Iron Status of Vegetarian

8/17/2019 Iron Status of Vegetarian

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m C lin Nutr 1 99 4:5 9(supp l):1 23 3S -7S . P rin ted in U S A . © 199 4 A m e ric an S o ciety for C lin ica l N u trition

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Iron s ta tu s o f vege ta r ians ’

Wins ton raig

ABSTRACT

A n approp ria te ly p lanned w ell-ba lanced v eg -

e tar ian die t is co m p atib le w ith an ad equ ate iro n sta tus . A lth ou gh

th e iro n s to res o f vege ta rian s m ay be reduced , the inc idence of

i ron -de fic ienc y ane m ia in v ege tar ians is n o t sign ifica n tly d iffe r-

en t

from th at in om niv ore s. R es tric tiv e veg eta ria n d iets (e g , m ac -

rob io tic) are a sso ciated w ith m ore w ide spread iron -de fic ien cy

ane m ia . W este rn veg eta rian s w ho con sum e a va rie ty of food s

have a b ette r iro n s ta tus th an do th ose in d eve lo p ing co un tries

w ho co nsu m e a lim ited d ie t b ased o n u n leav en ed , unref in ed cc-

reals. W h ere as phy tates, poh yp hen oh ics, a nd oth er p lan t con stit -

uen ts fo und in vege ta rian d ie ts inh ib it no nhem e-iron absorp tion ,

vita m in C , citr ic a cid , an d o the r o rga n ic acid s facil ita te non hem e-

iro n a bs or ptio n.

A m J C lin Nu tr

1994 ;59(supp l) :h233S-7S .

KEY W ORDS Iro n absorp tion , v eg eta rian , v itam in C , iro n

sta tus, phy tates

Introduction

Iro n d efic iency is co nside red to be o ne o f the m os t com m on

nu trit ion al def ic ie ncies in the w o rld . M ore tha n 50 0 m illion pe o-

p ie are b elieve d to hav e iron-def ic ie ncy an em ia (I) , par tly b e-

ca use of the rela tiv ely p oo r a bso rp t ion in th e bod y of iro n f rom

foo d . F urthe rm o re , in T h ird W orld cou n tries the re is a su bstan tia l

d rain o n hu m a ns’ iron s to res th at is c aused b y p ara sit ic in fe ctio ns,

in ad d ition to th e heavy burden on iron s to res in fem ales tha t

re su l ts fro m re pea ted pregn anc ies . T he p rev ale nce o f an em ia in

the U nited S ta tes h as declined o ver the pas t decade because of

the inc reased use of iron-fo rtified foo ds, th e inc reased use o f iro n

su pp lem en ts, the in crea sed in tak e of v ita m in C , an d th e use of

b irth -c on tro l p ills (2 ).

I ron defic iency resu lts w hen iro n absorp tion is n o t su ff ic ien t

to m ee t the n eed s of th e b ody . T h is occurs w hen there is poo r

ab so rp tion of iro n f rom th e d iet, w he n rap id b od y g row th o ccu rs,

or w hen subs tan tia l b lood loss occurs (3 ). A lack of iron causes

iron s to res to d ecrease , w h ich is fo llow ed by a drop in seru m

fem tin con cen tra tions becau se se rum fem tin is in equ ilib rium

w ith th e b od y’s iro n sto res . E ac h m ic rog ram of fcm tin p er li ter

of se rum equa ls 0 m g s to red iron (4 ). In the U n ited S ta tes,

m ale a dults typ ical ly h ave iro n sto re s of 1 g w hereas fe m ales

have sto res th at a re usua lly < 0 .5 g 5 . T he bod y com pensa tes

fo r lo w iron s to res by subs tan tia lly in creas ing iron absorp tion

ab ove th e am ou nt tha t occurs w hen iron s to res a re ad eq ua te (6 ).

Iron sto res tend to be low er in prem enopausa l w om en , ado les-

cents, and you ng ch ild ren , w h o there fo re have h igh er r isk of iron

def ic ienc y (2). I ron -de fic ienc y an em ia de ve lop s on ly af ter iron

sto res are ser iou sly d ep leted an d hem o glo b in prod uction s low s

un til hem oglob in co ncen tra tion s a re be lo w norm al (7 ).

T here a re m an y de le te rio us ef fects o f iro n defic ien cy , inc lu d-

in g a de cre ase d cap aci ty for w ork , a greater ten de ncy to fatigue ,

decreased a th le tic perfo rm ance, an im pa ired ab ility to m ain ta in

body tem pera tu re in a co ld en v ironm ent, im p aired in te llec tua l

pe rfo rm ance , a decrease in a tten tiveness , b eh av io ra l abnorm ah i-

ties in sm a ll ch ild ren , a greater risk of pre m a ture d elivery an d

how birth w eigh t in neona tes, com plications of p regnancy , an

im p aired im m u ne fu nc tion , an d an in cre ase d r isk of lea d poison -

ing (2 , 8 -10 ).

Iron ab so rption

T he bo dy care fu lly gu ards aga ins t iron losses an d co nserv es

iro n w h ere ver po ssib le . Iron b ala nce is pre cis ely re gu late d m ain ly

th rou gh changes in the am ou n t o f iro n absorbed (6 ) . U n der no r-

m al cond itions . iron ab sorp tio n is 1 0 - 15 , bu t it can v ary

grea tly from as little as 1 to 4O ( 1 1

).

T he ac tu al am oun t o f

iro n a bso rbe d fro m th e g astro in tes tina l tra ct is determ ine d by the

iro n co nte n t o f th e m ea l, the ch em ica l fo rm o f the iron , the iron

sta tu s of th e ind iv idua l, and th e com po sit ion o f th e inge ste d foo d

(8 ) . A bou t 4 0 o f th e iro n in m ea t, p ou ltry , and f ish is hem e

iro n , w hereas the rest is non he m e iron

( 1 2) . T he iron in da iry

pro duc ts, eg gs, and a ll p lan t foods is nonhem e iron . A ltoge ther,

non hem e iron co m prises

>

80 o f to tal d ieta ry iron . B ecause

hem e iron is genera lly m uch be tter ab sorbed (h5 -35 ) than

is no nhe m e iro n (2-2 0 ), i t h as be en su gg ested tha t v ege tarians

m ay be at g rea ter risk of iron de fic ien cy I 3 ). N on he me -iro n

a bso rp t ion is stro ng ly influ en ced b y m any in h ib ito ry an d e n-

h an c in g fac to rs in th e d ie t w hereas hcm e-iron abso rp tion is v ery

lit tle affecte d by oth er d ietary co m p one nts . T he ef fic ien t a bso rp-

t ion of he m e iron is b eca use o f spe cific he m e -b ind ing site s in the

in te stin al t ract (8 ).

T he so lub ih ity o f non hem e iron in the sm all in tes tin e is a m ajo r

fac to r in de te rm in ing its absorp tion . P o lyph enoh ics and p hy ta tes

in

p lan t fo od s a rc kn ow n to b in d w ith no nhe m e iron an d thus to

inh ib it its ab so rp tion . F o r ex am ple , tan n in s in tea an d co ffee fo rm

iro n -tanna te com plexes th at sub stan tially red uce nonh em e-iro n

ab sorp tio n (14- 17). T he inh ib ition of iron by tann ic ac id app ears

to be stro ng ly do se-re la ted (17 ). P o lyphen oh ics in so m e vege ta -

b les an d herba l teas m ay a lso have an adverse e ffec t on th e up take

of iron . P hy ta tes in w hole -g ra in cerea ls, legum es , n u ts, and seeds

From the D epartm en t o f N utrition , A nd rew s U n iv ersity , B errien

S p rin gs, M l.

R eprin ts n o t ava ilab le. A ddress co rrespo ndence to W J C raig , D c-

partm en t o f N utrition , A ndrew s U niversity , B errien S pring s, M I 49 104 -

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1234S CRAIG

can b ind n onhem e iron and grea tly reduce its ab sorp tio n (18).

W h ereas phy ta tc in h ib its iron absorp tion , fibe r apparen tly does

no t (8 ). T he iron b a lance of v o lun tee rs w ho con sum ed a low -

fibe r d iet w as no t adv erse ly a ffec ted by th e consum ption o f a

h ig h-fibe r d ie t (19) . I ron ab sorp tio n from w hea t b read m ay dc-

pen d on its b ran con ten t because bran is rich in phy ta tes (20 , 21).

H ow ever, in a t least one s tudy , th e reduc tion of p hy ta te in w h ea t

b ran produced n o effec t on nonhem e-iro n absorp tion (2 2). M uch

of the phy ta te in w hea t flou r is h ydro lyzed during the leav en in g

process and during b read bak ing so tha t iron abso rp tion from

leavened b read is im pro ved com p ared w ith tha t fro m unleavened

bread . Iron ab sorp tio n from bahad i, a trad itiona l E g yp tian flat-

b read m ad e fro m high-ex trac tion f lo ur, w as on ly on e-six th o f tha t

ob se rved from E uro pean bread (23 ).

A bsorp tion of iron from a varie ty of com m only ea ten legum es

(len tils, sp lit peas, m ung beans , b lack beans , and soy bean s) p re -

pared as sou ps w as observed to be on ly I -2 (24). Fu rthe r-

m ore , the add ition of so y to a m ixed d ie t inh ib its the overa ll

b io av ailab ih ity o f iron from the m ea l (25 , 26). O ne iron abso rp -

tion s tudy tha t used hy dropo n ica lly cu ltu red soyb ean s of d iffe ren t

phy tate con ten ts revea led tha t the p hy ta te w as no t respons ib le fo r

the low absorp tion of iron from soy (27). O n the o ther hand ,

S w is s re sea rch ers study ing iron ab sorp tio n from liq u id -form u la

m eals tha t con ta ined a num ber of soy-p ro tein iso la tes w ith d if-

fe ren t ph y ta te con ten ts observed a four- to fiv efo ld inc rease in

iron absorp tion w hen ph y tic ac id w as essen tia lly rem oved from

the so y-p ro te in iso la te (28 ). T hey no ted tha t the phy tic ac id con-

ten t o f the soy -p ro te in iso late had to be red uced to ho w am o unts

to ensure a m ean ing fu l and sub stan tia l inc rease in iron abso rp -

tion . T h is n eed to redu ce phy ta te to

<

10 m g/m ea l co u ld exp la in

w hy o ther s tud ies fa iled to dem on stra te an y inh ib ito ry effect o f

phy ta te .

O ther resea rch w ith soy sug gests tha t it is th e pro te in th at is

respons ib le fo r th e low iro n absorp tion (29 ). T he m odification of

so y pro te in b y food processin g can in fluence the ava ilab ility o f

iron . A bsorp tion o f iron from tem pch w as sho w n by L yn ch e t a l

(30) to be s lig h tly im proved w hereas iron absorp tion from tofu

w as increased th ree fo ld . In on e stud y , iso la ted soy pro tein w as

m ore inh ib ito ry than w as so y flo ur (26) , w h ereas in ano ther s tudy

iso la ted soy pro te in w as fou nd to be less inh ib ito ry than w as soy

flour w ith respec t to iron abso rp tion (31 ). V itam in C has been

show n to im prov e iro n abso rp tion fro m so y to v ary ing degrees

(3 1 , 32 ). Ferm en ted soy pro duc ts (tem peh , m iso , and na tto ) as

w ell as silken to fu (coagu la ted w ith a g lucon ic ac id deriva tiv e)

show enhan ced iron absorp tion com pared w ith th at o f so y flo ur

(29). O n the o ther hand , iron absorp tio n from to fu tha t w as pre -

c ip ita tcd b y ca lc ium salts w as no be tte r th an th at from soy flo ur

b ecause of its h ig h ca lcium con ten t. C a lc iu m is kno w n to inh ib it

i ro n a bs or pt io n.

A lthou gh the add ition of nu ts to a m ea l can produ ce a su b-

s tan tia l inh ib ito ry effect o n iron abso rp tio n , M acfarlane e t a l (33)

dem ons tra ted tha t a m od est add ition of v itam in C to a m ea l w ill

o vercom e th e inh ib ito ry effec t o f the nu ts . Sw ed ish resea rchers

h ave subsequen tly show n tha t m odera te am o un ts o f v itam in C

can coun te rac t the inh ib ito ry effec t o f ph y ta tes in cerea ls o n iron

abso rp tion (34).

A scorb ic ac id is a pow erfu l p ro m oter o f non hem e-iron ab-

so rp tion . A bou t 7 5 m g asco rb ic ac id inc reases no nhem e-iron ab-

so rp tion th ree - to fou rfo ld (13 , 35) . In a non vege tar ian ,

u3

oz of

m ea t in th e d ie t has the sam e effect on n onhem e-iron absorp tion

a s do es 75 m g v itam in C (8). T h e enh anc em en t o f non hem e- iro n

absorp tion b y ascorb ic ac id is though t to o ccu r on ly w hen it is

consum ed w ith th e m ea l ( I 3 ). T he effec t o f ascorb ic ac id on iro n

absorp tion m ay be due to its ab ility to fo rm so lub le co m plex es

w ith fe rric ion s and to its reduc ing action on iron , w hich p rodu ces

the m o re so lu b le fe rrou s fo rm . Ferro us iron is be tter absorbed

than is fem c io n (1 8). In ad d itio n , sm all am ou n ts o fc itric , m alic ,

a nd ta rta ric

a cids , fo un d in fru its and ve getab les, an d lact ic ac id ,

fou nd in sau erk rau t (8 , 14) , can a ll sub stan tially enh an ce iron

absorp tion . T h e effec t o f c itric ac id on iron absorp tion is add itiv e

to tha t p rod uced by ascorb ic acid a lone (3 6).

In add ition to the fac t tha t v itam in C an d the organ ic ac ids

fou nd in fru its and vege tab les a re go od fac ilita to rs o f nonhem e-

iron absorp tio n , the w h ole-g ra in cereals an d legum es in a v eg e-

ta rian d ie t p rov id e sub stan tial am oun ts o f iron (T ab le 1 ).

W hereas the percen tag e o f iron absorbed fro m refined-g rain

p rod ucts is m o re than d oub le that ab so rbe d f rom the w h ole -grain

pro duc ts, the ne t absorp tion of iron from the w hole -g rain an d

re fined prod uc ts is ab ou t th e sam e because w hole -w hea t b read

and bro w n rice con ta in abou t tw o to th ree tim es the am oun t o f

iron fo und in w hite b read and w hite rice. T h is is a lso true fo r soy

beans . A lth ough the percen tage of iron absorbed from soy m ay

be reduced , the to tal am ou n t o f iron ab sorb ed is m odes t

because

so y beans na tu ra lly con ta in re la tive ly la rge am ou n ts o f iron

(2 5 , 37) . F actors th at in fluen ce th e ab so rp tion of no nh em e iro n

a r c l i s t e d i n T a b l e 2 .

T A B L E I

Iron con ten t o f p lan t food s

L e g u m e s

90 g (‘/2

cu p) S oy be ans

95 g (‘/2

cu p) L im a b ea ns

90 g

‘ /

cu p) R ed k idn ey bea ns

100 g

( 2 c up) L en tils

8 0 g (‘/2 c u p P e a s

G rain s an d p asta

240 g ( I c up) O atm e al

14 0 g ( I c up) S pag he tti, en ric hed

140 g (1 cup) M acaron i, en rich ed

2 00 g (I cup) B row n r ice

I s lice W ho le-w hea t b read

V ege tab les

95 g (“2 cu p) C ollard s, c ook ed

I T o m ato , m ed ium

8 0 g (V 2 cu p) B ro cco li

1 P ota to , m ed ium

N uts an d seed s

2 8 g (1 oz ) S unf low er seed s

2 8 g 1 o z Al mo n d s

2 8 g 1 o z Pe a n u t s

F ru its an d dried fru its

S P run es, la rge

5

D ates , m ed iu m

1 slic e W ate rm elo n 15 cm dm x 2 c m )

10 S traw berries , la rge

2 8 g ( 1 oz) ra isins

2 35 m L ( 1 cu p) O rang e ju ice

3 F i g s , me d i u m

2 35 m L (I cu p) P inea pple ju ice

I O range , m ed ium


3/5

I R O N ST A T U S O F V E G E T A R I A N S

h 2 3 5 S

T A B L E 2

Fac tors th at in f luen ce the ab sorption of no nhe m e iron ’

S ubs tan ces that in hib it no nh em e-iron ab sorption

Phytates

P la nt p ol yp he no hi cs

H igh d ietary am oun ts o f z inc and other d iv alen t catio ns

S oy pro tein

B r a n

Eg g

M l k

T ea an d co f f ee

C alciu m -ric h an tac ids

C alciu m p hosph ates

S ub stance s that en han ce n onh em e-iron ab sorption

As c o r b i c a c i d

M eat, p o u ltry , an d f ish

C itric , m alic , lactic , and tartaric ac ids, and oth er organ ic acids

Ferm en tatio n p ro d u c ts o f so y b ean

O th er f ac to rs

L ow iro n sto res o f in d iv id u als

L o w iro n co n ten t o f m eals

Iro n in f e rro u s f o rm

‘A dap ted f rom ref eren ces 8 and I 8.

H ow d o v eget ar i an s f ar e?

W ith all o f th e ab o v e f ac to rs co m in g in to p lay , h o w d o es th e

v eg e tarian f are? W h at is th e iro n s tatu s o f o n e w h o co n su m es a

d ie t o f g rain s, leg u m es, n u ts, f ru its, an d v eg e tab le s , w ith o r w ith -

o u t so m e d airy p ro d u c ts an d eg g s? A lth o u g h v eg e tarian s ten d to

h av e lo w er seru m v itam in B - I 2 co n cen tratio n s an d red u ced iro n

s to res, sev eral s tu d ie s h av e sh o w n th at h em o g lo b in co n cen tra-

tions of v e getarians arc sim ilar to tho se of no nv ege tarians . A d ult

v ege tarians w h o ate a hactoo v o v eg etarian die t f or m any y ears h ad

se ru m iro n co n cen tratio n s, tran sf em n satu ratio n v alu es , an d h e -

m o g lo b in v alu es th at w ere n o t s ig n if ican tly d if f e ren t f ro m th o se

o f n o n v eg e tarian su b jec ts (3 8 -4 0 ). T h e v eg e tarian s co n su m ed

s im ilar am o unts of iro n in th eir d iet, b ut ing este d s ign if ic antly

m o re f ib er th an th e n o n v eg c tarian s. In a B ritish s tu d y , ad u lt v eg -

an s w h o co n su m ed a to tal v eg etarian d ie t f o r 6 y h ad h em o-

g lob in co nce ntratio ns sim ilar to tho se of om niv oro us co ntrol su b-

je c ts an d n o su b jec t h ad a h em o g lo b in co n cen tratio n b elo w th e

lo w er lim it o f n o rm ah ity (4 1 ). A lth o u g h m an y s tu d ie s h av e sh o w n

th at h em o g lo b in co n cen tratio n s in v eg e tarian s arc n o rm al, o th er

s tud ies o f y o ung adu lt and eld erly su bje cts w h o con su m e d v eg -

e tarian d ie ts f o r so m e tim e co n sis ten tly sh o w ed th at v eg etarian s

(esp ec ially f em ales ) h av e lo w er seru m f crritin co n cen tratio n s an d

h en ce red u ced iro n s to res co m p ared w ith o m n iv o res (4 2 -4 6 ).

N ote that th e to tal am ou nt o f sto rag e iron can v ary ov e r a w ide

ran g e w ith o u t an y ap p aren t im p airm en t o f b o d y f u n c tio n (4 7 ).

N ev erth e le ss , red u ced iro n sto res arc asso c iated w ith an in creased

risk o f iro n d e f ic ien cy .

Is a sim ilar p ic tu re reg ard in g iro n statu s seen f o r v eg e tarian

ch ild ren as f o r v eg e tarian ad u lts? C h ild ren w h o co n su m e a re -

stric ted m acro b io tic d ie t co m m o n ly m an if e s t iro n d ef ic ien c ie s,

w h ereas ch ild ren w h o co n su m e a b alan ced h ac to o v o v eg e tarian o r

v eg an d ie t h av e an iro n statu s s im ilar to ch ild ren w h o are o m -

n iv o res . Iro n d e f ic ien cy h as b een rep o rted in 1 5 o f y o u n g

m acro b io tic ch ild ren in B o s to n an d in T h e N e th erlan d s (4 8 , 4 9 ).

T h e p aren ts o f th ese ch ild ren h ad f o llo w ed a m acro b io tic d ie t

th em se lv es f o r sev eral y ears . O n th e o th er h an d , ch ild ren ag ed

6 - 1 2 y w h o co n su m ed v eg e tarian d iets th at w ere m o re v aried

an d b alan ced h ad h em ato lo g ical v alu es th at w ere n o t s ig n if ican tly

d if f e ren t f ro m th o se o f s im ilarly ag ed n o n v eg e tarian ch ild ren

50). I t is in tere stin g to no te that th e no nv ege tarian sch oolchil-

d ren in th is latter s tu d y co n su m ed o n e -th ird le ss d ie tary iro n th an

did th e v e getarian c hildre n. T he he m atological data (tran sf errm n

satu ratio n an d seru m f em tin , se ru m iro n , an d h em o g lo b in co n -

cen tratio n s ) f o r th e su b g ro u p o f ch ild ren w h o ate a v eg an d ie t

w as n o t sig n if ican tly d if f e ren t f ro m d ata f o r th e lac to o v o v eg e -

tarian ch ild ren (5 0 ). In f ac t, < 5 of bo th the no nv e getarian an d

v eg e tarian ch ild ren h ad m easu rab le iro n -d e f ic ien cy an em ia.

L o w seru m f erritin co n cen tratio n s as w e ll as iro n -d e f ic ien cy

an em ia w ere rep o rted in m id d le -ag ed E as t In d ian im m ig ran ts to

C an ad a w h o f o llo w ed a lac to o v o v cg c tarian d iet b ased o n u n -

leav en ed ch ap atis m ad e f ro m w h o le -w h eat f lo u r (5 1 ). Iro n d e f i-

cienc y w as m o re co m m on in f e m ales

(3 3 ) th an in m ales 5 ).

T h e Pu n jab i In d ian s also co n su m ed su b s tan tial q u an titie s o f

spices and tea, w hic h w ere hig h in tan nin s (5 1 ). T h e h ig h p rey -

alen ce o f iro n d e f ic ien cy w as su g g ested to b e th e resu lt o f h ig h

in tak es o f p h y tatc s an d tan n in s th at in h ib ited d ietary iro n ab -

sorption .

T h e to tal d ietary iro n in tak e o f v eg e tarian s w h o f o llo w a b al-

an ced d iet h as b een rep o rted to b e h ig h er th an th at o f n o n v eg e -

tarian s (5 2 ). T h ere is a v arie ty o f p lan t f o o d s th at su p p ly m eas -

u rab le am o u n ts o f iro n f o r v eg e tarian s. T h e m ajo r so u rces o f

d ie tary iro n f o r v eg e tarian s in c lu d e w h o le -g rain an d f o rtif ied cc -

reals. leg u m es, d ark -g reen v eg etab le s , n u ts , seed s, an d d ried

f ru its (cg , dates, f igs , rais ins , and p ru nes ) (T ab le I

). S o m e f ru its

su ch as w ate rm e lo n an d s traw b errie s an d o ran g e ju ice m ay also

su pp ly re aso nab le am ou nts o f iron . Fru its an d v eg etab les are im -

p o rtan t so u rces o f v itam in C an d o th er f acilitato rs o f iro n ab -

sorp tion . B ecause m ilk is not a g oo d sou rce o f iron an d the iro n

eg g h as a lo w b io av aih ab ih ity (8 . 1 8 ), v eg an s w h o f o llo w a

w e ll-b alan ced d ie t sh o u ld n o t b e co n sid ered to b e at an y ad d i-

tio n al risk reg ard in g th e ir iro n statu s . In f act, so m e stu d ie s rep o rt

th at v eg an s co n su m e am o u n ts o f d ietary iro n th at are w e ll ab o v e

reco m m en d ed d ie tary allo w an ces (R D A s) (5 3 -5 5 ) an d h ig h

quanti ties o f f ru its and v ege tab les ric h in v itam in C .

Pr ev en t i on of i r on d ef i ci en cy

T h e w id esp read iro n f o rtif icatio n o f re f in ed b read s , cereals , an d

pas ta pro du cts has h elp ed to red uce iron de f ic ien cy . Iron def i-

cien cy is les s c om m o n tod ay be cau se of no t o nly th e use of iron-

f ort if ie d f o od s, in clu din g iro n-f o rti f ied in f ant f o rm ulas, but also

b ecau se o f an im p ro v ed v itam in C in tak e . O th er im p o rtan t f ac to rs

in clu d e th e w id esp read b reas t-f eed in g o f in f an ts, a d ecreased u se

o f co w m ilk in in f an cy , an d th e co n su m p tio n o f a w id e v ariety

o f iro n -rich f o o d s (2 ). T h e ty p ical A m erican d ie t co n tain s I .4 3

m g FeIM J. In situ atio n s o f red u ced en erg y in tak e , su ch as d u rin g

w e ig h t-lo ss d ie ts , it b eco m es d if f icu lt to o b tain su f f ic ien t iro n f o r

th e b o d y ’s n eed s w ith o u t th e u sc o f iro n su p p lem en ts o r co n -

su m p tio n o f ad eq u ate iro n -rich f o o d s . T h e u se o f iro n su p p le -

m cn ts w h en n eed ed (su ch as d u rin g p reg n an cy ) an d an ad eq u ate

iro n in tak e d u rin g tim es o f rap id g ro w th arc im p o rtan t step s in

th e p rev en tio n o f iro n d e f ic ien cy . B ecau se an tacid s can in h ib it

n o n h em e- iro n ab so rp tio n , th e ex cessiv e u se o f an tac id s sh o u ld

b e a v o i d e d 5 6 .

C an a p erso n g e t to o m u ch iro n ? Fin n ish research ers h av e su g -

g es ted th at h ig h b lo o d co n cen tratio n s o f iro n are asso c iated w ith


4/5

1 2 3 6 S

C R I G

an e leva ted risk of heart d isease (57 ). Iron m ay ass ist w ith th e

fo rm ation of free rad ica ls, w h ich p rom ote the form a tion of a th -

erogen ic ox id ized lo w -d en sity -lipopro te in (L D L ) partic les . T he

F inn ish study foun d th at e leva ted L D L c ho lestero l pre d ic ted

h eart a ttacks o n ly w h en seru m ferritin concen tra tions w ere h igh ,

an d fo r every 1 inc rease in se rum ferritin concen tra tions the re

w as a 4 inc rease in heart a ttack risk . A m erican resea rchers h av e

also su gge ste d tha t h ig h iro n in tak es m a y b e asso cia ted w ith a

h ig her risk of co lon cancer (5 8). C lea rly , those w h o are no t an e-

m ic o r pregn an t sh ould th in k tw ice abo ut tak ing iron su pplem ents

on a regu la r bas is . In ad d itio n , abou t on e in every 2 50 A m ericans

h as an inh erited d iso rde r-h cm och rom atosis -th at m ake s th eir

b od ies u nab le to s to re excessive am o un ts o f iron (2 ) , w h ich can

b e fa ta l if un trea ted .

S u m m a r y

V egetar ian d ie ts can be con struc ted to be of h igh iro n b io -

ava ilab ility (13). F or the vege ta rian , a d ie t h igh in v itam in C -

rich fru its an d vege tab les can prov id e ad equa te am ou n ts o f iro n

so lon g as the d ie t a lso con ta ins a v ar ie ty of w hole grains ,

leg um es, nu ts , and seeds tha t a rc r ich in iro n . A lth ough iro n

sto res of som e ve getaria ns are m arg ina l, the risk of iron -de fi-

c ienc y an em ia resu ltin g fro m the c onsum ption o f a w e ll-b ala nce d

W este rn v eg e ta rian d ie t tha t con ta ins a varie ty of ap propr ia te

p lan t foo ds sho u ld no t be a m ajo r co ncern and , in fac t, the risk

of iro n defic iency is no d iffe ren t from tha t fo r peop le w ho ca t a

nonv ege ta rian d ie t. A w ell-ba lanced vege ta rian d ie t is com patib le

w ith a hea lth y nu tritiona l s ta tus (59 ). El

R e f e r e n c e s

1

D c M aeyer E M , A die ls-T egm an M . T h e prev a lence of an em ia in th e

w o rld . W orld H ea lth S ta t Q 198 38 :3 02-16 .

2 . D a llm an PR . Iron . In : B row n M L , ed . P resen t kn ow ledg e in nu tri-

tion . 6 th ed . W a shin g to n , D C : In tern ationa l L ife S cienc e In sti tu te-

N utrition Fo unda tion , 1990 :2 41-50 .

3 . F A O IW H O . R eq uire m e nts of v ita m in A , iron , fo la te and vitam in B -

1 2 . R ep ort o f a Jo in t F A O IW H O E x pe rt G rou p . G e nev a,

S w itze rland : W HO , 198 9 .

4 . H erb ert V . E v ery one sh ould be tested for iron d iso rders. J A m D iet

As s o c l 9 92 ; 9 2 : 1 5 0 2 - 9 .

S . B oth w e ll T H , C h arl ton R W , C o ok JD , F inch C A , eds . Iron m etab-

o lism in m an. O xford , U K : B la ckw elh S c ien tific P u blic ations , 197 9 .

6 . F inch C A , C o ok JD . I ron defic iency . A m J C lin N utr 1984 :39 :4 71-

7 .

7 . H erbert V . R ecom m ended d ie tary in takes (R D I) o f iron in h um ans.

A m J C lin N utr 1987 :4 5 :679-8 6 .

8 . B ay nes R D . B o thw cll T H . Iron d efic ien cy . A nnu R ev N utr

1 9 90 : 1 0 : 1 3 3- 4 8 .

9 . D allm an P R . I ron defic ien cy : d oes

it

m atte r? J In t M cd

1 9 89 ; 2 2 6 : 3 6 7 - 7 2 .

10 . C ook JD , L ynch S R . T he liab ilitie s o f iron defic iency . B lood

l986 ;68 :803-9 .

I 1. C ha rlto n R W , B o thw ell T H . I ron a bso rp t ion . A n nu R ev M e d

1 9 8 3: 3 4 : 5 5 - 6 8 .

1 2 . N ationa l R e sea rch C o un cil. R eco m m en ded dietary allo w a nce s. 1 0 th

cd . W ash ing ton , D C : N ationa l A cad em y P ress, 1 989 .

1 3 . M onsen E R . Iron n u trition and ab sorp tio n : d ieta ry fac to rs w h ich

im pa ct iro n b ioav aila b ih ity . J A m D ie t A ssoc 1 988 ;88 :78 6-9 0 .

14 . G ilb oo ly M , B oth w c ll T H , T orran ce JD , et a l. T he effects of organ ic

a cid s, phy tate s an d p oly phe no ls o n th e ab sorp tion of iron fro m ve g-

e tab les. B rJ N u ts l9 83 ;49 :33 1-4 2 .

15.

D isle r P B , L yn ch S R . C har lton R W , et a l. T he e ffe ct o f te a o n iro n

a bsorp tion . G ut 1 975 :16 :19 3-200 .

1 6 . R ossander L , H allb erg L , B jo rn -R asm u ssen E . A bsorp tion of iron

from b reak fast m eals . A m J C lin N utr 197 9 :32 :248 4-9 .

1 7 . B run e M , R ossan de r L , H allberg L . I ron ab sorp tion an d phe no lic

c om po und s: im por tan ce o f d ifferen t phe no lic stru ctu res . E ur J C lin

Nu t r 1 98 9; 4 3 : 5 47 - 58 .

1 8 . H allberg L . B ioa vai lab ility o f d ieta ry iro n in m a n. A nn u R ev N utr

1 9 8 1: 1 : 1 2 3 - 4 7 .

1 9 . K elsay JL , B eha ll K M . Prathe r E S . E ffec t o f fibe r from fru its

and vege tab les on m etabo lic respon ses o f h um an sub jec ts. II.

C alc ium , m ag nes ium , iron and si lico n balanc es. A m J C lin N utr

1 97 9; 3 2 : 1 87 6- 8 0 .

2 0 . B jorn -R asm ussen E . I ron a bso rp tion f rom w h eat b read . In flu en ce of

various am ou n ts o f b ran . N uts M e tab 1 97 4; 1 6: 101 -10 .

21 . H allb erg L , R ossan der L , S ka nb erg A -B . P hytate s and th e inh ib ito ry

e ffec t o f bra n on iro n ab sorp tio n in m an . A m J C lin N u tr

1 9 87 : 4 5 : 9 8 8- 9 6 .

22 .

S im p son K M . M om s E R , C oo k JD . T he in h ib ito ry ef fect o f bran on

iro n ab sorp tion in m an. A m J C lin N utr 1 98 1 :34 :14 69 -78 .

23 . E l-G uin d i M , L y nc h S R . C ook JD . I ron a bso rp t ion f rom fo rtif ied

fla t b read s. B rJ N u tr 198 8:5 9 :2 05 -13 .

24 . L y nch S R . B eard JL , D a sse nko S A , C oo k JD . Iro n a bso rp t ion f rom

leg um es in hum an s. A m J C lin N utr 198 4:40 :42-7 .

25 . H a llbe rg L , R ossan de r L . E ffect o f soy pro tein on n onh em e a bsorp -

tio n in m an . A m J C lin N u tr 19 82:36 :514 -20 .

26 . C ook JD , M orc k T A , L y nch S R . T h e inh ib i to ry e ffe ct o f soy prod-

ucts on non -he m e iron a bso rp t ion in m an. A m J C hin N utr

1 9 81 ; 34 :2 6 22 -9 .

27 . B eard JL , W eaver C M , L y nch 5 , e t a l. T he effec t o f soy bean ph os-

pha te and phy tate c on ten t on iron b io av aila b il ity . N u tr R es

1 9 88 : 8 : 3 4 5 - 5 2 .

2 8 . H urrell R F , Ju il lera t M -A , R ed dy M B , et a l. S oy p ro tein , ph y ta te .

and iron absorp tion in hu m ans. A m J C lin N utr 19 92 :56 :57 3-8 .

2 9 . M a cfa rlan e B J , van der R ie t W B , B o thw ell T H , B ay nes R D .

S ie gen be rg D . E ffec t o f trad itio nal o rien tal soy produ cts on iro n

absorp tio n . A m J C lin N uts 1990 :51 :873-80 .

3 0 . L yn ch S R . H usa in 5 , D a sse nko S A , et a l. A soyb ea n pro du ct w ith

im p rov ed iro n b ioav aila b il ity for hum an s. A m J C lin N u tr

1 9 8 4 : 3 9 : 6 6 4 a b s t r .

3 1 . D erm a n D P . B a llo t D , B othw ell T H , e t a l. F a cto rs in fluen cin g th e

absorp tio n of iron fro m soy a-b ean p ro tein p rod uc ts. B r J N u ts

1 9 87 : 5 7 : 3 4 5- 5 3 .

3 2 . M orck T A , L yn ch S R . C ook JD . R edu c tion of the soy -induced in -

h ib i tio n o f non hem e iron a bso rp tion . A m J C lin N utr 1 98 2:3 6 :2 19 -

2 8 .

3 3 . M acfarlane B J, B ezw od a W R , B o thw ell T H , et a l. Inh ib ito ry e ffec t

o f n u ts on iron ab so rp tion . A m J C lin N utr 198 8:4 7 :2 70 -4 .

34 . H allb crg L , B ru ne M , R o ssa nde r L . Iro n ab sorp tio n in m an : asc orb ic

a cid a nd do se-dep end en t in h ib itio n by p hytate . A m J C lin N u ts

1989 :49 :140-4 .

35 . C oo k JD , M o nse n E R . V itam in C , the co m m on c old and iro n a b-

so rp t ion in m an. A m J C lin N uts 1 97 7:3 0 :2 35-41 .

36 . B allo t D , B ay nes R D . B o thw ell T H , et al . T he effe cts o f f ru i t ju ices

and fru its on the abso rp tion of iron from a rice m ea l. B r J N u tr

1 9 87 : 5 7 : 3 3 1- 4 3 .

37 . H a llb erg L , R ossan der L . Im pro vem en t of iron n utri tio n in de vel-

op ing co un trie s: co m p arison of add ing m e at, soy p ro tein , a sco rb ic

ac id , c itric acid , and ferro us su lfa te on iro n a bso rp t ion from a sim ple

L atin A m erican-typ e m eal. A m J C lin N uts 19 84 :39 :57 7-83 .

38 . A rm s tron g B K , D a vis R E , N ico l D J, va n M erw yk A J, L a rw ood C J.

H e m a to log ical, v itam in B - 1 2 , a nd fo la te s tud ies on S e ven th-day A d -

ve n tis t v ege tarians . A m J C lin N utr 19 74 :27 :71 2-8 .

39 . A n de rson B M , G ib son R S , S a bry JH . T h e iro n a nd zin c s ta tu s o f

hon g-te rm vege ta rian w om en . A m J C lin N utr 198 1 :34 :10 42-8 .

40 . L a tta D , L iebm an M . Iron and z inc s ta tu s of v ege tarian and no nv ege -

tarian m ale s. N uts R e p In t 1 984 :30 :14 1-7 .


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I R O N ST A T U S O F V E G E T A R I A N S

1 2 3 7 5

4 1 . S an ders T A B , E llis F R , D ickerson JW T . H aem ato log icah stud ies on

v eg ans. B r J N utr 1 978 ;40 :9 -1S .

4 2 . L oco ng A . N utr itio nal sta tu s an d dietary in tak e o f a se lected sa m p le

o f y oung adu lt vege tar ians . C an D ie t A ssoc J 19 86 ;47 :l01 -6 .

4 3 . M cE ndree L S , K ies C V , F ox H M . Iron in take and iron nu tritiona l

s ta tu s of la cto -ov o-v ege tan ian an d om nivore stu den ts e atin g in a

lac to -ovo -vege ta rian food serv ice . N u tn R ep In t 198 3 ;27 : 1 99-20 6 .

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te rm effec ts o f a v eg e ta rian d ie t o n the n u trition al sta tus o f e lde rly

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1 9 9 0 ; 9 : 6 0 0 9 .

45 . H elm an A D , D arn ton-H ilI I. V itam in and iro n s tatu s in n ew v eg e-

tan ians . A m J C lin N utr 1 987 ;45 :7 85-9 .

46 . R ed dy 5 , S an de rs T A B . H ae m a to lo g ic al s tud ies o n pre -m eno pau sal

Ind ian and C au cas ian vege ta rians com pared w ith C au cas ian o m ni-

vores. B r J N utr 1 99 0;6 4 :3 31-8 .

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49 . D agne lie PC , van S taveren W A , V ergo te F JV R A , D ing jan PG . van

den B erg H , H au tvast JG A J. Inc reased risk of v itam in B -1 2 an d iron

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1989 ;50 :818-24 .

SO . K im

Y C.

T he effec t o f a vege ta rian d ie t o n the iron an d z in c s ta tus

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A mh e r s t 1988 .

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905 .

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Documents

Iron Status of Vegetarian