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What is a Vitamin? Lecture 11: Vitamins and Metabolism • Organic compound (made mainly of carbon, hydrogen, and oxygen) Nutrition 150 • Essential nutrients (must be consumed in the diet, not made by body) Shallin Busch, Ph.D. Vitamins and Metabolism Vitamins and minerals – Are required for proper metabolism – Do not directly provide energy – Are necessary for obtaining energy from the macronutrients – Often function as coenzymes Coenzymes Coenzymes: Complex organic molecules that work with enzymes to facilitate the enzyme’s activity. B Vitamins and Metabolism B Vitamins Thiamin (B1) Act as coenzymes Riboflavin (B2) - In reactions that Niacin (B3) 1) Release energy from food 2) Regulate metabolism - In cell multiplication Biotin Pantothenic Acids B6 1) Red blood cells Folate 2) Cells of the GI lining Vitamins and Metabolism B12 Aerobic Catabolism of Glucose Glucose Uses energy (ATP) Coenzyme Coenzyme Yields energy (ATP) Coenzyme Coenzyme 2 Pyruvate Pantothenic Acid Coenzyme Coenzyme 2 CoA Coenzyme Coenzyme 2 Carbon dioxide CoA CoA 2 Acetyl CoA To TCA Cycle B6 To Electron Transport Chain Makes ATP Niacin To Electron Transport Chain Makes ATP Catabolism of Fatty Acid Catabolism of Amino Acids 16-C fatty acid Amino acids Niacin Pyruvate CoA CoA Pantothenic Acid Coenzyme Pantothenic Acid Uses energy (ATP) Coenzyme Carbon dioxide CoA Coenzyme To Electron Transport Chain Coenzyme CoA Pyruvate Coenzyme Acetyl CoA (from carbon dioxide) CoA Niacin Riboflavin (Biotin) Coenzyme Acetyl CoA B6 Makes ATP The TCA Cycle CoA All B Vitamins are involved in the TCA cycle! Thiamin (B1) Coenzyme Riboflavin (B2) Coenzyme Coenzyme Coenzyme Coenzyme Coenzyme Coenzyme Coenzyme Coenzyme (as carbon dioxide) Coenzyme To Electron Transport Chain (makes ATP) Yields energy (captured in high-energy compound similar to ATP) (as carbon dioxide) Niacin (B3) Biotin Pantothenic Acids B6 Folate To Electron Transport Chain (makes ATP) Makes ATP To TCA Cycle Oxaloacetate Coenzyme To Electron Transport Chain B12 B vitamins and the Electron Transport Chain Metabolic Pathways Involving B Vitamins Glycogen Glucose Some amino acids Pyruvate Niacin Ribolavin Some amino acids Some amino acids Some amino acids Acetyl-- TCA Cycle Yields energy Other compounds Yields energy Foods with B vitamins • In general, B vitamins are found in a wide range of foods • B vitamins are more likely found in foods of animal origins (B12), proteinrich foods, whole-grain foods, fortified foods • Many B vitamins are found in lots of different food Fat Yields energy Keeping B Vitamins in Foods • Easily destroyed by UV rays (sun), heat, exposure to oxygen – Implications for cooking and storage • Water soluble – They leach out of foods when washed and cooked in water In-text Figure Page 322 Is more always better? No! More is better up to a point and then is harmful. To minimize vitamin losses, wrap cut fruits and vegetables or store them in airtight containers. B Vitamin Toxicity Some B vitamins are toxic if too much is consumed: – Niacin: Flush, Liver damage, Impaired glucose regulation – B6: Nerve degeneration, skin lesions – Folate: Masks B12 deficiency B Vitamin Deficiency Diseases With general B deficiencies, can see: glossitis - smooth, glossy tongue due to atrophy of the tissue B Vitamin Deficiencies Diseases Niacin: Pellagra - Diarrhea, dermatitis, dementia, death Thiamin: Beriberi - Muscle wasting and nerve damage, sometime edema Riboflavin: Ariboflavinosis - Sore throat, swollen mucous membranes Folate Deficiency - Failure to replace tissues that turnover frequently (GI tract, red blood cells) - Anemia: not enough red blood cells present or properly functioning - GI tract deterioration - Spinal bifida: Improper development of spinal chord in fetus Folate - Involved in DNA synthesis, amino acid metabolism - Helps prevent heart disease and cancer - Critical for cell division of very early embryos - Critical for formation of neural tube in developing fetus Vitamin B12 • Part of coenzymes for blood formation • Required for nerve functioning • Required for homocysteine breakdown • Deficiency results in anemia, low energy, fatigue, shortness of breath, and can lead to pernicious anemia • Deficiencies seen in vegetarians, older people with GI system complications Manganese • Mineral (not a vitamin) • Coenzyme involved in energy metabolism In-Class Activity Work with a partner to design a meal that is high in B vitamins - Meal should include protein, carbohydrates, and vegetables