| The Nutrient Density Index is an estimate of the mean (“average”) value - per calorie - for the sum of the total amounts of each of up to 25 nutrient factors, most of which are specified in the DRI and are tracked in the USDA Nutrient Database. We call the NDI an “estimate” because it is rarely possible to know the values for each and every nutrient we want to evaluate. NDI values will change somewhat over time as research quality nutrient databases are updated with more accurate data and missing values are filled in.
One way to understand what the NDI tells you is to consider what an NDI value of “1.00” means. An NDI of “1.00” means that one calorie of this food item provides a mean value of 1% of the overall DRI goal per calorie for all nutrients that were evaluated." Thus, 100 calories of this food item would provide you a mean value of 100% of your DRI goal amounts for the nutrients evaluated in this food. As you can see from this example, an NDI of “1.0” is a very high value. Keep in mind that a mean value of 1% of the overall DRI goal can be the average of your getting 5% of one nutrient and 0% of four other nutrients – the mean (“average”) value of these five nutrient would still be 1% per nutrient per calorie. This underlines the fact that the path to good nutrition will continue to involve eating a wide variety of foods. |
