Folsom, Calif – June 30, 2023 – A new study published in Nutrients found that daily consumption of blueberries for 6 weeks, consumed as 30 g/day of freeze-dried highbush blueberry powder (equivalent to 1 ¼ cup of fresh blueberries), relieves abdominal symptoms and improves general markers of well-being, quality of life, and life functioning in patients with functional gastrointestinal disorders. 
Functional gastrointestinal disorders (FGID), including irritable bowel syndrome and functional dyspepsia (FD), are among the most frequent causes of gastrointestinal distress and affect between 10-15% of most populations.  Symptoms of FGID include abdominal pain, changes in bowel habits, bloating, nausea and other discomforts that can affect overall quality of life and functioning. Though the root cause and underlying mechanisms of FGID remain unclear, dietary factors are known to affect the interrelated components of FGID including inflammation and the microbiome. 
This randomized, double-blind, placebo-controlled cross-over study, “Blueberries Improve Abdominal Symptoms, Well-Being and Functioning in Patients with Functional Gastrointestinal Disorders,” looked at the effect of blueberry consumption on symptoms and overall quality of life in 43 adults ages 18-60 with a body mass index of 18.5 – 32.9 kg/m2 having IBS or FD or both at the Gastroenterology Group Practice in Bern, Switzerland.
Participants were randomly assigned to begin the study with either 30 g/day of freeze-dried highbush blueberry powder or the placebo treatment, which was 30 g/day of energy-, color-, appearance- and taste-matched powder. Participants consumed two 15 g doses of powder dissolved in tap water daily after breakfast and dinner.
Participants followed their assigned treatment protocol for six weeks, then crossed over to the alternate 6-week treatment protocol after a washout period of two to four weeks. Before the first and second treatment periods and in the sixth week of each treatment period, participants completed an outcome questionnaire that tracked changes in important, interdependent areas of life functioning and overall quality of life related to physical symptoms and mental health.
Results showed that blueberries improved abdominal symptom relief, well-being, quality of life, and life functioning compared to the placebo treatment. Overall, 53% of patients reported moderate or significant symptom relief after the blueberry treatment compared to 30% of patients after the placebo treatment. Quality of life and life functioning scores improved with blueberries as well, with only 44% of patients indicating a decreased quality of life after the blueberry treatment compared with 58% of patients after the placebo. Researchers note that the improved overall functioning, performance, and quality of life scores during the blueberry treatment may be related to a reduction in GI symptoms. However, technical issues are challenging in prolonged cross-over supplementation studies such as this one and more studies in other settings with a wider range of berry doses would be helpful.
Researchers suggest that the symptom relief may be due to the polyphenols in blueberries, which may have potential antioxidant, anti-inflammatory, antibacterial and neuroprotective properties. “The polyphenol and fiber components found in blueberries may have a positive mechanistic effect in the pathogenesis of FGID, which can potentially lead to improvements in inflammation, neural sensitization, intestinal permeability, and the composition and metabolism of the enteric microbiota,” explains Clive Wilder-Smith, MD, Director, Brain-Gut Research Group and the study’s lead investigator.
This study, which was funded by the US Highbush Blueberry Council, adds to a growing body of research on the connection between blueberry consumption and gut health. Further research is warranted to determine which specific components in blueberries exert beneficial effects on gastrointestinal function.
Overall, the findings from this study suggest that eating blueberries may be a useful strategy to help reduce symptoms in patients suffering from FGID. Gut-related conditions can be stressful to navigate, and many patients report excluding entire categories of food from their diets including fresh fruit . An opportunity exists to build on the momentum from National Digestive Diseases Awareness Month in May, and use it as a springboard to promote convenient and effective ways to manage FGID symptoms, such as eating blueberries, year round.
The USHBC had no role in study design, data collection, data analysis, data interpretation, or writing of the study. For more information on blueberry nutrition research visit blueberrycouncil.org/health-professionals/health-research/
 Wilder-Smith CH, Materna A, Olesen SS. Blueberries Improve Abdominal Symptoms, Well-Being and Functioning in Patients with Functional Gastrointestinal Disorders, Nutrients 2023;15(10):2396.
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