NEW YORK (Reuters Health) - Ultra-processed foods might be associated with an increased risk of irritable bowel syndrome (IBS), observational data suggest.

As reported June 15 online in The American Journal of Gastroenterology, Laure Schnabel of the University of Paris and colleagues analyzed data from the web-based NutriNet-Sante Study, which was set up to investigate nutrition and health relationships.

The team examined dietary data from 33,343 of the more than 160,000 participants in the study. Questionnaires were completed online and covered at least three 24-hour food records. Most participants (76.4%) were women; the mean age was 50.4 years.

On average, ultra-processed foods accounted for 16.0% of food consumed daily in weight, corresponding to 33.0% of total daily energy intake. Factors that were significantly associated with such consumption included younger age, lower income and lower physical activity. Similar results were seen using ultra-processed food consumption as a percentage of energy intake.

A total of 3516 participants (10.5%) reported IBS. After adjustment, the researchers found that an increased proportion of ultra-processed foods in the diet was associated with a higher prevalence of IBS. In the highest versus the lowest quintile, the adjusted odds ratio was 1.25.

They also observe, however, that "despite the various confounding factors accounted for in the multivariable regression models, we cannot exclude the hypothesis of residual confounding due to the observational design of the study."

The investigators note that ultra-processed foods "are usually affordable products, highly marketed, ready-to-eat, with a long shelf life. Moreover, they constitute the major part of supermarket supply and are therefore widely available."

"The results of this study," they go on to say, "provide arguments for collecting data on the degree of food processing in food surveys in order to explore ultra-processed foods consumption and its suspected deleterious impact on health. Further longitudinal studies will be needed to ascertain the association observed between ultra-processed food consumption and IBS."

In an email to Reuters Health, Schnabel stressed that the findings were limited to a French adult population. "The study design being observational, it must be emphasized that we cannot conclude as to a causal link and that other studies will be necessary in different populations and settings," she said.

Commenting by email, Dr. Peter Gibson of Monash University, Melbourne, Australia, told Reuters Health, "This seems like a very good study. The results are in line with the idea that eating a diet based upon whole foods is the best for the promotion of good health. However, the study does not show this. It only indicates association of ultra-processed food consumption with one type of symptom pattern (IBS)."

Dr. Gibson, who is Professor and Head of the Department of Gastroenterology, concluded, "The paper itself is correctly very restrained in assigning a causal relationship between ultra-processed food consumption and IBS."

SOURCE: https://go.nature.com/2zgZxEv