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Hunger and health

Breast-feeding in Xinhui district in South China
Iron, immunity, and infection: is there a causal link?

Breast-feeding in Xinhui district in South China

Zhi-Chien Ho
Vice-Director, Faculty of Public Health, Zhong Shan Medical College, Guangzhou, China

INTRODUCTION

Human breast milk is recognized as one of the most nutritious foods for the human infant, and breast-feeding has long been the traditional practice in most areas in Guangdong Province in China. An important question is how long breast milk can provide nourishment sufficient to meet the needs of a growing child and what critical factors influence current feeding practices. To investigate this question, an area in Xinhui District was surveyed. This area is located about 160 kilometres south of Guangzhou (Canton) in Guangdong Province. It is typically rural, with average economic and cultural conditions. Rice is the staple food. In the agricultural off-season, industrial crops are raised as well. Other secondary occupations include some stock raising, fishing, and handicrafts.

MATERIALS AND METHODS

Breast-feeding practices were investigated in six production brigades (one brigade usually has a population of about one to three thousand). Two hundred and eighteen mothers and their babies were visited and studied individually, and all mothers with babies under one year old were visited by our medical team with the assistance of the local doctors. Investigations were carried out along the following lines:

1. The examination of each infant included dietary and medical histories from birth to the time of the survey, as well as anthropometric measurements. The average height and weight of the babies in this region were compared to those of babies of the same ages in the city of Guangzhou or other places. For purposes of comparison, babies under one year old were divided into five grades using the upper and lower limits of one and two standard deviations of their weight from a reference standard based on well nourished infants in Guangzhou.

2. A balance scale sensitive to 10 grams was used for measuring the change in weight of the babies before and after a full breast-feeding. Using these measurements, the average of total milk volume provided daily by the mother was determined from two types of data: (i) the average volume of 62 random, single feedings was multiplied by the average number of feedings daily; (ii) the total weight of milk fed in one day was obtained by measurements for 12 individual mothers. The measurements were made by a female doctor who remained in the mother's house during the 24-hour period.

3. The feeding pattern and conditions surrounding lactation were observed. Attention was given to cases in which mothers complained of lack of milk. The method of evaluating this complaint of "lack of milk" was to compare the infant's weight with the median line of the reference standard, and to determine whether the mother used substitutes as the main food before three months. Consideration was also given to the perception of the mothers.

4. The dietary habits of the mothers during the period of breast-feeding were investigated by determining their food intake using a 24-hour recall of dietary intake. The accuracy of the data was improved by knowledge of the minimum ration provided by the local government and the amount of food purchased from the market each week. From this, the total was determined by interviewing the mother. The daily intake of nutrients was calculated from a food table (1).

Foods that the mothers claimed affected or promoted their milk secretion were also listed.

RESULTS

All but one of the 218 mothers in six production brigades breast-fed their children (the one exception used artificial feeding because of illness). That is, more than 99 per cent of the mothers chose breast-feeding. The average body weight of the infants up to one year old in Xinhui District was slightly but significantly lower than that of infants of the same age in Guangzhou measured in 1978 by the public health authority (tables 1 and 2).

TABLE 1. Body Weights of Xinhui and Guangzhou Infants (1978)

Average weights in kg and SE.

TABLE 2. Grades of Body Weight of 112 Infants One to Nine Months Old in Xinhui

Grade	Number	%
Highest ( >+2SD)	1	0.9
High (+1 SD < < +2 SD)	19	16.96
Medium ( ± 1 SD)	82	73.21
Low ( - 2 SD < < - 1 SD)	6	5.36
Lowest (< - 2SD)	4	3.57

TABLE 3. Total Quantity of Breast Milk Consumed in 24 Hours of Feeding (in Grams)

* The mother claimed her milk was inadequate.

1. The Quantity of Milk Fed

The average quantity of milk ingested per 24 hours by one to six-month-old infants was estimated by multiplying the weight change before and after a full feeding by the average feeding frequency. There were variations apparent in the intakes among babies of the same age. In 62 random single measurements, the minimum quantity per feeding was about 50 g and the maximum 210 g. The average amount per feeding was 108 ± 42 g, and the average frequency of feeding in 24 hours was 7.8 ± 1.7 times. Hence, the average calculated total daily intake of an infant under six months old is approximately 7.8 x 108 = 845 g, ranging from 600 to 900 g.

The intake of 12 infants, also determined by the weight change method but followed for a 24-hour period, averaged 868 ± 177 g and ranged from 625 to 1,180 g (table 3). Thus, the two average outputs determined by two different methods were in close agreement. The volume of milk secreted did not increase in parallel with the infant's growth after four months post-partum. It is likely that breast milk alone may provide an infant with a caloric intake of 95 kcal/kg and a protein intake of 1.87 g/kg under normal conditions in the first and second months of life but not beyond three or four months.

According to the above-stated criterion for determining inadequate milk output, 19 of 114 mothers (16.6 per cent) lacked sufficient milk to different degrees according to this relatively objective observation When the percentage of mothers who were "lacking milk" was based on the mother's perception, however, the rate was higher, especially for those with infants older than five months (table 4).

2. The Nutritional Status of Breast-feeding Mothers

Dietary evaluation was made for each of the 114 breast-feeding mothers with babies one to six months old. Mothers were divided into three groups according to the age of their babies: (i) mothers of children younger than three months old; (ii) mothers feeding three- to six-month-old infants; and (iii) mothers nursing babies over six months of age (table 5). Over all, the average daily nutrient intake was best in group 1, but when nutrient intake was calculated separately for mothers with adequate milk and for mothers with inadequate milk within each group, there were significant differences (p < 0.05) between the two subgroups (table 6), especially in protein and calorie intakes.

The main food in this district is rice, which is complemented by different amounts of beans, peanuts, pork, fish (mostly preserved by salt), green vegetables, vegetable oils, and a small amount of sugar. Plant sources contribute the main component of the mothers' food. Protein of animal origin was 30 per cent of the total protein intake in group I, and 22 per cent and 23 per cent in groups II and III, respectively. It is customary for the people in the rural areas of Guangdong to treat with esteem the mother who has just delivered and begun to breast-feed her baby, especially if the baby is a boy, and to pay special attention to the new mother's diet. After one to two months, however, people may not show the same degree of concern about what she eats. The total protein in the diet of lactating mothers in this study was higher for the first and second months after delivery, although the proportion of available protein calories remained about 10 per cent because the increase in protein intake at this stage was always accompanied by an increased intake of calories as well.

TABLE 4. Feeding Conditions of 114 Infants One to Six Months of Age, Based on Mother's Perception of Milk Adequacy

* Deficit of milk as perceived by the mother, expressed as a fraction.

TABLE 5. Average Daily Nutrient Intake of Mothers

* Group I, mothers with infants under three months old; group II, mothers with infants three to six months old; group III, mothers with infants over six months old.

TABLE 6. Caloric and Protein Intake of Mothers with "Adequate" and "Inadequate" Breast Milk

* As in table 5.
The difference in caloric intake between adequate and inadequate sub-groups is significant in all three groups (p < 0.05).
The difference in protein intake within group l is significant between the two sub-groups (p < 0.05).

The remaining calorie intake of the mothers was largely provided by carbohydrates, i.e., 67 to 70 per cent of total calories consumed, with a small percentage coming from fat. Calcium and riboflavin were relatively low in the diets, but symptoms of riboflavin deficiency have not been observed.

3. The Addition of Supplementary or Weaning Food to the Infants' Diets

Half of the infants at three months post-partum were not fed any supplementary food, and one-quarter of the infants six to eight months old were not given any weaning food in addition to breast milk. The common practice is to breast-feed for up to one year (table 7). Some of the mothers either were not aware of, or did not recognize, the full importance of giving supplementary foods to their babies at the proper time and in sufficient quantities, or they simply were unable to obtain such foods. Most of the mothers' practices are guided by their own family traditions -habits that are quite different among villages and even families-and are also influenced by variations in economic conditions.

The basic component of baby food used for supplementation is rice and products made from it in the home, such as gruel, soup, and rice-flour paste. Minced fish, pork, and sometimes different forms of egg are added to the basic rice dish. The quantity depends largely on how much the baby will accept. Cow's milk is not common in villages; fruit and vegetable purees are not usually given, although some mothers give diluted vegetable purees in spoonful quantities. In our survey, no significant clinical nutritional symptoms were observed, other than a body weight lower than average in some babies.

4. Foods Thought by Mothers to Promote Milk Secretion

There were four kinds of foods that mothers perceived as their first choices for improving the secretion of breast milk:

a. Concentrated soups made from pigs' legs or tail bones cooked with either beans or peanuts or from fish tails boiled with papaya or coconut. Forty-five per cent of the mothers in this survey said that these white, milky emulsions were effective for them .

b. Just after delivery, or at the beginning of breast-feeding (these mothers begin nursing shortly after delivery, thus providing their infants with the anti-infective protection of colostrum), a concentrated soup is made from pigs' legs boiled with ginger in vinegar without water. Sometimes hard-boiled eggs are added, or rice wine is used in place of vinegar. This soup can be preserved for a long time and thus may be eaten daily in different amounts after heating. All mothers claimed that they like to eat this soup, and 23 per cent of them suggested that, in their experience, it was quite effective in promoting milk secretion.

c. Salt-preserved marine fish, including small fish that are often eaten with the bones, are a very common food in this sub-tropical part of China. This food provides animal protein and many minerals and was reported to stimulate the mothers' appetite. Fourteen per cent of the mothers emphasized its effect.

d. Some mothers use traditional Chinese herbs such as the seeds of the wolf-berry (Lycium chiensis), the danggui (Ligusticum actilobum), shouwu (the tuber of fleece flowers), and weishan to make soup with fish, meat (pork), or poultry. These medicines are recognized as tonic drugs, because they are expensive and not all the mothers can afford to use them.

TABLE 7. Addition of Supplemental Foods for Breast-fed Infants

TABLE 8. Comparison of Monthly Increments in Weight in the First Six Months of Life (Boys)

Original data from Waterlow. UK data from Ministry of Health Standards of Normal Weight in Infancy, Reports on Public Health and Medical Subjects, no.99 (Her Majesty's stationery Office, London, 1959).

DISCUSSION

Breast-feeding is still the dominant custom for feeding infants at least up to one year of age in the rural areas and small towns of Guangdong. It can be conjectured that the situation is quite similar in other parts of southern China. How long breast milk alone can sustain normal growth and development of infants under conditions in the rural areas of developing countries remains a question. Waterlow recently reviewed studies concerning this question from several developing countries (2). The monthly increments in weight in the first six months of life of babies in ten countries or areas were significantly lower after three to four months compared with those in the UK. This phenomenon was observed in this survey, but the monthly increments after three months were even lower (table 8). The criterion of so-called "enough milk" or adequacy of breast milk in different periods after delivery is also not the same from study to study (3, 4).

The data show that over 16 per cent of the mothers, in apparently healthy condition, did not provide adequate milk for their babies after the first four months. The correct figure is almost certainly higher, since some of the mothers were giving supplementary foods by this time, even if these foods were only a minor proportion of the babies' diets. Average birth weights of infants in Xinhui District and of American infants are very similar - around 3.3 kg for males and 3.2 kg for females, but the weight gain after birth differs between the two groups. In the third month, weight gain reached a plateau in the Xinhui infants. One might consider that this is the average limit of time during which sufficient nourishment can be provided solely by the mother's milk.

The average output of about 800 grams of milk per day that we found is very similar to that observed in Europe (5) and Burma (6), but higher than in areas where mothers were underprivileged (7). Eight hundred grams of breast milk may provide about 95 kcal and 1.87 g of protein per kilogram of body weight for a three-month-old infant in a rural area such as Xinhui, but the growth curve after three months becomes somewhat flattened and lower than that of American infants (figure 1). A similar phenomenon was seen in other developing countries (8). Many factors may affect the growth curves among countries, such as the influence of infectious diseases and, possibly, genetic factors, but it is reasonable to regard nutritional factors as having been primary in this survey.

Many factors can influence the amount of milk secreted (9). One factor-the nutrient intake of the mothers- was apparent in this survey, particularly with respect to dietary calorie and protein intake in the first two months of lactation. Some observers report that the caloric intake of the mother before delivery has a positive effect on milk production ( 10), and such an effect may apply to mothers in this study. The foods that mothers claimed promoted or accelerated their lactation performance did provide them with more protein and fat, hence increased energy intake, as well as supplying B vitamins, calcium, and some trace elements. Another consideration is that those foods and herbal medicines perceived as galactogogues possibly played some part in promoting milk secretion through psychological as well as physiological effects. The concentrated meat soups and even the table salt may have an influence on appetite, and their milky appearance may have been reassuring emotionally, relieving anxieties that could affect the "let down" reflex.

FIG. 1. Comparison of Growth Curves of Xinhui and American Babies (American data adapted from: National Center for Health Statistics, NCHS Growth Charts, 1976; Monthly Vital Statistics Report, vol. 25, no. 3, supp. (HRA) 76-1120; Health Resources Administration, Rockville, Md., USA, June 1976; Ross Laboratories, Columbus, Ohio, USA, 1976.)

The rural female peasants of this region return to field work or handicraft work about one month after delivery while they are still nursing their infants. Even though their work is lighter and the length of working hours shorter, the household tasks increase because of the added child care. The average body weight of mothers in Xinhui is about 50 kg. Light physical labour for women of this weight would require about 2,400 kcals daily; an additional 600 kcal would presumably be needed for production of milk. To this should be added the energy required for the synthesis of milk and energy expenditure of attending the infant and feeding at night. It is reasonable that an intake of at least 3,500 kcals daily should be provided for lactating mothers under ordinary circumstances in rural Guangdong.

The definition of "weaning food" differs widely, but any kind of nutritious food acceptable to infants, affordable by the people, and adaptable to their culture should be made available to meet the need for a food supplement. Supplementary food to sustain the nutritional requirements of the growing infant should be started progressively after three months among the population we studied in this survey. A more extensive use of nutritious traditional foods such as soybeans and the fortification of other affordable local foods that are accepted by the babies is a practical, immediate solution (11-14). The manufacture of supplementary foods for different stages of growth and the different needs of the infants is an important measure to protect the future of the next generations.

ACKNOWLEDGEMENTS

This survey was made at the suggestion and under the guidance of Dr. Nevin S. Scrimshaw. Thanks are due to Dr. Barbara Underwood for her enthusiasm and helpful advice in completing this paper, and to Dr. William Rand for his advice, and to Dr. S.F. Wong and C.L. Yuen for their assistance with the technical aspects of this survey.

REFERENCES

1. The Food Table of the National Institute of Health (People's Health Publisher, Peking, 1976).

2. J.C. Waterlow, "faltering in Growth in Less Developed Countries," Lancet, ii: 1176 (1980).

3. J.C. Waterlow and A.M. Thomson, "Observation on the Adequacy of Breast Feeding," Lancet ii: 238 (1979).

4. J.C. Waterlow, "Adequacy of Breast Feeding," Lancet ii: 897 (1979).

5. B. Lönnerdal, E. Forsum, and L. Hambraeus, "A Longitudinal Study of the Protein, Nitrogen, and Lactose Contents of Human Milk from Swedish Well-Nourished Mothers," Am. J. Clin. Nutr., 29:1127 (1976).

6. Khin-Maung-Naing, Tin-Tin Oo, Kywe-Thein, and New-New-Hlaing Study on Lactation Performance of Burmese Mothers, Am. J. Clin. Nutr., 33: 2665 (1980).

7. C. Martinez and A. Chávez, `'Nutrition and Development in Infants of a Poor Rural Area," Nutr. Rep. Internat, 4:139 (1971).

8. E. Lanber and M. Reinhardt, "Studies on the Quality of Breast Milk during 23 Months of Lactation in a Rural Community of Ivory Coast," Am. J Clin. Nutr., 32:1159 (1979).

9. E. Forsum and B. Lönnerdal, "Variation in the Contents of Nutrients of Breast Milk during One Feeding," Nutr. Rep. Internat., 19:815 (1979).

10. Joint PAD/WHO Memorandum, "Protein and Energy Requirements,"Bull. Wld Hlth. Org., 57:65 (1979).

11. M.T. el-Ghamay, "A Study of Effectiveness of Iron and iron/ Lysine Fortification of Cereal Products in South Tunisia," Fed. Proc., 37: 486 (1978).

12. UM. Sarrinen, "Need for Iron Supplementation in Infants on Prolonged Breast-Feeding," J. Pedant., 93:177 (1978).

13. S. Ghosh, "Weaning Foods in Developing Countries,'' Am. J. Clin. Nutr., 32: 1984 (1979).

14. C.W, Woodruff, "The Science of Infant Nutrition and Art of Infant Feeding," J.A.M.A., 240:657 (1978).

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