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close this bookMaternal Diet, Breast-Feeding Capacity, and Lactational Infertility (UNU/WHO, 1983, 107 pages)
close this folder3. Effect of diet on maternal health and lactational performance
View the document(introductory text...)
View the documentBody size and composition
View the documentProtein status of the mother
View the documentMaternal vitamin status
View the documentDiet and breast-milk composition
View the documentDiet and the quantity of milk produced
View the documentThe effect of maternal dietary supplementation on milk output and composition
View the documentGeneral conclusion
View the documentReferences

Diet and the quantity of milk produced

3.15. The general consensus is that the content of the proximal constituents of milk can be maintained within remarkably normal limits even in markedly undernourished mothers, and it is considered more likely to be the total volume produced that suffers. A major problem in defining the precise effect on volume is that we do not know with any degree of certainty how much milk one can expect from the average healthy, well-nourished mother. An arbitrary value of 850 ml has been used for theoretical calculations, but most measured, mean values in the industrial world have been less than this. In virtually every country so far investigated, volume rises steeply during the first month of life, but, as shown in figure 9 (see



FIG. 9. Mean Daily Breast-milk Outputs during Infancy from Various Sources Compared with the Range Needed to Meet Estimated Requirements, Based on the Mean Values of the Department of Health and Social Security (DHSS) (36) (Source: ref. 31))(31), the rate of rise in milk output then falls off dramatically and total volumes quickly become less than those theoretically needed to satisfy energy requirements as the child grows older and larger. From table 10 it seems reasonable to conclude that the mean maximum volume in a wealthy country is more likely to be 700-800 ml than 800-900 ml.

TABLE 10. Milk Output (ml/24h) of Well-nourished Mothers from Industrialized Societies

 

Month of lactation

Author

Country

1

2

3

4

5

6

Wallgrena
(24)
Sweden

610

727

766

784

-

778

 

(416-839)

(508-964)

(497-1,029)

(577-1,065)

 

(510-1,123)

Lönnerdal
et al. (17)
Sweden

724

752

-

-

756

-

 

(490-958)d

(575-929)d

   

(476-1,036)d

 
Hofvander
et al.b (25)
Sweden

660

755

780

795

566

450

 

(380-860)

(575-985)

(600-930)

(560-1,045)

(170-950)

(50-1,145)

Whitehead
and Paulb (26)
UK

740

785

784

717

588

493

 

(480-1,059)

(380-1,235)

(280-1,114)

(210-1,091)

(183-1,020)

(135-906)

Chandraa (27) Canada

-

-

793

856

925

872

       

(651-935)d

(658-1,054)d

(701-1,149)d

(602-1,124)d

Rattigan
et al.bc (28)
Australia

1,187

1,238

-

-

-

1,128

 

(799-1,611)

(862-1,543)

     

(608-1,610)

Pao et al.b
(29)
USA

569

-

523

-

-

436

 

(398-989)

 

(242-1,000)

   

(147-786)

Picciano
et ala (30)
USA

606

601

626

-

-

-

 

(336-876)d

(355-847)d

(392-860)d

     

a. Exclusively breast-fed.
b. Includes mixed feeding.
c. Data obtained by weighing the mother, not the child (see text, 3.16).
d. Ranges calculated from mean ±2SD.

It is unwise, however, to think only about mean values; the range in Cambridge around two to three months is 4901,115 ml, and in Sweden the corresponding range from Holvander's data is 600-930 ml. An important and as yet unanswered question is whether mothers with low milk outputs did not have the capacity to produce more milk, or whether a whole variety of social and biological constraints were acting against them, such that they were functioning well below their maximum capacity.

3.16. The highest volumes reported in recent times are those from Hartmann's group in Western Australia (28). These values were obtained by test-weighing the mother. This method is highly correlated with the more usual method of test-weighing the baby. The regression co-efficient of 0.8 indicates that higher values are obtained by weighing the mother. Most of the difference between the two procedures is due to the sweating losses of both the mother and baby. Thus, the mean value for Western Australian mothers at two to three months compared with the European data would be around 1,000 ml rather than 1,200 ml. Clearly, even this value is significantly greater than any others that have been published, with the exception of old reports on "wet nurses" (37). The upper level of Hartmann's data is around 1,600 ml.

It is of obvious importance that the apparently much greater ability of Western Australian mothers to produce milk should be confirmed on a larger representative number of mothers from that community, and that the detailed and varied advice provided by the Australian Nursing Mothers Association is objectively evaluated to determine any crucial difference between European and Australian nursing practices. Recent evidence of the high incidence of breast-feeding in a wider range of Western Australian mothers is provided by the prospective growth study of Hitchcock and Owles (38), who found that 64 per cent of mothers were still breast-feeding at six months.

3.17. The study of twins and the mother's ability to feed two babies rather than one is also likely to be informative. Although twins, in the Third World, frequently suffer from infantile malnutrition, there is evidence that mothers in the industrialized countries can respond by producing milk well in excess of the normal range for singletons. Data obtained by Hartmann in Western Australia (39) on milk outputs in mothers with twins compared with mothers of single infants are given in figure 10 (see



FIG. 10. Milk Outputs of Western Australian Women Breast-feeding Twins and Exclusively Breast-feeding Single Babies (Source: ref. 39)). This indicates that the greatly enhanced capacity exists only for the first six months of lactation.

3.18. The importance of the plane of nutrition on milk production has been extensively studied in dairy cows, and feeding standards based on the level of milk production have long been considered to be an important determinant of the profitability of the dairy industry. The influence of maternal diet on the level of milk production in women is much less clear. A summary of a number of studies on breast-milk consumption in developing countries is given in table 11. The ranges for the different countries are remarkably similar to those in table 10 for affluent countries. Mean values are, however, generally about 100 ml/d less at two to three months, though the mothers continue to breast-feed for much longer. These data are surprising when one considers the gross differences in dietary intake between the two types of country. The possibility exists, however, that the European mothers could have produced more milk if they had adopted different feeding practices, such as by feeding more frequently as is the custom in Western Australia, and thus the true effect of a poor diet might be masked. There is an obvious need for the optimization of milk production to be studied in wealthy countries as well as in poor ones.

There is evidence, however, that when food-energy intake falls to exceptionally low levels the mother's capacity to adapt is exceeded and milk output falls dramatically. This is illustrated in figure 11 (see



FIG. 11 Seasonal Variation in Energy Intake and Breast-milk Output in the Gambia (Source: ref. 1)), which describes the situation in the Gambia (1) during the rains when food energy intake in August-September drops to as low as, 1,100-1,200 kcal/d. Milk output drops markedly, but the mean volume of milk produced during the 12 hours of daylight is still 280 ml, which corresponds to around 600 ml/24 hr. Values of around 500-600 ml/d have also been reported from India by Gopalan (41), from Zaire by Vis et al. (34), by Van Steenbergen in Kenya (32, 33), and Martinez and Chavez from Mexico (35).

TABLE 11. Milk Output (ml/24h) of Women from the Developing World

Author and country

Month of lactation

1 2 3 4 5 6 7-9 9-12
Holemans et al.
(40)
               

436

405

380

417

415

-

323

-

Zaire                
Hennart and Vis
(34)
               

517

-

605

-

-

525

580

582

Zaire

(250-780)

 

(390-920)

   

(180-1,080)

(210-950)

(270-850)

Van Steenbergen et al. (32, 33)

-

675

-

-

555

-

487

-

Kenya  

(271-1,079)a

   

(189-921)a

 

(153-821)a

 
Martinez and                
Chavez (35)

-

577

-

537

-

561

-

462

Mexico  

(433-842)

 

(455-663)

 

(432-850)

 

(337-670)

Prentice et al.

-

677

-

-

617

-

595

542

Gambia
(unpublished data)
 

(525-1,055)

   

(355-885)

 

(435-744)

(210-730)

               

a. Ranges calculated from mean ±2SD.

Vis, from his work in Zaire (34), has suggested that milk output may be more affected in primary protein deficiency than in energy deficiency, hence the particularly low values in the Kivu province of Zaire. It is also possible that similar deficiencies may have existed in the Kenya study. It may be concluded that, to be sure of the effect of diet on breast-milk output, both variables, protein and energy intake, need to be measured. We need to determine unequivocally whether dietary composition, particularly a limiting protein content, is associated with an especially reduced milk production.

3.19. The major problem in comparing milk outputs between countries is the difficulty of doing so with a sufficient degree of precision. The test-weighing procedure inevitably interferes with normal life-styles and the interaction between the mother and her child: the child has to be separated from the mother at the beginning and end of each feed, even if just for a short time. Another problem is that the weight difference at each feed can be quite small. In Europe, where women feed their babies on average four to eight times per day, typical weight differences range between 100200 9, while in the developing world, where a child may be fed 10-15 times, this value is only 30-100 9. It is also necessary to modify the procedure to fit in with local circumstances and customs. With such scope for measurement error it is surprising there is so much uniformity in the data emerging from different parts of the world.

3.20. The net benefit of breast-milk to a child clearly depends on the product of volume and nutrient content. Table 12 shows such calculations made by Rajalakshmi (3) for lower and higher income families in India relative to the NRC RDA (42). As might be expected from the discussion in previous sections, infant energy and protein intakes exhibit relatively moderate deficits (20-25 per cent), while folate, vitamin A, and iron intakes suffer dramatically; intakes are of the order of only 10 per cent of the recommended value. Clearly, the effect will be different for different countries; in Ethiopia, for example, infant riboflavin intake would be more affected than in India, while iron intake would be relatively satisfactory.

TABLE 12. Nutrients Derived by Indian Breast-fed Babies as Compared with Recommended Allowances a

 

Low-income
group

High-income
group

Recommended
allowances
NRC (1974) (42)

Food energy
(per kg body-weight)

90

97

117

Protein (9)
(per kg body-weight)

1.6

1.6

2.2

Calcium (mg)

230

230

360

Iron (mg)

1.2

1.3

10

Vitamin A (µg)

21

42

420

Thiamin (mg)

0.084

0.112

0.15

Riboflavin (mg)

0.168

0.217

0.20

Pantothenate (mg)

0.942

1.288

-

Niacin (mg)

0.791

1.057

2.5

Cyanocobalamin (µg)

0.063

0.077

0.15

Biotin (µg)

1.13

2.17

-

Pyridoxine (µg)

60.9

70.0

150

Folate (µg)

1.54

2.17

25

a. Calculated from milk composition data for 700 ml milk.
Source: ref. 3.