United States

United States AA pregnant woman child

Project—Micronutrient Surveillance


To determine whether Americans are consuming adequate amounts of micronutrients (vitamins and minerals) and make results available to improve and develop policies and nutrition programs.


The US data on micronutrients are from the National Health and Nutrition Examination Survey (NHANES). The survey combines interviews and physical exams of a nationally representative sample of about 5,000 people each year.

For this project, the micronutrients of highest priority are iron and iodine. These nutrients are critical for healthy birth outcomes, fetal and child growth, and brain development. Iron and iodine are especially important from the time children are conceived until they are 2 years old. This period is referred to as the first 1,000 days.

Iron and Anemia

NHANES data from 1999–2010 show that 16% of US pregnant women and 15% of toddlers had iron deficiency. Anemia is commonly caused by iron deficiency. NHANES data from 2003–2012 show that 9% of pregnant women had anemia, with substantial disparities by race/ethnic group.

Another analysis of pregnant women participating in Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) found that the percentage of participants with anemia increased from 10% in 2008 to 11% in 2018 and increased significantly in approximately one half of WIC agencies. The percentage with anemia was higher among non-Hispanic Black women overall and those assessed during the third pregnancy trimester.


NHANES data from 2007–2014 indicate that iodine status among pregnant women is insufficient. Another analysis showed that although approximately 75% of pregnant women took a prenatal supplement in 2011–2014, only 18% of the supplements contained iodine.

Yet the US data have several limitations:

  • No iron or iodine status data are available for children younger than 1 year.
  • Few pregnant women are included, requiring multiple survey years to generate estimates.
  • Data for pregnant women offer limited ability to look at sociodemographic differences.
  • State-level surveillance data are not available on iron or iodine among pregnant women and children younger than 5 years.


CDC is supporting ways to improve national surveillance of key micronutrients. This includes improving case definitions for micronutrient malnutrition. CDC is also reviewing existing state-based data to determine innovative ways to incorporate surveillance of key micronutrient and address the data limitations.

Potential Impact

Better information on micronutrient intake and status will guide the development of US programs and policies to help ensure the most vulnerable populations have the micronutrients they need to grow healthy and strong.

Next Steps

In addition to continued surveillance with NHANES, CDC is exploring the use of innovative and relatively low-cost data sources to fill data gaps for micronutrient surveillance. These alternative sources include electronic health records and administrative claims data.

CDC is also working with federal partners to improve micronutrient surveillance. One example is a collaboration with the US Department of Agriculture to establish state-based anemia estimates among participants in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).

Connect with Nutrition, Physical Activity, and Obesity