Introduction
Adequate intakes of vitamins and minerals are essential for maintaining human health. The contribution of micronutrients such as iron, vitamin A and iodine to the prevention of morbidity and mortality in large sectors of the global population, particu-larly low and middle-income countries, is well documented.1 The Global Burden of Disease Study 2010 estimates that 340,000 child and maternal deaths were caused by defi ciencies in vita-min A, zinc and iron that year. These accounted for almost 3% of the global disease burden, representing a large decrease since 1990 but still unacceptably high for preventable conditions.2 Food insecurity and nutrient defi ciencies in high-income coun-tries also exist. For example, in 2008 14.6% of households in the United States were considered food insecure and 5.7% had very low food security, with higher rates found in households with children.3 Nutrient inadequacies may be found in specifi c sub-populations; reports show that factors such as ethnicity, household income, education, age and gender aff ect intakes and biochemical markers of nutritional adequacy.4–7
Development of
an Interact ive Web-Based
Tool to Depict US
Nutr ient Adequacies
Key messages
> Micronutrient defi ciencies continue to contribute to the global burden of disease worldwide.
> While low nutrient intake is more prevalent in low-income countries, developed countries are also aff ected by nutrient defi ciencies in sub-populations.
> The National Health and Nutrition Examination Survey (NHANES), conducted continuously in the United States of America (USA) since 1999, provides nationally representa-tive nutrient intake data that can be used to identify sub-populations at risk of nutritional defi ciency.
> The Micronutrient Calculator website was created to improve access to NHANES data for public health nutritionists, the food industry and others interested in the nutritional status of the USA’s population.
> Low intakes of fi ber, choline, vitamin E, vitamin K, calcium, magnesium, potassium, and the carotenoids were found in the general population.
> Diff erences in the pattern of nutrient intakes were found according to gender, age, ethnicity and household income sub-populations.
> The website can be visited at www.micronutrientcalculator.org
Julia K Bird
Nutrition Innovation Center, Human Nutrition
and Health, Delft , The Netherlands
Food insecurity in high-income countries is related to the dis-tribution of wealth throughout all sectors of society. Disposible household income determines not just the amount but also the types of foods consumed. This ultimately changes the pattern of foods consumed and nutrient intakes. In ethnically diverse countries such as the USA, cultural background can also have a strong influence on food preferences and intakes.8 Disparities in health outcomes amongst common US ethnic groups are found for many diseases that are related to nutrition. For example, the burden of obesity and its related morbidities are higher in people of African American descent than in other groups that make up the rest of the general population.9 Looking at intakes of particular nutrients, Hispanic women are at a higher risk of having a pregnancy affected by a neural tube defect, relating to lower intakes of folic acid through culturally appropriate staple foods.10 Knowledge of the nutrients 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 representa-tive NHANES since 1999.11 Using a complex, multi-stage prob-ability design, a representative sample of non-institutionalized civilians is selected. 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 deter-mine nutrient intakes, two 24-h dietary recalls are performed on non-consecutive days and compared to a database of the nutri-ent contnutri-ent 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, however it is static and can be difficult to locate and interpret for public health nutritionists. 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 an interactive website.
Data preparation
Dietary and demographic datasets were downloaded from NHANES cycles 2003–2004, 2005–2006, and 2007–2008. Di-etary data was taken from both 24-h diDi-etary recalls and the Na-tional Cancer Institute (NCI) method was used to estimate usual intake and percentiles of intake from foods.12 A balanced repli-cation approach was used in conjunction with the NCI method to develop standard errors and confidence intervals. In the model, co-variants included day of the week (weekday / weekend) and interview type (in person/ telephone). The dataset was strati-fied for gender and grouped by age. Further sub-groups based on income categories (up to $24,999, $25,000–$74,999, and above $75,000), and ethnicity (White, African American and Mexican American) were calculated. Where possible, Estimated Average Requirements (EARs) from the US Dietary Reference In-takes (DRI)13 were used to compute the percentile of each age, gender, ethnicity and household income group not meeting the recommendation. EARs are set at levels that meet the nutrient needs of 50% of the population. Exceptions to this were made for the nutrients fiber, choline, vitamin K, calcium, and potas-sium, for which only an Adequate Intake (AI) has been set; iron, for which only data for the RDA was available; and the carot-enoids α-carotene, β-carotene, lutein and zeaxanthin, lycopene and total carotenoids, for which no recommended intake exists, therefore levels based on carotenoid intake achieved through recommended fruit and vegetable consumption were used.14
All analyses were performed using SUDAAN software (ver-sion 10.0; Research Triangle Park, NC), and the data was ex-ported into Excel worksheets, re-coded and imex-ported into Micro-soft Access 2003. To further improve the utility of the data for public health nutritionists, recommendations for each age and gender group were added to the data. A prototype that included interactive and visual elements was created using Microsoft Ac-cess 2003. The interactive elements consisted of pages to allow selection by age / gender, age / ethnicity and age / household in-come, with drop-down menus to offer the user a choice of sub-groups within these categories. Conditional formatting based on a percentage of the population not meeting the recommendation was used to offer a visual means to assess nutrient adequacy. Technical aspects of website design
The main website was created using html and css from a tem-plate.15 After basic testing, these were converted to aspx for server implementation. The Microsoft Access database was con-verted to Microsoft SQL Server 2008 in order to upload it to the server. The conditional formatting on the percentage of the population not meeting the recommendation was presented in a “traffic light display” similar to the one used by Troesch et al.16
to effectively provide visual cues indicating nutrient adequacy. General nutrition information about each nutrient on the web-Practicum objectives
1. Provide NHANES data summarizing nutrient intakes, grouped by age, gender, household income and ethnicity, in a format that can be easily accessed and used by Public Health Nutritionists.
2. Use a visual element to enhance data interpretation and identification of risk nutrients.
3. Place intakes in context by linking them to nutritional recommendations.
site was created and added behind a pop-up window in the table. Other content was created to complement the data and provide fu rther information on nutrient intakes, sources and other simi-lar web-based nutrition tools. The website is available at: www. micronutrientcalculator.org.
How do nutrient intakes vary by age group, ethnicity and household income in the USA across the population? The amount of data presented on the website is considerable and an in-depth analysis is beyond the scope of this article. Nev-ertheless, there are some clear trends in the data that can be fu rther investigated.
For all age groups and genders, nutrient intakes are almost universally adequate for a number of vitamins, minerals and macronutrients. These nutrients are carbohydrate and protein, the B-vitamins, phosphorus, selenium and zinc. For other nutri-ents, less than half the population met the EAR or AI, indicat-ing a marked risk of inadequacy across the population. These nutrients included fi ber, choline, vitamin E, vitamin K, calcium, magnesium, potassium, and the carotenoids. Low intakes of many of these nutrients are related to poor adherence to fr uit and vegetable intake recommendations; only around 7% of US adults meet age and sex-specifi c food-based dietary guidelines for fr uits and vegetables.14 Choline intakes are low because there are few foods rich in choline, and the few good sources are not consumed in large enough quantities on a population level.17 Calcium intakes in adults decline with age, as total ener-gy intakes decline, therefore the lower intakes are seen in older age groups. 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 fr ying, much of the vitamin E is destroyed, therefore fatty foods that are commonly consumed in the US such as fr ied potatoes contain low levels of vitamin E. Magnesium is commonly found in whole grain prod-ucts, nuts and legumes; food items that are in line with US di-etary guidelines yet are not consumed at adequate levels.18,19
The mean intake of vitamins A, C and D provided evidence that at least half the population met requirements. However, overall intakes were low and a signifi cant number of people in the population may actually be at risk of inadequacy and de-fi ciency. This is backed up by biochemical data showing that 0.3%, 6% and 17.2% of the general population is defi cient in vitamins A, C and D, respectively.20 Large diff erences in the DRI for iron between women aged 14 and 50 and the other popula-tion groups mean that even though overall intakes are adequate, iron defi ciency is more common in women of childbearing age.
Men tend to have higher nutrient intakes than women due to higher overall food consumption. For some nutrients, the DRI is higher and does not impact the percentage of the population meeting requirements. Nutrient intakes in toddlers and young children are generally better than older populations, while for adolescents aged 14–18, high nutritional requirements mean that they are most at risk of inadequate intakes.
The income categories chosen refl ect low, average and high economic status when compared to the median US household income of around $50,000, and the 130% threshold of the Fed-eral Poverty Level Guidelines, which was $24,505 for a family of four in 2004.21,22 Overall nutrient intakes are higher in the The Micronutrient Calculator off ers public health nutritionists a convenient tool to quickly assess nutrient intake needs
The micronutrient requirements of diff ering demographic groups can easily be accessed using the Micronutrient Calculator.
founded with socioeconomic status, and this may refl ect social, political disadvantages or neglect. Ethnic diff erences in cultural cohesion may also infl uence the eff ectiveness of general nutri-tion educanutri-tion intervennutri-tions,24 refl ected by a lower percentage of minority populations meeting nutritional guidelines.8 Diff er-ences in food consumption patterns due to variants in the cultur-al or socio-politiccultur-al environment underlie the disparities found in micronutrient intake by ethnicity.
The interactive website developed based on NHANES data off ers public health nutritionists and other interested parties a convenient tool to quickly assess nutrient intake needs of a broad range of age, gender, ethnicity and household income cat-egories.
Correspondence:
Julia K Bird, Nutrition Innovation Center,
Human Nutrition and Health, Alexander Fleminglaan 1, 2613 AX Delft , The Netherlands E-mail: [email protected]
highest income category, a phenomenon that has been found in other examinations of nutrient intake by income level in the US.8 Nutrient-rich diets tend to be associated with a higher cost; a diet high in the nutrients dietary fi ber, vitamins A, C, D, E, and B₁₂,
β-carotene, folate, iron, calcium, potassium, and magnesium was associated with increased dietary cost.23 Higher intakes of fr uits, vegetables, whole grains and dairy in higher income groups ac-counted for higher intakes of vitamin C, β-carotene, potassium and magnesium in a recent analysis of the NHANES dataset.8
Looking at ethnicity, there were some diff erences in intakes found. Afr ican Americans generally had the greatest risk of in-adequacy, Whites had the lowest risk of inin-adequacy, and Mexi-can AmeriMexi-cans had nutrient intakes that mostly lay in between. Some exceptions to these trends were seen for folate, choline, calcium, and magnesium, where the highest intakes were seen in the Mexican American subjects; vitamin C, where the Whites clearly had lower intakes than the other ethnic groups; and for vitamin K, the Afr ican Americans had the lowest risk of inad-equacy. In the USA, ethnicity aff ects not only cultural practices surrounding general eating patterns, but is also somewhat
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