Nutrients Involved in Energy Metabolism

1. 8 Nutrients Involved in Energy Metabolism

2. Energy Metabolism • Vitamins and minerals • Do not directly provide energy • Are needed for generating energy from macronutrients • B-complex vitamins are particularly important in assisting energy metabolism • Often function as coenzymes

4. Energy Metabolism • Coenzyme: a molecule that combines with an enzyme to activate it • Thiamin, riboflavin, vitamin B6, niacin, pantothenic acid, and biotin function primarily in energy metabolism • Folate and vitamin B12 function in cell regeneration and red blood cell synthesis

8. Thiamin (vitamin B1) • Coenzyme thiamin pyrophosphate is required for metabolism of carbohydrate and branched-chain amino acids • Assists in production of DNA and RNA and synthesis of neurotransmitters • Good sources: pork products, sunflower seeds, beans, whole or enriched grains • Deficiency (beriberi): muscle wasting, nerve damage

11. Riboflavin (Vitamin B2) • Involved in oxidation−reduction reactions • Part of coenzyme glutathione peroxidase (antioxidant) • Good sources: milk, enriched foods, meat • Light sensitive (use opaque milk cartons) • Ariboflavinosis: riboflavin deficiency; sore throat, swollen mucous membranes

15. Niacin (Vitamin B3) • Two forms: nicotinic acid and nicotinamide • Required for oxidation–reduction reactions of carbohydrates, proteins, and fats • Can be made from amino acid tryptophan • Good sources: meat, fish, poultry, enriched breads and cereals • Toxicity symptoms from supplements • Pellagra: severe niacin deficiency

17. Vitamin B6 (Pyridoxine) • Group of three related compounds • Coenzyme in amino acid metabolism and gluconeogenesis • Good sources: meat, fish, poultry, enriched cereals, starchy vegetables • Toxicity from high-dose supplements: nerve damage, skin lesions • Deficiency involves skin, blood, nerve tissues

21. Pantothenic Acid • Essential for fatty acid metabolism • Required for synthesizing cholesterol, steroids, detoxification of drugs • Good sources: chicken, beef, egg yolk, potatoes, oat cereals, tomato products • No adverse effects from excess amounts • Deficiencies are very rare

23. Biotin • Coenzymes for fatty acid synthesis, gluconeogenesis • Carbohydrate, fat, and protein metabolism • Content determined for very few foods • Deficiency seen in large consumption of raw egg whites over time

25. Choline • Vitamin-like substance: metabolism, cell membranes, neurotransmission • Fat and cholesterol metabolism/transport • Homocysteine metabolism • Widespread in foods • Deficiency: fat accumulation in the liver • Toxicity from excess supplementation

26. Iodine • Component of thyroid hormones • Regulates body temperature, metabolism • Important for reproduction and growth • Good sources: saltwater fish, iodized salt, foods prepared with iodized salt • Excess interferes with thyroid function • Goiter: enlarged thyroid gland

29. Iodine • Iodine deficiency disorders (IDDs) • Cretinism: mental retardation, stunted growth • Hypothyroidism: low thyroid hormone results in decreased body temperature, cold intolerance, weight gain, fatigue, sluggishness

30. Iodine • Hyperthyroidism: high levels of thyroid hormone caused by Graves’ disease • Weight loss, increased heat production, muscular tremors, nervousness, racing heartbeat, and protrusion of the eyes

31. Chromium • Assists insulin to transport glucose from the bloodstream into the cells • Important for RNA and DNA metabolism • Supports immune function and growth • Dietary adequacy controversial • Widely distributed in foods • High-dose supplementation safety is unknown • Deficiency induced in labs: inhibit glucose uptake into the cells, causing a rise in blood glucose and insulin levels

32. Manganese • Cofactor in protein, fat, and carbohydrate metabolism, gluconeogenesis, cholesterol synthesis, and urea formation • Part of antioxidant superoxide dismutase • Good sources: whole-grain foods • Toxicity impairs the nervous system, causing spasms and tremors

34. Sulfur • A major mineral • Component of thiamin and biotin • Part of amino acids: methionine, cysteine • Required by liver for alcohol detoxification • Assists in maintaining acid–base balance • Obtained from dietary proteins

35. Inadequate B-Vitamin Intake • Impacts ability to perform physical activity • Limited studies show poor work performance: lower intensity and duration • Diets high in unenriched processed foods provide inadequate levels of B-vitamins • Some B-vitamins lost in milling of grains are replaced by the enrichment process