Drinks sweetened with sugar — but not natural juices or drinks sweetened artificially — were linked to a higher risk of inflammatory bowel disease (IBD) in people who drank more than one a day in a study of more than 120,000 people.
IBD has previously been linked with high consumption of sugar, but population-based evidence has been inconclusive, and natural juices have not been studied, write lead author Tian Fu, with the Department of Gastroenterology, the Third Xiangya Hospital of Central South University in Changsha, China, and colleagues.
Their study compared the associations of sugar-sweetened drinks, artificially sweetened beverages, and natural juices (including pure fruit or vegetable juices) with IBD risk.
“As one of the major sources of free sugar, beverages have been related to inflammation-related health outcomes but received less attention in the field of IBD,” the authors write.
“Our findings, if proven causal, suggest reduced consumption of sugar-sweetened beverages as a strategy for prevention of IBD, especially Crohn’s disease (CD), but further studies are needed to confirm these findings and explore the underlying mechanism,” they write.
The study was published online in Alimentary Pharmacology and Therapeutics.
Link Significant for Crohn’s Disease but Not Ulcerative Colitis
The researchers used data from 121,490 participants in the UK Biobank who did not have IBD at trial recruitment in 2006–2010. The average age of the participants was 56 years, and almost all (96.9%) were White. Researchers studied their intake of beverages with 24-hour diet recalls from 2009–2012.
Participants were sorted into three groups according to the consumption of each beverage: 0 unit (glasses/cans/250 mL/cartons) per day (reference group), more than 0 to 1 unit per day, and more than 1 unit per day.
While most (66.3%) did not drink any sugar-sweetened beverages, participants who reported drinking more than 1 unit per day were more likely to have a higher body mass index (BMI) and consume higher amounts of total energy and sugar.
During an average follow-up of about 10 years, the investigators documented 510 incident IBD cases: 143 cases of CD and 367 cases of ulcerative colitis (UC).
Compared to people who did not drink sugar-sweetened beverages, those who drank at least 1 unit per day had a significantly higher IBD risk (hazard ratio [HR], 1.51; 95% CI: 1.11 – 2.05), but the trend was statistically nonsignificant.
The association was significant for CD (HR, 2.05; 95% CI: 1.22 – 3.46) but not for UC (HR, 1.31; 95% CI: 0.89 – 1.92). The positive association between sugar-sweetened drinks and risk of CD, but not UC, was in line with previous studies showing that dietary patterns were more associated with CD risk, the authors note.
They also highlight that there was no positive link between artificially sweetened beverages, natural juices, or total sugar intake and IBD risk. They note that the inflammatory role of artificial sweeteners is still being debated.
Additionally, the effect of natural sugar in juices may be counteracted by fiber and bioactive compounds in the juices, the authors write.
A limitation of the study is that at baseline, all participants in the UK Biobank were older than 40 years, so the researchers could not examine any links with younger-onset IBD.
Additionally, the self-reported questionnaires are subject to recall bias, though the survey has been validated.
Study Adds to Previous Evidence
Hasan Zaki, PhD, an assistant professor with the Department of Pathology at University of Texas Southwestern Medical Center in Dallas, told Medscape Medical News that the size of this population-based study adds evidence that simple sugar can increase the risk for IBD. Zaki studies the relationship of inflammatory disorders and diet and was not involved in the study.
“This study is very strong evidence of the association between high sugar and IBD,” he said. He noted that more studies are needed because there are few studies in this area and results have varied.
His lab conducted work on the subject previously in mice. In a 2020 study, they found that a high-sugar diet helped promote IBD development and gut microbiota dysfunction.
Zaki pointed out that among people in the United Kingdom and those in the United States, diets, demographics, and IBD incidence are similar, a fact that may make the findings more generalizable.
However, studies comparing the categories of sweetened drinks should be conducted in a US population to assess the results in a diverse group to see whether ethnicity plays a role, because almost all of the people in the UK group were White, he said.
Also important, Zaki said, will be follow-up studies of the link between sweet drinks and IBD in US children, among whom consumption is particularly high and the IBD incidence is rising. One study showed the prevalence increased 133% from 2007–2016.
The results of this study should help gastroenterologists counsel patients on an ideal diet to avoid IBD or reduce IBD severity, he said.
The study was supported by the National Natural Science Foundation of China and Key Project of Research and Development Plan of Hunan Province. The study authors and Zaki report no relevant financial relationships.
Aliment Pharmacol Ther. Published online July 18, 2022. Full text
Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune, Science News, and Nurse.com, and was an editor at the Chicago Sun-Times, the Cincinnati Enquirer, and the St. Cloud (Minnesota) Times. Follow her on Twitter at @mfrellick.