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Human lactation

Effect of dietary supplementation on lactation performance of undernourished Burmese mothers

 

Effect of dietary supplementation on lactation performance of undernourished Burmese mothers

Khin-Maung-Naing and Tin-Tin-Oo
Department of Medical Research, Rangoon, Burma

Introduction

An earlier study of ours indicated that maternal undernutrition affects milk output, but that major constituents of the milk - protein, fat, and lactose - are not affected [1]. Improved breast-milk output will provide many nutritional advantages to infants. Increased breast milk intake not only ensures an increase in the infants' nutrient intake but will delay the untimely introduction of supplements, which are often contaminated and therefore hazardous to infants' health.

A study was therefore conducted to see if dietary supplementation of undernourished mothers would improve their lactation. This issue has been controversial. A few studies have been conducted in other countries on hospitalized subjects [2, 3], and many field studies have monitored infant growth without including direct measurement of breast-milk output [4, 5]. The results of those field studies that did measure milk volume are conflicting [6, 7]. The present study describes the effect of food supplementation on the lactation of undernourished Burmese mothers in a poor urban community.

Materials and methods

The subjects included in this study were undernourished lactating mothers (weight for height less than 80% of standard, using standards cited by Jelliffe [8]). They were between 18 and 35 years of age, of any parity, and one to four months post-partum. The women were randomly divided into two groups - 12 women who received a supplement, and 9 controls. The study was conducted in the subjects' home settings. Those in the supplemented group were offered a dish of curry (animal protein cooked in oil) twice a day at mealtimes that was taken with the home diet.

The basal milk output of the mothers and milk intake of the infants were measured for three consecutive days according to the method we reported earlier [1, 9]. These measurements were made again two weeks later, after the supplemented group had received the food supplement for 14 days.

Individual food intake was weighed for three consecutive days for both groups of mothers to provide baseline data. Food intake was also measured for the 14 consecutive days during which the mothers were receiving the food supplements. Energy and nutrient intake was computed using a food composition table for use in Asia and the Far East [10]. The nutrient composition of snacks and of those foods not identified in the table was determined in our laboratory using standard methods.

The mothers' weight, height, and skinfold thickness at four sites-biceps, triceps, subscapular, and supra-iliac areas-were measured at the start of the study and two weeks later. The infants' weights were measured at the same times.

Breast-milk samples were collected between 9 and 10 a.m. at the start of the study and two weeks later. Total nitrogen and non-protein nitrogen (i.e., the nitrogen content of the filtrate after proteins were precipitated by 12% TCA) were determined by the micro-Kjeldahl method [11]. Protein nitrogen was calculated indirectly by subtracting non-protein nitrogen from total nitrogen. A conversion factor of 6.38 was used to convert nitrogen to protein.

TABLE 1. Effect of dietary supplementation on lactation performance of undernourished Burmese mothers

  Milk output ( mean g/day + SE) Infants' milk intake (mean g/day + SE) True protein content of breast milk (mean g/100 ml + SD)
Basal After 2 wks Basal After 2 wks Basal After 2 wks
Supplemented group 661.949.2 787.352.4a 570.542.9 672.953.6b 0.85+0.12 0.880.18
Control 697.950.3 713.3+56.9 618.944.8 615.744.8 0.80+0.16 0.760.15

a. significantly higher than corresponding basal level (p<.001). using Student's t test for paired samples.
b. Significantly higher than corresponding basal level (p<.01k)

TABLE 2. Daily intake of calories and nutrients by mothers in supplemented and control groups (means + SE)

  Calories (kcal/day) Protein (g/day) Fat (g/day) Carbohydrate (g/day)
Basala During
supplemen-
tation
b
Basala During
Supplemen-
tation
b
Basala During
supplemen-
tation
b
Basala During
Supplemen-
tation
b
Supplemented 2,425172 3,331 133 55.84.9 95.2 2.9 49.04.9 95.5 3.7 449.2 14.2 526.8 27.8
Control 2,482210 - 57.83.0 - 43.22.8 - 470 29.2  

Calorie and nutrient intakes of the mothers in the supplemented group during the supplementation period were a significantly higher than the corresponding values for the basal period (p<.001)
a. Mean of 3 days.
b. Mean of 14 days.

TABLE 3. Anthropometric measurements of mothers and infants at the basal point and after two weeks ( means + SD)

  Mothers Infants' weight (kg)
Height (cm) Weight (kg) Sum of skinfolds (mm)
Basal After 2 wks Basal After 2 wks Basal After 2 wks
Supplemented 150.9 3.4 3912.7 39.92.5 34 59.4 37.39.6a 5.14 1.1 5.350.99a
Control 149.14.9 39.12.6 39.33.0 37.59.3 38.57.6 5.140.96 5 30.91a

a. Significantly higher than corresponding basal values (p<.001).

Results

The milk output of the mothers, milk intake of the infants, and true protein content of the breast milk at the basal level and after two weeks are shown in table 1. The milk output of the mothers and milk intake of the infants of the supplemented group were significantly increased (p < .001 and p < .01, respectively), whereas there was no improvement in the lactation of the mothers in the control group. There was no significant difference in the true protein con tent of the breast milk between the basal level and after two weeks in either group.

The mean daily intakes of calories and nutrients in the two groups are shown in table 2. There was an increase in consumption of 906 calories and 39.4 9 of protein per day in the supplemented group during the study compared to basal levels. This was highly significant (p < .001). The increase in carbohydrate intake was due to the increased consumption of cooked rice (staple food), which was eaten together with the supplemented dish.

The anthropometric measurements of the mothers and their infants are shown in table 3. Although the increased weight of the mothers in the supplemented group was not statistically significant, the sum of skinfolds was significant (p < .001), No significant change in weight or in the sum of skinfolds was observed in the control group.

The infants' weight after two weeks was significantly higher than the corresponding basal values in both groups; but there was no significant difference between the groups in infants' weight gain. This may have been due to the short duration of the experiment.

Discussion

Supplementing the diets of undernourished Burmese mothers with an additional 900 calories and about 40 9 of protein (from 55 9 to 95 9) per day for two weeks caused a significant increase in breast-milk production. When the diets of undernourished Indian mothers were supplemented with protein and calories (about 1,000 kcal/day) for 10 days, the average milk yield significantly increased when protein intake was raised from 60 to 100 9 per day; an additional increase of protein intake to 114 g had no further effect on milk output [2]. A dietary protein supplement fed to Nigerian mothers also produced a significant increase in milk output; the increase was usually evident by the third or fourth day, and the maximum response was reached by the seventh day [3]. In a recent field study in Gambia, dietary supplementation of calories and protein had no effect on breast-milk volume, but the protein content was significantly increased [7].

The effect of alterations in mothers' dietary intake on the protein content of breast milk is uncertain. Gopalan [2] reported that protein supplementation of the maternal diet caused a significant decrease in the protein content of breast milk, while Prentice et al. 17] noted a significant increase. Edozien et al. [3] observed no alteration, in agreement with our findings. Forsum and Lonnerdal [12] showed that a low protein diet as well as a high-protein diet resulted in a significant difference in the nitrogen and protein content of the milk of well-nourished lactating Swedish mothers.

The present study demonstrates that it is possible under field conditions to increase the breast milk output of undernourished mothers by dietary supplementation. Supplementation also brought about a significant increase in maternal fat stores.

According to Gopalan [41, the remarkable ability of poor women to breast-feed their infants successfully over prolonged periods should be considered a valuable asset to be preserved and protected. The question has to be considered from the point of view of the mothers as well as the infants, however. Gopalan reported that successful lactation may be achieved at the expense of the undernourished mother's own tissue. Thus the basic problem with regard to infant feeding in poor communities should be directed toward improving maternal diet, so that mothers will be able to provide more breast milk without depleting their tissue stores.

References

1. Khin-Maung-Naing, Tin-Tin-Oo, Kywe Thein, Nwe-Nwe Hlaing. Study on lactation performance of Burmese mothers. Am J Clin Nutr 1980;33:2665-2668.

2. Gopalan C. Effect of protein supplementation and some so-called galactogogues on lactation of Indian women. Ind J Med Res 1958;46:317-324.

3. Edozien JC, Rahim Khan MA, Waslien Cl. Human protein deficiency: results of Nigerian village study. J Nutr 1976; 106:312328.

4. Gopalan C. Studies on lactation in poor Indian communities. J Trop Pediatr 1958;4:87-97.

5. Herra MG, Mora JO, de Paredes B. Wagner M. Maternal weight/height and the effect of food supplementation during pregnancy and lactation. In: Aebi H. Whitehead RG, eds. Maternal nutrition during pregnancy and lactation. Bern: Hans Huber, 1980:252-263.

6. Chavez A, Martinez C. Effects of maternal undernutrition and dietary supplementation on milk production. In: Aebi H. Whitehead RG, eds. Maternal nutrition during pregnancy and lactation. Bern: Hans Huber, 1980:274-284.

7. Prentice AM, Roberts SB, Prentice A, Paul AA, Watkinson M, Whitehead RG. Dietary supplementation of lactating Gambian women. l. Effect on breast-milk volume and quality. Hum Nutr Clin Nutr 1983;37(C):53-64.

8. Jelliffe DB. The assessment of nutritional status of the community. WHO monograph series, no. 53. Geneva: W H O. 1966: 240-241.

9. Tin-Tin-Oo, Khin-Maung-Naing. A comparison of milk out put of Burmese mothers by three different methods. Food
Nutr Bull 1982;4(41:66-68.

10. Food and Agricultural Organization. Food composition table for use in Asia and Far East. Rome: FAO, 1972.

11. Varley H. Practical clinical biochemistry. London: White friars Press, 1963.

12. Forsum E, Lonnderdal B. Effect of protein intake on protein and nitrogen composition of breast milk. Am J Clin Nutr 1980;33: 1809-1813.


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