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Lecture 10 Nutrients involved in Energy Metabolism

Lecture 10 Nutrients involved in Energy Metabolism -...

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Unformatted text preview: Lecture 10: Nutrients involved in Energy Metabolism Energy 3/1/10 3/1/10 Metabolic Pathways are Catalyzed By Enzymes • • • Enzymes—proteins (and RNA) that catalyze reactions but are not used up or changed during the reaction Coenzyme—a molecule that binds with an enzyme to activate it and help ti to do its job —“enzyme helper” B-vitamins play roles as coenzymes Coenzyme in metabolic Pathways • Pyruvate → acteyl CoA • Carbon skeleton of proteins are used B vitamins are components of coenzymes * imp stlide* • coenzymes are important for protein, carb, & fat metabolism Vitamin B1 (Thiamin) • • • • • Part of thiamin pyrophosphate (TPP) RDA: men 1.2 mg/day women: 1.1 mg.day Toxicity: none known Deficiency: Beriberi (people eating brown rice did not have this disease, but people eating white rice did), anorexia/weight loss, apathy, decreased short term memory, confusion and white irritability, muscle weakness, enlarged heart irritability, Thiamin • Vitamin → Coenzyme (change in phosphate groups) Food sources of Thiamin • RDA 1.2-1.1 mg/day • whole grain, ¾ cup – 2.3 mg • oat bran, raw, 1 cup --1.1 mg • pork loin, cooked --1.0 mg Riboflavin • part of coenzyme FAB & FMN • RDA men 1.3 mg/day • Women 1.1 mg/.day • Toxicity—none • deficiency: sore throat; swelling of mouth & throat, dry/cracked lips, inflammation of mucous throat, membrane of the mouth; magenta tongue; anemia, dermatitis membrane Sources of Riboflavin: • milk, sensitive to light • • opaque containers protect riboflavin from light other sources: eggs, meats, milk & milk products, broccoli, cereals Niacin • Component of NAD + and NAD and NADP+ • DNA replication/repair & cell differentiation • RDA: men 16 mg/day // women 14mg/day • Toxicity: flushing, liver damage, glucose intolerance, blurred vision, eye edema • Deficiency: Pellagra (this is a disease of 3 Ds, dermatitis rough skin, diarrhea and dementia), pigmented rash, vomiting, constipation, bright red tongue, apathy, depression, headache, fatigue, memory loss Vitamin B6 (Pyridoxine) • part of coenzyme PLP • metabolism of homocysteine • RDA: 19-50 year old: men & women 1.3 mg/day • 51 years and older men 1.7 mg/day // women 1.5 mg/day • Toxicity: sensory neuropathy, skin lesions, deficiency: dermatitis, microcytic anemia, convulsions, depression & confusion • Sources: Halibut, tuna Folate • • • • • B12 • • • • Coenzyme THF or THFA involved in DNA synthesis & amino acid metabolism Metabolism of homocysteine RDA: men & women = 400 mg/day Toxicity: masking of symptoms of Vitamin B12 deficiency, neurological damage Deficiency: macrocytic anemia, weakness & fatigue, difficulty concentrating, irritability, headache, palpitations, shortness of breath, elevated levels of homocysteine, neural tube defects headache, in developing fetus in Coenzyme involved in formation of blood, nervous system function & homocysteine metabolism RDA: men & women = 2.4 micrograms/day toxicity: none Deficiency: pernicious anemia, pale skin, diminished energy, fatigue, shortness of breath, diminished palpitations, tingling and numbness in extremities, abnormal gait, poor concentration, palpitations, disorientation, dementia Pantothenic acid Pantothenic • • • • component of coA that assists with fatty acid metabolism RDA: men & women 5 mg/day no known toxicity deficiency: rare Sources of B Vitamins • mushrooms very high Biotin • • • • Compoenent of coenzymes involved in CHO, fat & protein metabolism RDA: men & women 30 micrograms/day Toxicity: none known Deficiency: red, scaly skin rash, depression, lethargy, hallucinations, burning, tingling, tickling sensations Enriched ready-to eat Cereals • Good sources of B-complex vitamins • % DRI (dietary reference intakes) DRI intakes) Thiamin 125% Riboflavin 131% Niacin 125% Vitamin B6 154% Folate 168% Pantothenic acid 198% Total Ceral =) Minerals in Energy Metabolism • Iron = component of hemoglobin (blood) and myoglobin(muscle) – carries and delivers oxygen Iron myoglobin(muscle) • Iodine = critical component of thyroid hormones → regulate human metabolism Iodine regulate • Chromium = plays important role in CHO metabolism • Manganese = cofactor involved in CHO, fat and protein metabolism Manganese protein • Sulfur = component of the B-complex vitamins thiamin and biotin Sulfur thiamin Iron • RDA ◦ Men 19 years and older 8 mg/day ◦ Women 19-50 years old 18 mg/day ◦ 51 and older 8 mg/day ◦ Pregnant 27 mg/day • Too little → iron deficiency anemia (pale skin, fatigue, reduced work performance, impaired immune & cognitive response • Too much--> constipation, GI stress Iron Sources • Clams – canned, Cereals Kellogg, Soybean, Pork & beans – canned, Tomato paste, Lentils, Spinach, Beef Worldwide deficiencies in vitamins and minerals are recognized: • Iron, Iodine, Zn, Vit A Summary • B-complex vitamins are components of coenzymes that are involved in metabolic pathways to B-complex coenzymes produce energy produce • Certain minerals are also involved in energy metabolism Certain metabolism ...
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