Childhood anemia poses a significant public health challenge among children under five years of age in India, with the prevalence estimated at 58.5% according to recent national survey 1. The consequences are very serious, including impaired cognitive and motor development, reduced immunity and reduced physical capacity, which collectively have a negative impact on educational performance and future economic productivity 23. For decades, public health interventions efforts to combat anemia have predominantly focused on iron deficiency 4. However, the pathological landscape of childhood anemia is complex and often not caused by a single nutrient deficiency. Large numbers of literature suggests that deficiencies of other micronutrients, including vitamin A, vitamin B12, folate, zinc and vitamin D, are not only widespread but also significantly contribute to the etiology of anemia and have independent adverse effects on child health 567. For instance, vitamin A is essential for erythropoiesis and iron mobilization 8, vitamin B12 and folate are vital for DNA synthesis in red blood cell precursors 9 and zinc deficiency can compromise immunity and growth, indirectly exacerbating the burden of infection-related anemia 10. Additionally researches have indicated a potential role for vitamin D in regulating hepcidin and inflammation, thereby influencing iron metabolism 1112.

The World Health Organization (WHO) defines ‘Micronutrients’ as compounds needed in very smaller amounts, less than100 mg/d 13. Minerales and vitamins are examples of Micronutrients. They are essential for the production of hormones, enzymes, and other substances that regulate growth and development 14. "Hidden Hunger" or "Micronutrient Malnutrition" can have detrimental consequences that include mental illness, learning impairment, stunted growth, poor health, early death and lassitude.

The co-existence of two or more micronutrient deficiencies is known as multiple micronutrient deficiencies (MMNDs). Synergistic interactions among these deficiencies may exacerbate overall health consequences beyond the effects of any one deficiency 15. This overlapping burden arises primarily from the combined effects of poverty, inadequate nutrition and high prevalence of infectious diseases 6. Household poverty limits access to a variety of nutritious foods, leading to deficiencies in essential vitamins and minerals 7. Poverty is also associated with poor sanitation and poor living conditions, which increase the risk of diarrhea and respiratory diseases 816. These infections act as biological amplifiers of mal nutrition by suppressing appetite, obstructing nutrient absorption and elevating metabolic losses, thereby aggravating existing deficiencies and perpetuating a vicious cycle that is difficult to break 910.

A study conducted by Houghton et.al (2019) in Delhi slum found that over half of the children (57%) aged 12-23 months were suffering from three or more micronutrients, with the highest incidence among children from poor families 17. However, research related to anemia and its coexistence with micronutrient deficiencies at the national level in India remains limited and insufficient.

Socioeconomic status (SES) is recognised as a major determinant of nutrition and micronutrient status. Children from low-income families are at risk of malnutrition due to food insecurity, poor dietary diversity, inadequate sanitation, and limited access to healthcare 1819. Understanding the relationship between economic status and micronutrient deficiency is crucial for targeted public health interventions.

The Comprehensive National Nutrition Survey (CNNS 2016-18) offers a valuable opportunity to address this gap through providing national level representative data. For the first time in India, this survey collected biochemical data on micronutrients from a nationally representative sample, allowing for the simultaneous measurement of the burden of anemia and MND. Therefore, the objectives of this study are: 1) To present the prevalence of iron, zinc, vitamin A, vitamin B12, folate and vitamin D deficiencies among children aged 1-4 years in India; 2) To highlight how multiple micronutrient deficiencies differ across socioeconomic classes.

This study provides nationally representative data on micronutrient deficiencies among children aged 1-4 years in India. The high prevalence of multiple micronutrient deficiencies (MMND) among children under five years of age in India poses a significant public health challenge for the country. Insufficient dietary diversity, poor sanitation and socio economic disparities may be playing a crucial role such deficiencies. In this study it is clearly evident that socio economic disparities is one of the important factors of micronutrient deficiency. This micronutrition burden severely damages children's development, resulting in impaired intellectual development, growth, weakened immunity and increased mortality. This leads to poor human capital formation and perpetuating intergenerational cycles malnutrition and poverty. This problem cannot be addressed by any single program, this requires coordination of various programs, including food security, diversified complementary foods and WASH programs in our national health and development agenda. There are dearth of national level study which have measured micronutrient deficiencies among young children.

Findings of this study represents lower estimates of three or more micronutrient deficiencies among children compared to a study conducted in Delhi slum where 57 percent of children had at least 3 deficiencies 17. The most common deficiencies—folate, zinc, and vitamin A—indicate that there exists significant gaps in the quality of the diet consumed by young Indian children. Folate which is crucial for cell division and growth, is abundant in green leafy vegetables and legumes. Meat, eggs and whole grains are rich in Zinc, which is essential for immune system and linear growth.

The most important finding of the study is the inverse relationship between household poverty and the micronutrition status of young children. This pattern is more evident in case of vitamin A, Zinc and folate. This demonstrates how nutrient-dense foods like dairy, eggs, fruits and vegetables are more expensive and less accessible for low-income families 21. Additionally, poorer households frequently have less hygienic conditions, which increases the risk of recurrent infections and parasites, which can both cause and worsen micronutrient deficiencies by increasing nutrient losses and impairing absorption 22.

This study has many limitations. There is no data on household food intake patterns or morbidity information of the indexed child. If they were available, it would be possible to study how food intake patterns affect micronutrient deficiency and how morbidity is affected by micronutrient deficiency. Despite such limitations, this study is very important because it provides national and state level statistics of various micronutrient deficiencies among pre school children in India.

This study clearly demonstrates that malnutrition and micronutrition deficiencies among Indian children aged 1-4 is not simply due to anemia or one or two micronutrient deficiencies, rather, there are co-existing multiple micronutrient deficiencies, which is deeply rooted in socio-economic inequality.

The current existing nutrition program of the Government of India, such as the Anaemia Mukt Bharat (Anemia Free India) strategy and distribution of iron-folic acid supplements through Integrated Child Development Services (ICDS), important steps to improve nutritional status, however, it is clear from this study that a paradigm shift in the approach is needed to address multi-micronutrient deficiencies in current nutrition interventions.

To eliminate the inverse relationship between multiple micronutrients and household income, the first step is to ensure the accessibility of balance diet to all households across different economic strata. To do that, the first thing that is needed is to improve the people's economy through various development programs and to make some positive changes in agricultural policy and food fortification.