Water soluble Vitamins

1
Water soluble Vitamins

• Chapter 8

2
Water Soluble Vitamins

• Objectives
• List the major functions and deficiency symptoms
  for each water soluble vitamin
• Lit three important food sources for each water
  soluble vitamin
• Describe toxicity symptoms for excess consumption
  of certain water soluble vitamins
• Describe some cancer causing mechanisms, and
  describe how diet and nutrition are related to
  their minimization

3
Water Soluble Vitamins

• Excess readily excreted from the body
• Large amounts can be lost in food processing and
  preparation
• Stir fry, steam best for retaining vitamin
  content
• focus on regular intake of water soluble
  vitamins, which are
• Eight B vitamins and Vitamin C
• Table 8-3 Summary
• B vitamins
• often found together in foods
• lack of one, may indicate others are low
• function as coenzymes fig 8-1
• key roles in metabolism
• breakdown and synthesis of energy containing
  nutrients

4
B vitamins

• Many B vitamins are inter-dependant in metabolism
  (Fig 8-6)
• 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
• Due to fortification and availability
• other areas of world - health concern
• elderly / alcoholics also a concern
• long term deficiency - not clear
• short term - fatigue, other physical symptoms
  related to slowing of metabolic processes

5
B vitamins

• Grains and seeds 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, E, zinc and magnesium, and fiber
• choose whole grains
• Brown rice, whole wheat breads, whole wheat or
  brown rice pasta

6
Thiamin (B1)

• Used to release energy from carbohydrates (fig
  8.6)
• 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 cells
• occurs after only 10 days on thiamin free diet
• Thiamin in Food
• pork, whole grains, soy milk, fortified cereals,
  enriched flour (fig 8.7)
• RDA 1.1-1.2 mg / day
• average 150 (M) 100 (F)
• poor and elderly at risk
• supplements non toxic - lost in urine
• No upper limit set for intake - no extra benefit

7
Riboflavin (B-2)

• Used in many energy yielding pathways as
  coenzymes (fig 8.6)
• Also in vitamin and mineral metabolism and as an
  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 as
  these nutrients often occur in the same foods
• Riboflavin in food (p 256)
• milk, enriched grains, fortified cereal,
• RDA 1.1-1.3 mg / day
• alcoholics at risk
• no toxic indications for megadoses

8
Niacin (B-3)

• Is a pair of related compounds
• Co-enzyme in energy utilization and in synthetic
  pathways for fatty acids
• Fig 8.6
• broad use - widespread symptoms
• pellagra - deficiency syndrome
• rough or painful skin
• early symptoms - poor appetite, weakness and
  weight loss
• Symptoms - dementia, diarrhea and dermatitis
  (skin exposed to sun)
• Niacin in foods
• tuna, poultry, fortified cereal, wheat bran,
  asparagus, peanuts (p 265)
• niacin is heat stable
• RDA 14 - 16 mg / day
• risk with alcoholism and disorders of tryptophan
  metabolism
• toxic gt 35 mg/day - headache, itchy

9
Pantothenic Acid

• Co enzyme for energy release from carbohydrate,
  fat and protein -fig 8.6
• forms coenzyme A
• deficiency - rare - burning/tingling in feet or
  hands
• Pantothenic acid in foods
• present in all food
• sunflower seeds, mushrooms, peanuts, eggs
• Adequate Intake 5 mg/day
• alcoholism - poor diet
• symptoms are likely to be masked by other B
  vitamin deficiencies
• No toxicity in known

10
Biotin

• 2 forms - active in fat and carbohydrate
  metabolism
• synthesis of glucose, Fatty acids, DNA
• breakdown of Amino Acids
• deficiency - scaly inflammation of skin
• decreased appetite, nausea, anemia, depression,
  muscle pain and weakness
• Biotin in food
• cauliflower, egg yolk, peanuts, cheese
• intestinal bacteria synthesize biotin
• Antibiotics reduce absorption
• raw egg whites - have the protein avidin - binds
  biotin so that it is not absorbed
• Adequate intake 30 ug/day - avg 2X
• relatively non toxic

11
B - 6

• Family of three compounds
• coenzyme for metabolism
• Carbohydrate, fat and protein
• deficiency - widespread symptoms
• depression, vomiting, skin disorders, nerve
  irritation, impaired immunity
• metabolism of AA - needs B-6
• split Nitrogen from AA - synthesis of
  non-essential AA
• synthesis of neurotransmitters- communication
• 1950s infant formula - heat destroyed B-6 -
  deficiency resulted in convulsions
• synthesis of hemoglobin (O2) and white blood
  cells (immunity)
• role in recycling homocysteine along with B12 and
  folate - elevated levels of homocysteine
  associated with CVD risk

12
B-6 in foods

• Fig 8-8
• Animal products, fortified cereal, potatoes,
  milk, banana, avocado
• 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
• Usually sufficient from increased food and
  protein intake in athletes

13
B-6 (continued)

• Alcoholism -metabolites formed in ethanol -
  increase destruction of B6
• dec. absorption, and synthesis of coenzyme as
  well
• 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
• B-6 tablets can be up to 500mg, taking a toxic
  dose is quite easy

14
Folate

• Helps in formation of DNA
• Metabolism of AA (homocysteine)
• deficiency - early phases of red blood cell
  synthesis - immature cells can not divide -
  because DNA is not formed
• Form megaloblasts - enlarged cells
• macrocytic anemia - dec O2 carrying
• after 7-16 weeks on folate free diet
• Maternal deficiency - neural tube defects in
  fetus - fig 8-9
• Spina bifida and anencephaly
• Cancer therapy - methotrexate - hampers folate
  metabolism
• affects rapid cell division of cancer cells as
  well as intestinal and skin cells
• hair loss, Diarrhea, vomiting

15
Folate in foods

• Green leafy veg., organ meats, sprouts, orange
  juice
• food processing and preparation destroys 50-90
  of folate in food (heat)
• RDA 400 ug/day DFE-(Dietary Folate Equivalent)
• synthetic folate absorbs a lot better than
  natural folate
• multiply intake by 1.7 for dietary folate
  equivalent - DFE
• Many have inadequate intake - this has gotten a
  lot better since mandatory enrichment of grain
  products in 1998
• Folate enrichment now mandatory
• Women of child bearing age of concern
• Pregnant women - 600 ug / day
• As are the elderly and alcoholics

16
B - 12

• Family of compounds that contain mineral cobalt
• synthesized by bacteria and fungi
• complex means of absorption
• B-12 released by digestion - food interacting
  with stomach acid
• free B-12 binds with intrinsic factor
• B-12 / intrinsic factor complex absorbed in Small
  Intestine
• 30-70 of dietary B-12 absorbed
• without I Factor only 1-2 absorbed
• 95 of deficiencies due to absorption problems
• decline in intrinsic factor and absorption with
  age
• Require monthly injections of B-12

17
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 - which is
  irreversible
• Generally starts after middle age
• 10-20 of older adults
• infants breast feeding from vegan mothers that
  are B12 deficient
• long term nervous system problems
• brain growth, spinal cord, intellectual
  development

18
B - 12 in food

• Meat, milk, eggs, seafood
• Fortified soy milk
• RDA 2.4 ug/day
• Average intake 2-3 times RDA
• Provides enough for 2-3 years storage in liver
• takes 20 years without B-12 absorption to exhibit
  nerve destruction
• Vegans, elderly at risk
• Supplementation non toxic

19
Vitamin C

• Most animals make vitamin C from glucose
• absorbed in SI - 70-90
• 50 absorbed with mega dose
• Role in synthesizing collagen (protein)
• connective tissue, bone, teeth, tendons, blood
  vessels,
• wound healing
• water soluble antioxidant
• Reduces formation of nitrosamines (cause cancer)
• Maintain folate and vit. E function
• Enhances iron absorption
• toxicity of vitamin C due to over absorption of
  iron
• vital for function of immune system

20
Vitamin C

• Dr. Linus Pauling - 1g -
• common cold - may decrease duration but not
  incidence
• Large dose eliminated in urine
• absorption saturated at 200mg/day
• Vit C in Food - fig 8-11
• Red and green peppers, cauliflower, brocolli,
  cabbage, fruits
• lost in processing
• heat, iron, copper, O2 exposure
• RDA 75-90 mg/day (smokers -add 35 mg a day to
  RDA)
• Average intake twice the RDA
• deficiency - scurvy -
• 20- 40 days without vit C
• Weakness, opening of healing wounds, bleeding
  gums, pinpoint hemorrage

21
Toxicity of Vitamin C

• Probably not toxic below 1g
• regular consumption of high doses
• stomach inflammation, diarrhea, iron toxicity
• Hemochromatosis
• over storage of iron
• mega-dose - alert physician
• can alter medical test results for diabetes
• Fig 8-12,13 review- vitamins in foods
• functions, deficiency, toxicity, absorption Table
  8-3

22
Choline

• Latest addition to the list of essential
  nutrients - not yet classified as a vitamin
• Choline is part of acetylcholine a
  neurotransmitter
• Choline is also part of phospholipids (lecithin)
• and participates in some aspects of homocysteine
  metabolism
• Found in milk, liver, eggs and peanuts
• Average intake twice the RDA of 425-550 mg/day
• Vitamin like compounds
• carnitine, inositol, taurine and lipoic acid are
  required for proper metabolism
• but are not essential in the diet, as they can be
  manufactured in the body