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Energy
Protein
Vitamins and Minerals
The Influence of Socio-economic Status in the Developing World on Nutrient Intake
General Conclusion
References
2.1. The energy and nutrient intake of the majority of lactating mothers in the developing world falls well below the RDA. There is now evidence that even the average woman from the industrialized countries also consumes less food than theoretical reasoning would indicate she should. This section reviews available data, but it must be emphasized that there is an unfortunate paucity of really accurate information. Many studies of dietary intake have been on whole families, and it is quite impossible to compute the intake of an individual from this information, especially an individual with specific physiological needs.
There has also been a diversity of techniques used: it is generally accepted that the method based on the precise weighing of the food eaten by each individual produces the most satisfactory data. This method is time-consuming, however, and it also requires an accurate knowledge of the nutrient composition of cooked dietary components to make optimum use of the data. Such information is rarely at hand in the developing world, and facilities for nutrient analysis are rare. Many investigators have had to fall back on semi-quantitative methods such as the 24-hour recall method. While this can be remarkably accurate in experienced hands, results from the recall method can also be of very dubious value. It is apparent that much more carefully controlled measurements of dietary intake are essential.
2.2. Table 2 summarizes the mean energy intakes that have been obtained in a number of studies carried out in the developing world on lactating women. The average WHO/FAO estimate of needs in a moderately active woman is 2,750 kcal/d (see section 1.3), and it is quite clear that measured values are considerably less. The highest mean intake was 1,950 kcal/d by found Martinez and Chavez (18) in Mexico during 1971; the rest of the measured intakes were 1,750 kcal/d or less. There is also evidence of seasonal variation; for example, measured intakes dropped to as low as 1,200-1,300 kcal/d during the worst part of the wet season in the Gambia (1). At this time, the traditional hungry season, food from the previous harvest has been used up and that from the new one is not yet ready. Some of the values in table 2 are so low, ranging from 40-70 per cent of the RDA, that many are near the theoretical amount required for only resting metabolism.
TABLE 2. Reported Energy Intakes of Child-bearing Women in Developing Countries
| Source | Country |
Energy intake (kcal/d) |
| Pregnancy | ||
| Prentice (11 (wet season) | Gambia | 1,350-1,450 |
| Oomen and Malcolm (2) | New Guinea | 1,360 |
| Gopalan (3) | India | 1,400 |
| Venkatachalam (4) | India | 1,410 |
| Lechtig et al. (5) | Guatemala | 1,500 |
| Gebre-Medhin and Gobezie 16) | Ethiopia | 1,540 |
| Rajalakshmi (a) | India | 1,570 |
| Mora et al. (8) | Colombia | 1,620 |
| Prentice (1) (dry season) | Gambia | 1,600-1,700 |
| Arroyave (9) | Guatemala | 1,720 |
| Maletnlema and Bavu (10) | Tanzania | 1,850 |
| Demarchi et al. (11) | Iraq | 1,880 |
| Bagchi and Bose (12) | India | 1,920 |
| Thanangkul and Amatyakul (13) | Thailand | 1,980 |
| Mata et al. (14) | Guatemala | 2,060 |
| Lactation | ||
| Prentice (1) (wet season) | Gambia | 1,200-1,300 |
| Karmarkar et al. (15) | India | 1,300 |
| Devadas and Murthy (16) | India | 1,400 |
| Karmarkar et al. (17) | India | 1,440 |
| Arroyave (9) | Guatemala | 1,600 |
| Rajalakshmi (7) | India | 1,620 |
| Prentice (1) (dry season) | Gambia | 1,600-1,750 |
| Martinez and Chavez (18) | Mexico | 1,950 |
One is tempted to question the validity of such surprising data, but comparable information, also contained in table 2, for pregnant women is of the same order of magnitude. It is apparent that there is little or no increase in dietary energy intake between pregnancy and lactation. Since it seems highly unlikely that non-pregnant, non-lactating women could have been customarily eating much less than these amounts, it can reasonably be assumed that women in the developing world must subsist on the same low plane of energy intake, averaging about 1,600 kcal/d, throughout most of their reproductive life.
2.3. There have been few similar studies on lactating mothers in industrialized countries, although it has been reasoned that physiological needs for dietary energy may be lower because of the reduction in general level of activity that is possible in such societies: few women, for example, are forced to go out to work, especially to perform heavy manual labour, while they are nursing.
Table 3 describes some studies that have been carried out in different industrialized countries. The data of Thomson (20) date back to Scotland in the 1950s and contrast markedly with the more recently obtained values of Whitehead and colleagues (25) collected in Cambridge in 1980. There has, in fact, been a generalized reduction in food energy intake by most sectors of the community in the United Kingdom during this time period, perhaps reflecting different life-styles, but whether the differences can be explained on this basis is not certain. Generally speaking, earlier measured values did average around the RDA, but clearly this is not the case in present-day Cambridge. The data from Sweden for lactating mothers, collected in 1977 (23), and more recent data from Australia (26) are also identical with those from Cambridge. In contrast to the data from the developing countries, all the studies in the United Kingdom show that nursing mothers consume more dietary energy when they are lactating than in their non-pregnant, non-lactating state, although in Cambridge the increment is not as great as that recommended.
TABLE 3. Energy Intakes (kcal/d) of Mothers in Developed Countries with Breast-fed or Bottle-fed Infants
Breast-feeding |
Not-feeding |
||
| English and Hitchcock (19) | Australia | 2,460 |
1,880 |
| Thomson et al. (20) | Scotland | 2,716 |
2,125 |
| Naismith and Ritchie 121) | London, UK | 2,930 |
2,070 |
| Whichelow (22) | London, UK | 2,728 |
1,958 |
| Abrahamsson and Hofvander (23) | Sweden | 2,280 |
- |
| Sims (24) | USA | 2,124 |
- |
| Whitehead et al. (25) | Cambridge, UK | 2,295 |
2,029 |
| Rattigan et al. (26) | Perth, Australia | 2,305 |
- |
2.4. The very low intakes of dietary energy that have been recorded in the developing world represent a scientific enigma, especially when it is recognized that most of the women are successfully involved in lactation over an extended period of time - anything up to two years. It will be emphasized in subsequent parts of this report (see section 3.2) that there is a need for more extensive work on energy balance during lactation and on how maternal physiology adapts to the very considerable energy drain of lactation in women on a low intake.
2.5. It has already been pointed out in section 1.5 that the recommended allowance for dietary protein during lactation represents a proportionately greater increment than that for pregnancy. A combination of low-baseline total energy intakes, plus the virtual lack of any significant increase in food intake during lactation, or any change in dietary pattern towards more protein-rich foods, inevitably means that the RDA for protein may not be achieved during lactation in some developing countries. The situation is understandably worse in those countries that have starchy root crops like cassava of plantains as their dietary staple. In contrast to studies on the preschool child, however, there have been few comparative studies on the relative effects of protein and energy deficiencies on the process of lactation, although it is known that a clinical state closely resembling that of kwashiorkor can occur in lactating women who are forced to live solely on cassava or plantain without added foods such as meat, fish, or beans (section 3.3).
2.6. If the gap between the RDA and actual levels of energy consumption seems large, that for many vitamins and minerals is frequently even greater. It must be borne in mind, however, that the RDA for these nutrients has not always been precisely and rigorously defined (sections 1.6-1.15).
Table 4 shows the mean energy and nutrient consumption levels of lactating mothers of poor socioeconomic status in Baroda, India (27). Energy intake is about 60 per cent of the RDA, as is protein after allowing for the relative protein value of the diet. Calcium intake is, however, only 30-40 per cent of the international allowance, while that for vitamin A plus carotene precursors is as low as 10-15 per cent. Likewise, niacin (nicotinic acid equivalents), riboflavin, B12, and vitamin C amount to only 30 per cent or less of the RDA. The data also illustrate unexpected features, for example the intake of iron is untypically high, partly because of the use of iron cooking pots, although the availability of the iron might be low in view of the low vitamin C content of the diet. In most developing countries iron-deficiency anaemia is a considerable problem, both in children and their mothers.
TABLE 4. Maternal Dietary Intake of Poor Women in Urban Baroda, India, during Pregnancy and Lactation
| kcal | 1500-1600 |
| Protein (9) | 35-40 |
| Fat (9) | 30 |
| Calcium (mg) | 400 |
| Vitamin C (mg) | 10-15 |
| Vitamin A (µg) | 125 |
| Iron (mg) | 20-25 |
| Folate (mg) | 0.5-0.7 |
| Vitamin B12 (µg) | 0.5 |
| Thiamin (mg) | 1.0-1.5 |
| Riboflavin (mg) | 0.5 |
| Niacin (mg) | 5-6 |
Source: ref. 27.
Figures 1-3 illustrate comparable data from the Gambia in West Africa. Here the special emphasis is on seasonal variations. Intakes of vitamin C ((see FIG. 1. Variations in Vitamin C Intake during Different Months of the Year by Pregnant and Lactating Mothers in the Gambia (Source: ref. 28))) (281 are high during the season when mangoes and citrus fruits are available, but exceptionally low at other times. Likewise, vitamin A plus carotene precursors are eaten by lactating mothers in variable amounts, although never up to the RDA (see FIG. 2. Variations in Vitamin A Intake and Retinol Precursors during Different Months of the Year by Lactating Women in the Gambia (Source: Paul and Bates, unpublished data)). The June peak coincides with the mango season. In contrast, riboflavin intake is especially low at all times of the year. The overall position of riboflavin consumption relative to the RDA is very poor (29) and comparable with the situation found in Baroda.
Figure 3 (see FIG. 3. Zinc Intakes by Lactating Gambian Mothers during Different Months of the Year (Source: A.A. Paul, unpublished data)) shows corresponding intakes of dietary zinc and its dietary sources. The drop in groundnut consumption during the hungry season has a profound effect on zinc intake, although intakes are always low. It is a reasonably accurate rule-of-thumb to say that good sources of protein are frequently good sources of the trace elements, and dietary recommendations that used to be given for certain foods for their protein content might be just as valid for the trace elements! The NRC recommended allowance for zinc during lactation is 25 mg/d (30). In the Gambia at a good time of the year mean intake is only 40 per cent of this value and can be as low as 25 per cent of the RDA. There is certainly no evidence of a 33 per cent increase during pregnancy, let alone a 66 per cent one in lactation. Figure 4 (see FIG. 4. Average Calcium Intakes of Lactating Mothers in the Gambia (Source: A.A. Paul, unpublished data)) shows the overall situation with calcium; throughout the year average intake is only about 350 mg/d, less than the increment recommended by the NRC and all other expert committees.
The Influence of Socio-economic Status in the Developing World on Nutrient Intake
2.7. Within any community, particularly one in the developing world, one also finds marked differences in intake reflecting socio-economic status. Figure 5 (see FIG. 5. Average Daily Energy and Nutrient Intake by Pregnant Ethiopian Women, Compared with FAO/WHO Recommendations (Source: refs. 6 and 31)) shows the average daily energy and nutrient intakes of pregnant Ethiopian women (6, 31). Unfortunately, there are no comparable quantitative data for lactation, but with the exception of the immediate post-natal period when, as Gebre-Medhin has described, special highly nutritious foods are provided, it is reasonable to conclude that the pattern of nutrients in the diet during most stages of lactation will be similar. It is readily apparent that the social differential for nutrients such as vitamin C and niacin (nicotinic acid) is substantially greater than for dietary energy. The data also serve to demonstrate important inter-country differences. In Ethiopia, in contrast to India and the Gambia, vitamin A and to a relative extent, riboflavin are in good supply. A further important difference occurs during lactation, when mothers are not only permitted but encouraged to drink a thick, nutritious traditional beer called tell. This has been shown to be a good source of folate and even B12 (31 ).
2.8. The failure of most women in developing countries to meet nationally and internationally recommended dietary allowances is clearly widespread. Although regional and socio-economic differences need to be taken into account, the discrepancy between actual and recommended dietary intakes in lactating women suggests that the basic assumptions used in formulating the dietary recommendations are in part incorrect and there is an urgent need for further research to define the physiological basis of this discrepancy.
Nevertheless it is clear that nutritional inadequacies exist in developing countries. It would be an oversimplification to say that this nutritional problem would be overcome if mothers could be encouraged to eat more of their existing foods. This advice would most certainly be ineffective and impracticable for a number of reasons.
First, the energy density of the customary diet in many developing countries is very low either because the staple has an intrinsically low energy content per unit of mass and volume, such as with cassava and plantain; or because the food has a lot of water added during the course of preparation, as in a stew or porridge; or because the raw materials used have a low fat content, and no fat or oil is used in food preparation. Thus, in the Gambia the average diet has an energy density of 1 kcal/g, and a woman would have to eat 3 kg of that food to achieve an intake of 3,000 kcal/d. As far as individual nutrients are concerned, dietary composition, in terms of nutrient content per head, is such that for many nutrients an excessive amount of dietary energy would have to be eaten if that individual were to meet the RDA. This is particular so during lactation, when the RDA is almost always proportionally higher for nutrients than for energy. Quite obviously major changes in food composition and methods of food preparation would be necessary if this discrepancy between current scientific theory and prevailing practice were to be resolved.
The energy, and especially the nutrient, gap during lactation presents nutritionists and health planners with a problem just as complex as the old "protein gap." As it was with protein, it is necessary to ask the question: Are the amounts recommended really necessary for adequate physiological function, health, and well-being? The following section of this report reviews the effects of these shortfalls in energy and nutrient intake both on lactational performance and on the health of the mother.
