Hl#L
H
#
+rtfr*'!'
ffiffiffi@@ffiffiffi
f#fibft F
^SrlEtFz'
E
H!
E E
H
E
Wr
H.,
,t
FFb{
Z*fi
{Ufr
C€
Ft
*r€lAffi
,
tlfrhZ/#+tuftA€*&*=
,
ftR2/,#fb-'^p'a
€FtmTffi,F
'
frAZf#fufr
c
€*teEmffi
, f&.2!#fb''^p'o
€4t'l€'fg,F#
; lEfr*-tE
iEEffi
.
EfffiX.r€#.
aE{gtl+gfA(il{FfiH,(FF+r&EF}E
' ?64+n5
lLAn
,
,iHE
F-fiE#H*
' Ejf,'EgttlHinratrIE+,8trHlE*EiE
E
"
tr
tL,
ffi
fi:--JJ.H
IEI+
,A
E
H
T
Hffi h
#E'tUtrp
51 *ln
F"lZHrl'
T
Ei
F-5
gt
3A
-'br
ffi
h f#Itufrfinfi
'f
b
Fll
f!
ffi
ft
E|J'{F
E
"
gil#.
ilr
Liu Zhi-Shan
BEWARE
OFTHETOXIC
EFFECTS
OF
VITAMINS
Vitamins are essential for health.
Small quantities required are already
in
the
normal
well-balanced diet.
ln fact,
excessive doses of some fat-soluble
vitamins, e.9., vitamin A and
D, are
harmful. However, as vitamin C
is
eas-
ily
destroyed by heat and
cooking,
inadequate
fresh fruits and
salads
require supplements.
Nevertheless,
much controversy exists about vitamins
because some of them are useful
as
anti-oxidants,
not
just
their
funclion
as
vitamin. Vitamin E
is
a
fat-soluble
vitamin with antioxidant properties.
A
hypothesis
is
that
it
slows the progres-
sion
of
atherosclerosis.
Basic science
and animal studies generally supported
this hypothesis but clinical trials,
e.9.,
the Cambridge
Heart
Antioxidant
Study,
showed mixed results. The current
recommended dietary allowance (RDA)
tor
vitamin
C
for
adult non-smoking sub-
lects
is only
60
mg/day
with
reference
to
the prevention
of
scurvy
(or
"rickets").
However, recent scientific
evidence
showed higher doses are associated
with a reduced
risk
of cancer, cardio-
vascular diseases and
cataract,
probably
through
its
anti-oxidant
mechanisms. Currently,
an
intake of
around 120 mg/day is deemed more
appropriate
for
chronic disease preven-
tion
(rather than
just
scurvy).
Beta-
carotene, a precursor of vitamin
A,
is
partially converted to vitamin A
in
the
body.
Although beta-carotene itself has
no
toxic
effects,
the skin and
even
the
eyes stain
a
characteristic yellow color.
#ffiLft
E
E
-
fExF
{d'l+fr\
f,#
fifi.ft
' EftH
EfrtNWEIE"+'J
H'8,:
.
A
EVW-IlYfiJ
H
8
ts"'
zs"t"
E
E
,
{lE++,J
fIHtrPi€ruAUAIEf,N.
ffil\.iqj-'.
"
k9tfi,ft
E
HlnFtr
H lH
E
94?flffi.flfrELLF+'1fi
'
)LHftEft
ffifrHffi,.
ETfrflJLtA
"
X.EIs/rlr#IM
ftEul*M'tre.ffi+#tfr
"
ZK1Efr
NH
z
tFff
t
nr.H!€'Eaf
frHtR
ffi
ry',?^9fifi,ft
E
tP.H
ffi.EfrtJfl'l+
€,l4fnFIE614
"
-Laff
/\ffizJr
4
.
rg.Wft
Bt
ffi
,t4 *,{,Eff
tu
e
€
1r
"
-=,t,Eft
+Xffi ,F lE
F!
ruAtlfl A|lE
(-f&
roo
-
32oo
WWHft,/X.)
*18fr.W
ffih+rB\
rc.
H
"
Itr".Elhft
E
6EH+fr+'/*+ffr+hW.lFH
,
&
H
+&.€---#'
H
W
#
Z,A9tfi;fr:t'
r
F!
^,
f,#l&ft
E
A?,W_rfi.H
tht
fr.h
6E'
ffi
+Tffi
fi.?,,gttu
ftK(
B|J,fEEH
AIEH!)
ffiWE
"
,{E,fd-ft's&6E€
iE
-
fE
+i
ir
4,
t[.t$,fr\&&
L
frtr
fru.
"
h
+E
a\
+fi
+
Hflft
H?,#ifi,ft
E
€JBfu H.fi
,L.A
A,{J
X[ft
FA
"
lE
f,f
'
-IF/(*F,tHEt
ffi
t+-=,{,ffi
+R
E
,
EF,H?,#'f&-ft'e
@lflnBf-ftfr\
fitr
fi frr&-g
.
80
+,ft
+tr
1fr"1-?#
HrrEf'Jfr
rnq.fiElfi,ftE
,
1ft48m
€trJ
?
I
Tgffi
E
H!
ETiE,ITET€f4
"
HH
E'fEtt
r
5oo
H
H!
+f
Hrf,
ffi
Xfrii
s'Jfi
n
EE*E.fe-ft
F'tr{F#+,&n'W
ffitrWff"Mh.
"
rtLtl
,
6Ifne,E<:-n!.,
tr'tt
frEfifrJ(9lr*H&fs
'/\ff&
,r,
ffi D)^ftE4Ffr.,l-El+€,1+
"
F
66
