Relationship between serotonin transporter gene polymorphism and constipation in cancer patients

The Association between Dietary Patterns and Chemotherapy Side Effects in Patients with Breast Cancer (BrCa)

This study aimed to determine the relationship between food pattern and dietary intake before and during chemotherapy with the severity of gastrointestinal side effects, cancer-related fatigue, and chemotherapy-induced pain. This study was performed on 204 patients with breast cancer who were undergoing chemotherapy. Dietary pattern was collected by food frequency questionnaire and dietary intake during chemotherapy using a 24-hour food recall questionnaire. The severity of chemotherapy side effects including nausea, vomiting, constipation, diarrhea, CRF, and pain was also assessed by valid questionnaires. The relationship between dietary pattern and mean score of chemotherapy side effects was calculated using linear regression analysis. Three dietary patterns were extracted from the participants. After adjusting the effect of all possible confounders, no significant relationship was found between the dietary pattern one year before the start of treatment and the mean of chemotherapy side effects severity. Although the mean of daily energy intake with the severity of nausea and vomiting (r = -0.258, P-value <0.01), constipation, fatigue, and pain have a significant inverse relationship. Nutrition education and following a healthy diet are needed to reduce the severity of chemotherapy side effects during this period.

Probiotics, prebiotics, and synbiotics in chronic constipation: Outstanding aspects to be considered for the current evidence

This integrative aimed to evaluate the effects and the potential mechanism of action of prebiotics, probiotics, and synbiotics on constipation-associated gastrointestinal symptoms and to identify issues that still need to be answered. A literature search was performed in the PubMed database. Animal models (n = 23) and clinical trials (n = 39) were included. In animal studies, prebiotic, probiotic, and synbiotic supplementation showed a decreased colonic transit time (CTT) and an increase in the number and water content of feces. In humans, inulin is shown to be the most promising prebiotic, while B. lactis and L. casei Shirota probiotics were shown to increase defecation frequency, the latter strain being more effective in improving stool consistency and constipation symptoms. Overall, synbiotics seem to reduce CTT, increase defecation frequency, and improve stool consistency with a controversial effect on the improvement of constipation symptoms. Moreover, some aspects of probiotic use in constipation-related outcomes remain unanswered, such as the best dose, duration, time of consumption (before, during, or after meals), and matrices, as well as their effect and mechanisms on the regulation of inflammation in patients with constipation, on polymorphisms associated with constipation, and on the management of constipation via 5-HT. Thus, more high-quality randomized control trials (RCTs) evaluating these lacking aspects are necessary to provide safe conclusions about their effectiveness in managing intestinal constipation.

Impact of serotonin transporter gene polymorphism on gut motility in patients with type 2 Diabetes mellitus

Background/Aims

The pathogenesis of gastrointestinal (GI) symptoms in patients with type 2 diabetes mellitus (T2DM) is yet to be delineated clearly. Serotonin, a monoamine neurotransmitter, resides primarily in the gut and plays a vital role in GI system. However, no study has been documented the role of serotonin and serotonin transporter gene (SLC6A4) polymorphism in the development of GI symptoms in T2DM patients.

Methods

Three hundred diabetes patients attending diabetes clinic at Postgraduate Institute of Medical Education and Research, Chandigarh, and matched healthy controls were enrolled for this study. Plasma from collected blood sample was used for serotonin measurement by enzyme-linked immunosorbent assay method and buffy coat was used for isolation of DNA by phenol chloroform method. Serotonin transporter gene polymorphism was analyzed by polymerase chain reaction method.

Results

The frequency of short allele (S) and SS genotype was significantly higher in patients with T2DM than controls and was associated with increased risk of T2DM. The frequency of LS genotype showed an association with protection from the disease. Regarding GI symptoms, 78.2% of patients with constipation showed LL and LS genotypes, and 97.7% of patients with diarrhea had SS genotype. The patients without GI symptoms did not show any association of gut motility with genotype. Furthermore, serotonin was significantly higher in diabetic patients who belonged to SS genotype compared to LS or LL genotype and who presented with diarrhea.

Conclusion

SS genotypes are prone to develop diarrhea because of faster gut motility resulting from higher serotonin levels as compared to LS and LL genotype in T2DM patients.

Link between diet and chemotherapy related gastrointestinal side effects

AIM OF THE STUDY

To evaluate an association between food products consumption, dietary intake and the incidence of selected gastrointestinal symptoms (nausea, vomiting, diarrhea and constipation) in cancer patients undergoing chemotherapy.

MATERIAL AND METHODS

Fifty six women receiving chemotherapy for ovarian cancer were eligible for the study. Anthropometrical measurements were assessed. The dietary intake was evaluated by 24-hours food records. The association between the consumption of selected food products and gastrointestinal symptoms incidences was assessed by modified semi-quantitative food frequency questionnaire including 77-different food items that was developed and applied in cancer patients undergoing chemotherapy.

RESULTS

BMI values indicated 9%, 45%, 30% and 16% of patients as underweight, normal weight, overweight and obese respectively. Only 23% and 32% of patients never experienced nausea and constipation when 43% and 45% never experienced vomiting and diarrhea. Nausea was promoted by oils, constipation by chocolate and chocolate products and diarrhea by dairy products, stone fruit and apple. Significant inverse correlations were found between vomiting and the intake of energy, fat, protein, carbohydrates, B groups vitamins, vitamin D, phosphorus and zinc. The difference in energy intake between marginal values of vomiting incidence exceeded 400 kcal.

CONCLUSIONS

Dietary intake as well as specific food products influence on gastrointestinal side effect of chemotherapy in cancer patients. The dietary approach based on either exclusion or limited intake of selected food products and improvement of diet could reduce and prevent chemotherapy induced gastrointestinal symptoms therefore should be taken under consideration in clinical practice.