Viewing entries tagged
Zinc assessment

The India CNNS: A monumental survey identifying those at most risk of zinc deficiency

The India CNNS: A monumental survey identifying those at most risk of zinc deficiency

India’s 2016-2018 Comprehensive National Nutrition Survey (CNNS) is a truly admirable undertaking, as it is one of the largest micronutrient surveys ever conducted. This month, full results of the serum zinc status of children and adolescents were published in the American Journal of Clinical Nutrition with an accompanying editorial

Serum zinc concentrations (SZC) were assessed in more than 28,000 pre-schoolers, school aged children, and adolescents. Nationally, the prevalence of low SZC was 31.1% among adolescents, 15.8% among school-aged children and 17.4% among preschool children. State-level prevalence estimates ranged from 2.4% in Mizoram to 38.8% in Himachal Pradesh, using data for pre-school children as an example.  By providing much-needed data on zinc status at the national- and state- levels, the CNNS highlights the importance of biochemical data on micronutrient status to guide the targeting of interventions to the most vulnerable populations.  

It is helpful to start with what these prevalence estimates actually mean. India is the second most populous country in the world. While the prevalence of low SZC among children and adolescents may be lower in comparison to most of the 26 other low- and middle-income countries with available data on SZC, the CNNS findings indicate that approximately 38 million Indian children and 71 million Indian adolescents have an elevated risk of zinc deficiency. Those are staggering numbers.

It is important for individual governments to decide upon criteria to define national public health problems given a variety of contextual factors.  However, IZiNCG considers the risk of zinc deficiency to be of public health concern when the prevalence of low SZC is higher than 20%. This means that, at 31.1%, the prevalence of low SZC among adolescents calls for further investigation and action, particularly considering the intergenerational cycle of undernutrition and the fact that many girls who are zinc-deficient in adolescence will likely continue to be zinc-deficient during pregnancy in the absence of any intervention.   

Although the national prevalence estimates for zinc deficiency among pre-school and school-aged children were below 20%, state-level analyses revealed that the prevalence of zinc deficiency among preschool and school-aged children exceeded the 20% threshold in 10 out of 30 and 8 out of 30 states, respectively.  

Drilling down further, the results show that low SZC was more common among preschool children with rural residence, mothers with lower levels of education, and poorer household socioeconomic status and sanitation facilities. These findings identify vulnerable subgroups that should be prioritized to receive zinc interventions through existing platforms such as the Public Distribution System, Mid-day Meal program, and the Integrated Child Development Services, as well as new delivery channels.

An excellent review of the survey’s methods can be found in the editorial by Brown et al. As these authors note, no external quality assessments were reported for the laboratory assessment of SZC, which highlights the need for an easily accessible, global laboratory standardization program for SZC analysis.

In summary, the government of India is to be commended for undertaking such a monumental survey and generating the data needed to guide future interventions. The next challenge is to develop programs to address zinc and other micronutrient deficiencies in populations most in need.

Determining the risk of zinc deficiency: Assessment of dietary zinc intake - Second Edition published!

Determining the risk of zinc deficiency: Assessment of dietary zinc intake - Second Edition published!

Assessing the prevalence of inadequate dietary zinc intakes provides information on the risk of zinc deficiency in a population. 

Determining the risk of zinc deficiency: Assessment of dietary zinc intake takes you through the five main steps of assessing the adequacy of dietary zinc intake. These steps are:

  1. Determine the survey design

  2. Select a representative population sample

  3. Determine food intakes

  4. Estimate dietary intake of absorbable zinc

  5. Determine the prevalence of inadequate zinc intakes

Updates in this Second Edition of IZiNCG Technical Brief no. 3 include instructions for calculation of absorbable zinc, including a worked example, and a section on additional resources.

All of IZiNCG’s Technical Briefs are available here.

New IZiNCG technical brief: The value of measuring plasma or serum zinc concentrations in national surveys

New IZiNCG technical brief: The value of measuring plasma or serum zinc concentrations in national surveys

“Micronutrient deficiencies are estimated to impact a significant number of people around the world, but there remains far too little information on micronutrient status and deficiencies. More essential information and surveillance need to be gathered to make substantial progress on global targets.” 

Global Nutrition Report 2018

There is an urgent need for more and better data on the zinc status of vulnerable populations to effectively target and monitor zinc intervention programs. IZiNCG’s new Technical Brief no. 9 outlines the value of measuring plasma/serum zinc concentration in national nutrition or health-related surveys. If a population is considered at high-risk of zinc deficiency based on inadequacy of zinc in the food supply or a high prevalence of child stunting, IZiNCG recommends that plasma/serum zinc be measured in vulnerable groups.

We are pleased that plasma/serum zinc data are now included in the World Health Organization’s Vitamin and Mineral Nutrition Information System Micronutrient Database and have partnered with the Micronutrient Forum to initiate a working group to promote the inclusion of micronutrient biomarkers in large-scale surveys. 

For more information about the measurement of plasma or serum zinc concentrations, refer to previous IZiNCG Technical Briefs and Technical Documents, and the Biomarkers of Nutrition for Development (BOND) - Zinc Review.