In the largest study of its kind in Australia, researchers looked at 3,213 food products across 10 food categories (bread, ready-to-eat cereal, dry pasta, cereal bars, cake mixes/cakes, sweet biscuits, ice cream, corn and potato chips, cured meats, sausages and hot dogs, and sugar-based confectioneries).
Nutritional information on the Nutrition Information Panel was obtained from all packaged foods at four large supermarkets in Sydney, Australia, in 2013. Researchers classified food products as gluten-free if a gluten-free declaration appeared anywhere on the packaging, or non-gluten-free if the products contained gluten, wheat, rye, triticale, barley, oats or spelt.
Researchers used the Health Star Rating (HSR) system, a voluntary nutrient-profiling scheme endorsed by the Australian government with the goal of helping consumers to choose healthier foods. The HSR system rates a product between 0.5 and 5 stars (increasing in ½ star increments, with more stars indicating higher nutritional quality).
On average, gluten-free dry pasta scored nearly 0.5 stars less compared with non-gluten-free products, but the researchers noted no significant differences in the mean HSR for bread or RTE cereals. Relative to non-gluten-free foods, gluten-free products consistently had lower average protein content across all the three core food groups, in particular for pasta and bread.
As for products that are naturally gluten-free (processed meats and corn and potato chips), the study said that food manufacturers may be using GF labeling as a marketing tool. Researchers found the average nutritional values of gluten-free discretionary foods were not superior to those of non-gluten-free products, although some were better than their gluten-containing counterparts.
“There has been a tidal wave of gluten-free products coming onto the market in recent years, and many people have been caught in the wash as they search for a healthier diet,” said Jason Wu of The George Institute for Global Health and lead author of the study. “The foods can be significantly more expensive and are very trendy to eat, but we discovered a negligible difference when looking at their overall nutrition. Gluten-free products are necessary for people with coeliac disease, but this information is important because of their broader use in the community.”
Dr. Wu cautioned consumers to be aware of the so-called health halo effect.
“Fancy labels on gluten-free foods have the potential to be used as a marketing tactic, even on products that traditionally don’t have any gluten in them anyway,” he said. “Misinterpretation by consumers, especially of junk foods, that gluten-free means they are healthy is a real concern. Whole grains along with fruit and vegetables are an important part of a healthy diet, while highly processed junk foods should be avoided. Consumers can also use the Health Star Rating system, which helps them to compare the healthiness of different products, regardless of whether they are gluten-free or not.”
The study was published in the British Journal of Nutrition.