NUTRITION UPDATE
Vi amin C and he Common Cold
TERENCE W. ANDERSON, M.D., Ph.D., To on o, On a io
The idea ha an inc eased in ake o i amin C may be
help ul in igh ing he common cold has been a ound since a
leas he 1930's bu i was no un il 1970 ha he publica ion
o Linus Pauling's bes selle , "Vi amin C and he Common
Cold," u ned he issue in o a public con o e sy1, Fo -
una ely, as a esul o he in e es gene a ed by his con-
o e sy, a numbe o scien i ically sound expe imen al
s udies ha e been ca ied ou and al hough he e a e s ill
ques ions ha emain unanswe ed, i is now clea ha
i amin C is, un o una ely, no panacea o colds o o he
espi a o y in ec ions.
Howe e , e en i he p omise o i ual e adica ion o he
common cold (sugges ed as a possibili y a one poin in Linus
Pauling's book) has p o ed o be un ealis ic, he e emains
enough in iguing e idence o some in e ac ion be ween his
i amin and he in ec ious p ocess o sugges ha i is wo h
in es iga ing u he and ha i may ha e a ole, howe e
limi ed, in educing he bu den o his ela i ely i ial bu
annoying a lic ion.
PREVENTION OR TREATMENT?
In ying o un a el some o he con usion and con lic ing
e idence o e he use o i amin C in uppe - espi a o y
in ec ions, i is help ul o ecognize ha i s use has been
sugges ed ei he o p e en he disease om occu ing o o
ea i once i has occu ed. These a e wo qui e di e en
app oaches and ca y wi h hem di e en p ac ical implica-
ions. Thus, i i amin C is o be used p ophylac ically in an
e o o p e en he common cold, no only is one aced wi h
he p oblem o compliance (many people will no be bo h-
e ed wi h aking egula medica ion when ee o symp oms)
bu also wi h an inc eased possibili y o side e ec s since
hese a e mo e likely o occu wi h some hing ha is aken
egula ly o mon hs o yea s han wi h some hing ha is
used only occasionally and b ie ly as a ea men .
Simila ly, wo o he issues o which indi iduals o en lose
sigh in he he o ic a e he ques ions o e ec i e dose and
he basic nu i ional s a us o he popula ion. Thus, i a daily
in ake o 1000 mg o i amin C is ound o p oduce a
bene icial e ec i is impo an o es ablish whe he he same
e ec could be achie ed wi h a much smalle dose since
undesi able side e ec s a e mo e likely om la ge doses han
small ones, Fu he , wha e e size dose is aken, i is only
likely o show an e ec in a popula ion ha has oom o
imp o emen —in o he wo ds, well-nou ished indi iduals
a e likely o be poo expe imen al subjec s o demons a ing
an e ec o supplemen al i amin C.
So a , ew o he expe imen al s udies ha ha e been
ca ied ou ha e shown much change in p e en i e e ec
om he egula in ake o la ge doses o i amin C. E en
whe e he e seems o ha e been some e ec , i is p obably
maximal a in akes p oducing "sa u a ion." In no mal
heal hy subjec s, his is achie ed a abou 100-150 mg o
i amin C daily bu he amoun needed may be conside ably
inc eased by acu e o ch onic illness and a imes o en i on-
men al s ess. Examples o he la e a e ex eme cold and
physical exe ion and i is o in e es ha wo o he ew
posi i e s udies on egula in ake o i amin C ha e in ol ed
people in hese ci cums ances; one in ol ing s uden s a a ski
school in he Swiss moun ains2, he o he in ol ing Canadian
A my oops in A c ic exe cises.3
In ela i ely a luen u ban subjec s, i has been di icul o
demons a e much bene i om he consump ion o g am
quan i ies o i amin C ei he on a p ophylac ic o he a-
peu ic basis. Recen s udies ha e been e iewed by Chalme s4
and Dykes.5
In ou own s udies in To on o, we ound li le e ec om
he pu ely p ophylac ic egimens wi h no e idence o g a-
dien in e ec ac oss he dosage ange o 250, 1000 o 2000
mg pe day,6 Indeed, he only imp essi e di e ences ha we
ha e seen in ou expe imen al g oups ha e been wi h a
combina ion o p ophylac ic and he apeu ic egimens,6,7,8
E en in hese g oups he e was li le o no e idence o an
e ec on he equency o colds, upon hei o al du a ion o
upon local (nasal) symp oms, Ra he , he e ec seemed o be
es ic ed o he se e i y o he cold as measu ed by he
amoun o ime spen o wo k o con ined o he house.
The he apeu ic alue o i amin C in la ge doses has
ecei ed s ong, anecdo al suppo . Fo example, I win
S one has claimed ha o e 95 pe cen o colds can be
abo ed by he p omp adminis a ion o app oxima ely 1,5 g
o i amin C e e y hal hou o h ee o ou doses.9 I
some indi iduals eally ha e expe ienced his so o e-
* Rep in ed wi h pe mission o Con empo a y Nu i ion 3:10 (Oc o-
be ) 1978, a newsle e om he Nu i ion Depa men o Gene al
Mills, Inc. Minneapolis. D , Ande son is P o esso o Epidemiology,
Depa men o P e en i e Medicine and Bios a is ics, Facul y o
Medicine, Uni e si y o To on o, To on o, On a io, Canada.
VOL. 76—NUMBER II—OCTOBER 1979 765
sponse, hen one mus conside he possibili y ha he e is a
subg oup o he popula ion o whom i amin C is e ec i e;
whe eas, o he emainde , i is ela i ely (o comple ely)
ine ec i e since la ge-scale con olled ials ha e been qui e
unimp essi e.10,11
In summa y, one may a emp o econcile he con lic ing
e idence by sugges ing ha inc eased in ake o i amin C on
a egula basis o a he ime o illness may exe a sligh
bene icial e ec , mo e ma ked when he wo egimens a e
combined. The size o he e ec p obably a ies be ween
indi iduals—wi h many being ela i ely insensi i e—and i
also will a y acco ding o basic nu i ional s a us, gene al
s a e o heal h and exposu e o en i onmen al o o he s ess.
MECHANISM
Some in es iga o s ha e concluded ha al hough he e
may be a sligh e ec o i amin C on he common cold, i is
oo small o be o any p ac ical alue and he subjec is,
he e o e, no wo h pu suing. Bu his may be somewha
sho -sigh ed since i is possible ha i we ully unde s ood
he mechanism in ol ed in p oducing e en a sligh e ec , we
migh be able o de elop i u he and p oduce e ec s ha
we e quan i a i ely mo e wo hwhile. As i is, e y li le is
known abou he mechanisms ha migh be in ol ed in
in e ac ions be ween i amin C, he common cold and a
numbe o o he disease p ocesses.12
Some ha e sugges ed ha he e may be a ype o an ibio ic
e ec in which high concen a ions o asco bic acid ha e a
speci ic an i- i al o an i-bac e ial e ec . Human expe i-
men s ha e no len much suppo o his belie al hough i i
we e ue, one would expec o see a ia ion in e ec i eness
depending on he ype o i us o bac e ium causing he
illness and such a ia ion migh help o explain some o he
con lic ing esul s ob ained in i amin C ials.
Ano he possibili y is ha i amin C has a ype o
an ihis amine e ec and al hough he e is some expe imen al
e idence o suppo his iew, in ou s udies we saw li le
e idence o a educ ion in nasal i i a ion o s u iness.
A hi d possibili y and one ha I ind he mos c edible is
ha any e ec o i amin C is ia he hos esis ance o
in ec ion. This would be consis en wi h animal expe imen s
ha ha e shown an imp o ed esis ance o s ess and wi h
ou own expe ience o a educ ion in gene al cons i u ional
symp oms ("malaise"). I would also be consis en wi h he
high concen a ion o i amin C no mally ound in he
ad enal co ex and i s deple ion a imes o s ess,
TOXICITY
The e ha e been i ually no documen ed ins ances o
se ious oxic eac ions o i amin C e en when used in e y
la ge doses. This is no al oge he sup ising since i is a
subs ance essen ial o li e and one o which we and ou
ances o s ha e been exposed o millions o yea s. Howe e ,
i is well o emembe ha none o ou ances o s could
ha e been exposed o he quan i ies ha a e now easily
a ailable as a esul o he p oduc ion o he pu e subs ance
and al hough i is a e y simple molecule (simila o glucose),
i is a s ong educing subs ance, an acid, and is biologically
e y po en . The e o e, i is impo an o be cau ious in i s
use.
The e a e a numbe o di e en ways, in heo y a leas , in
which undesi able e ec s migh occu , Fi s , as an acid, la ge
doses could p ecipi a e acid s ones in he u ine and as a
educing subs ance, i amin C could in e e e wi h some o
he common diabe ic u ine es s. Second, in suscep ible
indi iduals, i could ha e unusual me abolic e ec s (a g ea ly
inc eased ou pu o oxala e is one ha has been iden i ied),
which a e ex emely di icul o de ec since hey may be oo
a e o be ecognized e en in la ge-scale s udies. Thi d, a
po en ially ha m ul eac ion is he wi hd awal e ec on
blood le els when cu ing back a e p olonged in ake o
la ge doses. Blood le els o he asco ba e each a pla eau
("sa u a ion") a an in ake o 100-150 mg pe day and he
in ake o e en se e al housand millig ams a day does no
g ea ly change his pla eau le el. Howe e , i a e a ew
weeks on high in ake he ex a in ake is s opped, blood le els
can d op well below no mal o se e al days. Whe he his
has any physiological signi icance is no known bu i is
possible ha i i occu ed a he same ime as a se ious
illness ( o example, on admission o a hospi al wi h a hea
a ack), i could handicap he body's a emp s o deal wi h
he ex a s ess.
SUMMARY
Ca e ully con olled expe imen al s udies ha e ailed o
suppo claims ha he in ake o la ge doses o i amin C will
p e en o cu e he majo i y o colds. Howe e , an inc eased
egula in ake o a la ge he apeu ic dose a he ime o
illness may ha e a small bene icial e ec and his e ec
appea s o be on se e i y a he han equency o o al
du a ion o colds. The magni ude' o he e ec p obably
a ies be ween indi iduals, in di e en en i onmen s, and
possibly acco ding o he ype o in ec ing agen . The use o
e y high doses o i amin C migh be ha m ul o some
indi iduals, pa icula ly i he in ake is p olonged. Howe e ,
o mos people, a modes inc ease in he egula daily in ake
o b ie episodes o high in ake a e unlikely o cause ha m
and may imp o e esis ance o o he ypes o illness, no only
he common cold,
REFERENCES
1. Pauling L: Vi amin C and he Common Cold, San F ancisco,
WH F eeman, 1970.
2. Ri zel G: Hel Med Ac a 28:63, 1961,
3. Sabis on BH, Radomski MW: D.C.I.E.M. Repo No 74-R
1012. De ence Resea ch Boa d, Canada, 1974.
4. Chalme s TC; Am J Med 58:532, 1975.
5. Dykes MHM, Meie P: JAMA 231:1073, 1975.
6. Ande son TW, Su anyi G, Bea on GH: Can Med Assoc J
111: 31, 1974.
7. Ande son TW, Reid DBW, Bea on OH: Can Med Assoc J
107: 503, 1972.
8. Ande son TW, Bea on GH, Co ey PN, Spe o L: Can Med
Assoc J 112: 828, 1975.
9. S one I: Ni(i iiinn Today 10:3:35, 1975,
10, Elwood PC, Hughes SJ, S Ledge AS: P ac i ione 218:133,
1977.
11, Ty ell DAJ, C aig JW, Meade TW, Whi e T: B J P e Soc
Med 31:189, 1977.
12, Ande son TW: Nu i ion Toda 12:1:6, 1977.
766 THE JOURNAL OF THE MEDICAL SOCIETY OF NEW JERSEY
