The potential relationship between dietary supplement consumption and the onset or exacerbation of inflammatory bowel disease (IBD) remains underexplored. This study aimed to describe clinical characteristics and supplement use patterns among patients with newly diagnosed IBD.

Methods: We reviewed data from five patients presenting with IBD-like symptoms and a documented history of supplement use. Demographic, clinical, and laboratory data, as well as supplement type, dosage, and duration, were collected. Symptom resolution following supplement discontinuation was also recorded.

The mean age of participants was 31.6 years (range 20–50), with a mean BMI of 26.2 kg/m². All patients reported regular exercise, predominantly bodybuilding (n=4) or wrestling (n=1). Commonly used supplements included whey protein (n=4), creatine (n=2), L-arginine (n=1), beta-alanine (n=1), and glutamine (n=1), with durations ranging from 20 days to 35 years. Omega-3 supplementation was reported in two cases. Gastrointestinal bleeding (GIB) was present in four cases, while abdominal pain and diarrhea were less frequent. Two patients experienced complete symptom resolution after discontinuing supplements. Family history of IBD was noted in two patients, and psychiatric comorbidity (generalized anxiety disorder) was observed in two cases. Laboratory evaluation showed variable vitamin D levels (range: 35–50 ng/mL) and no consistent pattern in lipid or liver enzyme abnormalities.

This case series highlights a potential temporal association between certain dietary supplements—particularly high-dose, long-term whey protein and creatine—and IBD symptom onset. Further controlled studies are warranted to determine causality and underlying mechanisms.