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Dietary intervention to control vitamin A deficiency in seven- to twelve-year-old children
A. Wadhwa, A. Singh, A. Mittal, and S. Sharma
The efficacy of a dietary intervention programme to control vitamin A deficiency through inexpensive, locally available sources of ß-carotene was evaluated in 121 children 7-12 years old. The subjects were randomly divided into experimental and control groups. A three-day food intake was first recorded for each subject using a 24-hour recall method and repeated at the end of the study on a randomly selected subsample. The intervention period lasted one month, during which carrots, papayas, coriander, and mint were offered daily as sources of ß-carotene. There was no significant difference in the dietary intakes of the groups before the study. After the intervention period, the serum vitamin A values of the experimental subjects were significantly higher than those of the controls. These results indicate that consumption of small amounts of inexpensive, readily available vegetable sources of ß-carotene could help prevent and control vitamin A deficiency. Nutrition education programmes are needed to encourage the use of these foods for home consumption as well as in feeding programmes for schoolchildren.
Vitamin A deficiency is a major public health nutrition problem in India. It contributes to a sizeable proportion of preventable blindness, particularly in young children. It is estimated that 12,000 to 15,000 preschool children belonging to poor income groups become blind as a result of vitamin A deficiency . The major cause is inadequate dietary intake of vitamin A . Hence the most rational method to prevent and control the disorder is to increase the dietary intake of the vitamin. Preformed vitamin A is present only in foods of animal origin, which are expensive and beyond the reach of a large proportion of the population. On the other hand, rich sources of ß-carotene such as carrots (Daucus carota), green leafy vegetables, and yellow fruits such as papayas (Carica papaya) and mangos (Mangifera indica) are inexpensive and can totally meet the requirements of children belonging to low socio-economic groups. Unfortunately, these items do not find their way into the diets of this most vulnerable section of the population.
Implementing the use of only one source of ß-carotene in daily diets is impractical, as variety in the diet is essential. Therefore, a number of sources should be used in a dietary intervention programme to control vitamin A deficiency.
This study was designed to evaluate the efficacy of a dietary intervention programme to control vitamin A deficiency in 7-12-year-old children through rich but cheap, easily available, and varied local sources of ß-carotene.
Materials and methods
The study was conducted in an orphanage in Delhi, India. All 121 inmates between 7 and 12 years of age made up the sample. The sample was randomly divided into two groups, experimental and control, that were matched with respect to sex. The investigation was conducted in three phases:
1. Collection of dietary data
A dietary survey was conducted with the help of an interview schedule using the 24-hour-recall method. Food intake was recorded for three days (two weekdays and one holiday, including Sunday). The diets were analysed for their energy, protein, fat, ß-carotene, and retinal content using food composition tables . To check the authenticity of the data, the survey was repeated at the end of the study on a randomly selected subsample of 40 children.
2. Dietary intervention
Four rich sources of ß-carotenecarrots, papayas, coriander (Coriandrum sativum), and mint (Mentha viridis)were used for the intervention, which lasted for one month. These foodstuffs were selected as they were cheap and available in abundance during the time of the investigation. The use of four sources of 9-carotene ensured better acceptability.
The experimental group was given raw carrots five times a week, and papaya and coriander-mint chutney twice a week. Since the foodstuffs were not analysed for their é-carotene content, they were incorporated in sufficient amounts to provide more than the recommended allowance for the vitamin. Since the children belonged to two age groups whose recommended dietary allowances are not the same, they were given different amounts of the supplements (table 1).
TABLE 1. Supplementary foods
a. Coriander 15 g, mint 10 g, lemon juice 30 g.
The control group was given a supplement of radishes, which provide almost no ß-carotene.
3. Evaluations and collection of blood samples
The difference between the serum vitamin A levels of the two groups after the dietary intervention was used as an index for assessing the efficacy of the intervention. Serum vitamin A levels were estimated with a Farrand spectrofluorometer, model MK1 (Farrand Optical Co., Valhalla, N.Y., USA), using the microspectrofluorometric method of Selvaraj and Susheela .
One blood sample was drawn per child. (It took three consecutive days to collect all the samples.) About 5 ml of venous blood was taken and let stand for two hours. It was then centrifuged and the serum was separated. The serum samples were stored in a freezing chamber of a refrigerator, and all were analysed within one week of collection.
Dietary and nutrient intakes
The average daily intake of foods is presented in table 2. The children were consuming a vegetarian diet that was grossly deficient in cereals, green leafy vegetables, and milk and milk products, and moderately deficient in sugar and fat. Despite the low intake of milk and the absence of meat and eggs, the diet was qualitatively adequate with respect to proteins, as the pulse and cereal protein ratio was high (1:1).
TABLE 2. Average daily food intake (grams)
|Food group||Average consumption||Recommended allowancea|
|Cereals||184 ± 30||285|
|Pulses||77 ± 18||65|
|Milk and milk products||38 ± 21||250|
|Green leafy vegetables||4 ± 3||85|
|Roots, tubers, and other vegetables||102 ± 50||62|
|Fruits||63 ± 50||50|
|Fat||17 ± 4.5||30|
|Sugar||24 ± 12||50|
N = 121.
a. Indian Council of Medical Research, 1978.
The average intake of significant nutrients is shown in table 3. The diet was inadequate with respect to energy, fat, and vitamin A, but was adequate in protein.
TABLE 3. Mean daily intake of nutrients prior to supplementation
Total vitamin A equivalents (µg retinol) 256±63
The diet survey conducted at the end of the supplementation period revealed no deviation from the pattern observed in the initial survey other than the supplement. There were no appreciable differences between the dietary intakes of the control and the experimental groups, or between the sexes.
Serum vitamin A levels
The guidelines of the Interdepartmental Committee on Nutrition for National Defense (ICNND) for the interpretation of serum vitamin A levels were used for the investigation. Of the total sample of 121 children, the serum vitamin A levels of 114 could be estimated (table 4).
TABLE 4. Mean serum vitamin A levels (µg/dl)
t = 2.02 ( p < .05).
In the control group, 49 subjects (91%) had low levels of serum vitamin A, and 5 (9%) had acceptable levels. The mean level of the control group was 15.5±2.53 µg/dl. Despite the low serum levels, no clinical manifestations of vitamin A deficiency were seen among the children. Similarly, other investigators have found no association between low or deficient serum levels and clinical signs of vitamin A deficiency .
The children in the experimental group, who had received about 2,313 µg (7-9-year-olds) or 3,268 µg (10-12-year-olds) of ß-carotene per day for one month, showed much higher serum values than the control subjects. Of the 60 subjects, the serum values were acceptable in 57 (95%) and low in 3 (5%) (range 18.04-27.33 µg /dl).
There was no appreciable difference in the dietary intakes of the experimental and control groups. However, the vitamin A intake of the experimental group increased significantly with 0-carotene supplementation. Estimations after the intervention indicated that, while the majority of the control subjects (91%) had low serum vitamin A levels, the majority of the experimental subjects (95%) had acceptable levels. There was a highly significant difference (p=.005) in the serum levels of the two groups. We concluded that the levels in the experimental subjects were higher solely due to the additional ß-carotene in their diet. Similar observations have been reported in preschool children [6-8].
The investigation shows that encouraging the consumption of rich but cheap sources of ß-carotene without introducing any other change in the dietary pattern can go a long way toward controlling and preventing vitamin A deficiency. It is an inexpensive and feasible way to ensure an adequate dietary intake of ß-carotene and does not involve any difficult cooking. Thus the workload of the people who would be implementing the method would not be unduly increased. The use of four different sources of ß-carotene would contribute to variety in the diets and consequently improve acceptance by the population at large.
As an outgrowth of our study, we recommend establishing rigorous nutrition education programmes to encourage the consumption of carotene-rich foods and setting up kitchen gardens to grow such foods. Such measures will need to be adopted for the application of the results of this investigation.
Our results may find application at the national level also. India is conducting a number of continuing feeding programmes for schoolchildren. Their major emphasis is on providing additional calories and protein, but ß-carotene could also be provided without much difficulty. The national prophylaxis programme covers only children 1-5 years old and does not ensure life-long protection against vitamin A deficiency. However, it is essential to maintain an adequate vitamin A status at all stages of life. It has been suggested that the vitamin is involved in the immune mechanism; therefore, maintaining adequate vitamin A levels is imperative during childhood, when there is a high prevalence of infections. Furthermore. children with inadequate vitamin A reserves are likely to have a progressive worsening of status. This can be of great significance in women, particularly during the reproductive years, as maternal vitamin A status determines foetal stores.
We express our sincere gratitude to our subjects for their cooperation.
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