Agenda

1. Agenda • Water Soluble vitamins • The B family • Vitamin C • Choline • Supplements • Water

2. Lecture 10: Vitamins Will Brown 02/09/2012

3. Water Soluble Vitamins • Soluble in water • Consist of the B family (and a related nutrient choline) and vitamin C • Rapidly excreted if taken in excess • Most are lost during food processing • Most B vitamins occur together so a lack of one indicates a lack of the others • B vitamins act as coenzymes – that is the act so that enzymes can function • Play key roles in metabolism of carbs, fats and amino acids • Needs increase as energy needs increase

4. Water Soluble Vitamins: Background • Most B vitamins are broken down in the stomach and SI, then reassembled inside various cells • Water soluble vitamins have a high bioavailability; typically 50-90% • Most north Americans get plenty of the water soluble vitamins in their diet • A few exceptions include the elderly and those with high alcohol consupmtion

5. Thiamin: Vitamin B-1 • Coenzyme that helps release energy from carbohydrates and amino acid breakdown • Required for all living organisms; however only made in bacteria, fungi and plants • The most common source of Thiamin is whole grains • Refined grains, such as flour, loses most of its thiamin which is why it is fortified • Other sources include pork, green beans, milk orange juice, peanuts, dried beans and seeds

6. Thiamin: Vitamin B-1 • RDA for Thiamin: 1.1 to 1.2 mg/day • The value of 1.5 mg/day used to calculate the % value on nutrition labels • No known upper limit for thiamin because it is cleared so fast • Thiamin deficiency results in beriberi – a condition that can develop after only 10 days on reduced thiamin diet

7. Riboflavin: Vitamin B-2 • Name comes from the Latin word for yellow: flavus • Functions • Coenzyme in metabolism, fatty acid pathways • Antioxidant • Deficiency leads to epithelial disorders; such as inflammation of the mouth and tongue, dermatitis, etc; develops after 2 months • Sources include milk and milk products, meat, eggs, and veggies like asparagus and broccoli • RDA: 1.1-1.3 mg/day – No toxic upper limit

8. Niacin: Vitamin B-3 • Functions as one of two compounds: nicotinic acid or nicotinamide • Similar to other B vitamins, functions as coenzyme for metabolism; fatty acid synthesis • Wide spread use in virtually every metabolic pathway • Deficiency known as pellagra – means rough and painful skin • Symptoms include dementia, dermititis, and diarrhea • Has the distinction of being the only dietary deficiency to reach epidemic proportions in the USA. • From mid 1800-1930s

9. Niacin: Vitamin B-3 • Sources • Preformed: meat, fortified foods, asparagus, peanuts and coffee (Yea for coffee!) • Niacin can also be synthesized – metabolized from the amino acid tryptophan • 60mgs of tryptophan yields 1mg of niacin • 50% of daily needs supplied this way • RDA:14-16 mg/day – supplements use 20mg/day • Similar to retinol, has NE niacin equivalency units • Most adults double the RDA • Has upper limit toxicity of 35 mg/day, severe at 100mg/day • Symptoms include vasodilation, headache, itching, flushing • Long term overexposure results in GI tract and liver damage

10. Quick review • Thiamin, Riboflavin and Niacin all play key roles in metabolic pathways and energy metabolism • Deficiency in one usually comes with deficiency in the others • Alcoholism compounds the likelihood of deficiency • Reason is alcohol consumption ramps up the Krebs cycle in which most of these are used • Severe alcoholics get a ton of calories from alcohol but no nutrition to support the energy output

11. Pantothenic Acid: Vitamin B-5 • Like the other B vitamins plays a role in energy metabolism • Specifically, required for the formation of Coenzyme A (CoA); CoA plays key role in metabolism of pyruvate to yield energy • Very wide spread in just about every food you put into your mouth • Which is where the name comes from, the greek word pantothen meaning “from everywhere.” • RDA: 5mg/day – no toxicity so no upper limit • Deficiency masked by other B vitamin deficiencies

12. Biotin: Vitamin B-7 or Vitamin H • Involved in fat and carbohydrate metabolism • Helps to synthesize glucose and fatty acids from the breakdown of certain amino acids • Deficiency symptoms include scaly inflammation of skin, changes in tongue and lips, decreased appetite, nausea, vomiting, etc • Sources include cauliflower, egg yolks, peanuts, and cheese • RDA: 30ug/day – no toxic limit

13. The Biotin Avidin relationship • Biotin is found in egg yolks • Avidin is found in egg whites • Avidin binds to biotin with such high affinity that the biotin can not be absorbed. • There is another form called streptavidin that is produced by Streptomyces bacteria • One of the strongest non-covalent interactions in nature = Kd=10-14mol/L • This relationship is used extensively in molecular biology

14. Vitamin B-6 • Exists in 3 pro-vitamin forms; most common is called pyridoxine • Functions • Aids in metabolism of protein and amino acids • Synthesis of neurotransmitters • Involved in hemoglobin synthesis and function • Sources include animal products, fortified foods and some fruits and veggies such as banana, cantaloupe, broccoli, and spinach • Animal form is better absorbed than plant form

15. Vitamin B-6 • RDA: 1.3-1.7 mg/day • Average daily intake is usually above the RDA • Athletes usually require more but usually consume higher protein levels and thus enough • Alcohol metabolites can displace B-6 coenzyme • Liver damage also decreases the ability to convert pro-vitamin to functional form • Can help alleviate nausea symptoms in first trimester – make sure you check with your physician first

16. Vitamin B-6 • Deficiency leads to depression, vomiting, skin disorders, nerve irritation • Upper limit set at 100mg/day • High intake is associated with nerve damage • Studies demonstrate that 2-6g/day for 2 months results in irreversible nerve damage • Toxic side effects – walking difficulties, hand and foot numbness • Peripheral nerves can recover somewhat • Damage to ganglia nerves is permanent • Average supplement is 500mg tablets – makes over dose easy

17. Folate: Vitamin B-9 • Comes in many forms; most common food additive is Folic acid • Food form has lower bioavailability-extra residues need to be removed prior to absorption • Destroyed during cooking, also water soluble so 50-90% lost during the cooking process • Eat Salad! • Critical in the synthesis of new DNA • 10% of population has reduced folate metabolism • Require twice the RDA

18. Folate: Vitamin B-9 • Sources include green leafy vegetables, organ meats, sprouts, veggies, dried beans, and orange juice • RDA for adults is 400ug DFE/day • DFE used to calculate the difference in potency of synthetic folate and food folate • In 1998, grain products mandated to have folate fortification by FDA • Increased daily intake ~200ug • Studies show this reduced the incidence of neural tube defects • Upper limit of 1mg/day but only for synthetic folate

19. Consequences of folate deficiency: Megaloblastic Anemia • Just prior to going into circulation RBC expel nucleus in order to carry more hemoglobin • With out folate, RBCs can not properly divide • Results in a large immature RBC with nucleus (megaloblast) going into circulation • The nucleus takes up critical “real estate” with in the cell and reduces hemoglobin concentration • Low hemoglobin = low O2 concentration

20. Consequences of folate deficiency: Neural Tube Defects • Lack of maternal folate linked to neural tube defects such as spina bifida and anencephaly • Complications arise due to high cellular division rate in early embryo • Neural tube closes at day 28; usually before most women realize they are pregnent • Spina bifida occurs when neural tube does not close entirely • Results can include paralysis, incontinence, learning disabilities • Anencephaly means “without brain” • Babies die shortly after birth • RDA for women wanting to become pregnant: 600ug DFE/day • Women who have previous child with neural tube defects need higher amounts (4mg/day) but consult your physician

21. Vitamin B-12 • Family of compounds that contain cobalt • All are synthesized by bacteria, fungi, and other lower organisms • Complex digestion and absorption • B-12 is digested from other materials by stomach acid • Protected from stomach acid by a compound present in the saliva that is made in the mouth • Once in the SI, B-12 is released from the protection protein and associates with a protein called intrinsic factor • Carried to the ileum for absorption – the amount absorbed is dependent on the bodies need • Most B-12 deficiencies result from poor absorption • As we age, intrinsic factor production decreases

22. Functions of Vitamin B-12 • Aids in folate metabolism – required to convert folate coenzymes to active forms • This results in deficiencies that mimic folate deficiency • Involved in the maintenance of the myelin sheath that surrounds/protects neurons • Eventually causes paralysis and death • Involved in homocysteine metabolism • Non-protein A.A. that is used to synthesize other A.A.

23. Sources and Needs of Vitamin B-12 • Sources high in vitamin B-12 include our old friend organ meat! Also, meat, milk, poultry seafood and eggs • Adults over 50 are encouraged to take B-12 supplements • Strict vegan and vegetarians encouraged to find alternate sources for B-12; ie: fortified soy milk or supplements • RDA: 2.4 ug/day; 6 ug used for supplements and food labels • Most people consume twice the RDA • Stored in the liver – most people have 2-3year supply

24. Consequences of Vitamin B-12 Deficiency: Pernicious Anemia • Pernicious means “leading to death” • Called anemia because it mimics folate associated anemia • Early symptoms include: weakness, sore tongue, back pain, and tingling in the extremities • B-12 can be stored so symptoms aren’t detected until ~3 years after onset • Usually already have significant nerve damage • Effects elderly more than young; 2 reasons • The older you get the lower the stomach acid • The older you get the lower the production of intrinsic factor • Can occur in breastfed babies of vegetarian and vegan mothers because those diets have reduced B-12

25. Vitamin C: AKA Ascorbic Acid • Found in all living tissues • Most animals make it • The exceptions being humansand guinea pigs • Only the L-enantiomer is biologically active • D-enantiomer does nothing • Interesting absorption in that the more you eat the less you take up • Between 30-180mg ~70-90% • >1000mg absorption is ~50% • Any extra is excreted in feces and super high doses can cause diarrhea

26. Vitamin C Functions • Collagen Synthesis • Collagen is a major structural component in the body – cartilage, teeth, tendons, blood vessels • Required for cross linkage in collagen fibers • Antioxidant activity – can act as an antioxidant • Speculated and not proven yet so all benefits from this a pure conjecture • Enhances iron absorption • Keeps iron in most absorbable form as it travels through the alkaline environment of the SI • Those suffering from anemia are encouraged to eat vitamin C with iron rich meals • Plays a role in immune function • Not certain how it works but found in high concentrations in phagocytes • Despite the myth, Vitamin C does not shorten the duration of a cold

27. Sources and Needs of Vitamin C • Sources include Papayas, citrus fruits, green peppers, cauliflower, broccoli, cabbage, and strawberries • Eating the recommended 2 ½ cups of fruits and veggies a day will meet needs • Not heat stable –eat raw for max vitamin C • RDA: 70-95 mg/day; 60mg/day used for labels • Smokers need an additional 35 mg/day • Upper limit is 2g/day • Hard to overdose because increased intake results in reduced absorption • Usually develop diarrhea and stomach problems at doses >500mg

28. Choline: the Newest Edition • Part of acetylcholine, which is a neurotransmitter, and phospholipids. • Also involved in homocysteine metabolism • One human study and several animal studies have shown choline to “essential” but not yet labeled as a vitamin • Widely distributed in food • Also, lecithin used as an emulsifier is a source • Adequate intake is 425-550 mg/day • 3.5 g is upper limit due to “fishy body odor” and increased blood pressure

29. Other Vitamin-like Compounds • Carnitine – needed to transport fatty acids into mitochondria • Inositol – Cell membrane components • Taurine – bile components • Lipoic Acid – acts as antioxidant and carbohydrate metabolism • Not deemed essential because we can produce them but they also come from the diet

30. Carbohydrate Lipid Protein B-6, B-12,C, K, niacin, folate B-6 Niacin Fatty Acid & glycerol Amino Acids Monosaccharides All B vitamins, not B-6 Thiamin, pantothenic acid, niacin, biotin Thiamin, B-6, B-12, biotin, folate Chemical Intermediates Riboflavin, niacin, folate, B-12 B-6, B-12,C, K, biotin folate CO2 + H2O + Energy

31. Let’s Talk About Supplements • Supplements are not regulated by the FDA • Compounds in the vial are not subject to FDA inspection and can be sold with out proving safety or efficacy • Some supplements interfere or counter act some medications • Claims to prevent or cure disease can not be made • Other claims made by manufacturers do not need to be supported or substantiated • Most experts agree that the general population does not need to take supplements • Certain vitamins have toxic effects very quickly • Most experts suggest that specific supplements need to be taken by specific populations • B-12 for elderly • Folic Acid for women of child bearing age • Something to chew on: health supplements are a $25 billion a year industry

32. Water

33. Water • Water acts as a solvent for most of the nutrients we consume • Needs constant replenishment – due to respiration, excretion, urination, digestion, etc. • Need to take in ~13 cups of water for men and 9 cups for women • About 50-70% of body weight is water • The thinner you are the higher % of water you are • Lean muscle = 73% water • Fat = ~20% water

34. Water • Water is thought to move freely once inside the body • When inside the cells called intracellular fluid • Outside or in the blood is called extracellular fluid • Electrolyte movement is controlled across cell membranes • Water is controlled by osmosis • Intracellular fluid regulated by potassium and phosphate • Extracellular regulated by sodium and chloride • Certain instances when this is not the case • Blood/Brain barrier • Blood/Testis barrier • Intestinal barrier

35. Functions of Water • Acts as a solvent • Regulate body temp • Water has a high specific heat = 5861.8 joules/kg • Much lower than fat; oleic acid = 2884 joules/kg • This helps keep the body from freezing quickly • Perspiration helps to cool the body via evaporation • Remove waste – Urine is water soluble • Important in mucous production • Amniotic fluid is primarily water

36. Significant Water Loss • If to little water is ingested, the body will increase water retention • Antidiuretic hormone – released from the pituitary gland and causes kidneys to preserve more water than normal • Aldosterone – causes retention of sodium • 1-2% fluid loss the body will feel thirst • At 4% muscles begin to lose strength • At 10-12% heat tolerance is decreased and weakness • At 20% death is soon to come

37. Daily Water Intake and Output Input Output Skin perspiration 750 ml or 3 cups Lung Respiration 300 ml or 1.25 cups Urine 1650 ml or 6.75 cups Feces 100 ml or 0.4 cups Total water output 2800 ml or 10 cups • Fluids • 2000 ml or 8 cups • Water content in foods • 500 ml or 2 cups • Water produced from metabolism • 300 ml or 1.25 cups • Total water intake • 2800 ml or 10 cups