Effects of moderate sugar intake on glycaemic control of patients with type 2 diabeted mellitus

English: The prevalence of diabetes mellitus in South African communities is increasing aggressively, due to population and lifestyle changes associated with rapid urbanization. It is estimated that the prevalence of diabetes is due to triple within the next 25 years. Currently 10% of the total energy intake as sucrose is allowed as part of a balanced diabetic diet, according to the Diabetes Education Society in Southern Africa. Health professionals are ignorant and/or sceptical about this guideline and are reluctant to advise the patients they consult with. The aim of this study was to evaluate the effects of 15% of the total daily energy intake as sucrose on the glycaemic control of patients with type 2 diabetes mellitus. To accomplish this aim, the effects of the inclusion of 15% of the total daily energy intake as sucrose were compared to the exclusion of sucrose in the diets of free-living patients with type 2 diabetes mellitus on glycaemic control (fasting plasma glucose concentrations, serum fructosamine, HbA1cpercentages) and lipid profiles (serum cholesterol, serum HDL cholesterol, serum LDL cholesterol and serum triglycerides). The study was a randomized, controlled, single-centre clinical trail. Only 22 of the possible 401 subjects screened, who had type 2 diabetes mellitus (determined by GAD 65 and C-peptide values), and who volunteered to comply with a prescribed diet for the 16 week study period, participated in the study. At baseline, a food record and validated quantitative food frequency questionnaire was filled in by the researcher. Anthropometrical measurements (weight, height, BMI and body-fat percentage) were measured, and blood samples were analysed. Prior to baseline, subjects were advised to increase their activity level as part of a healthy lifestyle. Lifestyle patterns (smoking, alcohol consumption, exercise and medication) had to be maintained throughout the study period. Individual diets were calculated for all subjects. After a 12 week period during which all subjects were stabilized on a diabetic diet, subjects were randomized into two groups. Group 1, received a sucrose inclusive diet (SlD) and Group 2, a sucrose free diet (SFD), for a four week trial period. The type of control, namely, oral medication and diet alone, stratified these groups. There was, thus, a separate computer-generated randomization list for each of these two strata; randomizing the subjects into a study and control group. During the entire 16 week study period the researcher and' nurse had contact sessions with the subjects (fortnightly and weekly, respectively). A short informative talk to motivate and encourage subjects to adhere to, and gain insight into dietary aspects of type 2 diabetes mellitus, was given by the researcher. A registered nurse measured weight and venous plasma glucose concentrations of all subjects on a weekly basis. The registered nurse measured serum fructosamine concentrations on a fortnightly basis. At the end of the study each subject's body-fat percentage was measured and fasting blood samples (blood lipid concentrations and HbA1c percentages) were analyzed statistically to test for significant differences between the two dietary groups. The habitual dietary intake after recruitment showed that all subjects followed a low carbohydrate, high fat diet. The habitual sucrose intake in Group 1 (SlD) showed a sugar intake of 4.5%, and Group 2 (SFD) of 4.2%, respectively. The mean BMI of subjects in both groups was within the class I, obese range (BMI= 30-34.9kg/m2). Although all subjects in the study showed weight maintenance, both dietary groups experienced reduction in their body-fat percentage. However, Group 2 (SFD) showed statistically significant improvement (95% Cl: -8.5;-0.6) in body-fat percentage (4.5%). The reduction in body-fat percentage of Group 1 (SlD) could be considered as clinically significant (1.1%). No differences occurred in body-fat percentage between the groups. The fact that there was a change in body composition without weight loss may be attributed to the strict compliance and adherence of . subjects to their dietary guidelines and exercise. The mean plasma glucose concentrations for both groups were within the acceptable glycaemic control reference range of 6-8 mmol/I throughout the study period. The mean serum fructosamine concentrations of Group 1 (SlD) remained unchanged during the trial period. The mean serum fructosamine concentrations of Group 2 (SFD) showed statistically significant improvement (95% Cl: -25.3;-3.2) during the trial period. No significant differences were observed between the two groups. Both groups maintained a mean HbA1c percentage within the optimal fasting reference range of < 7% throughout the study period. Group 1 (SlD) showed an improvement (from 6.8% at baseline to 6.3% at the end of the study period) in HbA1c percentage that were close to statistical significance and were clinically significant, while Group 2 (SFO) showed a statistically significant improvement (95% Cl: -2.6;-0.2). It can be concluded that subjects with type 2 diabetes mellitus can safely include a moderate amount (15% of the total energy) of sucrose in a balanced diet, without deleterious effects on their glycaemic control. The long term glycaemic control (as measured by the HbA1c percentages) improved with good dietary compliance in both diets that included/excluded sucrose. Results of this study suggest that moderate intake of sucrose (15% of the total energy) had no aggravating effects on blood lipid concentrations of these subjects for a trial period of four weeks. However, the long term effects of sucrose on blood lipid concentrations could not be assessed. This sucrose modification in the diabetic diet may lead to improved adherence by subjects, as it minimizes the sense of deprivation. The inclusion of moderate sucrose in a balanced diet will enhance overall palatability and might improve long term compliance. Compliance to a balanced diet will improve diabetic control. Furthermore, fewer restrictions in the diet of subjects with type 2 diabetes mellitus may also lead to a reduction in short and long term complications. More research is needed to determine the long term effects of sucrose on blood lipid concentrations in subjects with type 2 diabetes mellitus. If health care workers continue to be reluctant to advise the inclusion of sucrose in the type 2 diabetic diet, because of personal prejudice or ignorance regarding the benefits of research such as this, it may create confusion and disbelief among diabetic patients concerning the efficacy of the diet. The colloquial concept of diabetes mellitus being merely a "sugar disease", and the misconception that sucrose causes diabetes mellitus, should be dispelled forthwith.