Water Soluble Vitamins
= Soluble in water,
contain nitrogen
Thiamin (B1) Riboflavin
(B2)
Niacin (B3) Pyridoxine
(B6)
Pantothenic Acid Folic
Acid
Biotin Choline
Cobalamin (B12)
Also heart disorders, CNS dysfunction
Children lack knee reflex
Alcoholics often show deficiency
Increased need with increased CHO intake
B1 Functions
•
Carbohydrate
metabolism
•
Make
ribose to form RNA
•
Maintenance
of normal appetite and in normal muscle tone in G. I. tract
•
Called
the "Morale Vitamin"
•
Deficiency
became widespread with advent of polished rice
B1 Deficiency Effects
Nervous system Mental
confusion
Peripheral
paralysis
Loss
of ankle & Knee Jerk
Muscles Weakness
Wasting
Painful
Calf muscles
Cardiovascular Edema
Enlarged
heart
Death
from cardiac failure
B1 Requirements
•
Beriberi
is rare in the U.S.
•
Marginal
deficiencies may be observed: During growth, pregnancy, lactation or with
alcoholism
•
Need ~
0.5 mg/1,000 kcal
Function: part
of coenzyme involved in oxidation-reduction reactions
•
No
deficiency disease
B2 Functions
•
Main
function = cofactor for enzymatic reactions
•
Functions
in oxidation-reduction reactions as a carrier of hydrogen
•
Commonly called flavin adenine dinucleotide (FAD)
B2 Requirements
•
FNB
recommends 0.6 mg/1,000 kcal
•
RDA
for college age men is 1.8 mg,
women is 1.4 mg
•
Minimum
of ~ 1.2 mg/day required to maintain normal body stores
•
Enrichment
adds ~ 0.33 mg riboflavin per day to average diet
Deficiency disease =
Pellagra (rough skin)
• 60 mg tryptophan = 1 mg niacin
Niacin Function
•
Component
of two coenzymes involved in oxidation-reduction reactions:
Ø NAD
Ø NADP
•
Corn
is a poor source of tryptophan
•
Pellagra
was widespread in southern U.S.
4 D’s
•
Dermatitis
– esp. skin exposed to sun
•
Diarrhea
•
Dementia
– Irritability, mental confusion progressing to psychosis or delirium
•
Death
Niacin Requirements
•
FNB
recommends:
14
mg/day for college age women
20
mg/day for college age men
6.6
mg/1,000 kcal
•
Clinical
signs of deficiency are seen in U.S. in significant numbers
•
Almost
10% incidence in low-income aged
Niacin & Tryptophan
•
Some
synthesis of niacin occurs by intestinal flora
•
Niacin
can be made tryptophan:
60 mg tryptophan required for 1 mg niacin
•
Diets
rich in foods, like corn, low in both niacin & tryptophan can lead to
pellagra
•
Consumption
of 30x RDA has no effect
•
Nicotinic
acid can function as a drug in doses of 2 - 3 grams/day
•
May be
prescribed for certain cardiovascular problems and to lower serum cholesterol
•
Results
in flushing, chest pain (not a heart attack)
Enrichment of Refined Grains
•
Refining
of grains removes B vitamins and has resulted in historical deficiencies
•
U.S.
requires that nutrients lost during refining be added back to grains to the
level found in the whole grain
Required Optional
Thiamin Calcium
Riboflavin Vitamin
D
Niacin
Iron
Folic Acid (Added in
1997)
Pyridoxol
Pyridoxal Pyridoxamine
Pyridoxine
B6 Function
• Metabolism of amino acids
• Conversion of glycogen to glucose
• Deficiency is rare
• RDA adult = 2 mg
• More B6 needed during pregnancy
Deficiency is rare
• Part of Coenzyme A
Functions in fatty acid
metabolism
• Deficiencies are rare
Biotin Requirements
•
Average
American excretes more biotin than he/she consumes in a day
•
Human
intestinal flora produce considerable amounts of biotin
•
Therefore,
FNB has made no recommendation.
For labeling, an RDA of 300 mg/day is used
Folic Acid - Metabolic Role
•
Coenzyme
form = tetrahydrofolic acid
•
Functions
in transfer of methyl groups
•
Required
for synthesis of purines and pyridines
•
Required
for efficient use of histidine
•
Related
to serum homocysteine level
Folic Acid Requirements
•
Deficiency
most likely toward end of pregnancy
•
FNB
recommends intake of 400 ug/day
•
Average
American gets 200-1,500 ug/day
•
Low
consumption during pregnancy has been linked to neural tube disorders
•
New
requirement to fortify foods
Folic Acid & Pregnancy
A women of reproductive
age who may become pregnant should ensure she consumes adequate amounts!
Crucial stage of pregnancy
is very early on, if she knows she’s pregnant, it is usually too late to
reverse effects of a deficiency
(Warning: Next slide is graphic)
Sources of Folic Acid
Do the Foods You Eat
Provide 400 ug?
180 - 300 ug per serving
•
Beans
(Black, Great northern, Kidney, Lima, Navy, Pinto, White) - _ cup, cooked
•
Black-eyed
peas, Chickpeas, Lentils _ cup, cooked
100 - 179 ug per serving
•
Asparagus
or Brussel sprouts - _ cup cooked
•
Broccoli
- _ cup cooked, _ cup chopped raw
•
Spinach
- 1 cup leafy raw, _ cup cooked
•Became a vitamin in 1998
• Deficiencies very rare
•
Very
large molecule
•
Some
storage in body - 5 years supply
•
Sensitive
to acid
•
Absorption
from intestine requires “intrinsic factor”
B12 Functions
•
Coenzyme
in all body cells
•
Nucleic
acid synthesis
•
Neural
function - odd chain fatty acids required for myelin
•
Amino
acid synthesis
•
Blood
cell formation
B12 Deficiencies
Megaloblastic anemia =
first symptom is fatigue; excess folic acid can mask this symptom (don’t
feel tired)
Pernicious anemia (Deadly
anemia) - loss of neural function
Often due to a lack of
intrinsic factor
Child vegans - risk of
deficiency - no body stores & B12 is not in plants
Many vitamins and minerals function as cofactors
If
cofactor is an organic compound (vitamin), it is a coenzyme
Example of Vitamin Coenzyme
Lactate dehydrogenase (LDH) = enzyme with key role in glycolysis making ATP but
requires hydrogen
Coenzyme of LDH enzyme = NAD/NADH
Neither enzyme alone nor coenzyme alone can cause reaction;
together glycolysis continues
Human body can make NADH from niacin!
Vitamin Coenzymes
Thiamin (B1)
Riboflavin
(B2)
Niacin (B3)
Vitamin B6
Pantothenic
acid
Biotin
Folic acid
Vitamin B12
Vitamin C
= Ascorbic acid
Least stable of all vitamins
Oxidizes rapidly in light or air
Degradation is enhanced by copper or iron
1,500 mg stores
Excess excreted in urine
Vitamin C Functions
Collagen formation
Necessary for conversion of proline to hydroxyproline and
lysine to hydroxylysine
Wound healing
Iron absorption
Conversion of amino acids to neurotransmitters
Antioxidant
Vitamin C Deficiency
Deficiency Disease =
Scurvy Aching joints
Dry skin
Weakness,
anemia
Swollen gums,
gingivitis
Loose teeth
Skin
hemorrhages, old wounds bleed
Seen in older, malnourished adults; rarely in U.S.
Scurvy
Non Vitamins
= Microbial (but not human)
growth factors
PABA (para-amino benzoic acid)
5% solutions make a
great sunscreen
Inositol
Lipoic Acid
Ubiquinone
Bioflavinoids (~Vitamin P) - humans don't need
Laetrile & Amygdalin
Used as an anticancer treatment in humans worldwide; not
approved by FDA
No controlled clinical trials have been conducted
Active ingredient thought to be cyanide
Pangamic Acid
=
Non-vitamin B15
= Di-methyl glycine, derivative of amino acid glycine
Compounds are mild stimulants
Claims not
substantiated
- Oxygenator of body tissues
- Free radical scavenger
Send
Mail to Mike Mangino