The study involved 1,357 New Zealander shoppers split into three groups of about 400 each and randomly allocated to one of three labels: Traffic Light labels, Health Star Rating labels, or Nutrition Information Panels.

Participants used their smartphones to scan food products in supermarkets to ‘see’ the allocated nutrition labels.

The study concluded that labels, which interpret healthiness such as Traffic Light labels and Health Star Rating labels, had little impact on food purchases among study participants, compared with the traditional Nutrition Information Panel label.

Those using the interpretive labels found them significantly more useful and easier to understand than those using the Nutrition Information Panels.

“The study also found that frequent users of the two interpretive labels had significantly healthier food purchases than frequent users of Nutrition Information Panels,” says lead author, Professor Cliona Ni Mhurchu from the University’s National Institute for Health Innovation. “The trial results suggest that interpretive front of pack labels do not significantly influence food choices at a population level, although they appear useful for a subgroup of people who use labels a lot.”

“Our findings, together with the known effects of these labels on food industry product improvement, support including interpretive front-of-pack labels like the Health Star Rating labels in strategies to improve diets.”

“Comprehensive nutrition policies will however be essential to achieve meaningful improvements in population diets,” she says. “These include World Health Organization-backed strategies such as restricting marketing of unhealthy food to kids, taxes on sugary drinks, and healthy food policies in schools and hospitals.”

She says there is evidence from overseas that mandatory or widely implemented front-of-pack labelling of foods has an effect on enhanced efforts by the food industry to improve the nutrient profile of food products. “Front-of-pack labels are designed to support healthier consumer food choices but the main mechanism through which these labels work to affect diets may be by creating an incentive for the food industry to create better quality products.”

The University of Auckland study was a world-first randomised controlled trial of nutrition labelling in a real-world setting, where participants could check randomly assigned nutrition labels on packaged products in any store across the entire country.

The trial delivered Traffic Light labels, Health Star Rating labels, or Nutrition Information Panels via a smartphone app, developed specifically for the study. The research was funded as part of a programme grant from the Health Research Council NZ.

The paper was published online in the American Journal of Clinical Nutrition.

Source: University of Auckland