Double burden of malnutrition in ethnic minority school-aged children living in mountainous areas of Vietnam and its association with nutritional behavior

Malnutrition is defined as “an imbalance between the need and intake of essential nutrients” [1]. Therefore, the double burden of malnutrition referring to either under-or over-nutrition is presented within individuals, households, and populations throughout their life course [2]. At the individual level, this situation can be manifested by the simultaneous development of 2 or more types of malnutrition (stunting/underweight and overweight/obesity). This burden is also observed at the household level, in which the contrasting forms of malnutrition in multiple family members coexist. Finally, at the population level, the presence of under- and over-nutrition is mentioned in the same community, nation, or region. This phenomenon has profound consequences that can deteriorate individuals' physical and mental development, particularly during childhood and puberty [3, 4]. Moreover, this significant public health challenge also places heavy tolls on families, economies, and the healthcare systems [2].

In recent years, Vietnam has achieved a remarkable reduction in child under-nutrition owing to the positive effects of maternal and child health care programs [5]. In addition, the nutrition transition accompanied by rapid economic development and urbanization has promoted the nutritional status of individuals and gradually increased the incidence of overweight/obesity and other non-communicable diseases simultaneously [2, 6, 7]. Therefore, the transition from a predominance of under-nutrition to over-nutrition, known as the double burden of malnutrition among children, should be considered.

In Vietnam, many ethnic groups live together; the Kinh ethnic group accounts for the largest percentage, approximately 86%, with 53 ethnic minority groups comprising the remainder [8]. Ethnic minorities mostly live in mountainous regions, midlands, or rural parts of the north of Vietnam, while people of the Kinh group live primarily in urban and metropolitan areas. A previous study conducted among school-aged children and adolescents in Ho Chi Minh City, a large metropolitan of Vietnam, reported that 20–30% of primary school were overweight/obese while 6–18% of high school children were under thinness [9]. Although children of ethnic minority groups are experiencing this nutritional transition trend, there is little evidence of a dual-malnutrition burden among those vulnerable subjects.

Adolescence is the period of transition that begins during puberty and ends in early adulthood and is characterized by the development of habits persisting into adult life [10]. Healthy nutrition is critical in this period because it covers deficits in childhood time and provides the required nutrients for adequate physical and cognitive growth to produce stores of energy against illnesses and for improving reproductive health [11]. The available evidence shows that adolescents are becoming increasingly independent in their food choices and factors affecting their nutrition practices include socioeconomic status (age, sex, location, and family income), kinds of food available at home, and lifestyle [10, 12, 13]. A previous study conducted in Ho Chi Minh City (2019) showed that the percentage of under-nutrition and over-nutrition among secondary school children were 3.8–12.4% and 12.1–28.0%, respectively [9]. In Vietnam, however, there is a scarcity of evidence related to the nutritional status and nutritional practices of school-aged children in ethnic minorities, and the evidence available focuses primarily on children under 5-yr-old instead. Therefore, this examined the double burden of malnutrition among school-aged ethnic minority children living in mountainous areas and its relationship with their diets. This phenomenon is a complex problem, and these findings are crucial for stakeholders to support national planning and appropriate public health policies to tackle the opposite ends of the malnutrition spectrum.

This study is one of the first in Vietnam to provide empirical evidence on the double burden of malnutrition among ethnic minority school-aged children living in mountainous areas and the association with dietary factors. The findings show that stunted growth was more prevalent than overweight/obesity among ethnic minority children. Households with more than 2 children and children of Muong, Cao Lan, and other ethnicities were more likely to show stunted growth than those with Tay ethnicity. Regarding dietary intake, consuming potatoes and tubers weekly or daily and never having fat and cooking oil were positively related to under-nutrition. By contrast, children who consumed fish, shrimps and crabs, or milk and dairy products weekly/daily were less likely to show stunted growth and thinness compared to those who never consumed these foods. In terms of over-nutrition, children who ate fruits or food rich in vitamin A precursors and vitamin A weekly/daily had a lower likelihood of being overweight/obese. On the other hand, those who consumed snacks/chips and did not track their weight regularly were more likely to show over-nutrition.

In this study, under-nutrition was more prevalent among ethnic minority children than over-nutrition. This finding is consistent with the result of the National Nutrition Survey of Vietnam 2019–2020 [18], which showed that the percentage of stunting among school-aged children (5–19 yrs old) was 14.8%, while this percentage was 23.4% in 2010 [19]. In addition, the prevalence of overweight/obese children in the present study was also similar to the result of the National Nutrition Survey 2019–2020, indicating that over-nutrition among those living in mountainous areas was 6.9% [18]. A comparison with another study conducted among 24 to 60-mon-old children in the mountainous areas of Vietnam (2019) showed that the proportion of those showing stunted growth in the present study was much lower (29% to 43.9% in different ethnics), while the figure for overweight/obesity was significantly higher (0% to 2.3% in different ethnics) [20]. The prevalence of stunting and thinness among children in the present study was higher than that of the previous study conducted in Ho Chi Minh City, Vietnam, which reported that 3.8% and 4.6% of secondary school children showed stunted growth and were thin, respectively [9]. At the same time, however, the prevalence of overweight/ obesity was significantly lower than the study mentioned above (23.5%) [9]. This can be explained by the fact that children from poorer households are more likely to suffer from stunted growth than those from wealthier households, particularly with the predominantly ethnic minority-populated Northern Midlands and Mountainous regions of Vietnam [21]. It is undeniable that childhood undernutrition is rooted in poverty. Ethnic minority groups of Vietnam comprised 14% of the national population but accounted for 73% of the poor in 2016 [21]. This study also found that thinness among boys was more prevalent than among girls. This difference could be based on the biological explanation, in which males are generally more vulnerable and have a higher chance of morbidity and mortality than females in early life [22, 23].

Regarding the socioeconomic factors, children in households with more than 2 children were more likely to show stunted growth. Having larger numbers of children or being relatively young are typical demographic characteristics of ethnic minorities in Vietnam, which may increase the risk of poverty regardless of ethnicity [21]. Income poverty among ethnic minority families has a widespread impact on their children’s malnutrition and poor education [24]. Many households cannot ensure nutritious meals for their children [25]. In addition, they face food insufficiency for several months per year between the 2 harvests, which increases the burden of malnutrition on their children [25, 26]. These findings also show that a low percentage of children strictly followed hygiene requirements, including washing hands before eating and after using the toilet or undergoing deworming treatments once every 6 mon. Previous studies reported that poor sanitation is one of the main reasons for the high stunting proportion in mountainous areas [27, 28, 29]. Unhygienic conditions and practices may trigger incipient diarrhea and other digestive-related diseases among children [30].

In terms of the nutritional practices, children who consumed potatoes and tubers daily/weekly compared to monthly/seasonal or never consumed fat/cooking oil were more likely to be undernourished while eating fish, shrimps, and crabs monthly/seasonal or weekly/daily were negatively related to showing stunted growth. These findings are similar to results from the National Institute of Nutrition report, which indicated that poor energy intake, fatty food, animal fats, and micronutrients were associated with a high level of malnutrition among ethnic children living in mountainous regions [31]. A previous study reported that the meal composition of the mountainous ethnic minorities lacked diversity, predominantly rice, green leafy vegetables, and tubers, which were self-grown staple food crops [32]. Carbohydrates were the main energy supply throughout the year, accounting for more than 60% of the total energy. Other available local food sources were poor, especially protein and iron-rich food, such as meat, fish, eggs, and seafood [32]. Seasonal changes were also considered contributing factors to the lack of these products [33]. For example, in the rainy season, mothers confessed that it was more difficult to feed their children with meat, fish, and seafood because of the inaccessibility of markets. Moreover, in the pre-harvest period, mothers did not want to buy these products because they could not afford them [33]. In addition, children in mountainous areas were less likely to consume some types of seafood, such as fish, shrimps, crabs, eels, snails, and mussels, which resulted from the insufficient nutritional knowledge and practices of the mothers [34]. They were unaware of the nutrient values and how to prepare these food items. In addition, they were afraid of the risk of gastrointestinal problems if their children consumed these foods. Therefore, there has been less attention to ensuring proper nutrition in meals by ethnicities living in mountainous areas. These people only care about having adequate food for 3 meals per day, particularly during the pre-harvest months, which is the peak of food shortages.

Children who consumed milk and dairy products daily or weekly were less likely to show stunted growth or be thin. As part of the school nutritional program to improve the nutritional status of school-aged children, the Vietnamese government introduced a program of giving milk to children daily to reduce the rate of malnutrition and increase the stature and physical strength of children [35]. This program is expected to improve the stature of children in mountainous areas and reduce inequalities of the nutritional conditions between children in remote areas and regions with higher economic conditions. On the other hand, the program is currently being piloted in several provinces, focusing on preschool and primary school children, but improvements in the stunted growth of adolescents enhancements in the adolescent growth spurt are negligible [21]. The skeletal system rapidly grows during adolescence, in which more than 95% of the adult bone mineral content is achieved by the end of this period [36]. Milk makes a vital contribution to bone development, and the recommended amount of consumption for children and adolescents is based primarily on its calcium content [37]. Fortified milk, a good source of calcium and vitamin D, is a vital factor for peak bone mass and high mineral density and is expected to increase the height around puberty [38, 39].

In addition to undernutrition, overweight and obesity are increasing in a certain population of school-aged children in mountainous areas. The Muong, Dao, and other ethnic minorities were less likely to be overweight/obese than the Tay people, which is the second-largest ethnic group in Vietnam after the majority Kinh ethnic group [40]. Regarding the food frequency, sweet food was consumed most commonly, followed by snacks and junk food. The consumption of snacks or junk food daily was associated with overnutrition, compared to never/rarely consuming these foods. This can be explained by the available foods in convenient stores with affordable prices and the ability to make independent choices among ethnic boarding children living away from home with reduced parental control. By contrast, the odds of being overweight/obese were lower among those who ate foods rich in vitamin A precursors and vitamin A or fruits daily/weekly than those who never consumed these foods. This result is consistent with a previous study in that adding vegetables to diets (adjusted OR, 0.26; 95% CI, 0.19–0.35) reduced the chance of developing overnutrition [41]. It was reported that those keeping track of their weight regularly or being on a diet were much less likely of being overweight/obese among children, suggesting the importance of a positive lifestyle in preventing overnutrition. Previous studies also reported differences in the healthy eating habits, level of physical activity, and self-efficacy between children with a normal weight and those with obesity [42, 43]. Secondary school-aged children become capable of making independent decisions regarding their diet and exercise in keeping the body fit and healthy [41]. Therefore, increasing self-efficacy and having adequate knowledge of healthy nutrition are essential for obesity management programs among those subjects.

These findings provide critical evidence to develop a long-term strategy to enhance the childhood nutritional status nationally, particularly for adolescent children of minor ethnicities. Several implications can be drawn from this study. First, intervention programs that promote parental nutrition education are essential to reduce the prevalence of stunting and thinness. Such a program is expected to provide sufficient knowledge of the nutrient value of various food types, especially protein and iron-rich foods, and how mothers can prepare foods to avoid gastrointestinal diseases in their children. Second, it is also important to integrate household food security into children’s nutrition improvement plans in remote and mountainous areas, supported by taking advantage of locally available foods. Secondary school children of ethnic minorities should benefit from nutritious food and the school milk program of the government to improve their weight and height during puberty. On the other hand, to reduce over-nutrition among children, students should be instructed to self-develop and manage positive lifestyle changes, such as keeping track of their anthropometric indices, building a healthy diet, regularly consuming vegetables and foods rich in vitamin A, and reducing the frequency of eating snacks and junk food.

This study had several limitations. The study design was cross-sectional and could not establish a causal relationship between undernutrition/over-nutrition and the risk factors. In addition, this study assessed nutritional practices based on non-validated food frequency, and the energy intake per day was not taken into account. Finally, recall bias may occur due to differences in the accuracy or completeness of the recollections retrieved by the participants regarding the events or experiences from the past.

Overall, this study showed that undernutrition remains common among school-aged children and adolescents of ethnic minority groups living in the mountainous areas of Vietnam, while the coexistence of over-nutrition is increasing. Moreover, nutritional practices were strongly associated with the nutritional outcomes in children, particularly protein/iron-rich food and milk/dairy products, and a lower risk of showing stunted growth/thin. In addition, self-development and management of positive lifestyle changes related to nutrition should be encouraged in public health nutrition programs and strategies to reduce the risk of overweight and obesity among school-aged children.