Adv Nutr Exam 2

• Water-Soluble Vitamins include numerous compounds involved in energy metabolism, diverse coenzyme functions, and are toxic in massive quantities.
• Vitamin C (Ascorbic Acid) is a water-soluble vitamin that prevents scurvy, donates/accepts hydrogen atoms, acts as an antioxidant, and its isomer is the L- active form.
• Vitamin C is destroyed by alkali, oxidation, and light, and its food sources include fruits and vegetables.
• Collagen synthesis, iron absorption, carnitine formation, neurotransmitter production, serotonin production, water-soluble antioxidant activity, adrenal hormone release, and protection of LDLs from oxidation are functions of Vitamin C.
• Scurvy is the vitamin C deficiency disease, characterized by abnormal bone growth, joint pain, bleeding gums, and tiny hemorrhages beneath the skin.
• Thiamin is composed of a pyrimidine group and thiazole ring, with food sources including pork, whole grains, enriched cereals, liver, poultry, fish, eggs, potatoes, legumes, nuts, dark green vegetables, brewer’s yeast, and wheat germ.
• Thiamin phosphates are digested to yield free thiamin, with absorption primarily occurring in the jejunum, secondarily in the duodenum and ileum, and alcohol reducing thiamin absorption.
• Thiamin is transported by an active, sodium-dependent mechanism, with functions including metabolism and release of energy from carbohydrates, oxidative decarboxylation of α-ketoacids and 2-keto-sugars, conversion of pyruvate to acetyl CoA, reactions in the Krebs cycle, pentose phosphate pathway, membrane conduction of nerve tissue, branched-chain amino acid metabolism, and LIV.
• Fat-Soluble Vitamins are substances that are organic and are essential players in at least one necessary chemical reaction or process in the body.
• Thiamin deficiency causes disease being beriberi, characterized by mental confusion, muscular problems, cardiac disorders, CNS problems, anorexia, and fluid imbalance.
• Vitamins cannot be made in the body and are noncaloric, required in small amounts (mg and mcg).
• Riboflavin is important in energy metabolism, acts as riboflavin mononucleotide (FMN) or riboflavin adenine dinucleotide (FAD), is light sensitive, and its dietary sources include milk, dairy, leafy green vegetables, liver, beef, meat, enriched cereals, and grains.
• Vitamin A is a preformed vitamin A (provitamin A) which comes in forms such as retinol (alcohol form), retinal (aldehyde form), and retinoic acid (acid form).
• Vitamin K is not stored well in human tissue, but deficiency conditions are uncommon.
• Previtamin A is a carotenoid structure that includes the carotenes and xanthophylls, with beta carotene being the most potent carotenoid.
• Vitamin K Toxicity is rare in the natural form, but the synthetic form, menadione, may pose a risk if taken in large doses.
• Vitamin K Deficiency is rare.
• Appreciable amounts of vitamin K are lost in the urine and feces each day.
• FAD and FMN are released in the upper part of the small intestine, with riboflavin absorbed by a saturable, sodium-dependent transport system, facilitated by bile salts, and transported in the plasma bound to albumin or other blood proteins.
• Infants are at some risk for a vitamin K deficiency, and individuals who take certain antibiotics for an extended period are at greater risk for a deficiency.
• Alcohol and some drugs decrease folate absorption.
• Methionine production from homocysteine is a function of folate.
• Vitamin B12 is a stable compound.
• B12 must eventually bind to intrinsic factor (stomach mucosa).
• IF protects vitamin B12 from degradation.
• Deficiency in folate leads to megaloblastic, macrocytic anemia; this leads to reduced oxygen-carrying capacity, changes to the digestive tract mucosa, leukopenia, deterioration in rapid cell division, psychosis, mental deterioration, and neural tube defects (in pregnancy).
• Dietary sources of folic acid include both animal and plant sources such as vegetables, legumes, nuts, fruits, organ meats, and whole grains.
• Deficiency in vitamin B12 leads to pernicious anemia slowly developing.
• Polyglutamates of folate are digested.
• Transcobalamin II is the binder for B12 inside the cells and the plasma transport protein.
• Tissue turnover is a function of folate.
• Normocytic hypochromic anemia is a result of folate deficiency.
• Symptoms of vitamin B12 deficiency include weakness, indigestion, abdominal pain
• Folate is found in food; folic acid is the synthetic form used in supplements and enriched food.
• The synthesis of nucleic acid precursor molecules is a function of folate.
• Potentially fatal condition, pernicious anemia, is the result of vitamin B12 deficiency.
• Vitamin B12 is involved in chemical reactions: conversion of homocysteine to methionine and conversion of l-methylmalonyl-CoA to succinyl CoA.
• Digestion and absorption of niacin involves digestion to nicotinamide and most absorption in the small intestine.
• Folate is absorbed by a sodium-dependent, saturable, carrier-mediated mechanism.
• Niacin is present as nicotinic acid or nicotinamide.