VITAMIN C
V
v ita m in C
A
w a t e r - s o l u b l e
v ita m in
t h a t
p l a y s
a n
e s s e n t i a l r o l e i n t h e a c t i v i t i e s o f v a r i o u s
e n z y m e s .
V i t a m i n
C
i s
i m p o r t a n t
f o r
t h e g r o w t h a n d m a i n t e n a n c e o f h e a l t h y
b o n e s , t e e t h , g u m s , b l o o d v e s s e l s , a n d
l i g a m e n t s ; i n t h e p r o d u c t i o n o f c e r t a i n
n e u ro tra n s m it te rs
( c h e m
i c a l s
t h a t t r a n s -
m i t n e r v e i m
p u l s e s ) a n d a d r e n a l g l a n d
h o r m
o n e s ; i n t h e
r e s p o n s e
o f t h e
im -
m u n e s y s t e m
t o
i n f e c t i o n ;
i n
w o u n d
h e a l i n g ; a n d i n t h e a b s o r p t i o n o f
iro n .
T h e
m a i n
d i e t a r y s o u r c e s
a r e
f r u i t s
a n d
v e g e t a b l e s .
C o n s i d e r a b l e
a m o u n t s
o f v i t a m i n C a r e l o s t w h e n f o o d s a r e
p r o c e s s e d , c o o k e d , o r k e p t w a r m .
DEFICIENCY
M
i l d d e f i c i e n c y o f v i t a m i n C m a y r e s u l t
f r o m a s e r i o u s i n j u r y o r s e v e r e b u r n . I t
m a y a l s o o c c u r f r o m u s e o f
o ra l c o n tra -
c e p t iv e s
o r c o n t i n u a l i n h a l a t i o n o f c a r -
b o n
m o n o x i d e ( f r o m
t r a f f i c
f u m e s
o r
t o b a c c o s m
o k e ) , o r a f t e r m a j o r s u r g e r y
o r a f e v e r . I t m a y c a u s e w e a k n e s s , g e n e r -
a l a c h e s , s w o l l e n g u m s , a n d
n o s e b le e d s
.
M
o r e s e r i o u s d e f i c i e n c y i s u s u a l l y d u e
t o a v e r y r e s t r i c t e d d i e t . S e v e r e d e f i c i -
e n c y l e a d s t o
s c u r v y
a n d
a n a e m ia
.
EXCESS
I f t h e d a i l y d o s e o f v i t a m i n C e x c e e d s
a b o u t 1 g , i t m a y c a u s e n a u s e a , s t o m a c h
c r a m p s ,
d i a r r h o e a ,
o r
k i d n e y
s t o n e s
( s e e
c a lc u lu s , u rin a ry tra c t).
v ita m in D
T h e c o l l e c t i v e t e r m f o r a g r o u p o f s u b -
s t a n c e s t h a t h e l p t o r e g u l a t e t h e b a l a n c e
o f
p h o s p h a t e
a n d
c a lc iu m
i n t h e b o d y , a i d
c a l c i u m a b s o r p t i o n i n t h e i n t e s t i n e , a n d
p r o m o t e s t r o n g b o n e s a n d t e e t h .
G o o d s o u r c e s
o f v i t a m i n D i n c l u d e
o i l y f i s h , l i v e r , a n d e g g y o l k ; t h e v i t a m i n
i s a l s o a d d e d t o m a r g a r i n e s . I n t h e b o d y ,
v i t a m i n D i s s y n t h e s i z e d b y t h e a c t i o n
o f
u l t r a v i o l e t
l i g h t
o n
a
p a r t i c u l a r
c h e m i c a l i n t h e s k i n .
DEFICIENCY
D e f i c i e n c y o f v i t a m i n D m a y o c c u r i n
i n d i v i d u a l s w i t h a p o o r d i e t , i n p r e m a -
t u r e
i n f a n t s ,
a n d
i n
t h o s e
w h o
a r e
d e p r i v e d o f s u n l i g h t . I t c a n a l s o r e s u l t
f r o m
m a la b s o rp t io n .
O t h e r c a u s e s i n c l u d e
l i v e r
o r
k i d n e y
d i s o r d e r s
a n d
s o m e
g e n e t i c d e f e c t s . P r o l o n g e d u s e o f c e r t a i n
d r u g s , s u c h a s t h e a n t i c o n v u l s a n t
p h e n y -
to in ,
m a y
a l s o
l e a d
t o
d e f i c i e n c y .
D e f i c i e n c y i n y o u n g c h i l d r e n c a u s e s t h e
b o n e
d i s o r d e r
ric k e t s ;
l o n g - t e r m
d e -
f i c i e n c y i n a d u l t s l e a d s t o
o s t e o m a la c ia
.
EXCESS
E x c e s s i v e i n t a k e o f v i t a m i n D m a y l e a d
t o
h y p e rc a lc a e m ia
( a n a b n o r m a l l y h i g h
l e v e l
o f
c a l c i u m
i n
t h e
b l o o d )
a n d
a b n o r m
a l c a l c i u m d e p o s i t s i n t h e s o f t
t i s s u e s ,
k i d n e y s ,
a n d
b l o o d
v e s s e l
w a l l s . I n c h i l d r e n , i t m a y c a u s e g r o w t h
r e t a r d a t i o n .
v ita m in E
T h e c o l l e c t i v e t e r m f o r a g r o u p o f s u b -
s t a n c e s t h a t a r e e s s e n t i a l f o r n o r m a l c e l l
s t r u c t u r e , f o r m a i n t e n a n c e o f t h e a c t i v i -
t i e s
o f
c e r t a i n
e n z y m e s ,
a n d
f o r
t h e
f o r m a t i o n o f r e d b l o o d c e l l s . V i t a m i n E
a l s o p r o t e c t s t h e l u n g s a n d o t h e r t i s s u e s
f r o m d a m a g e b y p o l l u t a n t s a n d i s b e l -
i e v e d t o s l o w a g e i n g
o f c e l l s . S o u r c e s
i n c l u d e v e g e t a b l e o i l s , n u t s , m e a t , g r e e n
v e g e t a b l e s , c e r e a l s , a n d e g g y o l k .
DEFICIENCY
D i e t a r y d e f i c i e n c y o f v i t a m i n E i s r a r e ;
d e f i c i e n c y i s m o s t c o m
m o n i n p e o p l e
VITAMINS AND MAIN FOOD SOURCES
A varied diet usually provides all the body’s vitamin needs. For vegans (who eat
no fish or animal products, including dairy products), vitamin B12 and vitamin D
may be lacking; these vitamins can be obtained from supplements or, in the case
of vitamin D, through adequate exposure to sunlight.
Fat-soluble
Good sources
Vitamin A
Liver, fish-liver oils; egg yolk, milk and dairy products; margarine,
various fruits and vegetables (such as oranges and carrots)
Vitamin D
Cod-liver oil, oily fish (such as sardines, herring, salmon, and tuna);
liver; egg yolk; margarine
Vitamin E
Vegetable oils (such as corn, soya bean, olive and sunflower oils);
nuts; meat; green, leafy vegetables; cereals; wheat-germ; egg yolk
Vitamin K
Green, leafy vegetables (especially cabbage, broccoli, and turnip
greens); vegetable oils; egg yolk; cheese; pork liver
Water-soluble
Good sources
Thiamine
(vitamin B1)
Wheat-germ; bran; whole-grain or enriched cereals; wholemeal
bread; brown rice; pasta; liver; kidney; pork; fish; beans; nuts; eggs
Riboflavin
(vitamin B2)
Brewer’s yeast; liver; kidney; milk; cheese; eggs; whole grains;
enriched cereals; wheat-germ
Niacin
Liver; lean meat; poultry; fish; nuts; dried beans; enriched cereals;
bread; wheat-germ; potatoes
Pantothenic acid
Liver; heart; kidney; fish; egg yolk; wheat-germ; most vegetables;
most cereals
Pyridoxine
(vitamin B6)
Liver; chicken; pork; fish; whole grains; wheat-germ; bananas;
potatoes; dried beans
Biotin
(vitamin H)
Liver; peanuts; dried beans; egg yolk; mushrooms; bananas;
grapefruit; watermelons
Folic acid
Green, leafy vegetables; mushrooms; liver; nuts; dried beans; peas;
egg yolk; wholemeal bread
Vitamin B12
(cyanocobalamin)
Liver; kidney; chicken; beef; pork; fish; eggs; milk; cheese;
enriched cereals
Vitamin C
Citrus fruits; tomatoes; green leafy vegetables; potatoes; green
peppers; strawberries; blackcurrants
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