Theses (MSc. Medical and Health Sciences)

Isomaltulose is a disaccharide in which glucose is α- 1,6 linked to fructose. The capacity of fasted Malaysian adults to tolerate boluses of isomaltulose (25 g, 50 g, 75 g, 100 g) was investigated by serial measurements of breath hydrogen. A response of > 20 ppm was considered to indicate spill-over of isomaltulose to the colon. Twenty-eight consenting participants [10 males, 18 females, 20 - 36 years of age, with body mass index (BMI) ranging from 15 – 31 kg/m2] underwent crossover studies using a portable apparatus over five hours. 9/25 (36 %) participants gave evidence of spill-over at 75 g and 19/28 (70 %) to 100 g of isomaltulose. In 6 males and 11 females, glycaemic responses were compared to sucrose with a two-week washout period. The blood glucose response to isomaltulose (6.6 ± 0.9 SD mmol/L) was significantly lower than to the same bolus of sucrose (8.7 ± 1.8 SD mmol/L; p = 0.001). Faecal pH changes were measured to test for possible prebiotic effects. After a bolus of 75 g of isomaltulose, the acidity of both the first and second subsequent faecal samples was significantly greater than pre-test samples, suggesting that isomaltulose may possess a prebiotic potential. The finding of intolerance to isomaltulose suggests that caution should be exercised in its use as a carbohydrate nutrient.

Previous studies show that L. casei Shirota (Lcs) ease certain constipation-related symptoms. Use of LcS as treatment in otherwise-healthy subjects with Rome II-defined functional constipation has not been investigated. The study was aimed to evaluate the effects of LcS in adults with functional constipation. After screening of potential subjects from a database, 100 adults living in the Klang Valley who were diagnosed with functional constipation and met all other eligibility criteria were recruited for the study. The subjects were randomised (stratified based on constipation severity score and age) to receive either fermented milk containing live LcS (3.0 x 1010 colony forming units) or placebo drink without LcS once daily for 4 weeks under single-blind condition after a run-in observation period of 2 weeks and followed by a 1-week post-intervention observation period. Primary outcomes were constipation severity score measured using the Chinese Constipation Questionnaire and stool frequency; secondary outcomes were stool consistency and stool quantity estimations. During the 7-week study period, subjects completed bowel movement diaries and constipation severity was assessed weekly via questionnaire. Subjects were required to maintain their usual diet and lifestyle, which was monitored weekly via questionnaire. Dietary intake, physical activity and stress levels were assessed twice using three-day 24-hour diet recalls, International Physical Activity Questionnaire and Depression, Anxiety and Stress Scale questionnaire respectively. Eighty two subjects completed the study. Intent-to-treat analysis showed trend of improvement in constipation severity and stool consistency with probiotic administration versus placebo; but the improvements were not significant with the 4-week intervention (n=90). With re-evaluation at α=10% level, improvement in constipation severity was significant at Week 4 (P=0.058). The magnitude of the probiotics effect on stool consistency grew over time and was small but statistically significant at Week 4 (d = 0.19, 95% CI [0.00, 0.35]) and at post-intervention (d = 0.29, 95% CI [0.11, 0.52]). This indicates the stool softening effect was significant in the study sample but cannot be generalized to the population. No trends of change were observed in stool frequency and quantity. Post-hoc analysis showed improvement in severity of incomplete evacuation. Diversity of diet may have influenced the results. Four-week administration of LcS did not alleviate constipation severity or stool frequency, consistency and quantity compared to placebo, thus, null hypothesis could not be rejected. To obtain conclusive results, further studies with longer intervention of 6 to 8 weeks are warranted as the intervention period may have been insufficient.

In Malaysia, the rising incidence of type 2 diabetes mellitus (T2DM) among adolescent and adults is linked to obesity. Pharmaceutical therapy has been brought in to curb T2DM, more famously in the form of biguanides (metformin) and sulfonylureas (gliclazide). However, variation in the individual glycaemic response to metformin treatment might be due to heritability factors. Importantly, metformin has been reported to alter the microRNA (miRNA) expression profiles. Thus, the present study aims to provide data on differential expression of salivary miRNAs in responders and non-responders among T2DM patients under combined treatment of metformin and gliclazide. A total of 50 subjects were recruited each for responder and non-responder groups at the endocrine clinic of the Hospital Canselor Tuanku Mukhriz Universiti Kebangsaan Malaysia (HCTM). Subjects with HbA1c reduction levels of 0.5% or more were categorised as responders. The patients' demographic data including age, gender, BMI, WHR, ethnicity, smoking status, exercise routine and medical history were recorded. Total RNAs were isolated from the saliva collected and pooled prior to reverse-transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. The levels of microRNA namely, miR 28-3p, miR 135a-5p, miR 126-5p, and miR 320a3p were determined using RNU6P as the endogenous control. Pearson's corelation coefficient analysis demonstrated significant (p<0.05) positive correlation between BMI (29.2 ± 1.25 kg/m2) and HbA1c reduction levels (0.78 ± 0.36%) and between WHR (0.91 ± 1.35) and HbA1c reduction, while age and HbA1c reduction had a negative correlation r = -0.126 with p-value = 0.008. Meanwhile Pearson's chi-square test demonstrated only smoking status (p<0.001) had a significant correlation with the HbA1c reduction levels. Based on the miRNA PCR assays, miR 135a-5p, miR 1265p, and miR 320a-3p were upregulated while miR 28-3p was downregulated in responders compared to non-responder regardless on ethnicity and smoking status. Among the Malay subjects, miR-126-5p was downregulated in the responders among smokers but upregulated in the responders among the non-smokers when compared to their counterparts of non-responder groups. Interestingly, smoking status was also found to be significantly correlated with the HbA1c reduction levels. The deregulation and upregulation of these four targeted miRNAs have been recognized as a contributing factor in several pathways across T2DM spectrum, encompassing insulin resistance, adherens junction, hippo signalling, and AMPK signalling, proposing these four targeted miRNAs to be potential biomarkers of T2DM while miR-126-5p downregulation within VEGF pathway should be researched further and within various ethnic groups as an indicator for both T2DM with smoking-related diseases.

Vitamin D insufficiency is a widespread phenomenon globally, affecting all ages. In Malaysia, despite being a tropical country, there are increasing reports of vitamin D insufficiency among women. Vitamin D intake adequacy in child-bearing age women is important for reproductive health including in fertility, conception and birth outcomes. In line with international guidelines, the Malaysian recommended nutrient intake for vitamin D is 600 IU/day. However, the efficacy of the recommended vitamin D intake for healthy child-bearing age women to achieve sufficient plasma 25-hydroxyvitamin D [25(OH)D] levels (≥50 nmol/L) is currently unknown. This study aimed to investigate the efficacy of a 16 weeks vitamin D supplementation on plasma 25(OH)D and intact parathyroid hormone (PTH) concentrations in Malaysian women of child-bearing age. In this double blind, randomised controlled trial, 106 healthy women aged 20-45 years were randomised into four groups receiving daily 500 mg of calcium with either 0, 600 IU, 1200 IU or 4000 IU vitamin D supplement for 16 weeks. Questionnaires and anthropometric measurements were collected at baseline and post 16 weeks supplementation trial. Primary outcomes were plasma 25(OH)D and intact PTH measured at baseline and post 16 weeks trial. Baseline characteristics, including anthropometric status, sun exposure, vitamin D intake, plasma 25(OH)D and intact PTH did not differ significantly between groups (p > 0.03). Half of the participants showed vitamin D deficiency (25(OH)D <30 nmol/L), while another 40% were in the insufficiency category (25(OH)D 30-49 nmol/L) at baseline. After 16 weeks of supplementation, mean plasma 25(OH)D concentrations increased significantly (p < 0.03) among the test groups in a dose-dependent manner, with the group receiving 4000 IU/day vitamin D showing the highest increase (p < 0.03). About 30% of the women receiving 4000 IU/day vitamin D attained plasma 25(OH)D sufficiency level by 16 weeks of supplementation. Plasma intact PTH showed no significant changes between baseline and post-supplementation in the test groups (p > 0.03). General linear model revealed a significant correlation between plasma 25(OH)D concentration and skin colour tone (F = 9.064, p = <0.001). No significant association was observed between plasma intact PTH and key covariates, namely sun exposure, dietary vitamin D intake and body mass index. In conclusion, vitamin D supplementation of 4000 IU/day, compared to 600 IU and 1200 IU/day, showed the highest efficacy for increasing plasma 25(OH)D levels among women of child-bearing age. There was no obvious suppression in plasma intact PTH with vitamin D supplementation. Further investigations are recommended for a better understanding of the inverse relationship between plasma 25(OH)D and PTH levels in childbearing age women.