Vitamin B group
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A group of water-soluble vitamins that
characteristically serve as components of
coenzymes.
Plants and many microorganisms can
manufacture B vitamins but dietary sources
are essential for most animals.
Heat and light tend to destroy B vitamins.
The vitamin B complex consists of 12
related substances.
Eight are considered essential vitamins
because they need to be included in the diet.
Four are not essential because the body can
synthesize them.
They include thiamin (B1), riboflavin(B2),
niacin, vitamin B6, pantothenic acid, folic
acid, biotin and vitamin B12 (cobalamin);
some authorities also include choline,
lipoic acid, inositol, and paraaminobenzoic acid.
 Although these vitamins are chemically
distinct, they are grouped together
because they are found with one another
in the same foods.

B1; or Thiamin
Function
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It is an organic compound
of two parts contains
sulphur and nitrogen.
Antineuritic vitamin
Destroyed by alkaline and
heat
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Precursor of the coenzyme thiamine
pyrophosphate (TPP), which
functions in carbohydrate
metabolism.
is essential to normal nerve function
and the utilization of carbohydrates
Stimulate" the appetite
Prevent and "cure" beriberi, or
multiple neuritis, characterized by
inflammation and degeneration of
the peripheral nerves, intense pain,
resulting, finally, in paralysis and
wasting of the muscles.
• Deficiency
• first symptoms of B1
deficiency is loss of
appetite.
• Beriberi (which can cause
weakness, leg spasms,
poor appetite, and loss of
coordination.) muscle
spasm include heart
• In alcoholic result in
Wernicke-Korsakoff
syndrome( mental
confusion, staggering, rapid
eye movement or
paralysis of eye muscle.)
• Sources:
Wheat germ, beans, peas,
and green vegetables
Meat Sunflower seeds
RDA
Men: 1.2 mg
Women: 1.1 mg
Requirement
increases with
energy expenditure
Toxicity: none known
B2 or riboflavin
Functions

composed of a single
type of sugar (ribose)
and a yellow pigment
(flavin)
 first discovered in milk
and also been called
lactoflavin.

It is a constituent of the
coenzymes FAD and
FMN, which have an
important role in the
metabolism of all major
nutrients as well as in
the oxidative
phosphorylation
reactions of the
electron transport
chain.(Kreb’s cycle
Flavin mononucleotide (FMN)
Flavin adenine dinucleotide (FAD)
Deficiency
-Skin lesions, especially
cheliosis, or fissures in
the corners of the
mouth and tongue
-Bloodshot eyes
RDA
Men: 1.3 mg
Women: 1.1 mg
Toxicity: none known
Sources:
Milk/products
Enriched grains
Liver
Mushroms green vegatbles
Brewer’s yeast
-Sensitive to uv radiation (sunlight)
B3; Niacin
Functions

Nicotinic acid
 Other forms of vitamin B3
nicotinamide
 Can be made from the
essential amino acid
tryptophan
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precursor to NADH,
NAD+, NADP+ and
NADPH, which play
essential metabolic roles in
living cells.
In larger doses, niacin can
reverse atherosclerosis by
lowering low density
lipoprotein (LDL)
Nicotinamide adenine dinucleotide
(NAD)
Nicotinamide adenine dinucleotide
phosphate (NADP)
Deficiency
Pellagra is characterized by diarrhea, dermatitis and dementia as
well as “necklace” lesions on the lower neck, hyperpigmentation,
thickening of the skin, inflammation of the mouth and tongue,
digestive disturbances, amnesia, delirium, and eventually death, if
left untreated[
Dietary niacin deficiency tends to occur in areas where people
eat maize("corn") as a staple food. Maize is the only grain low in
niacin( nixtamalization is needed)
Sources:
Mushrooms
Enriched grains
Beef, chicken, turkey, fish
Heat stable; little cooking loss
RDA
Men: 16 mg equivalents
Women: 14 mg equivalents
Body can make niacin from
tryptophan
skin flushing and itching
 Gastrointestinal
Toxicity
complaints
 such as dyspepsia
(indigestion) and liver
toxicity
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B5;
Pantothenic acid
needed to form coenzyme-A
(CoA
 and is critical in the
metabolism and synthesis of
carbohydrates, proteins, and
fats.
 PantothenicGreek word
meaning "from everywhere:
widely distributed
 Deficiency: rare.

Biotin
functions
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described as the most
powerful of all the
vitamins
 Names: vitamin H, a
second called it biotin
and a third called it
"coenzyme R,"
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Necessary for cell
growth, the production
of fatty acids, and the
metabolism of fats and
amino acids.
Need for carboxylation
reactions
Recommended for
strengthening hair and
nails
Need to make glycogen
Deficiency:
Rare
Depression
Numbness/tingling in
arms and legs
skin rash, hair loss,
convulsion,
neurological disorders,
impaired growth in
children
Sources:
Widespread in food
Cheese, egg yolk, liver, peanut
butter, soybeans, fish
Synthesized by GI bacteria
Adequate Intake is 30 ug/day for
adults
This may overestimate the amount
needed for adults
No Upper Limit for biotin
Vitamin B6 or pyridoxine
Functions
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Other names
• Pyridoxine
• Pyridoxal
• Pyridoxamine
Destroyed by heat
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It is a constituent of a coenzyme
(pyridoxal phosphate) involved in
amino acid metabolism.
assists in the balancing of sodium
and potassium.
promote red blood cell
production
Synthesize sertonin, histamine,
epinephrine and norepinephrine
Conversion of tryptophan to
niacin
• Deficiency :
• Microcytic anemia
• causes retarded
growth.
• dermatitis.
Convulsions
• Sources:
•
•
•
•
Meat, fish legume
Seeds and nuts
Liver
Noncitrus fruit
RDA
– 1.3 mg/day for adults
– 1.7 mg/day for men over 50
– 1.5 mg/day for women over 50
• Athletes may need more
• Alcohol increases vitamin B-6
destruction
Toxicity• Irreversable nerve damage, numbness in hands feet
• Difficult of work, Convulsion, Restlessness and
• Insomnia.
Folic acidB9 or folacin
Function
Essential for synthesis of
DNA, repair DNA, and
methylate DNA
 Important during periods of
rapid cell division and
growth.
 Breakdown homocysteine
 May reduce risk of some
cancer as breast and
pancreatic cancers.
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folate (the naturally occurring
form),
Folic acid is itself not
biologically active, but its
biological importance is due to
tetrahydrofolate and other
derivatives after its conversion
to dihydrofolic acid in the liver
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Deficiency
Neural tube in developing
embryos.
DNA synthesis and repair
are impaired and this could
lead to cancer development
Megaloblastic anemia
Sources:
400 ug/day for adults
Liver
Fortified breakfast cereals
Grains, legumes
Foliage vegetables
Susceptible to heat, oxidation,
ultraviolet light
B12 ; (cyanocobalamin;
cobalamin)
It is structurally the most
complicated vitamin and it contains
the biochemically rare element
cobalt
 Biosynthesis of the basic structure
of the vitamin can only be
accomplished by bacteria, but
conversion between different forms
of the vitamin can be accomplished
in the human body.
 A common synthetic form of the
vitamin, cyanocobalamin, does not
occur in nature, but is used in many
pharmaceuticals and supplements,
and as a food additive
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Vitamin B12 is normally involved in
the metabolism of every cell of the
body, especially affecting the DNA
synthesis and regulation , fatty acid
synthesis and energy production.
many (though not all) of the effects
of functions of B12 can be replaced
by sufficient quantities of folic acid,
since B12 is used to regenerate
folate in the body.
Helps maintain myelin sheath
around nerve cell.
Deficiency
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Pernicious anemia which include:
Megaloblastic anaemia, nerve damage,
creeping analysis, sore red tongue and
fatigue.
This can be masked by folate intake.
Food Sources
RDA
Almost exclusively animal
2.4 mg for adults
products
Toxicity: none known
Meat, fish, poultry, milk, cheese,
eggs
Fortified soy milk, fortified
cereals
Easily destroyed by microwave
cooking and oxygen.
Figure 10-12
Page 342
Normal and Anemic Blood Cells
Normal blood cells. The size, shape, and
color of the red blood cells show that
they are normal.
Blood cells in pernicious anemia (megaloblastic). Megaloblastic blood cells are
slightly larger than normal red blood
cells, and their shapes are irregular.