Is Nutri-Score misleading? New research advocates for rigorous independent testing

14 Feb 2024 --- A new comprehensive review of studies examining the Nutri-Score front-of-pack nutritional ranking system points out that many of the studies drawing positive conclusions about the system were conducted by its developers or associates. The researchers call for the system to be evaluated by independent scientific food authorities and for real-life evidence of its benefits.

“While it seems that the majority of study outcomes on Nutri-Score are favorable, the vast majority is carried out by team Nutri-Score,” Dr. Stephan Peters, manager of dairy, nutrition, health and sustainability at the Dutch Dairy Association and one of the study’s authors tells Nutrition Insight. “You should see this as if a producer makes a product that he wants to sell and, therefore, only publishes favorable results.”

The paper finds that the majority of papers conducted by “authors who are employed by or connected with the developers of Nutri-Score” are favorable toward the system. In contrast, the majority of those conducted by “independent” researchers are found to be unfavorable toward it.

The paper finds that affiliated researchers conducted the majority of studies favoring the Nutri-Score.The authors further question the adequacy of a multi-nutrient algorithm like the Nutri-Score system, which scores items’ healthfulness only within the food category it has been placed in but not against other categories, which could lead to confusion. 

“Nutri-Score does not function well for some product groups like cheese, potatoes, nuts and seeds, among others. The European Commission cannot make the Nutri-Score mandatory if it scores food groups incorrectly. First, these problems have to be solved,” Peters states.

“The golden bullet study on Nutri-Score’s efficacy would be a study where it is applied in a complete supermarket assortment, and then based on actual purchases, the effect on the algorithm should be applied. Such a study does not exist.” 

Potential bias
The study was conducted by Dr. Peters and Dr. Hans Verhagen, a scientific and regulatory expert at the Dutch Food Safety & Nutrition Consultancy and former senior science coordinator at the European Food Safety Authority (EFSA). The paper was published in the journal PharmaNutrition. 

The scientific review of 180 papers about the Nutri-Score published in 2016-2023, 104 were found to be relevant to the investigation. Of those 52 were conducted by scientists affiliated with the ranking system and have findings that are positive of the system and only four negative. Meanwhile, 19 of the studies by non-affiliated scientists have positive findings and 30 negative. 

Addressing the possibility of an EU-wide adoption of a front-of-pack nutrition label, with Nutri-Score being the front-runner, Peters comments: “We advocate for more studies on the potential efficacy of Nutri-Score to be carried out independently of ‘team Nutri-Score’. In addition, if Nutri-Score is a candidate for a mandatory front-of-pack label in the EU, then EFSA should make an independent opinion on its validation and efficacy.”

“Before any front-of-pack logo is introduced, the logo should be evaluated by independent scientific food authorities. This has not taken place yet. The only scientific evaluations we know of are carried out by the team behind Nutri-Score themselves.” 

The researchers call for more studies to be conducted in a complete supermarket range.The supermarket test
The authors of the paper argue that to demonstrate the usefulness of the Nutri-Score, studies need to be conducted in a complete supermarket range in order to show that more products with a Nutri-Score A and B or fewer products with D and E have been purchased.

The paper states that no such study has yet been applied to the Nutri-Score and that the one study examining the effects of shelf-tags with Nutri-Score in a real-life complete supermarket (a major retailer in Belgium) showed mixed results. 

“Some studies are available with the application of Nutri-Score in a complete supermarket assortment, and they give mixed and unpredictable results. One study in South Korea even showed that the use of Nutri-Score in a small supermarket led to unhealthier choices.”

Carried out independently of the Nutri-Score developers, the system was applied in a sports and a non-sports store in South Korea. In the sports store, the outcome was beneficial, with more customers choosing Nutri-Score A and B products, while customers of the non-sports store, compared to a small supermarket, purchased fewer Nutri-Score A products and more Nutri-Score B and E products. 

Competing scoring systems
Discussing the feasibility of front-of-pack nutritional ranking system alternatives, Peters argues that they face many of the same issues as the Nutri-Score and should thus all be “considered as experimental.”

 “We do not know exactly what the real-life effects are. This is not unique to the Nutri-Score. If they do have a positive effect, it will be very small. With Nutri-Score, we have observed that the effect can even be negative.”

Regarding the solution to the outlined hurdles, Peters asserts: “My advice consists of two essential parts. First, the scoring should be completely in line with a country’s food-based dietary guidelines. Second, it should be studied in a real-life supermarket environment with a complete assortment of food categories.” 

“A well-functioning front-of-pack labeling system should not lead to confusion among consumers as does the Nutri-Score,” he adds. 

Peters suggests consumers trying to navigate nutritional information to “ignore front-of-pack logos” and instead “look at the food-based dietary guidelines in your country and let those be the compass for healthy eating.” 

By Milana Nikolova