8/10/2019 Am J Clin Nutr 1976 Lnnerdal 1134 41

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1134

T h e A m e ric an Jo u rn a l o f C lin ica l N u tri tion 2 9: O CT OB ER 1976 , pp . 11 34 -11 41 . P rin ted in U .S .A .

B reas t m ilk com pos itio n in E th iop ian and

S w ed ish m o the rs . II. L ac to se n itro gen and

p ro te in con ten ts13

Bo L {246}nnerdal 4h.D. El isabeih Forsum 5 Ph.D. Mehari Gebre-Medhin 6 M. D. M.P.H.

a nd L eijH ar nb ra eu s 7 M

ABSTRACT B reas t m ilk from underp riv ile ge d a nd p riv ile ged E th io p ia n m othe rs w as co llec ted a t

d iffe ren t s ta ge s o f lac ta t ion a nd ana lyzed fo r to ta l n it rog en , no np ro te in n itroge n , lac tose , a nd

ind iv id ua l m ilk p ro te in s (la c to fe r rin , is -lac ta lbum in , se rum a lbum in , IgG and 1gM ). T he se va lu es

a nd th e m ilk vo lum e o f on e m ea l w ere com pared to co rrespo nd ing re su lts from w e ll-no u r ish ed

Sw ed ish m oth e rs . N o s ign ifica n t d iffe ren ce s b e tw een the le ve ls o f th ese con stituen ts o r the m ilk

v o lum es w ere fo un d be tw een th e tw o g rou ps o f E th io p ia n m oth e rs . W hen com pa ris on wa s m ade be -

tw e en brea s t m ilk from th ese tw o E th io p ia n g ro ups an d th e Sw ed ish g ro up , th e fo rm e r tw o sh ow ed

s ign ific an tly h igh e r v a lu es fo r th e iro n -b in d in g p ro te in lac to fe rrin . Am J C / in N u t r 2 9: 1 13 4-

1141 , 19 76 .

Hum an m ilk is the firs t food a fte r b irth fo r

the m a jo r ity o f ch ild ren . In m any coun tr ie s ,

e spec ia lly the deve lop ing ones , it is the on ly

food up to the age o f 4 to 6 m on ths . B reas t

m ilk is by na tu re ex trao rd ina r ily w e ll adap ted

to the needs o fthe in fan t and its supe rio r ity in

feed ing in fan ts has been und ispu ted th rough -

ou t the yea rs . The es tim a ted requ irem en ts o f

in fan ts fo r p ro te in s (1 ) and m any o the r

nu trien ts a re , the re fo re , based on the com -

pos ition o f b reas t m ilk . B reas t-fed in fan ts a re

le ss liab le to in fe c tions than bo ttle - fed in fan ts

(2 ). In a reas whe re nu tritio na lly adequa te

supp lem en ta ry foods a re sca rce b reas t m ilk is

a va luab le supp lem en t dur ing the second yea r

o f life .

C oncom itan t w ith the in creased ava ilab il-

ity and use o f a rtific ia l fo rm u lae a dec lin ing

trend in the frequency and du ra tion o f b reas t

feed ing has been obse rved in m ost pan ts o f the

w orld in recen t yea rs (3 , 4 ). A lthough nu tri-

tio na lly adequa te fo r the m a in tenance o f

g row th these a rtific ia l subs titu te s la c k som e

o f the un ique fea tu res o f hum an m ilk . B reas t

m ilk , fo r exam p le , con ta in s subs tan tia l

am oun ts o f secre to ry IgA (5 ) and the iron -

b ind ing p ro te in la c to fenn in (6 ) bo th o f wh ich

a re know n to enhance res is tance to in fe c tion .

B reas t m ilk a lso con ta in s com pa ra tiv e ly h igh

le ve ls o f the enzym e ly sozym e (7 ), w h ich is

capab le o f deg rad ing bac te ria l ce ll w a ll, and

re la tiv e ly lange am oun t o f a B 52-b ind ing p ro -

te in tha t has been show n to com pe te w ith

B 12 -rem ov ing m icroo rgan ism s the reby ac ting

bac ten io s ta tica lly (8 ). A no the r un ique fea tu re

is the pa tte rn o f essen tia l am ino ac id s and the

h igh con ten t

o f nonp ro te in n itrogen

( NPN )

(9 ).

It has been p roposed tha t the quan tity and

qua lity o f b rea s t

m ilk a re adve rse ly a ffe c ted

by m a te rna l unde rnu tr itio n bu t h ithe rto con -

duc ted s tud ie s a re in conc lu s ive . G opa lan (10 )

showed tha t the g row th pa tte rn o f b reas t- fed

in fan ts be long ing to unde rnou rished m o thers

w as sa tis fa c to ry , sugges ting adequa te m ilk

p roduc tion . These resu lts have subsequen tly

been con firm ed by o the r au tho rs (Il, 12 ). In

F rom th e In s ti tu te o f N u tr itio n , U n iv e rs ity o f U pp -

s a la Box

551 S -75 1 22 Uppsa la , Sw eden and th e

E th iop ian Nu trit ion Ins titu te , Ad d is Ababa .

2 Th is pa per is a lso lis ted as no . I II in th e se r ies Th e

pro te in co n te n t o f hum an m ilk p ub lis hed by th e Ins ti-

tu te o f N u tr itio n , U ppsa la .

F inanc ia l s upport w as p rov ided by the Swed ish

International Development Authority S IDA) and t he

Swed ish M ed ica l R e sea rch C ounc il (M FR ) (p ro je c t no .

B 7 6- 1 9 X- 47 2 2- Ol .

A ss is ta n t P ro fe sso r o f N u tri tion . A s s is tan t

P ro fes so r o f N utr itio n .

6

D irecto r, E th iop ian Nu tri-

tio n In sti tu te .

Pro fe sso r o f N u tritio n , Institu te o f

Nu trit ion , U ppsa la .

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BREAST MI LK COMPOSI TI ON

1 1 3 5

c on tras t, som e inv estiga to rs have show n re -

duc ed lacta tion pe rfo rm anc e in m a lnou rished

w om en (13 , 14 ). O f spec ia l in te rest a re the

obse rva tions m ade by D eb and C am a (15 )

and o f L indb lad

and

R ah im too la (16 ), ind i-

c a ting im pa ired p ro te in qua lity in the m ilk

from seve re ly m a lnou rished m o the rs .

The p res ent s tudy describes the p ro te in

c om position o f m ilk from m o the rs be long ing

to tw o d iffe ren t s oc ioec onom ic g roups in

E th iop ia . T he resu lts ob ta ined a re com pa red

to no rm a l da ta , repo rted ea rlie r (17 ), w h ich

a re based on m ilk sam p les c o llec ted from

w e ll-nou ris hed S w ed ish m o the rs .

M aterial

Ethiopia

T h e E th iop ian m o th e rs w e re a ll rec ru ited fro m a

c om pre he ns iv e s tu dy o f th e nu tri tion a l as p ec ts o f p re g -

na nc y an d lac ta tion d irec ted by E th io p ia n N u tritio n

Ins titu te (E N I). T he y rep re s en t tw o d if fe ren t s o c io ec o -

nom ic g rou ps .

Th e nonprivileged group c om pr is in g 78 m othe rs ,

w as selected from a m unicipal antenatal clinic in the

K irk os a re a o f A dd is A b ab a . A ll the m o the rs w e re

illite ra te a nd h ad a fam ily inc o m e o f le s s than E th $ 10 0

(Eth $1 .00 = U S $ 0 .50 ). T h is g ro up c o ns um es a

m onotonous d ie t w ith a n av e ra ge d ie ta ry p ro te in and

energy intake less than 6 0% o f tha t rec om m e nd ed by

F A O /W H O . O f the p ro te in 97 % is o f p lan t o rig in . In

e ffec t, th is d ie t is in ad equ a te in a ll re s p ec ts e x c e p t fo r

iro n an d th ia m in e (18 ) .

Th e privileged group

compr is ing

26 m oth e rs . w e re

re c ru ite d fro m a n an te na ta l c lin ic fo r p ay ing pa tie n ts in

the D epartm ent of O bstetrics and G ynaecology, A ddis

Ababa U n iv e rs ity ( fo rm e rly H a ile S e la s s ie U n iv e rs ity ) .

B o th the m o the rs a nd the ir s p ou s e s in th is g rou p had

com pleted at least secondary school education and their

fa m ily inc om e w a s g ene ra lly ab ov e E th $ 600 p e r m o n th .

T he d ie ta ry in tak e o f e ne rgy an d n u tr ien ts in th is g rou p

w as a m p le (18 ).

T he s tud y w as c on du c te d d u r ing the p e r iod A p ril to

Septem ber 19 73 . H ea lthy , la c ta tin g m o th e rs w ith ou t

g lu c os u ria o r a lbu m in u r ia , w ith n o rm a l b lo od p res s u re ,

a nd ha v in g no c lin ic a l s y m p to m s o f a c u te o r c h ro n ic

d is e as e w e re s e le c te d c on s e c u tiv e ly fro m b o th c lin ic s .

Further data related to dietary intake, hem atological,

a nd b io ch em ic al c ha ra cte ris tic s

in

th e th ird t r im es te r o f

pregnancy are presented elsew here 18, 19; M . G ebre-

M edhin et al., m a nuscript in preparation .

Sweden

T h e S w ed is h g ro up o f m o the rs w e re a ll he a lth y an d

s oc ioe c o no m ic a lly an d ed uc a tio na lly p riv i leg ed . In c om -

m o n w ith p rac tic a lly 1 00 % of c on te m p ora ry S w ed is h

m o thers they all gave birth to the ir b ab ies in a hos p ita l

and stayed in the w ard during S to 7 d ay s a fte r th e

de l i v e r y .

M ethods

M ilk c olle ctio ti

Ethiopia S a m p le s w e re c o lle c te d in the m o rn in g a t a

s pec ia l c lin ic a t

E N I. M o th e rs w e re in s truc ted no t to

b re as t-fe ed the ir c h ild ren a fte r m idn igh t p r io r to m ilk

c o llec tion . T h e m ilk s a m p le s w e re ta k en a fte r ov e rn ig h t

fa s ting ( fo r th e p u rp os e o f b lo od c o lle c tio n ) . B o th b reas ts

w ere em p t ied u s in g an e lec tric p um p (S is te r M a ja s

b re as t p um p ; P u m p E gn e ll A B , T ro l lh# {22 8 } ttan , S w ede n ) , o f

the ty pe u s ed in S w ed en fo r m a ny y e a rs . P um p ing w as

c o n tin ue d un t il m ilk no lon ge r app ea re d in je ts bu t

m ere ly in a tric k le o r d ro p -w is e . A ll s am p le s w ere

c o llec ted by on e p e rs on an d , a fte r re g is tra tion o f v o lum e ,

w ere p la c e d in a de ep free z e a t -20 C w ith in les s tha n I

h r a fte r c o llec tio n . T he s am p le s w e re s u bs e qu en tly

t ran s p o rted in a froz en c o nd itio n to S w ed en by d irec t

fligh t in spec ia l con ta ine rs w ith d ry ic e a nd s to red a t

-7 0 C .

Sweden

M ilk s a m p les fro m th e s e c o nd m e a l o n th e

4 th an d 5 th d ay p os t pa rtu m w e re c o llec ted by a n u rs e

w h ile th e m o th e r w as s t ill in the m a te rn ity w a rd . M o the rs

w ho s e c h ild ren w e re 3 w ee k s o ld o r o lde r w e re v is ited in

the ir ho m e s by a n u rs e . T he d ay be fo re the s a m p le s w ere

c o llec ted , the m o th e r w as ins tru c te d on h ow to w e igh th e

c h ild be fo re an d a fte r e ac h fe ed ing th rou gh ou t 24 h r

s ta rtin g ea rly in th e m orn ing . O n the s a m p lin g da y . th e

n u rs e v is ited the m o the r a t the s ec on d m ea l o f the da y

w he n th e in fan t w a s a llo w e d to nu rs e on o ne b rea s t w h ile

the o the r w as e m p tie d b y pu m p ing . A fte r m ix in g , a 20 -m I

a liqu o t w as tak en fo r an a ly s is an d th e res t o f th e m ilk

wa s

o ffe re d to th e c h ild . In s om e in s ta nc es s a m p le s w ere

k ep t in a n o rd in a ry re frig e ra to r fo r up to I w e ek b e fo re

b e in g p lac e d in a d eep free z e a t -7 0 C .

F u rthe r de ta ils reg a rd ing th e c lin ic a l m a te r ia l an d

s am p ling p roc edu re s in bo th th e E th io p ia n a nd S w e d is h

groups a re found in

the firs t o f the s e s e rie s o f inv e s tiga -

t ion s (2 0) .

A na lvtica l proce dure s

M etho ds fo r es t im a tio n o f to ta l n itrog en , N P N , lac -

to fe rrin , s e rum a lb um in , a - lac ta lbu m in , lg G , 1g M , an d

lac tose a re g iven in a com pa n ion pa per. In fo rm a tion

re ga rd ing th e s ta tis tic a l ev a lu a tio n c a n a ls o b e fo un d in

th is pa pe r (1 7 ).

R esults

The n itrogen d is tr ibu tion , lac tose c oncen -

tra tion , and m ilk vo lum e o f the firs t m ea l o f

th e d ay fo r e ac h pe rio d o f lac ta t ion fo r

E th iop ian and S w ed ish m o the rs a re s how n in

T ab le 1

.

The ind iv idua l va lues o f to ta l n itno -

gen and nonp ro te in n itrogen ob ta ined from

the E th iop ian m o the rs a re com pa red w ith the

S w ed ish no rm al m a te ria l in F igu re 1 . The

to ta l n itrogen conc entra tion dec reases rap id ly

du ring the firs t 20 days o f lac ta tion to reach

the leve l o f m a tu re m ilk . A s show n in T ab le I

the n itrogen concen tra tion in one o f the

8/10/2019 Am J Clin Nutr 1976 Lnnerdal 1134 41

3/8

T ot al n it r og en #{149 }non -pnv i teged

p r i v i L e ge d

*non - p r i v i t eged

N on -p ro te in n itro ge n

A

pr i v i Leged

8

2O

1. 0

.. S { 1 4 9 }

.. 8 #{149}

S.

2 I t

.

, I . .

I I 3 6

L ONNE R D L E T L

F IG . I

.

C on c e n tra tio ns o f to ta l n it rog en a nd n on p ro te in n itrog en in m ilk from E th io p ian m o the rs b e lo ng ing to tw o

soc ioeconom ic g roup s com pa red to

m ilk from w e ll-no u r is h ed S w ed is h m o the rs . S o lid lin e in th e m idd le o f striped

area = re g re s s ion l ine fo r th e S w e d is h m a te r ia l. S trip ed a rea = to le ran c e in te rv a l to th e re g re s s ion line .

T B L E I

N itro gen d is trib u t ion , la c to s e c o nc en tra tion , a nd m ilk v o lum e (firs t m e a l o f the d ay )a

M on ths post

p a r t u m

0-0 .5 0 .5 I .5 I .5 3 .5 3 .5 6 .5 6.5

T o ta l n it ro gen

( mg /mI )

E th . n o np ri vi le g ed

Eth .p r i v i l eged

S w e. p riv ile ge d

3 .14

0 .83

3 .0 5 0 .5 9

2 .50 O . l7

2 .89 0 .59

1 .93

0 .24

1 .77

0 .33

1 .97 0 .29

1 .61

0 .21

1 .69

0 .30

1 .48 0 .17

1 .74

0 .30

N PN

( mg /mI )

E th . n o np ri vi le g ed

E th . p ri vi le g ed

S we . p ri vi le ge d

0 .46 0 .06

0 .53

0 .09

0 .43 0 .05

0 .46 0 .08

0 .46

0 .03

0 .36 0 .05

0 .41 0 .05

0 .41

0 .04

0 .34 0 .05

0 .38

0 .07

0 .33 0 .05

Lac tos e

w /v )

E th . n on p ri vi le g ed

E th . p riv ile ge d

Sw e. p riv ileg ed

6 .46

0 .89

5 .93 0 .58

7 .42

0 .51

6 .60

0 .63

7 .02 0 .56

7 .43 0 .48

7 .64

0 .16

7 .33

0 .47

7 .49 0 .31

7 .64

0 .35

7 .78 0 .48

Mi l k v o l u me

m )

Et h . nonpr i v i l e ge d

Et h . p r i v i l e ge d

Swe . p r i v i l e ge d

1 9 7 94

1 5 7 13 1

16 9 91

1 2 4

26

15 3 66

12 6 61

14 5 4 4

18 8 8 8

2 0 6 7 0

1 0 9 72

n

Et h . nonpr i v i l e ge d

Et h . p r i v i l e ge d

S w e. p riv il eg ed

S

15

3

I S

12

1 4

S

12

2 6

11

4 5

2

V a lu es a r e m ea n

S D . S ig n if ic a n tly h ig he r tha n th e c o r res po nd ing v a lue from S w e d is h m o th e rs (0 .0 01

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