Low versus high carbohydrate diet : the effect on glycated haemoglobin in overweight people with type II diabetes

Abstract

Overview of topic: 13.2% of the Maltese population has Type II Diabetes (IDF, 2017), a metabolic disorder which causes an increase in glycated haemoglobin (HbA1c) (Soranzo, 2011). An increased HbA1c can lead to complications such as glaucoma, neuropathy, and renal disease (Winters & Jemigan, 2000). Recently, a low carbohydrate ―ketogenic‖ diet has been gaining popularity, claiming to be more effective at glycemic control than moderate carbohydrate diets (Abbasi, 2018). In this dissertation, the possibility of a low carbohydrate diet lowering HbA1c will be explored. The research question: Are low carbohydrate diets more effective in lowering HbA1c levels than moderate carbohydrate diets in overweight/obese adults with diagnosed type 2 diabetes? PICO elements: The population (P) concerned involves adults with type 2 diabetes and an elevated body weight. The intervention (I) is a low carbohydrate diet (< 50 g/carbohydrate daily), which is being compared (C) with a moderate carbohydrate diet / conventional diet. The outcome (O) of interest is a reduction in HbA1c. Method: Once the PICO question was constructed, key words were derived from the PICO elements. These were then inputted in scientific databases to conduct a systematic literature search, and five RCTs met the inclusion and exclusion criteria. These included studies in English over the last 10 years and that related to the research question. The studies were then appraised using the CASP tool. Results: All of the key studies found a reduction in HbA1c upon implementation of a diet, however the results were inconsistent as to whether the low or moderate carbohydrate diet yielded the best result. Furthermore, the studies could not be directly compared, and methodological limitations were identified. Results therefore need to be analysed well before being implemented. Conclusion: Due to the lack of literature, it is difficult to draw a conclusion. With the present literature, it is improbable that a low carbohydrate diet is more effective than a moderate carbohydrate diet in reducing HbA1c. However, more research is required to reach a definite answer. Implications and recommendations: While a low carbohydrate diet is not recommended to improve HbA1c, diet still plays a key role in its regulation. We must therefore use our resources to educate the Maltese population about a healthy diet. Furthermore, information with regards to our population’s current eating habits needs to be gathered in order to address the most pressing issues.