SummaryWe present the case of an adult female with type 1 diabetes, whose HbA1c was trending at 58 mmol/mol (7.5%) for the past 3 years. In August 2016, she reduced her total daily carbohydrate intake to 30–50 g and adjusted her other macronutrients to compensate for the calorific deficit. Her HbA1c fell to 34 mmol/mol (5.3%) by January 2017 and average daily blood glucose readings decreased significantly from 10.4 to 6.1 mmol/L. Moreover, she observed a marked reduction of average daily glucose variability. Notably, there were no significant episodes of hypo- or hyperglycaemia and her lipid profile remained static. Subjectively, she described an improvement in her quality of life and the dietary transition was extremely well tolerated. We discuss these findings in detail and the potential clinical benefits for patients with type 1 diabetes that can be gained by following a low carbohydrate diet.Learning points:A low carbohydrate diet was found to substantially reduce HbA1c values and blood glucose (BG) variability, as well as causing a significant reduction in average daily glucose values in a patient with T1DM.Although further research is warranted, low carbohydrate diets in patients with T1DM have the potential to positively impact long-term morbidity and mortality through reduction of BG variability and average daily BG values.The diet was well tolerated and not associated with any adverse effects within this study.

Klebsiella pneumoniae (NCTC, CL687/80) harbors a large indigenous plasmid (p(C3)), which in addition to encoding for citrate utilization, proline synthesis and glutamate excretion, it uniquely carries the structural gene (icd); encoding isocitrate dehydrogenase (ICDH). Flux analysis revealed that ICDH, despite its role in the generation of NADPH required for glutamate dehydrogenase, is not rate-limiting (controlling) in central metabolism as evidenced by a negative flux control coefficient and an adverse effect of overexpression (14-fold) on glutamate excretion. More significantly, however, this paper presents, for the first time, clear evidence that the accumulation of glutamate and its subsequent excretion is associated with the C3 plasmid-encoded regulatory elements, which trigger a shift-down in the activity of α-ketoglutarate dehydrogenase, both in the K. pneumoniae parental strain as well as in the E. coli exconjugants strains. This finding opens the door for the exploitation of regulatory elements as a tool for manipulating flux in microbial cell factories.

In recent years the successful treatment of Type 2 diabetes mellitus through total calorific and/or dietary carbohydrate restriction has been well established. The use of low-carbohydrate diets for the adjunctive management of Type 1 diabetes mellitus has been studied but to a lesser extent. Over the past 20 years, a growing body of evidence has examined the effects of daily carbohydrate restriction on the key markers of glycaemic control, including blood glucose variability, average daily blood glucose readings, and HbA1c. The majority of publications to date have demonstrated a beneficial impact of carbohydrate reduction on glycaemic control. Indeed, similar findings have also been replicated using diets restricted to foods with a low glycaemic index. Interestingly, following a low-carbohydrate diet can also uncover the hyperglycaemic effects of fat and protein consumption, and the clinical implications of this will be discussed within this review. There is evidence, however, to suggest that these diets can be difficult to adhere to and that they may even pose health risks to the patient. Acutely, they can cause hypo or hyperglycaemic events, potentiate the risks of ketosis, and deplete systemic glycogen stores. The long-term effects of a low-carbohydrate diet are not well documented; however, possible complications can include alterations in lipid profiles, micronutrient deficiencies, cardiac complications, and nephrolithiasis. This review presents an overview of the major studies to date that have looked at carbohydrate dietary manipulation and the subsequent impact on glycaemic control in populations with Type 1 diabetes mellitus.