Zinc nutritional status, mood states and quality of life in diarrhea-predominant irritable bowel syndrome: a case–control study

Zinc is an important trace element for structure, and regulation in the central nervous system, as well as the gut homeostasis. There are several mental disorders associated with zinc deficiency. The relationship between zinc nutritional status with mood states and quality of life (QoL) in diarrhea-predominant irritable bowel syndrome (IBS-D) has not been studied yet. This case–control study aimed to investigate the association between zinc nutritional status with mood states and QoL in IBS-D patients. Sixty-one newly diagnosed patients with IBS-D and 61 matched healthy controls were enrolled. Dietary zinc intakes and serum zinc levels were measured. Mood states and QoL were evaluated by validated questionnaires. Logistic regression was used to estimate the odds of IBS-D in relation to zinc deficiency. Decreased serum zinc levels were observed in the IBS-D group than in the controls (p = 0.001). There were higher scores of depression (p = 0.014), anxiety (p = 0.005), and stress (p = 0.001) among IBS-D patients. Moreover, overall QoL, physical and psychological health were lower in IBS-D patients compared to the controls (p < 0.001). “Food avoidance” had the lowest, while the “relationship” had the highest score among the patients (51.09 ± 26.80 and 78.14 ± 23.30, respectively). Dietary zinc intake was positively correlated with psychological health in the controls (r = 0.295, p = 0.022) and with body image in the patients (r = 0.266, p = 0.044). According to the logistic regression, zinc deficiency was not significantly associated with odds of IBS-D. Findings show that zinc deficiency may be associated with some parameters of IBS-D. Further clinical studies are needed to explore the causal relationship between zinc status and IBS pathogenesis.