|Year : 2018 | Volume
| Issue : 10 | Page : 1341-1348
Impact of cowpea fortified cookies on anthropometric and micronutrient status of primary school children: A randomized, single-blind controlled trial
Rufina N B Ayogu, Tochukwu P Onah
Department of Nutrition and Dietetics, University of Nigeria, Nsukka, Nigeria
|Date of Acceptance||18-Jun-2018|
|Date of Web Publication||8-Oct-2018|
Dr. Rufina N B Ayogu
Department of Nutrition and Dietetics, University of Nigeria, Nsukka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Micronutrient deficiencies are public health problems among school children. Food-to-food fortification may reduce the prevalence of these deficiencies. Aim: To assess the impact of cowpea (Vigna sinensis) fortified cookies on weight, height, body mass index (BMI), hemoglobin, serum vitamin A, and zinc status of primary school children aged 6–12 years. Methods: A randomized single-blind controlled trial was conducted for 4 weeks among 17 pupils who were voluntarily recruited and randomly assigned to experimental (Group A) and control (Group B) groups. Group A was fed wheat cookies incorporated with cowpea in a ratio of 60:40, while Group B received 100% wheat cookies. Data were collected through questionnaire, anthropometry, and biochemical analysis. Statistical analysis involved descriptive statistics and t-test. Significance was set at P < 0.05. Results: The study involved 17 school children out of which 10 (58.8%) were boys and 7 (41.2%) were girls; 12 (70.6%) were 10–12 years old and 4 (23.5%) were in lower primary (1–3). Group A had increases in hemoglobin (15.5%), serum ferritin (28.3%), serum zinc (38.9%), weight (3.0%), BMI (3.4%), and serum vitamin A (26.3%); only increases in hemoglobin, serum ferritin, and vitamin A attained significance (P < 0.05). Though there was increase in weight (6.1%), BMI (5.4%), hemoglobin (5.0%), serum ferritin (16.4%), zinc (20.8%), and vitamin A (17.5%) of Group B, these increases were not significant (P > 0.05). Group A had significantly (P < 0.05) higher serum ferritin (51.3 μg/L) than Group B (44.7 μg/L). Conclusion: Consumption of cowpea fortified cookies had significant positive effects on hemoglobin, serum ferritin, and vitamin A levels of school children and should be encouraged at household and industrial levels.
Keywords: Cookies, cowpea, fortification, micronutrient status, school children
|How to cite this article:|
B Ayogu RN, Onah TP. Impact of cowpea fortified cookies on anthropometric and micronutrient status of primary school children: A randomized, single-blind controlled trial. Niger J Clin Pract 2018;21:1341-8
|How to cite this URL:|
B Ayogu RN, Onah TP. Impact of cowpea fortified cookies on anthropometric and micronutrient status of primary school children: A randomized, single-blind controlled trial. Niger J Clin Pract [serial online] 2018 [cited 2019 Oct 16];21:1341-8. Available from: http://www.njcponline.com/text.asp?2018/21/10/1341/242849
| Introduction|| |
Causes of micronutrient deficiency among children are multidimensional and prominent among them is inadequate food and nutrient intakes. Morris  asserted that every year, hunger and under-nutrition claim more than 10 million lives—more than the deaths from AIDS, malaria, and tuberculosis combined. Micronutrient deficiency is only one form of under-nutrition with its characteristic invisibility. Iron deficiency is the most common micronutrient deficiency in the world, affecting more than 30% of the world's population. Over two billion people globally are at risk of vitamin A deficiency. About 17% of the global population is also at risk of zinc deficiency due to dietary inadequacy. Among school children in Nigeria, iron, vitamin A, and zinc deficiencies have also been reported as problems of public health significance with prevalence rates above 5%.,,, A child deficient in micronutrients may be able to go to school and carry on with school activities but the output is far from satisfactory as a result of the consequences of these deficiencies on growth, development, and the entire body physiologic processes.
Different intervention strategies aimed at controlling micronutrient deficiencies have been implemented but nutrition remains the most powerful adaptable environmental exposure to target in order to reduce the burden of diseases and death accruing from these deficiencies. Food-based nutrition interventions have potentials to achieve this. Pulses/legumes are nutrient dense  and when incorporated into cereals enhance the amino acid and micronutrient profile of their food products. Consumption of cereal foods such as cookies and bread is very popular in Nigeria, especially among the snack consuming population (children and adolescents). Without fortification, these cereal foods remain poor sources of protein and micronutrients. Copenhagen consensus of 2012 asserted that flour fortification with iron and folic acid is globally recognized as one of the most effective and low-cost micronutrient interventions  but in many settings, more than one micronutrient deficiency exists, suggesting the need for simple approaches that address multiple micronutrient deficiencies.
| Materials and Methods|| |
The study took place at St Andrew's Nursery and Primary School Ibagwa Aka in Igbo-Eze South Local Government Area (LGA), Enugu State, Nigeria. Ibagwa Aka is a rural community whose inhabitants are mainly farmers and traders. Agro products such as yam, palm oil, cassava, cocoyam, bambara groundnuts, cowpea, and livestock are produced, consumed, and traded on.
Subjects and study design
Participants for this study were recruited voluntarily from the general school population. The chart showing the selection process is shown in [Figure 1]. This randomized, single-blinded, controlled trial was performed with two parallel arms: A and B. All the participants were asked to maintain their habitual diet and food intake. They were also asked to remain in their usual home environment throughout the study period and to report any change in environment and new/unusual foods in their menu. Group A received cookies into which cowpea was incorporated in the ratio of 60:40 (fortified cookies), whereas Group B received 100% wheat cookies (unfortified cookies). The two types of cookies were produced with the same recipe and were similar in shape and size. Formulation of the cookies was based on 56 g protein basis to give similar protein intakes in the two groups. The nutritional value of the cookies  is presented in [Table 1]. The cookies were produced in the Diet Therapy Laboratory of the Department of Nutrition and Dietetics, University of Nigeria, Nsukka on weekly basis to ensure freshness and crispiness. These were wrapped in labeled polyethylene bags and supplied to the school. Four teachers were recruited, trained, and assigned two per group to ensure that the cookies were served and that the school children did not share their cookies. The cookies were served the pupils with water in two separate classrooms every school day for 4 weeks. No intervention took place during weekends. Children were not allowed to leave the classroom or return to their original seats before they had finished their cookies and water. The teachers ensured compliance and recorded attendance to school and daily participation in the trial, complaints of ill health, and desire to discontinue in a record book provided for this purpose. Both the teachers and the pupils were blinded to the type of biscuits served and consumed. The quantity of cookies fed to the children was based on one-third of the protein requirement  for age and gender of children aged 6–12 years, as shown in [Table 2]. Prior to commencement of the intervention, the children were dewormed with oral albendazole 200 mg stat. A total of 17 out of 21 school children who started the trial completed the study.
Exclusion criteria were applied only to children who gave consent. The exclusion criteria included overweight/obesity and low body mass index (BMI)-for-age, low hemoglobin (<11.5/12.0 g/dL), low serum zinc (<65 μg/dL), ferritin (<15 μg/L), and vitamin A (<20 μg/dL) levels.
Ethical approval and informed consent
Ethical approval for the study was obtained from the Ethical Committee of Enugu State Ministry of Health (MH/MSD/EC/0225). Written and informed consent was obtained from the school authority, parents/guardians of the pupils, and the pupils themselves. A laboratory technologist was employed to ensure that blood collection was safe and accurate.
Data collection methods
Questionnaire: Structured and validated questionnaire was used to obtain data on general characteristics of the school children.
Anthropometry: Weight and height of the school children were taken according to methods described by Dabone et al. BMI was calculated from these values and related to age according to WHO child growth standard  for age and gender. They were classified as thin if their Z-scores of BMI-for-age were low (≤ −2 SD); that is below the WHO median.
Three-day food record: Parents and their children were taught how to keep records of every meal and snack consumed within and outside the home for 3 days using a format developed for this purpose. The format included date, item consumed, the form in which it was consumed, ingredients in the food if known, and meal in which it was consumed (breakfast, lunch, supper), and if consumed as snack. The foods consumed were grouped into different food groups according to Ene-Obong.
Biochemical tests: A laboratory technologist collected 5 mL of venous blood from the subjects prior to and at the end of the trial. Blood was collected in two separate specimen bottles. One (2 mL) with ethylenediaminetetraacetic acid was used for hemoglobin determination by cyanmethemoglobin method. Anemia was defined as hemoglobin concentration of <11.5 and <12.0 g/dL for children <12 and 12 years, respectively. Blood (3 mL) in the screw capped glass vials without anticoagulant was allowed to coagulate. Both labeled bottles were put in a cooler lined with frozen ice packs and sent to the laboratory within 2 h of collection. The coagulated blood was centrifuged at 3000 rpm for 10 min to obtain clear serum. Serum vitamin A was determined by colorimetric method using trifluoroacetic acid. Cut-off for vitamin A deficiency was <20 μg/dL. Atomic absorption spectrophotometric method was used to determine serum ferritin  and zinc levels. Cut-off for iron and zinc deficiencies were <15 μg/L  and <65 μg/dL, respectively.
Statistical Product and Service Solution (Armonk, NY: IBM Corp) version 21 was used for statistical analysis of data. Results of descriptive statistical analysis were presented in frequencies and percentages. Differences within and among groups were evaluated with t-test. Significance was accepted at P < 0.05.
| Results|| |
[Table 3] illustrates the personal characteristics of the subjects. The study population was made up of 10 (58.8%) males and 7 females (41.2%); 12 (70.6%) school children were aged 10–12 years; only 5 (29.4%) were 6–9 years old. School children in primary 4–6 were 13 (76.5%), while those in primary 1–3 were 4 (23.5%). More than half (52.9%) of the children had lower birth order of 1–3. Majority (52.9%) had meal frequency of three times daily and 47.1% did not consume snacks at school.
[Table 4] shows the household characteristics of the subjects. A few (29.4%) had household size of 1–3 persons. About 6% came from households with monthly income of 21,000 Naira (66.68 USD) and above and 88.2% came from monogamous family.
Data from 3-day food intake record of the subjects are shown in [Table 5]. The food group with the highest frequency for breakfast 64.7% and lunch (70.6%) was cereal, starchy root, fruit, and tuber. Fat and oil had the highest consumption for supper (64.7%). Fruits and vegetables had low frequency of 11.8% for breakfast and 11.8% for lunch and 5.9% for supper.
The impact of the cookies on weight, height, and BMI of the subjects is presented in [Table 6]. No increase in height was observed at the end of the study for both groups. Both weight and BMI increased for the two groups, but these did not attain significance (P > 0.05).
|Table 6: The impact of the cookies on the anthropometric measurements of the subjects|
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The impact of the cookies on hemoglobin, serum vitamin A, ferritin, and zinc levels of the subjects is presented in [Table 7]. There were significant differences in mean hemoglobin (P < 0.05), serum ferritin (P < 0.01), and serum vitamin A (P < 0.05) levels of the subjects in Group A (experimental group) with end line values being higher. Though the end line values of hemoglobin, serum ferritin, vitamin A, and zinc in the control group were higher than the baseline, the differences were not statistically significant (P > 0.05).
|Table 7: The impact of the cookies on the micronutrient levels of the school children|
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| Discussion|| |
The low income of the households is a cause of worry and a problem in low income countries where majority live below poverty line. This agrees with the findings of Ibeanu et al. where 66.5% households earn between 10,000 and 15,000 Naira (31.75–47.62 USD). Low income is one of the causes of food insecurity and poor health status resulting from inability to access good food and health care services.
This study also showed that the most consumed food group is the cereal, starchy root, fruit, and tuber group. This was expected because these are readily available and affordable staple foods of the people. Cereal, starchy roots, fruits, and tubers are rich carbohydrate sources that are low in protein and micronutrients. They contribute to energy intake and excessive intake may result in overweight and obesity. Wasting (thinness) is a consequence of low energy intake. As most staples are consumed with stews, sauce, and soups prepared with crayfish, fermented African oil bean, oil, and vegetables, it implies that the children had chances of obtaining micronutrients from these sources. No child reported egg and milk consumption.
Results from this study showed that most of the subjects ate three times a day. Higher frequency of food intake may be positively related with higher nutrient intake. This is highly commendable and is consistent with the report of Olumakaiye et al. on food consumption patterns of Nigerian children. Nwamarah et al. also showed that school children had three meals per day (97.5% for breakfast, 90.7% for lunch, and 95% for supper). This may be one of the reasons for the high hemoglobin and serum ferritin level observed at baseline. Eating three times daily gives the children the opportunity to gain from the ingredients in the food. This may imply better food and nutrient intakes and therefore better nutritional status of the school children.
Differences in weight and BMI of the children which were not significant (P > 0.05) agreed with the findings of van Stuijvenberg et al. They assessed the micronutrient status of 115 children (6–11 years) before and after consumption of biscuits fortified with iron, iodine, and beta carotene and reported no significant difference in height and weight, height-for-age, and weight-for-age Z-scores between the intervention and control groups over the 12 months study period. A systematic review of 201 studies conducted on food fortification by Das et al. showed that multiple micronutrient fortification had no significant (P > 0.05) effects on height-for-age, weight-for-age, and weight-for-height Z-scores, although they showed positive trends. This affirms that the problems of low weight, height, and BMI are particularly problems of energy intake and not micronutrient.
The higher percentage increase in hemoglobin and serum ferritin of the children in Group A of this study was a surprise. This was because the wheat flour bought and used in this study to produce the cookies was fortified with iron and vitamin A by the manufacturers and one would expect Group B that received 100% wheat cookies to have a higher percentage increase but this was contrary to our finding. This result may be due to the interaction among hematinic nutrients in the two flours, which may have given a better amino acid profile and micronutrient boost than wheat alone despite its acclaimed fortification. Besides, amino acids and micronutrients (iron, zinc, vitamins A, B1, B6, and B12) play vital role in erythropoiesis and hemoglobin synthesis.
All biomarkers (hemoglobin, serum ferritin, zinc, and vitamin A) of micronutrient status showed improvement in their mean values for both the experimental and control groups. According to Goyle, this could be attributed to the fact that both groups received supplementation in the form of cookies. It is obvious to notice that though they all improved, the mean difference in the experimental group (Group A) was higher than observed in the control group. Although there were positive changes in the mean value of the nutrient biomarkers, further statistical analysis revealed that the changes in the experimental group were significant (P < 0.05) for hemoglobin, serum ferritin, and vitamin A and not for zinc [Table 7]. This result stands in agreement with van Stuijvenberg et al. who reported a significant increase in serum retinol, serum ferritin, serum iron, transferrin saturation, urinary iodine, hemoglobin, and hematocrit of their experimental group. A study carried out by Winichagoon et al. on 569 children aged 5–14 years from 10 schools in Thailand revealed that multi-micronutrient-fortified seasoning powder enhanced hemoglobin, and iodine status of school children. Studies by Goyle and Prakash  on 46 girls aged 10–16 fed micronutrient fortified biscuits for 75 days in 4 months in Jaipur, India, which resulted in increase in their vitamin A status as the supplementation augmented the percentage of adolescent girls in the “normal” category from 56.1 to 73.2% and decreased the percentage of adolescent girls in the “low” category from 41.5 to 26.8%. Jood et al.also studied the effect of supplementation on serum retinol levels in 66 school children 10–12 years of age from Hisar, India, for a period of 4 months. Hundred grams of cauliflower leaves powder supplements using biscuits were fed 33 deficient subjects. An increase of 33.27% was observed in the serum retinol levels after a period of 4 months. The lower percentage increase observed in this study may be attributed to duration of the study. The systematic review of 201 studies conducted on food fortification by Das et al. revealed that fortification for children showed significant impact in increasing serum micronutrients such as iron, folate, and vitamin A concentrations. Similar review by Liu et al. on food fortification in India showed that out of 47 papers, of which 25 were randomized controlled trials, 38 involved children less than 12 years, food vehicles used were 6 cereals, 18 oils and salts, and 23 others (e.g., school meals). Improvements in more than one biological markers were reported in all 35 papers (22 multiple micronutrients, 9 iron, and 4 iodine). More specifically, iron or hemoglobin improvements were noted in all studies with multiple micronutrients fortification. Most of the reports cited here were outcome of studies conducted on micronutrient-deficient children, in contrast to the children in this study who had normal values and still showed improvement. It implies that deficient children would show better improvement because nutrient absorption is higher in deficient states. The improvements observed in this study may be attributed to deworming because intestinal worms are known to interfere with nutrient absorption and intestinal helminths are problems of school children.
| Conclusion|| |
Cowpea (Vigna sinensi, apama) fortified cookies is a good vehicle for improving micronutrient status of school children and can be implemented in schools as snacks, especially where school feeding is difficult or impossible.
Limitation of the study
The study was conducted on only 17 pupils whose parents granted consent.
We acknowledge the pupils who volunteered to participate in the study and stayed on to the end. Our gratitude also goes to the four teachers who accepted to assist us in the field at no cost.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]