New Index Offers First Science-Based Definition of Nutrient Density

To use an objective approach to develop a nutrient density index that could be validated against the HEI, different formulas featuring hundreds of varying numbers and combinations of nutrients were evaluated.

Effective nutrition profiling should be based on existing science and validated against proven measures of diet quality, according to the August issue of the Journal of Nutrition. A study in the issue outlined the scientific approach taken to develop the NRF Index, a measurement of nutrient density validated against the USDA's scientifically based Healthy Eating Index (HEI). While the HEI mainly measures the recommended eating pattern from the five food groups, the NRF Index goes a step further by focusing on the nutrient density of individual foods and beverages. The NRF Index has implications for people of all ages, allowing them to choose more nutrient-rich foods first in order to build a healthier diet.

Both adults and children are overweight and undernourished – missing out on important nutrients because they are not choosing nutrient-rich foods first. In much of today's nutrition education the focus is on avoiding specific nutrients – such as sugar or fat – and it appears to have failed to provide Americans with the means to build a healthy, complete diet. For this reason, the 2005 Dietary Guidelines for Americans Committee requested the development of a scientifically valid definition of nutrient density to help with nutrition guidance. Thus, the NRF Index was created to provide a positive, science-based approach to inform people about what to eat rather than what not to eat, and how to choose more nutrient-rich foods. The Index balances beneficial nutrients and nutrients to limit in order to find the true nutritional value of a food, beverage, meal or total daily food intake.

To use an objective approach to develop a nutrient density index that could be validated against the HEI, different formulas featuring hundreds of varying numbers and combinations of nutrients were evaluated. A formula based on 100 calories and taking the sum of the percent daily values of nine nutrients to encourage (protein, calcium, magnesium, iron, fiber, potassium and vitamins A, C and E) minus the sum of percent daily values of three nutrients to limit (saturated fats, sodium and added sugars) resulted in the greatest correlation with the HEI, and was established as the NRF Index. Consumer research is currently underway to create tools that will help people use the NRF Index in their everyday lives.