitate the reactions. These coenzymes depend on the following vitamins: • NAD and NADP: niacin • FMN and FAD: riboflavin • TPP: thiamin • THF: folate • CoA: pantothenic acid • PLP: vitamin B6 • B12: vitamin B12 • Biotin Pathways leading toward acetyl CoA and the TCA cycle are catabolic, and those leading toward amino acids, glycogen, and fat are anabolic. For further details, see Appendix C. Fig. 10-13, p. 347

                                                        https://www.khanacademy.org/test-prep/mcat/biomolecules/enzyme-structure-and-function/v/cofactors-coenzymes-and-vitamins E:\Media\Animations\chapter10\Metabolic_Pathways\1013.html

B VITAMINS REGULATION OF METABOLISM IS BY DEGREE OF PRESENCE OF CORRECT FORM OF VITAMIN

-citrus fruits, cabbage type vegetables, Vitamin C- found in what foods – -citrus fruits, cabbage type vegetables, dark green vegetables(bell peppers and broccoli), cantaloupe, strawberries, lettuce, tomatoes, potatoes, papaya, mangoes

Vitamin C-functions         -collagen synthesis         -forms scar tissue(collagen)         -forms collagen matrix for bone growth         -antioxidant (toxic doses-prooxidant)         -thyroxin synthesis         -amino acid metabolism(conversion of tryptophan to serotonin and norepinephrine)          -helps in absorption of iron                                                    

Vitamin C-regulation of metabolism         REGULATION OF METABOLISM IS BY DEGREE OF PRESENCE OF CORRECT FORM OF VITAMIN                                                    

Class exercise Explain the connections between source and function of each of the water soluble vitamins                                                   

Fat soluble vitamins     Found in what foods         A- retinol-fortified milk, cheese, cream, eggs, liver             -Beta-carotene-spinach, dark leafy greens, broccoli, apricots, cantaloupe, carrots, sweet potato         D-sunlight, fortified milk, butter, cereals; veal, fish         E-polyunsaturated plant oils, leafy green vegetables, liver, yolks         K-gi bacteria synthesis, leafy green vegetables, cabbage type vegetables, milk

Fat soluble vitamins class-roles in metabolism and regulation of metabolism         A -retinol-protein synthesis                         -rhodopsin synthesis                         -not antioxidant(lipids)                   -Beta-carotene-antioxidant         D-regulates bone mineral metabolism, primarily calcium         E-antioxidant of lipids(fatty acids)         K-activates blood clotting proteins                                                    

FAT SOLUBLE VITAMINS REGULATION OF METABOLISM IS BY DEGREE OF PRESENCE OF CORRECT FORM OF VITAMIN                                                    

Class exercise             Explain the connections between source and function of each of the fat soluble vitamins