Dai y p oduc s and heal h: a e iew o he epidemiological e idence
E a-Elisa A
´l a ez-Leo
´n
1
, Blanca Roma
´n-Vin
˜as
2
and Lluı
´s Se a-Majem
1,2,3
*
1
P e en i e Medicine Se ice, Complejo Hospi ala io Ma e no-Insula , Las Palmas de G an Cana ia, Spain
2
Communi y Nu i ion Resea ch Cen e, Scien i ic Pa k o Ba celona, Spain
3
Depa amen o de Ciencias Clı
´nicas, Uni e sidad de Las Palmas de G an Cana ia, Ap o. Co eos 550, E-35080 Las Palmas de
G an Cana ia, Spain
E idence-based nu i ion is essen ial o mo e o wa d in he science o communi y nu i ion. The p esen s udy is a e iew o he epidemiological
e idence o dai y p oduc s and heal h. The e is an in e se associa ion be ween he in ake o dai y p oduc s and hype ension, s oke and colo ec al
cance . The e is no e idence o an associa ion be ween he consump ion o dai y p oduc s and b eas cance . The e is some e idence linking high-
a dai y p oduc s and an inc emen al isk o p os a e cance and weak e idence o he p o ec i e capaci y o dai y p oduc s on bone heal h. Mo e
p ospec i e s udies should be de eloped in o de o es ablish be e e idence o he ela ionship be ween dai y p oduc s and heal h. Due o he
impo ance o dai y p oduc s in public heal h nu i ion, quan i a i e ecommenda ions should be es ablished in he ligh o he scien i ic e idence.
Dai y p oduc s: Public heal h: Re iew li e a u e
Public heal h nu i ion should no be unawa e o he impo -
ance o e idence-based medicine. Sys ema ic e iews o he
epidemiological e idence and he c i ical analyses o ha
e idence ha e esul ed in a huge ad ance in he de elopmen
o p o ocols and guides o clinical p ac ice. E idence-based
medicine has esul ed in mo e app op ia e ac ions o sol e
e e yday clinical p oblems, based on he c i ical e alua ion
o such e idence, ins ead o in ui ion o expe ience.
To de elop public heal h nu i ion policies based on scien-
i ic e idence, i is impo an o igh agains misin o ma ion o
he gene al popula ion abou nu i ional aspec s o hei daily
ood in ake. F equen ly, he bene i s and isks a e pu down o
dai y p oduc s on he basis o physiopa hological heo ies, bu
wi h no epidemiological s udies o suppo hem.
The objec i e o he p esen wo k is o e iew pape s co e -
ing dai y p oduc s in bo h heal h p omo ion and disease p e-
en ion. Focus is placed on he c i ical analysis o he
scien i ic li e a u e, poin ing ou u u e needs in he esea ch
o e idence be ween dai y p oduc s and heal h.
Me hods
Rele an a icles we e ob ained h ough sea ching he MED-
LINE da abase ( om 1966 o Janua y 2005). Keywo ds used
in his sea ch we e he MeSH e m ‘dai y p oduc s’, de ined as
‘ aw and p ocessed o manu ac u ed milk and milk-de i ed p o-
duc s’ ha included he ollowing p oduc s: bu e , cheese, ice
c eam, ma ga ine, milk and cul u ed milk p oduc s (yoghu )
and some heal h condi ions. The selec ion o heal h condi ions
was ca ied ou on he basis o hei public heal h impo ance
(p e alence and/o se e i y) and included neoplasms, CVD
(myoca dial in a c ion, hype ension o ce eb o ascula acci-
den ), and os eopo osis o bones. The MEDLINE sea ch was
complemen ed wi h he au oma ic PubMed clinical que ies s a -
egy, which combined ‘dai y p oduc s’ sea ch wi h ci a ions
iden i ied as sys ema ic e iews, me a-analyses, e iews o
clinical ials, e idence-based medicine, consensus de elop-
men con e ences and guidelines. Ci a ions om jou nals spe-
cializing in clinical e iew s udies we e also included. To be
eligible, wo ks had o ul il he ollowing c i e ia: abs ac
mus be a ailable, be w i en in Spanish, English o F ench
and co e human popula ion. P io i y was gi en o me a-anal-
ysis and sys ema ic e iews.
E idence om epidemiological s udies o dai y p oduc s
and heal h was summa ized. To e alua e he s eng h o he
e idence, alidi y and accu acy we e aken in o accoun .
Validi y was assessed by analysing he p esence o possible
sys ema ic bias in he design o execu ion o he s udies. Accu-
acy was assessed by conside ing he size o he sample and
he wideness o he con idence in e als.
Resul s
The e we e mo e han 85 000 a icles on he consump ion o
dai y p oduc s. Once he inclusion c i e ia we e applied, ou -
een me a-analyses o sys ema ic e iews abou dai y p oduc s
and he selec ed heal h condi ions we e iden i ied, six on
cance , six on CVD and wo abou bone heal h. The esul s
a e p esen ed sepa a ely by heal h condi ion.
*Co esponding au ho : P o esso Lluı
´s Se a-Majem, ax þ34 928 453475, email [email p o ec ed]
Abb e ia ions: DASH, Die a y App oach o S op Hype ension; DBP, dias olic blood p essu e; OR, odds a io; RR, ela i e isk; SBP, sys olic blood p essu e.
B i ish Jou nal o Nu i ion (2006), 96, Suppl. 1, S94–S99 DOI: 10.1079/BJN20061709
qThe Au ho s 2006
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Dai y p oduc s and cance
The e we e six me a-analyses and one sys ema ic e iew ha
speci ically analysed he consump ion o dai y p oduc s and
cance isk (one o colo ec al cance , h ee o b eas cance
and h ee o p os a e cance ).
Colo ec al cance
One o he a icles analysed he isk o colo ec al cance . I was a
pooled analysis o en coho s udies ca ied ou by Cho e al.
(2004) as a pa o he Pooling P ojec o P ospec i e S udies o
Die and Cance . This pooling p ojec accumula es da a om sub-
jec s who had pa icipa ed in di e en p ospec i e s udies wo ld-
wide. Once amassed, he da a we e eanalysed, which esul ed in a
bigge sample size and longe ollow-up pe iod han hose o he
o iginal s udy alone. To da e, h ee pooled analyses ha e
been published o his pooling p ojec : a in ake and b eas
cance ; alcohol in ake and colo ec al cance ; and mo e ecen ly,
dai y oods and Ca and colo ec al cance .
Fo he pooled analysis o dai y p oduc s and Ca and colo -
ec al cance (Cho e al. 2004), en p ospec i e s udies we e
iden i ied. S udies had o mee p ede ined c i e ia: assessmen
o die a y in ake by a alida ed me hod, and a leas i y
people diagnosed wi h colo ec al cance . Finally, 534 536
men and women we e included, wi h a ollow-up pe iod ha
anged om 6 o 16 yea s. In ha pe iod 4992 inciden
cases o colo ec al cance we e documen ed.
In ela ion o consump ion, esea che s ook in o accoun
di e en g oups o dai y oods: milk (including skimmed,
low- a , medium- a , whole, e apo a ed and bu e milk),
cheese (including high- a , ha d, co age and ico a) and
yoghu (including low- a , egula yoghu and yoghu
d essing). They also conside ed in akes o Ca om he die
(and om supplemen s when a ailable) ca ego ized in deciles.
O he a iables associa ed wi h colo ec al cance isk we e
also conside ed. Resul s we e adjus ed o heal h- ela ed
a iables BMI, heigh , amily his o y o colo ec al cance , use
o non-s e oidal an i-in lamma o y d ugs and use o mul i i a-
mins), li e-s yle a iables (smoking, educa ion, physical
ac i i y, alcohol in ake) and die a y a iables (in akes o o al
ene gy, ed mea and die a y ola es). In women, o al con acep-
i es and pos menopausal ho mone use we e also conside ed.
O iginal s udies p o iding subjec s o he pooling p ojec
came om he USA, Canada and no h Eu opean coun ies
(Holland and Sweden). This geog aphical a iabili y ga e
he p ojec a wide ange o in a-indi idual a ia ion in he
consump ion o dai y p oduc s. Mean in ake o milk anged
om 137 o 687 g/d, mean in ake o yoghu anged om 11
o 104 g/d, and mean in ake o cheese anged om 8 o
27 g/d. Die a y Ca in akes anged om 674 o 1051 mg/d.
Milk consump ion was in e sely ela ed o colo ec al
cance . Compa ed wi h pa icipan s who consumed less han
70 g o milk daily, he ela i e isk (RR) o colo ec al
cance was 0·85 (95 % CI 0·78, 0·94) o hose who consumed
250 g/d o mo e, as shown in Fig. 1. In o he wo ds, people
who consumed less han a qua e o a glass o milk e e y
day had 15 % mo e isk o colo ec al cance han hose who
consumed $1 glass o milk a day. The associa ion be ween
milk consump ion and educed isk o colo ec al cance was
limi ed o cance o he dis al colon and ec um.
Cheese in ake was analysed in wo ways. Subjec s who
consumed $25 g o co age o ico a cheese daily had a RR o
0·83 (95 % CI 0·72, 0·96) o colo ec al cance , compa ed wi h
hose who did no consume co age o ico a cheese. Consump-
ion o o he kinds o cheese – excluding co age and ico a –
was weakly posi i ely associa ed wi h colo ec al cance , al hough
con idence in e als we e no signi ican o any o he di e en
ca ego ies no was he es o end be ween ca ego ies.
Yoghu in ake showed a weakly p o ec i e p ope y o e
colo ec al cance , al hough CI and es o ends we e again
no signi ican . O he e men ed dai y p oduc s (including
yoghu , bu e milk and sou c eam) showed simila esul s o
hose o yoghu . The o he dai y p oduc s measu ed, including
bu e , c eam and ice c eams, we e analysed, bu he e was no
s a is ical signi icance wi h ela ion o colo ec al cance isk.
As shown in Fig. 1, a high in ake o Ca was also associa ed
wi h a lowe isk o colo ec al cance . Subjec s in he highes
quin ile o die a y Ca in ake had RR o 0·86 (95 % CI 0·78,
0·95) o colo ec al cance , compa ed wi h subjec s in he
lowes quin ile. Fo o al Ca (combining die a y and sup-
plemen al sou ces), he RR o he highes quin ile was 0·78
(95 % CI 0·69, 0·88).
In conclusion, milk and Ca in ake we e associa ed wi h a
lowe isk o colo ec al cance . One o he s eng hs o he
pooled analysis p esen ed he e is ha all s udies included
we e p ospec i e, a oiding he bias associa ed wi h he di e -
en ecall o die a y habi s once a subjec knows he diagnosis
o a diges i e cance . Ano he s eng h is ha all s udies used
alida ed die assessmen me hods, minimizing he possibili y
o an inco ec egis a ion o he ac ual in ake o dai y p o-
duc s. Finally, he analysis o a da abase o mo e han
500 000 subjec s om di e en coun ies ga e su icien s a -
is ical powe o analyse speci ic dai y p oduc s ca ego ies.
Howe e , i is ema kable ha he au ho s did no adjus o
some die a y a iables ela ed wi h colo ec al cance , such
as ib e o ui and ege ables. Al hough he au ho s men-
ioned ha addi ional adjus men o die a y ib e in ake did
no ma e ially change he esul s o o al Ca in ake, i could
be ele an o adjus o hose die a y a iables, aking in o
accoun ha consume s wi h a highe consump ion o dai y
Fig. 1. Rela i e isk (RR) o di e en diseases o dai y p oduc s in ake. (1)
RR o subjec s who consumed $250 g milk daily compa ed wi h pa icipan s
who consumed ,70 g/d (Cho e al. 2004). (2) RR o subjec s who con-
sumed $25 g co age o ico a cheese daily compa ed wi h hose who did
no consume ha kind o cheese (Cho e al. 2004). (3) RR o e e y 100 g
liquid dai y p oduc s consumed daily (Missme e al. 2002). (4) Odds o high-
es . lowes milk consump ion ca ego ies (Qin e al. 2004). (5, 6) Rela i e
odds o highes . lowes milk consump ion ca ego ies (Elwood e al. 2004).
Dai y p oduc s and heal h: e iew o e idence S95
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p oduc s could ha e o he heal hy die a y habi s, such as a die
ich in ui , ege ables and ib e.
B eas cance
In he p esence o g owing e idence abou he impo ance o he
en i onmen in he isk o b eas cance , many s udies analysing
he die a y ac o s in his isk ha e been unde aken. Among
hese die a y ac o s, dai y p oduc s we e he main a iable
analysed in mo e han wen y a icles. Howe e , esul s we e
con adic o y. Wi h he pu pose o ge ing b oade e idence,
some 10 yea s ago a Canadian eam o esea che s published
he i s me a-analysis o combine he esul s o i e coho and
wel e case–con ol s udies abou dai y p oduc consump ion
and b eas cance isk (Boyd e al. 1993). This me a-analysis
ound a small inc eased isk o b eas cance in women wi h
g ea e in akes o milk, wi h RR o 1·17 (95 % CI 1·04, 1·30).
Since his wo k was published, mo e s udies ha e been unde -
aken wi h di e en esul s. Almos 10 yea s la e , in 2002 and
o ming pa o he Pooling P ojec , a pooled analysis o eigh
coho s udies was published by Missme e al. (2002). Fo his
pooled analysis, eigh p ospec i e s udies wi h a leas 200
cases o b eas cance each we e included, b inging a o al o
351041 heal hy women and 7379 in asi e b eas cance cases.
The inclusion c i e ia we e simila o hose men ioned o he col-
o ec al cance pooled analysis. Wi h espec o dai y p oduc s,
di e en ood g oups we e conside ed. Dai y p oduc s we e
di ided in o solid (bu e and cheese) o liquid (milk, yoghu ,
ice c eam, e c.). Subg oups we e also conside ed (whole, semi-
skimmed o skimmed milk). Thus, en di e en subg oups o
dai y p oduc s we e conside ed. Dai y p oduc in ake was ana-
lysed as a con inuous a iable (wi h inc emen s o 100 g daily
o all p oduc s excep bu e and c eam, and 10 g o he la e )
and as ca ego ical a iable compa ing highe . lowe qua iles
o in ake. O he die a y and non-die a y ac o s associa ed wi h
b eas cance we e also conside ed, like o al ene gy o alcohol
in ake, pa i y, menopausal s a us and BMI.
Simila o he da a men ioned in he colo ec al cance pooling
p ojec , he geog aphical a iabili y achie ed he e pe mi ed a
wide ange o in a-indi idual a ia ion in dai y p oduc con-
sump ion. In ha way, women in he ou h qua ile o liquid
dai y p oduc s consumed almos 630 g o his kind o dai y
p oduc e e y day, whe eas women in he i s qua ile consumed
360 g.
As shown in Fig. 1, esea che s did no ind any ela ionship
be ween dai y p oduc in ake and b eas cance isk, nei he
ea ing dai y p oduc s as a con inuous a iable no ea ing
i as a ca ego ical one. They did no ind s a is ically signi i-
can associa ions in any o he en subg oups o dai y p oduc s
conside ed, ei he . They concluded ha , aking in o accoun
da a o mo e han 350 000 women, he e was no e idence
ha a die ich in dai y p oduc s du ing middle o ad anced
age could inc ease o modi y he isk o b eas cance in
No h Ame ican o Eu opean women.
In a simila way, Moo man & Te y (2004) in hei ecen
e iew abou consump ion o dai y p oduc s and isk o
b eas cance concluded ha published epidemiological da a
do no p o ide consis en e idence o an associa ion be ween
he consump ion o dai y p oduc s and b eas cance isk.
They men ioned some limi a ions ha mus be conside ed.
One is he mode a e eliabili y o he me hods used o assess
dai y p oduc in ake, which could lead o some misclassi i-
ca ion. This misclassi ica ion could make i mo e di icul o
de ec he ela i ely small e ec s o mos die a y ac o s on
cance isk, which is especially impo an in p ospec i e
s udies, whe e he in ake o dai y p oduc s could change
g ea ly o e he long ollow-up pe iod.
O he limi a ions men ioned by au ho s is ha consump ion
o dai y p oduc s may be associa ed wi h o he die a y habi s
o o he a iable nu ien con en o dai y p oduc s (such as
i amin D, subjec o whe he he ood is o i ied o no )
ha could also in luence b eas cance isk. All hese ac o s
should be conside ed in he adjus ed model.
P os a e cance
P os a e cance is he mos p e alen cance in men in Eu ope and
he USA (Quinn & Babb, 2002; Jemal e al. 2005). I is no known
which ac o s induce his cance and which agen leads o la en
p os a e umou s – whose incidence is e y high in men wo ld-
wide – p og essing o a clinically de ec able p os a e cance ,
he incidence o which, by con as , shows a high a ia ion in
di e en geog aphical a eas. The e a e di e en isk ac o s p o-
posed ha included ho monal ac o s, amilial an eceden s and
die a y a iables. Among die a y a iables, a consump ion
was o g ea in e es because animal s udies sugges ed ha a
in ake, in combina ion wi h o he die a y a iables, could inc ease
umou g ow h. Dai y p oduc in ake was conside ed in h ee
di e en e iews all published in 2004.
In Canada, Fleshne e al. (2004) e iewed a icles pub-
lished o e he las wo decades looking a he ela ionship
be ween p os a e cance and a in ake ( o al a in ake o a
in speci ic oods like dai y p oduc s). They analysed se en
coho s udies, including mo e han 180 000 subjec s, and
only one showed a s a is ically signi ican associa ion, once
adjus ed; he o he six ound no associa ion. The Heal h P o-
essionals Follow-Up S udy obse ed ha subjec s wi h
highe in akes o dai y p oduc s had wice he isk o me a-
s a ic p os a e cance han subjec s wi h low in ake, bu he
au ho s men ioned ha mos o he excess isk could be
explained by known nu i ional componen s o hese oods
(Ca and a y acids). The Ne he lands coho s udy showed a
posi i e end in p os a e cance isk o consump ion o
milk p oduc s (P¼0·02), bu no o Ca in ake.
A me a-analysis o ele en case–con ol s udies compa ing
incidence o p os a e cance in highe . lowe consume s o
milk was published by Qin e al. (2004). The combined es ima ed
odds a io (OR) was 1·68 (95 % CI 1·34, 2·12), sligh ly smalle
when adjus ed o some a iables: 1·56 (95 % CI 1·30, 1·83;
Fig. 1). In he discussion, he au ho s men ioned ha eigh s udies
used hospi al-based con ols, which a e mo e p one o bias han
popula ion-based con ols. Also, milk consump ion was di icul
o classi y because o he ambigui y o ood i ems used in some
ques ionnai es. They declined o make a me a-analysis o
coho s udies because all we e de eloped in Ame ica and no h-
e n Eu ope, whe e he high le els o consump ion o dai y p o-
duc s would make i di icul o ind a g oup ee om dai y
p oduc consump ion. Ano he di icul y men ioned o he
inclusion o coho s udies in he me a-analysis was ha in hese
s udies he endpoin was no always he same.
Finally, in 2004, Dagnelie e al. e iewed p ospec i e coho
and in e en ion s udies o analyse he e ec ha
E.-E. A
´l a ez-Leo
´ne al.S96
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indi idual oods and nu ien s had on p os a e cance . The
au ho s excluded case–con ol s udies due o he inconclusi e
esul s ob ained and o he g ea e possibili y o selec ion and
in o ma ion bias. They iden i ied wen y-se en s udies ha ana-
lysed ela ionship be ween milk and dai y p oduc consump ion
and p os a e cance isk. Resul s we e equally dis ibu ed
be ween a posi i e associa ion ( hi een epo ed) and a null
esul ( ou een epo ed). Howe e , only i e o hese p ospec-
i e s udies men ioned ha he die a y ques ionnai e used was
alida ed. O hese i e s udies, wo had s a is ically signi ican
esul s. The Heal h P o essionals Follow-Up S udy showed an
inc eased isk o p os a e cance o di e en dai y p oduc s.
The RR o highe qua iles o in ake . lowe qua iles anged
om 1·06 o co age/ ico a cheese o 1·25 o milk (bo h
whole and skimmed o low- a ) and o 1·42 o bu e . A No we-
gian s udy o mo e han 25 000 men showed ha men consuming
skimmed milk had an RR o 2·2 (95 % CI 1·3, 3·7) o p os a e
cance compa ed wi h men consuming whole milk. The o he
h ee s udies ound no signi ican associa ion be ween dai y p o-
duc in ake and p os a e cance isk. Based on hese esul s, one
o he conclusions men ioned by he au ho s is ha he a ailable
e idence o speci ic dai y p oduc s emains limi ed o inconclu-
si e, which p e en s i m conclusions on ha ood p oduc . One
impo an limi a ion men ioned is ha s udies used incidence,
mo ali y, o bo h, as an endpoin . In ae iological s udies, inci-
dence is mo e app op ia e because mo ali y could be de e -
mined by o he non-die a y a iables (such as ea men ).
A me a-analysis de eloped wi h coho s udies o e en an
in e en ion s udy would cla i y he ela ionship be ween
o al a in ake and p os a e cance in o de o es ablish
public heal h ecommenda ions.
Dai y p oduc s and os eopo osis/bone heal h
The e ha e been wo me a-analyses o e iew a icles on bone
heal h and dai y p oduc in ake, he mos ecen one by
Weinsie and K umdieck published in 2000. They ound
wel e a icles wi h he highes le el o e idence, i.e. a an-
domized ial wi h a con ol g oup o coho s udies wi h
$3000 pa icipan s and an a e age ollow-up pe iod o 5
yea s and esul s adjus ed by mo e han h ee ac o s, such
as age, sex, BMI, physical ac i i y, menopausal s a us and/o
subs i u i e ho monal he apy. The au ho s did no de elop a
me a-analysis o hese s udies, and conclusions we e based
on he compa ison o he amoun o s udies wi h posi i e,
nega i e o non-de ini i e esul s. Among he wel e a icles,
he e we e six ha ound no e ec be ween he in ake o
dai y p oduc s and bone heal h, i e ound a posi i e e ec
and one ound a nega i e e ec . Women unde 30 yea s
seem o gain he mos bene i . Al hough s udies which ana-
lysed he composi ion o dai y p oduc s a e sca ce, milk
seems o be he mos p o ec i e. The au ho s men ioned limi-
a ions o he wo k published up o ha momen , bo h in me h-
odology and sample size. These limi a ions make i di icul o
ob ain conclusions and i m e idence abou he e ec s o dai y
p oduc consump ion on bone heal h. I is impo an o men-
ion ha some esul s a e s a is ically signi ican bu clinically
o li le ele ance because Ca in ake could be esponsible o
only 1 % o he in e -indi idual a iabili y in bone mass.
Ano he di icul y is ha wha is impo an o he le el o
densi y o he bone sys em is no he p esen dai y in ake,
bu he habi ual in ake h oughou li e. In addi ion, as a u he
limi a ion men ioned by o he au ho s, a icles mus ake in o
accoun he p esence o o he die a y and li e-s yle a iables
ha could in luence bone heal h, such as ui in ake, soda
be e ages, physical ac i i y, smoking and alcohol in ake.
In 1997, Cumming and Ne i published a sys ema ic
e iew o assess he e ec i eness o Ca (as supplemen s o
om die a y sou ces) o he p e en ion o os eopo o ic ac-
u es in pos menopausal women. This wo k was mo e
es ic ed han he p e ious one because only s udies wi h ac-
u e ou come we e eligible. They ound ou een s udies ha
e alua ed Ca supplemen s ( ou andomized ials, h ee non-
andomized ials and se en obse a ional epidemiological
s udies) and wen y- h ee obse a ional s udies ha e alua ed
die a y Ca (non- andomized ials). All ou andomized ials
epo ed a educed isk among women ecei ing Ca sup-
plemen s. The educ ion in ac u e isk anged om 26 o
70 %, wi h a mean Ca dose o 1050 mg/d. The au ho s men-
ioned some limi a ions; in one ial subjec s we e aking Ca
and i amin D
3
a he same ime, and in o he s he de ini ion
o ac u e di e ed ( adiological educ ion in e eb al body
weigh ; a io o an e io o pos e io e eb al body heigh ;
o symp oma ic ac u es o w is and hands). The au ho s
could use he me a-analysis me hod o analyse esul s o six-
een o he obse a ional s udies ha e alua ed he e ec o
die a y Ca, al hough among hese s udies indi idual indings
we e no consis en because o he he e ogenei y. Pooling
he esul s o hese six een s udies, au ho s eached an OR
o hip ac u e o 0·96 (95 % CI 0·93, 0·99) pe 300 mg/d
inc ease in die a y Ca and 0·88 (95 % CI 0·80, 0·97) pe
1000 mg/d. 300 mg is equi alen o one glass o milk daily
and 1000 mg is he amoun in a ypical Ca supplemen .
I hey es ic ed analysis o he i e coho s udies, he
pooled OR o 300 mg/d was also 0·96, bu he 95 % CI was
no longe signi ican ( om 0·91 o 1·02). The main conclusion
emphasized by he au ho s was ha inc eased Ca in ake
among pos menopausal women appea ed o be associa ed
wi h a small educ ion in isk o ac u e, wi h abou a 30 %
educ ion in ac u e isk among hose aking highe amoun s
o Ca (1 g daily as a supplemen ). The au ho s men ioned ha
s a is ical pooling o esul s does no emo e any scien i ic
bias in he pooled s udies, and men ioned he need o de elop
la ge s udies wi h symp oma ic ac u es as he ou come.
Dai y p oduc s and ca dio ascula diseases
CVD is a b oad g oup ha emb aces hea diseases (including
co ona y diseases and myoca dial in a c ion) and ascula
diseases (including hype ension and ce eb o ascula acciden
o s oke). The e ha e been almos 100 sys ema ic e iews
in ol ing CVD and dai y p oduc s, be ween o he die a y
and non-die a y a iables. Howe e , only six we e mo e
speci ically o ien ed o he in ake o dai y p oduc s.
Dai y p oduc s and hype ension
Hype ension is a majo isk ac o o CHD and s oke, wi h
a high p e alence in Eu ope. A wide e iew published in
a supplemen o he B i ish Jou nal o Nu i ion by He mansen
(2000) demons a ed ha he p e en ion and managemen o
hype ension – a indi idual and a popula ion le el – should
Dai y p oduc s and heal h: e iew o e idence S97
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be a p io i y o public heal h au ho i ies. One essen ial s ep o
achie e his objec i e by he leas in usi e means is die a y
modi ica ion. The e iew ied o explain ha he e idence
was ha die a y modi ica ions in luence he p opensi y o
de elop hype ension. I was poin ed ou ha he e was no
di ec e idence ha educing blood p essu e h ough die a y
measu es educes he isk o CVD. In his e iew die a y modi-
ica ion was e-examined. Two me a-analyses pooled da a om
andomized con olled ials o assess he e ec s o die a y Ca
supplemen a ion on blood p essu e (He mansen, 2000). Bo h
showed a change in sys olic blood p essu e (SBP) be ween
20·5 and 21·7 mmHg (highe educ ion in hype ensi e sub-
jec s), bu dias olic blood p essu e (DBP) was no a ec ed.
One poin men ioned in he e iew is ha , wi h he excep ion
o alcohol consump ion, he e we e no clinical in e en ion
s udies abou he ela ionship be ween mac onu ien in ake
and blood p essu e egula ion. They men ioned one inhe en
p oblem in s udying he e ec o a change in a speci ic mac onu-
ien . In o de o main ain o al ene gy in ake, subjec s mus
simul aneously change he in ake o o he mac onu ien s and
he genuine cause o he heal h ou come could, he e o e,
emain unce ain. Besides changes in one mic o- o mac onu i-
en , changes in o e all die a y pa e n may be o g ea alue. The
Die a y App oach o S op Hype ension (DASH) s udy was
speci ically men ioned in he e iew. The DASH s udy is a suc-
cess ul andomized con olled clinical ial ha s a ed in 1995
and has shown ha a die ich in low- a dai y p oduc s, ui s
and ege ables could lowe blood p essu e le els. The in e en-
ion consis ed o ollowing a ‘combina ion die ’ o 3 weeks. I
was ich in ui and ege ables ( en se ings daily) and ich in
low- a dai y p oduc s ( h ee se ings daily in ol ing 360 ml
skimmed o semi-skimmed milk, 86 g yoghu and 39 g
cheese). This combina ion die achie ed a educ ion in blood
p essu e in 2 weeks, sugges ing ha complex die a y
changes may ha e g ea e e ec s on blood p essu e han
single-nu ien modi ica ion. In he conclusions, he au ho men-
ioned ha li e-s yle changes p oposed o main ain
adequa e blood p essu e con ol migh ha e a wide ange o
addi ional bene icial e ec s, which is no ue o mos
an ihype ensi e d ugs.
In 2003, a e iew ha summa ized he esul s o he DASH
die was published by C addick e al. Th ee o ou daily se -
ings o dai y p oduc s could diminish SBP in hype ensi e
and non-hype ensi e subjec s by 22·7 mmHg (97·5 % CI
24·6, 20·9) and DBP by 21·9 mmHg (97·5 % CI 23·3,
20·6), compa ed wi h a die ich in ui s and ege ables
bu low in dai y p oduc s. On his basis, he au ho s ec-
ommended ha subjec s wi h blood p essu e o $120/
80 mmHg ollow heal hy li e-s yle habi s, such as main aining
heal hy weigh , educing Na in ake, inc easing egula physi-
cal ac i i y, limi ing alcohol in ake and should ollow he
DASH die , which is high in ui s, ege ables and low- a
dai y p oduc s and educed in a . This die has been shown
o educe blood p essu e signi ican ly and also has been
shown o educe blood choles e ol and homocys eine le els
and o enhance he bene i s o an ihype ensi e d ug he apy.
Ano he e iew published by Mille e al. (2000) wen o e he
DASH s udy his o y and also made a e ision o he p io e i-
dence o obse a ional s udies poin ed ou in he li e a u e
abou die a y Ca in ake and hype ension. Cappuccio e al.ina
me a-analysis ha was e ised by Bi ke 3 yea s la e ,
summa ized he obse a ional s udies in 1995. This me a-analysis
es ima ed a pooled educ ion o 20·39 mmHg (wi h a ange o
20·47 o 20·31) in SBP, and o 20·21 mmHg ( ange 0·67 o
20·02) in DBP, pe 100 mg die a y Ca inc ease. A he same
ime, Buche and co-wo ke s unde ook ano he me a-analysis
o andomized con olled ials o Ca supplemen a ion o blood
p essu e con ol, and his me a-analysis was also upda ed some
yea s la e . Al hough Ca supplemen s a e no in he scope o he
p esen e iew, analysis o o y- wo eligible s udies e ealed sig-
ni ican educ ions in SBP (21·44 mmHg, 95 % CI 22·2, 0·68)
and also in DBP, 20·84 mmHg (95 % CI 21·44, 20·24).
Looking a he published e idence, a die low in Na and
wi h adequa e in akes o Ca, Mg and K is ecommended o
p e en hype ension. Low- a dai y p oduc s ul il his
ecommenda ion.
Dai y p oduc s and s oke
Hype ension is he main isk ac o o s oke. Howe e , nea ly
50 % o s okes occu in subjec s wi h no mal o in he high–
no mal limi o blood p essu e. In 2001, a e iew o dai y ood
consump ion, blood p essu e and s oke was published by
Massey. Two s udies on dai y p oduc s and s oke we e men-
ioned. The Honolulu s udy showed ha men who did no con-
sume milk su e wice as many s okes han men who
consume wo glasses o mo e o milk daily (one glass ¼240 ml).
When hey analysed he o igin o he Ca (die a y o as sup-
plemen ), hey obse ed ha only die a y Ca was p o ec i e
agains s oke. This may be due o he p esence o o he p o ec-
i e componen s in dai y p oduc s, o o he unde lying adequa e
die a y Ca in ake in hose who also use Ca supplemen s. In he
Nu ses’ Heal h S udy, in akes o h ee mine als ha a e p esen s
in dai y p oduc s (Ca, Mg and K) we e associa ed wi h lowe isk
o ic us, wi h an RR a ound 0·7. This nega i e associa ion was
s onge o he Ca ha came om dai y p oduc s han o he
non-dai y Ca. Ano he e iew o nu i ional ac o s and s oke
was published by Ga iballa (2000). The au ho e alua ed one
s udy ha showed a p o ec i e e ec o milk consump ion on
he isk o ischaemic s oke in middle-aged men included in
he Honolulu Hea P og am. Inc eases in he in ake o die a y
Ca om dai y sou ces appea ed o ha e a p o ec i e e ec
agains h omboembolic s oke ha was independen o conco-
mi an isk ac o s (P,0·05). The e was a wo old excess isk
o s oke in men who we e no milk-d inke s . hose who con-
sumed nea ly 500 ml/d o mo e (P,0·05). In his s udy, Ca con-
sumed om non-dai y sou ces did no show a p o ec i e e ec ,
unde lying he impo ance o o he a iables ela ed o milk con-
sump ion. One limi a ion o his s udy is ha he Honolulu coho
showed lowe le els o dai y p oduc in ake han o he popu-
la ion-based samples, so he e ec s o g ea e in akes o die a y
Ca ha a e commonly obse ed in o he communi ies (o he
e ec s o die a y supplemen a ion) could no be examined.
Al hough wi h limi a ions, e idence suppo s he hypo hesis
ha he in ake o dai y p oduc s could be associa ed wi h a
lowe isk o ce eb o ascula acciden o s oke. I is di icul
o associa e he p o ec i e e ec o dai y p oduc s o a single
mic onu ien . An adequa e me abolic balance be ween Ca,
Mg and K is impo an . Dai y p oduc s a e good ood sou ces
o hese mine als. Mo e s udies o e alua e he e ec s o he
in ake o dai y p oduc s o e long pe iods a e necessa y.
In o de o es ablish adequa e ecommenda ions o ic us
E.-E. A
´l a ez-Leo
´ne al.S98
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p e en ion, p ospec i e s udies mus analyse o e all die a y
pa e n and ood consump ion, a he han he in ake o
nu ien s.
Dai y p oduc s and hea diseases
A coho s udy e iew on milk consump ion and IHD was pub-
lished ecen ly (Elwood e al. 2004). The au ho s included en
p ospec i e coho s udies in which inciden IHD we e ela ed
wi h milk in ake. A pooled es ima e o he ela i e odds o
IHD in he subjec s wi h he highes milk in akes was 0·87
(95 % CI 0·74, 1·03), compa ed wi h hose wi h he lowes
in akes. Au ho s also calcula ed a pooled es ima e o he odds
o s oke, ha was 0·83 (95 % CI 0·77, 0·90) o he same subjec s
(Fig. 1). Only h ee s udies adjus ed o o al ene gy in ake. The
pooled es ima e o he odds o a ascula e en (IHD and/o
ischaemic s oke) was 0·85 (95 % CI 0·70, 1·03). The au ho s
men ioned ha milk consump ion is no associa ed wi h any
inc eased isk o hea disease o s oke.
Conclusions
The e a e e hical and me hodological limi a ions o he de el-
opmen o andomized con olled clinical ials in public
heal h nu i ion. In o de o e alua e he e ec o any die a y
in e en ion, i is e y impo an o sol e he limi a ions o he
a ailable me hodologies. I is possible o de elop mo e s anda -
dized me hods o ecall die a y a iables. I has been men ioned
ha di e en die a y assessmen me hods migh yield di e en
esul s, due o he misclassi ica ion o subjec s. Mo e in es i-
ga ions should be unde aken in o de o de elop ools ha
a oid his limi a ion in he assessmen o die a y a iables. I
is impo an o accumula e he esul s o di e en s udies, in a
simila way o he Pooling P ojec (Boyd e al. 1993; Cho e al.
2004). In he Pooling P ojec , he e we e no pa icipan s om
Medi e anean and sou h Eu opean coun ies. In hese coun ies,
he in ake o dai y p oduc s and o he die a y habi s a e qui e
di e en o hose o no h Eu opean and No h Ame ican
coun ies. Due o he wide a ia ion in he a e age in ake o
dai y p oduc s, he same indi idual could be conside ed a big
consume o dai y p oduc s in one con ex and a low consume
in ano he . Dai y p oduc s nu ien composi ion could a y
depending on he coun y, due o he di e en o i ica ion
policy ollowed in each one. P omo ing p ospec i e s udies
in di e en coun ies (such as he Eu opean P ospec i e In es i-
ga ion in o Cance and Nu i ion and he Supplemen a ion en
Vi amines e Mine
´ aux An ioxydan s s udies in sou he n
Eu ope) and including he da a in he pooling p ojec , could
lead o a be e unde s anding o he ela ionship be ween
dai y p oduc s and heal h.
Some conside a ions based on he s udies men ioned could
imp o e u u e s udies. I is e y impo an o conside all
die a y and non-die a y a iables ha could in luence disease
isk. The consump ion o dai y p oduc s is likely o be associa ed
wi h highe o lowe in akes o o he nu ien s and i will be
associa ed wi h heal h beha iou o o he bene icial ac o s
which would be di icul o iden i y. I is also impo an o
de ine he bes endpoin o e e y disease. Fo example, symp o-
ma ic ac u es would be a good endpoin in bone heal h s udies
and cance incidence is a be e endpoin han cance mo ali y in
cance s udies.
The e is ano he inhe en p oblem when he e ec o a
change in a speci ic mac onu ien is unde s udy. In o de
o main ain he o al ene gy in ake, subjec s mus simul-
aneously change he in ake o o he mac onu ien s. Fo his
eason, he genuine cause o he heal h ou come could
emain unce ain. I is also e y impo an o e alua e he
e ec s o he in ake o dai y p oduc s o e long pe iods. In
o de o es ablish adequa e ecommenda ions o disease p e-
en ion, p ospec i e s udies mus analyse o e all die a y pa -
e n and ood consump ion, be e han nu ien in ake.
When ecommenda ions on die a y habi s a e made, i
should be poin ed ou ha li e-s yle changes p oposed o
dec ease isks may ha e an added alue. These li e-s yle
changes ha e a wide ange o addi ional bene icial e ec s,
which canno be said o be ue o mos d ugs.
Re e ences
Boyd NF, Ma in LJ, No el M, Lockwood GA & T ichle DL (1993)
A me a-analysis o s udies o die a y a and b eas cance isk.
B J Cance 68, 627–636.
Cho E, Smi h-Wa ne SA, Spiegelman D, e al. (2004) Dai y oods,
Ca, and colo ec al cance : a pooled analysis o 10 coho s udies.
J Na l Cance Ins 96, 1015–1122, E a um in J Na l Cance Ins
96, 1724.
C addick SR, Elme PJ, Oba zanek E, Vollme WM, S e key LP &
Swain MC (2003) The DASH die and blood p essu e. Cu A he -
oscle Rep 5, 484–491.
Cumming RG & Ne i MC (1997) Calcium o p e en ion o os eo-
po o ic ac u es in pos menopausal women. J Bone Mine Res 12,
1321–1329.
Dagnelie PC, Schuu man AG, Goldbohm RA & Van den B and PA
(2004) Die , an h opome ic measu es and p os a e cance isk.
BJU In 98, 1939–1950.
Elwood PC, Picke ing JE, Huges J, Fehily AM & Ness AR (2004) Milk
d inking, ischaemic hea disease and ischaemic s oke II. E idence
om coho s udies. Eu J Clin Nu 58, 718–724.
Fleshne N, Bagnell PS, Klo z L & Venka eswa an V (2004) Die a y
a and p os a e cance . J U ol 171, S19–S24.
Ga iballa SE (2000) Nu i ional ac o s in s oke. B J Nu 84, 5–17.
He mansen K (2000) Die , blood p essu e and hype ension. B J Nu
83, S113–S119.
Jemal A, Mu ay T, Wa d E, Samuels A, Tiwa i RC, Gha oo A,
Feue EJ & Thun MJ (2005) Cance s a is ics. CA Cance J Clin
55, 10–30.
Massey LK (2001) Dai y ood consump ion, blood p essu e and
s oke. J Nu 131, 1875–1878.
Mille GD, DiRienzo DD, Reusse ME & McCa on DA (2000) Bene i s
o dai y p oduc consump ion on blood p essu e in humans: a sum-
ma y o he biomedical li e a u e. J Am Coll Nu 19, S147–S164.
Missme SA, Smi h-Wa ne SA, Spiegelman D, e al. (2002) Mea
and dai y ood consump ion and b eas cance : a pooled analysis
o coho s udies. In J Epidemiol 31, 78–85.
Moo man PG & Te y PD (2004) Consump ion o dai y p oduc s and
he isk o b eas cance : a e iew o he li e a u e. Am J Clin Nu
80, 5–14.
Qin LQ, Xu JY, Wang PY, Kaneko T, Hoshi K & Sa o A (2004) Milk
consump ion is a isk ac o o p os a e cance : me a-analysis o
case–con ol s udies. Nu Cance 48, 22–27.
Quinn M & Babb P (2002) Pa e ns and ends in p os a e cance
incidence, su i al, p e alence and mo ali y. Pa I: in e na ional
compa isons. BJU In 90, 162–173.
Weinsie RL & K umdieck CL (2000) Dai y oods and bone heal h:
examina ion e idence. Am J Clin Nu 72, 681–689.
Dai y p oduc s and heal h: e iew o e idence S99
h ps://www.camb idge.o g/co e/ e ms. h ps://doi.o g/10.1079/BJN20061709
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