ONQI: The Science Behind The Scores



The ONQI® Algorithm



The NuVal® Nutritional Scoring System is powered by the Overall Nutritional Quality Index (ONQI®), a patent-pending algorithm for measuring the nutritional quality of foods and beverages based on the influence they have on overall dietary goals. 


Developed by a team of leading nutrition, public health, and medical experts, the ONQI algorithm uses the Institute of Medicine’s Dietary Reference Intakes (DRIs – quantitative reference values for recommended intakes of nutrients) and the Dietary Guidelines for Americans (advice from the Department of Health and Human Services and the U.S. Department of Agriculture about how good dietary habits can promote health and reduce risk for major chronic diseases) to quantify the presence of more than 30 nutrients – including vitamins, minerals, fiber, and antioxidants; sugar, salt, trans fat, saturated fat, and cholesterol. The system also incorporates measures for the quality of protein, fat, and carbohydrates, as well as calories and omega-3 fats. The NuVal System also takes into account how these nutrients influence health based on broadly accepted, published scientific literature. 



For more in-depth information on the Overall Nutritional Quality Index, download the ONQI® reference manual.


Additionally, several ONQI abstract references are available online:


Chiuve SE, Sampson L, Willett WC. The association between a nutritional quality index and risk of chronic disease. Am J Prev Med. 2011 May;40(5):505-13. doi: 10.1016/j.amepre.2010.11.022.


Katz DL, Ayoob KT, Decker EA, Frank GC, Jenkins DA, Reeves RS, Charmel P. The ONQI® is not a black box. Am J Prev Med. 2011 Sep;41(3):e15-6; author reply e16. doi:10.1016/j.amepre.2011.06.024. Comment on Am J Prev Med. 2011 May;40(5):505-13.


Katz DL, Njike VY, Rhee LQ, Reingold A, Ayoob KT. Performance characteristics of NuVal and the Overall Nutritional Quality Index (ONQI®). Am J Clin Nutr. 2010 Apr;91(4):1102S-1108S. doi: 10.3945/ajcn.2010.28450E.


Katz DL, Njike VY, Faridi Z, Rhee LQ, Reeves RS, Jenkins DJ, Ayoob KT. The stratification of foods on the basis of overall nutritional quality: the overall nutritional quality index. Am J Health Promot. 2009 Nov-Dec;24(2):133-43. doi: 10.4278/ajhp.080930-QUAN-224.


Reynolds JS, Treu JA, Njike V, Walker J, Smith E, Katz CS, Katz DL. The validation of a food label literacy questionnaire for elementary school children. J Nutr Educ Behav. 2012 May-Jun;44(3):262-6. doi: 10.1016/j.jneb.2011.09.006. 



How It Works

The NuVal Nutritional Scoring System takes more than 30 different nutrients and nutrition factors into account when developing a Score, making it a very robust food rating system. Boiled down to its simplest description, here is how the NuVal System works: 


  • Nutrients with generally favorable effects on health are placed in the numerator, where higher values increase the NuVal Score. See the numerator nutrients.
  • Nutrients with generally unfavorable effects on health are placed in the denominator, where higher values decrease the NuVal Score. See the denominator nutrients.

In addition to the numerator and denominator nutrients, the NuVal System takes into account other key factors that measure the quality and density of nutrients, as well as the strength of their association with specific health conditions. 


For example, trans fat has a very strong association with heart disease, a highly prevalent and serious condition. Therefore, the NuVal System assigns a "weighting coefficient" to trans fat which substantially lowers the Score of foods containing it. Those weighting coefficients are determined by the prevalence, severity, and strength of association with health conditions. 


The quality of macronutrients is another key factor in the overall equation. Fat quality, protein quality, and glycemic load (a measure of carbohydrate quality) are among the "universal adjustors" that can move a NuVal Score higher or lower. The higher the quality, the higher the Score. 


Foods with higher nutrient density – a significant amount of vitamins and minerals, but relatively few calories – also receive extra credit and higher Scores. The greater a food's "trajectory" toward numerator nutrients (generally favorable) and away from denominator nutrients (generally unfavorable), the higher the Score. 


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Numerator Nutrients: Nutrients considered to have generally favorable effects on health are placed in the numerator, where higher values increase the NuVal Score. 

  • Fiber
  • Folate
  • Vitamin A
  • Vitamin C
  • Vitamin D
  • Vitamin E
  • Vitamin B12
  • Vitamin B6
  • Potassium
  • Calcium
  • Zinc
  • Omega-3 fatty acids
  • Total bioflavonoids
  • Total carotenoids
  • Magnesium
  • Iron

Denominator Nutrients: Nutrients with generally unfavorable effects on health are placed in the denominator, where higher values decrease the NuVal Score. 

  • Saturated fat
  • Trans fat
  • Sodium
  • Sugar 
  • Cholesterol


Additional entries:

  • Protein quality
  • Fat quality
  • Glycemic load
  • Energy density

Nutrients for inclusion in the NuVal Nutritional Scoring System were selected based on their established relevance to public health as reported and published by the scientific community. For more detailed information on the inclusion of each nutrient, and a bibliography of sources upon which each decision was based, please contact us at info@NuVal.com.


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Information Used in the Scoring Process 

When scoring packaged foods, the NuVal System uses the information on the nutrition facts panel on the food’s packaging, as well as the ingredients list. We manually scan the on-package nutrient fact panel and ingredients list, from which a nutrient content profile is generated and processed through the ONQI™ algorithm (our scoring engine).


For foods without labels (non-packaged) – such as produce, seafood, and meat – the NuVal System uses a nutrient database from a respected research arm of a major university which is used by both government agencies and academia and contains all of the nutrients needed for our computations. Their data is obtained primarily from the USDA Nutrient Data Laboratory and supplemented by food manufacturers’ information and data from scientific literature.


The NuVal System measures “nutritiousness”, which is not the only thing about food that matters. However, the System doesn’t measure toxins, and in fact cannot, since there is no standard measure for the toxins in a food (because there aren't supposed to be any). The System doesn’t measure bacteria either. So while food safety and nutritiousness are both important, they are entirely separate issues. 


Regarding mercury content in certain seafood, the scientific literature shows that the net effect of eating fish regularly is a health benefit, in spite of the associated toxins. Consequently, the NuVal Scores provide reliable guidance to the role fish should play in the diet. 


As yet, there is no widely validated evidence that organic foods have a higher nutritional value or greater nutrient density than food not grown organically. Obviously, consumers who choose organic foods may be doing so for reasons beyond nutrition – the fact that it is grown without using certain chemical controls, for example. If the scientific community puts forward well-vetted evidence that organic foods do, in fact, offer greater nutritional value, the NuVal System is designed to be able to incorporate that information into the Scores.


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