Water soluble Vitamins

1
Water soluble Vitamins

• Chapter 7

2
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

3
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

4
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

5
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

6
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

7
Niacin (B-3)

• Pair of related compounds
• 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 gt 35 mg/day - headache, itchy

8
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

9
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

10
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
• 1950s infant formula - heat destroyed B-6 -
  convulsions
• synthesis of hemoglobin (O2) and white blood
  cells (immunity)
• role in recycling homocysteine

11
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

12
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

13
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

14
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

15
B - 12

• Family of compounds - cobalt
• 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

16
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

17
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

18
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

19
Vitamin C

• Enhances iron absorption
• 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)

20
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