Poor intake of vitamins and minerals is associated with symptoms among patients with irritable bowel syndrome

BACKGROUND AND AIM: Poor food habits with insufficient intake of micronutrients have been described in irritable bowel syndrome (IBS), which could be of importance for development of gastrointestinal and extraintestinal symptoms. The study aims were to examine intake and plasma/serum levels of micronutrients in IBS and whether these factors were associated with symptoms and restrictions and to study the effects of a starch‐ and sucrose‐reduced diet (SSRD). METHODS: One hundred five patients with IBS or functional gastrointestinal disorder (FGID) according to Rome IV criteria were included to SSRD/controls for 4 weeks. Patients completed a study questionnaire about lifestyle habits, medical health, IBS‐symptom severity score (IBS‐SSS), visual analog scale for IBS (VAS‐IBS), and diary books before and after study start. Plasma/serum levels of micronutrients were analyzed at baseline. RESULTS: Intake of micronutrients at baseline was lower than recommended according to national guidelines. Gastrointestinal symptoms were inversely associated with intake and plasma levels of iron. Extraintestinal symptoms and fatigue inversely associated with intake of vitamin B6, phosphorus, magnesium, and iodine, as was plasma levels of iron, and positively associated with plasma iron‐binding capacity. Fatigue was also inversely associated with calcium, iron, and zinc intakes. Plasma ferritin was lower in participants on restrictions. SSRD increased the intake of several vitamins, selenium, and fat, whereas sodium intake was decreased, with markedly reduced symptoms. CONCLUSION: Irritable bowel syndrome patients had low intake of micronutrients at baseline, which associated inversely with total IBS‐SSS, extraintestinal IBS‐SSS, and fatigue. SSRD increased the intake of several micronutrients, which correlated weakly with symptom improvement.