expert opinion

A new Micronutrient Calculator website indicating the nutritional status of the US population

July 15, 2013

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Julia K. Bird, Nutrition Innovation Center, Human Nutrition and Health, Delft , The Netherlands

“Adequate intakes of vitamins and minerals are essential for maintaining human health. The role that micronutrients, such as iron, vitamin A and iodine, play in the prevention of morbidity and mortality in large sectors of the global population, particularly in low and middle-income countries, is well documented. The Global Burden of Disease Study 2010 estimates that 340,000 child and maternal deaths were caused by deficiencies in vitamin A, zinc and iron that year (1). Food insecurity and nutrient deficiencies in high-income countries also exist. For example, in 2008, 14.6% of households in the US were considered food insecure and 5.7% had very low food security, with higher rates of food insecurity found in households with children (2). Nutrient inadequacies may be found in specific sub-populations. Reports show that factors, such as ethnicity, household income, education, age and gender, affect intakes and biochemical markers of nutritional adequacy. Disparities in health outcomes amongst common US ethnic groups are found for many diseases that are related to nutrition. For example, Hispanic women are at a higher risk of having a pregnancy affected by a neural tube defect related to lower intakes of folic acid due to culturally appropriate staple foods (3). Knowledge of the nutrient deficiencies that bring concern can help shape interventions targeted at risk groups.

The US Centers for Disease Control and Prevention (CDC) has been conducting a continuous survey of the US population’s health and nutritional status through the nationally representative NHANES since 1999. Using a complex, multi-stage probability design, a representative sample of non-institutionalized civilians is selec-ted. In every two-year cycle, 7,500 to 8,500 individuals are examined. Participants take part in a detailed battery of health and nutrition-based examinations. To determine nutrient intakes, two 24-hour dietary recalls are performed on non-consecutive days and compared to a database of the nutrient content of foods. The data, once stripped of all information that may identify the participants, are made available for public health purposes on a rolling basis. The CDC provides summary data online, but it is static and can be difficult for public health nutritionists to locate and interpret. As a practicum project for the Masters of Public Health in Nutrition at the University of Massachusetts, Amherst, the data was analyzed, summarized and presented via the new interactive website www.micronutrientcalculator.org. The website provide NHANES data that summa-rizes nutrient intakes, grouped by age, gender, household income and ethnicity, in a format that can be easily accessed and used by Public Health Nutritionists. It uses a visual element to enhance data interpre-tation and identification of risk nutrients, placing intakes in context by linking them to nutritional recommen-dations.

The data presented on the website show some clear trends:

  • For all age groups and genders, nutrient intakes are almost universally adequate for B-vitamins, phospho-rus, selenium and zinc ;
  • Less than half the population meet the recommendations – i.e. the Estimated Average Requirement (EAR) or the Adequate Intake (AI) – of vitamin E, vitamin K, the carotenoids (e.g. beta-carotene, lutein and zeaxanthin), calcium, magnesium and potassium, indicating a marked risk of inadequacy across the population;
  • Low intakes of many of these nutrients are related to poor adherence to fruit and vegetable intake recom-mendations; only around 7% of US adults meet age and sex-specific food-based dietary guidelines for fruits and vegetables (4);
  • Vitamin E is found predominantly in foods with a moderate to high lipid content, such as oils, nuts, seeds, grains and fatty meats. When oil or fat is heated for frying, much of the vitamin E is destroyed; therefore fatty foods that are commonly consumed in the US, such as fried potatoes, contain low levels of vitamin E;
  • The mean intake of vitamins A, C and D provides evidence that at least half the population meets the requirements. However, overall intakes are low and a significant number of people in the population may actually be at risk of inadequacy and deficiency;
  • African Americans generally have the greatest risk of inadequacy (except for vitamin K); Caucasions have the lowest risk of inadequacy (except vitamin C), and Mexican-Americans have nutrient intakes that mostly lay in between.

More detailed information can be found at www.micronutrientcalculator.org.”

Based on: Bird J. K. Development of an interactive web-based tool to depict US nutrient adequacies.
SIGHT AND LIFE. 2013; 27(1).

References

  1. Lim S. S. et al. A comparative risk assessment of the burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet. 2012; 380(9859):2224–2260.
  2. Eisenmann J. C. et al. Is food insecurity related to overweight and obesity in children and adolescents? 
    A summary of studies, 1995–2009. Obes Rev. 2011; 12(5):73– 83.
  3. Hamner H. C. et al. Modelling fortification of corn masa flour with folic acid and the potential impact on Mexican-American women with lower acculturation. Public Health Nutr. 2012; Nov 1:1–9.
  4. Murphy M. M. et al. Phytonutrient intake by adults in the United States in relation to fruit and vegetable consumption. J Acad Nutr Diet. 2012; 112(2):222–229.