WATER SOLUBLE VITAMINS

vitamin C

ascorbic acid -humans are unable to make vitamin C--> essential micronutrient -ABSORPTION: small intestine ; as intake increases, absorption DECREASES -EXCRETION: kidneys increase excretion with high intakes ; excess is eliminated in urine FUNCTION: facilitates chemical reactions, needed for connective tissue synthesis and maintenance; antioxidant that donates electrons to other compounds; synthesis of NTS and certain hormones; immune system functioning collagen synthesis: vitamin C helps create cross-connections between AA in collagen that greatly strengthen the connective tissue; scurvy symptoms: swollen gums, teeth falling out, bruised skin (primarily the result of weak connective tissue) antioxidant: donates electrons to radicals -donate electrons to another antioxidant- vitamin E --recycles vitamin E OTHER FUNCTIONS: immune function, bile synth, synth of NTs, cortisol production, aldosterone, BP hormone, thyroxin RDA: 75-90 mg (nonsmokers) -add 35 mg/day for smokers (increase radical formation in lungs) DIET: peppers, citrus, papaya, broccoli, cabbage, berries, orange juice, strawberries -unstable in heat, oxygen, light, alkaline, and the minerals iron and copper -preserved in cool conditions scurvy: poor wound healing, pinpoint hemorrhages, bleeding gums, bruises, depression adult UL: 2000 mg/day: -diarrhea and GI tract discomfort -vitamin has prooxidant effects in high -SI reduces absorption of the micronutrient when intakes of vitamin exceed 200 mg/day -excess oxalate excretion may inc. risk of kidney stones -quantities--> increase radical production

MYplate: water soluble vitamins

fruit: vitamin C folate veggies: folate vitamin C grains: thiamin riboflavin niacin folic acid other B vitamins dairy: riboflavin vitamin B-12 choline pantothenic acid protein: thiamin riboflavin niacin biotin vitamin B-6 vitamin B-12 choline pantothenic acid

choline

FUNCTION: NT (acetylcholine) and phospholipid synthesis ach: learning and memory, muscle control, and many other nervous system functions RDA: 425-550 mg/day -body can make choline from serine, an amino acid -vegans may develop deficiency DIET: widely distributed in foods and human biosynthesis (production), liver, wheat germ, eggs, beef, pork (richest sources of the nutrient) DEFICIENCY -liver damage TOXIC: fishy body odor and reduced blood pressure

pantothenic acid

FUNCTION: component of coenzyme A needed for synthesizing fat and releasing energy from macronutrients RDA: 5 mg DIET: beef and chicken liver, sunflower seeds, mushrooms, yogurt, soy milk, fortified cereals, peas --very widespread in foods deficiency: rarely occurs -if occurs: headache, fatigue, impaired ms. coordination, GI tract disturbances -possible in alcoholics unknown UL --> no reports of toxicity

B-6

FUNCTION: part of coenzyme needed for AA metabolism (conversion of AA tryptophan to niacin and transamination reactions that form nonessential amino acids), involved in NT and hemoglobin synthesis, conversion of toxic homocysteine, to cysteine, a nonessential amino acid -coenzyme participates in the synthesis of heme HEME: iron-containing portion of hemoglobin- the protein in RBCs that transports oxygen --> without vitamin B-6, a type of anemia develops --> too few RBCs and poor oxygen transport RDA: 1.3-1.7 mg/day -avg adult consumes more than this DIET: liver, meat, fish, poultry, potatoes, bananas, spinach, sweet red peppers, broccoli -lost from grains during refining process ; not added back during enrichment ; many ready-to-eat cereals have been fortified with the vitamin -excessive heat can cause losses DEFICIENCY: dermatitis, anemia, depression, confusion, neurological dods such as convulsions --due to alcoholism or genetic conditions ADULT UL= 100 mg/day (nerve destruction) -megadoses ARE TOXIC

folate

FUNCTION: part of coenzyme needed for DNA synth and conversion of cysteine to methionine, preventing homocysteine accumulation -folic acid: refers specifically to the synthetic form of the vitamin found in supplements and added to fortify foods -cells in body convert folate to folate-containing enzymes: tetrahydrofolic acid (THFA) - accepts a single-carbon group, such as CH3, from one compound and transfers it to another substance --> DNA synthesis and amino acid metabolism --THFA can transfer a CH3 group to vitamin B-12, which, in turn, transfers the CH3 group to homocysteine--> forming the essential AA methionine (recycles methionine) -when vitamin B-12 is unavailable, folate cannot be used, and deficiency occurs -destruction by heat, oxidation, and ultraviolet light, food processing RDA: 400 mcg DFE -risk highest in alcoholics, women of childbearing age, pregnant women, and ppl with dogs of the intestinal tract -MEGALOBLASTIC ANEMIA: without folate, RBC precursor cells that reside in bone marrow enlarge, but cannot divide normally; release of some of the abnormal RBCs into the bloodstream before they mature --> large, immature RBCs that still have nuclei and do not carry normal amounts of oxygen (RBCs are not normally supposed to have nuclei) -many of it's functions are related to vitamin B-12 DIET: dark green leafy veggies, liver, legumes, asparagus, broccoli, orange juice, enriched breads and cereals (folic acid), papaya, pinto beans -synthetic folic acid is better absorbed than naturally occurring -may be reported as dietary folate equivalents (DFEs) DEFICIENCY -megaloblastic anemia, diarrhea, neural tube defects in embryos adult UL: 1000 mcg/day --may stimulate cancer cell growth -folic acid supplementation does not prevent nervous system damage associated with b-12 deficiency

thiamin

FUNCTION: part of coenzyme needed for carb metabolism and metabolism of certain AAs, may help neurotransmitter production RDA: 1.1-1.2 mg (men = 1.2) DIETARY SOURCE: pork, wheat germ, enriched breads and cereals, brewer's yeast, legumes, orange juice, ham, cooked green peas -can be destroyed by cooking in alkaline solutions DEFICIENCY SIGNS: beriberi and wernicke-korsakoff syndrome: weakness, abnormal NS function --beriberi- very weak, poor muscular coordination; affected function of CV, digestive, and NS --WK syndrome: most cases in alcoholics bc alcohol reduces thiamin absorption and increases the vitamin's excretion: abnormal eye movements, staggering gait, distorted thoughts processes --> disability or death without treatment major toxicity signs and symptoms: none (upper level not determined) --readily excreted in the urine

riboflavin

FUNCTION: part of coenzymes needed for carb, AA, and lipid metabolism RDA: 1.1-1.3 mg (women- men) DIET SOURCES: milk, yogurt, enriched bread and cereal, liver, mushrooms, broccoli, asparagus, and spinach -exp to light: can break down the vitamin rapidly -riboflavin rich foods, should not be packaged in clear glass containers DEFICIENCY SIGNS: inflammation of mouth and tongue, eye dods -rarely occurs -symptom of mild deficiency: become fatigued easily -not well absorbed in the intestinal tract --> consuming large amounts does not lead to significant side effects toxicity signs: none (UL not determined)

B-12

FUNCTION: part of coenzymes needed for various cellular processes, including the transfer of CH3 groups in the metabolism of folate; convert folate to coenzyme forms that are needed for metabolic reaction (DNA synthesis), homocysteine metabolism, maintenance of myelin sheaths (without, segments of myelin sheath gradually undergo destruction that can lead to paralysis) RDA: 2.4 mcg/day DIET SOURCES: animals foods, fortified cereals, fortified soy milk ABSORPTION: 1. natural vitamin B-12 is bound to animal protein that prevents absorption 2. when food enters stomach, vitamin released from protein, due to HCl; 2a. synthetic B-12 not bound to protein--> no need for stomach acid 3. in small int. B-12 binds to intrinsic factor (IF) a compound produced by certain stomach cells 4. vitamin B-12/IF complex reaches the ileum, where the vitamin complex is absorbed 5. vitamin B-12 is separated from intrinsic factor and attached to transport molecules 6.transport molecules enter blood and travel to the liver via the hepatic portal vein 7. liver removes vitamin B-12 from carrier molecules and stores 50% of vitamin n HEALTHY LIVER: stores enough for 5 to 10 years PLANTS DO NOT MAKE VITAMIN B-12 ; must rely entirely on animals foods DEFICIENCY: pernicious anemia: megaloblastic anemia and nerve damage resulting in paralysis and death, ms. weakness, sore mouth, smooth and shiny tongue, memory loss, confusion, difficulty walking and maintaining balance, numbness and tingling (LE), due to problems that interfere with intestinal absorption of vitamin (cobalamin) in foods AGING: HCl in stomach declines--> food-cobalamin malabsorption bc they are unable to release vitamin B-12 from animal protein other risks for food-cobalamin malabsorption: alcoholism, gastric bypass surgeries, certain medications ; can still produce IF (can absorb synthetic vitamin B-12) AUTOIMMUNE Dod: inflammation and destruction of cells in stomach producing intrinsic factor; lack of IF prevents most of the micronutrient from being absorbed -pernicious anemia- ppl who lack IF - vitamin B-12 deficiency and even death --> TREAT: provide routine B-12 injections RISKS: advanced age, family history VEGANS: breastfeeding vegans need to be aware that breast milk may contain inadequate amounts of vitamin B-12--> can cause megloblastic anemia in babies and NS problems --> diminished brain growth and SC damage -as many as 15 % of Americans no UL determined

niacin

FUNCTION: part of two coenzymes needed for energy metabolism (200 reactions) -precursor- tryptophan --takes 60 mg tryptophan to yield about 1 mg of niacin --EX: eggs and milk lack niacin but they have high tryptophan that can be converted to niacin RDA: 14-16 mg DIETARY SOURCES: enriched grains, beef, liver, tuna, salmon, poultry, pork, mushrooms -chemical structure is heat stable, so food retains much of its niacin content during usual preparation DEFICIENCY SIGNS: pellagra: -diarrhea -dermatitis -dementia -death early signs: poor appetite, weight loss, weakness -ppl that eat corn are prone to develop pellagra --> Mexican ppl don't have issue with this because they soak the corn kernels in lime water before using them to prepare tortillas adult UL: 35 mg/day --> megadose prescribed to treat elevated blood cholesterol -ulcers -loss of vision -flushing of facial skin -itchy skin -nausea and vomiting -liver damage

biotin

FUNCTION: synthesizing glucose and fatty acids; breakdown of certain amino acids; participates in chem runs that add CO2 to other compounds RDA: 30 mcg DIET: liver, eggs, peanuts, salmon, pork, mushrooms, sunflower seeds -REDUCTION: surgical removal of a large part of colon, antibiotics LT DEFICIENCY: rarely occurs: skin rash, hair loss, convulsions, NS does, developmental delays in infants --intestinal bacteria produce some biotin and the vitamin is in a wide variety of foods --ppl that consume raw egg whites for long periods of time - avidin protein resists biotin digestion UL unknown

neural tube defects (folate)

a pregnant woman has an increased requirement for folate because DNA synthesis and cell division take place at a rapid pace during embryonic development spina bifida- spine does not form properly before birth, and it fails to enclose the spinal cord ; section of spinal cord with spinal fluid bulging through an opening in their backs ; cannot walk independently anencephaly - type of neural tube defect in which the brain does not form properly or is missing , usually die shortly after birth recommend that all women capable of becoming pregnant consume 400 mcg of folic acid daily to prevent neural tube defects -neural tube begins to form 21 days after conception

coenzyme

most water soluble vitamins function as components of specific coenzymes small, organic molecule that interacts with enzymes and, as a result, regulates a chemical reaction -to synthesize: cells combine one of the B vitamins with a nitrogen-containing, nonprotein compound (inactive compound) -when activated by the coenzyme, the enzymes --> enzyme can bind to a molecule that needs to be changed -many chemical reactions involved in the metabolism of carbohydrates, fats, and amino acids involve coenzymes that contain B vitamins -thiamin, riboflavin, niacin, vit B-6, pantothenic acid--> function as part of coenzymes involved in energy metabolism -coenzymes with these vitamins--> need for synthesizing glucose, Das, and certain lipids -foods contain B vitamins in coenzyme forms -coenzymes in food or supplements are not absorbed intact --> they undergo digestion to release B vitamin components