Carbohydrate restriction for glycaemic control in Type 2 diabetes: a systematic review and meta-analysis.

AIM: To conduct a systematic review and meta-analysis to evaluate the effect of carbohydrate restriction on glycaemic control in Type 2 diabetes. METHODS: We searched Medline, EMBASE and CINAHL for the period between 1976 and April 2018. We included randomized controlled trials comparing carbohydrate restriction with a control diet which aimed to maintain or increase carbohydrate intake, and that reported HbA1c as an outcome and reported the amount of carbohydrate consumed during or at the end of the study, with outcomes reported at ≥3 months. RESULTS: We identified 1402 randomized controlled trials, 25 of which met the inclusion criteria, incorporating 2132 participants for the main outcome. Definitions of low carbohydrate varied among the studies. The pooled effect estimate from meta-analysis was a weighted mean difference of -0.09% [95% CI -0.27, 0.08 (P = 0.30); I2 72% (P <0.001)], suggesting no effect on HbA1c of restricting the quantity of carbohydrate. A subgroup analysis of diets containing 50-130 g carbohydrate resulted in a pooled effect estimate of -0.49% [95% CI -0.75, -0.23 (P <0.001); I2 0% (P = 0.56)], suggesting a clinically and statistically significant effect on HbA1c in favour of low-carbohydrate diets in studies of ≤6 months' duration. CONCLUSIONS: There was no overall pooled effect on HbA1c in favour of restricting carbohydrate; however, restriction of carbohydrate to 50-130 g per day had beneficial effects on HbA1c in trials up to 6 months. Future randomized controlled trials should be of >12 months' duration, assess pre-study carbohydrate intake, use recognized definitions of low-carbohydrate diets and examine reasons for non-adherence to prescribed diets in greater detail.

Dietitians' practice in giving carbohydrate advice in the management of type 2 diabetes: a mixed methods study.

BACKGROUND: Carbohydrate is accepted as the principal nutrient affecting blood glucose in diabetes; however, current guidelines are unable to specify the optimal quantity of carbohydrate for glycaemic control. No studies exist that describe current practice amongst healthcare professionals giving carbohydrate advice in type 2 diabetes. The present study aims to improve understanding of the degree of variation in the current practice of UK registered dietitians (RDs) by describing how RDs advise patients. METHODS: UK RDs were contacted through national networks and asked to complete an online survey, which was analysed using stata, version 12 (StataCorp, College Station, TX, USA). Three consultations between dietitians and patients with type 2 diabetes were observed, followed by semi-structured interviews with the dietitians. RESULTS: In total, 320 complete survey responses were received. Dietitians' advice varied according to expertise, training and confidence, and the complexity of the patient's blood glucose treatment. Some 48% (n = 154) of respondents advised patients to restrict carbohydrate intake either occasionally or frequently, with 35.6% (n = 114) considering 30-39% of total energy from carbohydrate to be a realistic expectation. The overall theme from the interviews was 'Conflicting Priorities', with three sub-themes: (i) how treatment decisions are made; (ii) the difference between empowerment and advice; and (iii) contradictory advice. A disparity existed between what was observed and interview data on how dietitians rationalise the type of carbohydrate advice provided. CONCLUSIONS: Dietitians' advice varies for a number of reasons. Consensus exists in some areas (e.g. carbohydrate awareness advice); however, clear definitions of such terms are lacking. Clarification of interventions may improve the consistency of approach and improve patient outcomes.

Methods for the exclusion of circoviruses and gammaherpesviruses from pigs.

The use of porcine tissues is being developed as a means to alleviate the shortage of allogeneic tissues and organs available for transplantation. To reduce the possibility of a microorganism of pigs being inadvertently transferred to the recipient of the xenograft, recommendations have been published on the microbiological specifications for organ source pigs. The porcine circoviruses (PCV1 and PCV2) and porcine lymphotropic herpesviruses (PLHV1 and PLHV2) are two infectious agents of pigs which are considered to be of significance for the microbiological safety of xenotransplantation. To ensure the exclusion of these microorganisms from animals destined for use under clinical conditions, reliable breeding methodologies are required. We investigated the efficiency of established derivation procedures for the removal of PCV and PLHV. In comparison with conventionally reared pigs, caesarian and barrier derived animals showed a markedly reduced prevalence of PCVs and PLHVs. Our results indicate that the derivation of animals free of both of these microorganisms is achievable and will enhance the microbiological safety of xenotransplantation.