Water soluble Vitamins Chapter 7

Water Soluble Vitamins Readily excreted from the body focus on regular intake B vitamins and Vitamin C Table 7-4 Summary B vitamins often found together in foods lack of one, may indicate others are low function as coenzymes fig 7-1 key roles in metabolism breakdown and synthesis

B vitamins Many B vitamins are inter-dependant in metabolism (Fig 7-6) after ingestion, broken down into free vitamins in stomach and SI - absorbed in SI 50-90% reformed into coenzymes in cells as needed Intake is plentiful in our society fortification and availability other areas - public health concern elderly / alcoholics long term deficiency - not clear short term - fatigue, other physical symptoms

B vitamins Grains and seed modified by processing - milling crushed - germ , bran and husk removed leaving starch containing endosperm flour, bread and cereals enrich flour with thiamin, riboflavin, niacin folate and iron still lack B-6, and minerals choose whole grains

Thiamin (B1) Release energy from carbohydrate deficiency - beriberi (I cant I cant) weakness,loss of appetite, irritability, occurs when rice (white) is staple glucose poorly metabolized - primary fuel for brain and nerve occurs after only 10 days on thiamin free diet Thiamin in Food pork, whole grains, soy milk, fortified cereals, enriched flour RDA 1.1-1.2 mg / day average 150% (M) 100% (F) poor and elderly at risk supplements non toxic - lost in urine

Riboflavin (B-2) Many energy yielding pathways vitamin and mineral metabolism antioxidant Deficiency - inflammation of mouth and tongue dermatitis, cracking of skin around mouth develop after 2 months occurs with niacin , thiamin and B-6 deficiency Riboflavin in food milk, enriched grains, fortified cereal, RDA 1.1-1.3 mg / day alcoholics at risk no toxic indications

Niacin (B-3) Pair of related compounds pellagra - deficiency syndrome energy utilization and synthetic pathways (fat) broad use - widespread symptoms pellagra - deficiency syndrome rough or painful skin, dementia, early symptoms - poor appetite, weak Niacin in foods poultry, fortified cereal, wheat bran, tuna, asparagus niacin is heat stable RDA 14 - 16 mg / day risk with alcoholism and disorders of tryptophan metabolism toxic > 35 mg/day - headache, itchy

Pantothenic Acid Energy release from carbohydrate, fat and protein forms coenzyme A deficiency - rare - burning/tingling in feet or hands Pantothenic acid in foods present in all food sunflower seeds, mushrooms, peanuts, eggs AI 5 mg/day alcoholism - poor diet symptoms masked by other deficiencies

Biotin 2 forms - active in fat and carbohydrate metabolism synthesis of glucose, Facids, DNA breakdown of AA deficiency - scaly inflammation of skin dec. appetite, nausea, anemia, depression Biotin in food cauliflower, egg yolk, peanuts, cheese intestinal bacteria synthesize biotin antibiotics raw egg whites - avidin - binds biotin - not absorbed AI 30 mg/day relatively non toxic

B - 6 Family of three compounds coenzyme metabolism deficiency - widespread symptoms depression, vomiting, skin disorders, nerve irritation, impaired immunity metabolism of AA - needs B-6 split N from AA - synthesis on non-essential AA synthesis of neurotransmitters- communication 1950’s infant formula - heat destroyed B-6 - convulsions synthesis of hemoglobin (O2) and white blood cells (immunity) role in recycling homocysteine

B-6 in foods Animal products, fortified cereal, potatoes, milk animal sources are more absorbable measurement in food is difficult RDA 1.3 - 1.7 mg/day set high due to high protein intake high protein breakdown Athletes - may need slightly more increased glycogen and AA use as fuel higher protein intake sufficient intake from inc food and protein intake in athletes

B-6 Alcoholism -metabolites formed in ethanol - inc destruction dec. absorption, and synthesis of coenzyme liver disabled (cirrhosis and hepatitis) B-6 toxicity 2 - 6 g/day for 2 months irreversible nerve damage also with long term 200 mg/day abuse in bodybuilders symptoms - difficulty walking, hand and foot numbness upper limit 100 mg/day

Folate Formation of DNA Metabolism of AA (homocysteine) deficiency - early phases of red blood cell synthesis - immature cells can not divide - DNA not formed megaloblasts - enlarged cells macrocytic anemia - dec O2 carrying after 7-16 weeks Cancer therapy - hampers folate metabolism affects rapid cell division of cancer intestine and skin as well

Folate in foods Green leafy veg., organ meats, sprouts, orange juice food processing and preparation destroys 50-590% of folate in food (heat) RDA 400 ug/day DFE-Dietary Folate Equivalent) synthetic foalte absorbs a lot better than natural folate Folate enrichment now mandatory women, pregnant of concern elderly and alcoholism

B - 12 Family of compounds - cobalt complex means of absorption synthesized by bacteria and fungi complex means of absorption B-12 released by digestion - stomach acid free B-12 binds with intrinsic factor B-12 / intrinsic factor complex absorbed in SI 30-70% of dietary B-12 absorbed without I Factor, 1-2% absorbed 95 % of deficiencies decline in intrinsic factor with age

B-12 functions Variety of cellular processes conversion of folate to active form maintenance of myelin sheaths that insulate nerve fibers patchy degeneration -paralysis…..death Pernicious Anemia - weakness, sore tongue, back pain, apathy, tingling in extremities 3 years for nerve destruction - irreversible starts after middle age -10-20 % infants of vegan mothers long term nervous system problems brain growth, spinal cord, intellectual development

B - 12 in food Meat, milk, eggs RDA 2.4 ug/day takes 20 years without B-12 to exhibit nerve destruction Vegan, elderly non toxic

Vitamin C Most animals make from glucose absorbed in SI - 80-90% 20 % absorbed when mega dose role in synthesizing collagen (protein) connective tissue, bone, teeth, tendons, blood vessels, wound healing deficiency - scurvy - 20-40 days water soluble antioxidant nitrosamines (cancer) folate, vit. E

Vitamin C Enhances iron absorption vital for function of immune system toxicity of vit. C due to over absorption of iron vital for function of immune system Dr. Linus Pauling - 1g - common cold? Large dose eliminated absorption saturated at 200mg/day Vit C in Food green pepper, cauliflower, brocolli, cabbage, fruits lost in processing - heat, iron, copper, O2 RDA 60 mg/day (smokers -100)

Toxicity of Vitamin C Probably not toxic below 1g regular consumption stomach inflammation, diarrhea, iron toxicity hemochromatosis mega-dose - alert physician can alter medical results Fig 7-12 review- vit in foods functions, deficiency, toxicity, absorption