A randomised controlled trial of a probiotic and a prebiotic examining metabolic and mental health outcomes in adults with pre-diabetes

AIMS

To evaluate the effect of the probiotic Lactobacillus rhamnosus HN001 and/or cereal enriched with oat-derived beta-glucan (OBG) on metabolic and mental health outcomes when administered to adults with pre-diabetes.

DESIGN

2×2 factorial design randomised, parallel-groups placebo-controlled; double-blinded for probiotic, single-blinded for cereals.

PARTICIPANTS

Community-dwelling adults aged 18-80 years with pre-diabetes: glycated haemoglobin (HbA_1c) 41-49 mmol/mol.

INTERVENTIONS

Capsules containing Lactobacillus rhamnosus (HN001) (6×10⁹ colony-forming units/day), or placebo capsules; and cereal containing 4 g/day OBG or calorie-matched control cereal, taken daily, for 6 months. Study groups were: (A) HN001 capsules+OBG cereal; (B) HN001 capsules+control cereal; (C) placebo capsules+OBG cereal and (D) placebo capsules+control cereal.

OUTCOME MEASURES

Primary outcome: HbA_1c at 6 months.

SECONDARY OUTCOMES

fasting plasma glucose, fasting insulin, homeostatic model assessment of insulin resistance, fasting lipids, blood pressure, body weight, waist circumference, body mass index and mental well-being.

RESULTS

153 participants were randomised. There was complete HbA_1c outcome data available for 129 participants. At 6 months the mean (SD) HbA_1c was 45.9 (4.4) mmol/mol, n=66 for HN001, and 46.7 (4.3) mmol/mol, n=63 for placebo capsules; 46.5 (4.0) mmol/mol, n=67 for OBG and 46.0 (4.6) mmol/mol n=62 for control cereal. The estimated difference between HN001-placebo capsules was -0.83, 95% CI -1.93 to 0.27 mmol/mol, p=0.63, and between OBG-control cereals -0.17, 95% CI -1.28 to 0.94 mmol/mol, p=0.76. There was no significant interaction between treatments p=0.79. There were no differences between groups or significant interactions between treatments for any of the secondary outcomes.

CONCLUSIONS

This study found no evidence of clinical benefit from the supplementation with either HN001 and/or cereal containing 4 g OBG on HbA_1c and all secondary outcomes relevant to adults with pre-diabetes.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clincial Trials Registry number ACTRN12617000990325.

Potential Association Between Dietary Fibre and Humoral Response to the Seasonal Influenza Vaccine

Influenza vaccination is an effective public health measure to reduce the risk of influenza illness, particularly when the vaccine is well matched to circulating strains. Notwithstanding, the efficacy of influenza vaccination varies greatly among vaccinees due to largely unknown immunological determinants, thereby dampening population-wide protection. Here, we report that dietary fibre may play a significant role in humoral vaccine responses. We found dietary fibre intake and the abundance of fibre-fermenting intestinal bacteria to be positively correlated with humoral influenza vaccine-specific immune responses in human vaccinees, albeit without reaching statistical significance. Importantly, this correlation was largely driven by first-time vaccinees; prior influenza vaccination negatively correlated with vaccine immunogenicity. In support of these observations, dietary fibre consumption significantly enhanced humoral influenza vaccine responses in mice, where the effect was mechanistically linked to short-chain fatty acids, the bacterial fermentation product of dietary fibre. Overall, these findings may bear significant importance for emerging infectious agents, such as COVID-19, and associated de novo vaccinations.

Distinct Dysfunctional States of Circulating Innate-Like T Cells in Metabolic Disease

The immune system plays a significant role in controlling systemic metabolism. Innate-like T (ILT) cells in particular, such as mucosal-associated invariant T (MAIT) cells, invariant natural killer T (iNKT) cells and γδ T cell receptor expressing cells, have been reported to promote metabolic homeostasis. However, these different ILT cell subsets have, to date, been generally studied in isolation. Here we conducted a pilot study assessing the phenotype and function of circulating MAIT, iNKT, and Vδ2⁺ T cells in a small cohort of 10 people with obesity and type 2 diabetes (T2D), 10 people with obesity but no diabetes, and 12 healthy individuals. We conducted phenotypic analysis by flow cytometry ex vivo, and then functional analysis after in vitro stimulation using either PMA/ionomycin or synthetic agonists, or precursors thereof, for each of the cell-types; use of the latter may provide important knowledge for the development of novel therapeutics aimed at activating human ILT cells. The results of our pilot study, conducted on circulating cells, show clear dysfunction of all three ILT cell subsets in obese and obese T2D patients, as compared to healthy controls. Importantly, while both iNKT and Vδ2⁺ T cell dysfunctions were characterized by diminished IL-2 and interferon-γ production, the distinct dysfunctional state of MAIT cells was instead defined by skewed subset composition, heightened sensitivity to T cell receptor engagement and unchanged production of all measured cytokines.

Food 4 Health - He Oranga Kai: Assessing the efficacy, acceptability and economic implications of Lactobacillus rhamnosus HN001 and β-glucan to improve glycated haemoglobin, metabolic health, and general well-being in adults with pre-diabetes: study protocol for a 2 × 2 factorial design, parallel group, placebo-controlled randomized controlled trial, with embedded qualitative study and economic analysis

BACKGROUND

The rates of pre-diabetes and type 2 diabetes mellitus are increasing worldwide, producing significant burdens for individuals, families, and healthcare systems. In New Zealand, type 2 diabetes mellitus and pre-diabetes disproportionally affect Māori, Pacific, and South Asian peoples. This research evaluates the efficacy, acceptability, and economic impact of a probiotic capsule and a prebiotic cereal intervention in adults with pre-diabetes on metabolic and mental health and well-being outcomes.

METHODS

Eligible adults (n = 152) aged 18-80 years with pre-diabetes (glycated haemoglobin 41-49 mmol/mol) will be enrolled in a 2 × 2 factorial design, randomised, parallel-group, placebo-controlled trial. Computer-generated block randomization will be performed independently. Interventions are capsulated Lactobacillus rhamnosus HN001 (6 × 109 colony-forming units/day) (A) and cereal containing 4 g β-glucan (B), placebo capsules (O1), and calorie-matched control cereal (O2). Eligible participants will receive 6 months intervention in the following groups: AB, AO1, BO2, and O1O2. The primary outcome is glycated haemoglobin after 6 months. Follow-up at 9 months will assess the durability of response. Secondary outcomes are glycated haemoglobin after 3 and 9 months, fasting glucose, insulin resistance, blood pressure, body weight, body mass index, and blood lipid levels. General well-being and quality of life will be measured by the Short-Form Health Survey 36 and Depression Anxiety Stress Scale 21 at 6 and 9 months. Outcome assessors will be blind to capsule allocation. An accompanying qualitative study will include 24 face-to-face semistructured interviews with an ethnically balanced sample from the β-glucan arms at 2 months, participant focus groups at 6 months, and three health professional focus groups. These will explore how interventions are adopted, their acceptability, and elicit factors that may support the uptake of interventions. A simulation model of the pre-diabetic New Zealand population will be used to estimate the likely impact in quality-adjusted life years and health system costs of the interventions if rolled out in New Zealand.

DISCUSSION

This study will examine the efficacy of interventions in a population with pre-diabetes. Qualitative components provide rich description of views on the interventions. When combined with the economic analysis, the study will provide insights into how to translate the interventions into practice.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12617000990325. Prospectively registered on 10 July 2017.

The effect of additional mealtime insulin bolus using an insulin-to-protein ratio compared to usual carbohydrate counting on postprandial glucose in those with type 1 diabetes who usually follow a carbohydrate-restricted diet: A randomized cross-over trial

This randomized controlled cross-over study compared postprandial glucose concentrations and incidence of hypoglycaemia for mealtime bolus insulin calculated for both meal protein and carbohydrate content, with ordinary dosing for carbohydrate content alone, in adults with type 1 diabetes who usually follow a carbohydrate-restricted diet. All 16 participants completed three test meals under each of the two conditions. The primary outcome was the time normalized Area Under the Curve (AUC) of glucose measurements. The mean (SD) AUC glucose concentration for insulin dosing for both protein and carbohydrate was 8.3 (2.1) mmol/L compared with 10.0 (2.2) mmol/L for carbohydrate alone. The difference (95% CI) was -1.76 mmol/L (-2.87 to -0.65), P = .003. The mean (SD) glucose concentration ≥ 8.0 mmol/L was 54.8 (32.4)% for dosing for protein and carbohydrate and 73.7 (26.3)% for carbohydrate alone, rate ratio (95% CI) 0.75 (0.62 to 0.89), P = .002. For glucose concentration < 4.0 mmol/L 5.5 (15.1)% and 2.8 (11.7)%; rate ratio (95% CI): 1.97 (0.90 to 4.27), P = .087. Calculating the meal insulin requirements based on the carbohydrate and protein content may have advantages over calculations based on carbohydrate alone. Further studies are required to determine how to best optimize this.

Intermittent fasting in Type 2 diabetes mellitus and the risk of hypoglycaemia: a randomized controlled trial

AIMS

To establish whether the risk of hypoglycaemia is greater with 2 consecutive days of very-low-calorie diet compared with 2 non-consecutive days of very-low-calorie diet in people with Type 2 diabetes.

METHODS

This was a non-blinded randomized parallel group interventional trial of intermittent fasting in adults. The participants had a BMI of 30-45 kg/m² , Type 2 diabetes treated with metformin and/or hypoglycaemic medications and an HbA_1c concentration of 50-86 mmol/mol (6.7-10%). The participants followed a 2092-2510-kJ diet on 2 days per week for 12 weeks. A total of 41 participants were randomized 1:1 to consecutive (n=19) or non-consecutive (n=22) day fasts, of whom 37 (n=18 and n=19, respectively) were included in the final analysis. The primary outcome was difference in the rate of hypoglycaemia between the two study arms. Secondary outcomes included change in diet, quality of life, weight, lipid, glucose and HbA_1c levels, and liver function.

RESULTS

The mean hypoglycaemia rate was 1.4 events over 12 weeks. Fasting increased the rate of hypoglycaemia despite medication reduction (RR 2.05, 95% CI 1.17 to 3.52). There was no difference between fasting on consecutive days and fasting on non-consecutive days (RR 1.54, 95% CI 0.35 to 6.11). Improvements in weight, HbA_1c , fasting glucose and quality of life were experienced by participants in both arms.

CONCLUSIONS

In individuals with Type 2 diabetes on hypoglycaemic medications, fasting of any type increased the rate of hypoglycaemia. With education and medication reduction, fewer than expected hypoglycaemic events occurred. Although it was not possible to determine whether fasting on consecutive days increased the risk of hypoglycaemia, an acceptable rate was observed in both arms.

A feasibility study: association between gut microbiota enterotype and antibody response to seasonal trivalent influenza vaccine in adults

Objective

We investigated the potential feasibility of a randomized controlled trial of a nutritional intervention that may alter human gut microbiota and support immune defence against respiratory tract infection in adults (Proposed Study).

Methods

In total, 125 healthy adults aged 18–64 participated in a 6‐month study that measured antibody response to the seasonal trivalent influenza vaccine. We assessed completion rates, procedure adherence rates and the influence of possible exclusion criteria on potential recruitment into the Proposed Study. We examined whether the gut microbiota could be categorised into enterotypes, and whether there was an association between enterotypes and the antibody response to the influenza vaccine.

Results

The participant completion rate was 97.6% (95% CI 93.1–99.5%). The proportions (95% CI) of participants who may be excluded for antibiotic or corticosteroid use in the 30 days prior to the study, or due to receiving the influenza vaccine in the previous two years were 9.6% (5.1–16.2), 8.0% (3.9–14.2) and 61.6% (52.5–70.2), respectively. All participants were stratified into four gut microbiota enterotypes. There was no association between these enterotypes and the antibody response to the influenza vaccine, although the study was not powered for this outcome.

Conclusion

This study design is suitable for the Proposed Study. The completion rate is likely to be high, although exclusion criteria should be selected with care. Further analyses of gut microbiota composition or function in association with antibody and immune responses are warranted to explore the role of host–microbiota interactions on protective immunity.

Sublingual vitamin B12 compared to intramuscular injection in patients with type 2 diabetes treated with metformin: a randomised trial

MAIM: To compare a single 1mg intramuscular hydroxocobalamin injection with a 3-month course of 1mg/day sublingual methylcobalamin supplements on serum vitamin B12 concentrations in participants withtype 2 diabetes treated with metformin.

METHOD

Participants on metformin treatment with vitamin B12 concentrations below 220pmol/L were recruited through hospital diabetes clinics and primary care practices. They were randomised to receive either the injection or sublingual treatment. The primary outcome was serum vitamin B12 level after 3 months adjusted for baseline assessed by analysis of covariance (ANCOVA). The trial was registered on the Australia New Zealand Clinical Trial registry (ACTRN12612001108808).

RESULTS

A total of 34 participants were randomised; 19 to the tablet, and 15 to the injection. The mean (SD) age, duration of diabetes, and duration of metformin use were, 64.2 (7.3) years, 13.7 (6.4) years, and 11.6 (5.0) years, respectively. After 3 months, the mean (SD) vitamin B12 was 372.1 (103.3) pmol/L in the tablet group (n=19) compared to 251.7 (106.8) pmol/L in the injection group (n=15), ANCOVA estimated difference -119.4 (95% CI -191.2 to -47.6), p=0.002. After 6 months, the mean (SD) serum B12 was 258.8 (58.7) pmol/L in the tablet group (n=17) and 241.9 (40.1) pmol/L in the injection group (n=15); ANCOVA estimated difference -15.2 (95% CI -50.3 to 19.8), p=0.38. Higher metformin dose was associated with lower serum B12 at 3 months, but not at baseline or 6 months.

CONCLUSION

Decreased serum vitamin B12 level in patients with type 2 diabetes who are treated with metformin can be corrected through treatment with either hydroxocobalamin injections or methylcobalamin sublingual supplements.

From 'pleasure to chemistry': the experience of carbohydrate counting with and without carbohydrate restriction for people with Type 1 diabetes

INTRODUCTION

Matching carbohydrate intake with insulin dosage is recommended management for people with Type 1 diabetes. However, international interest in restricted carbohydrate diets is growing. General practitioners and practice nurses need to know how to advise people with Type 1 diabetes regarding low-carbohydrate diets. This study aimed to explore the carbohydrate counting experiences of people with Type 1 diabetes in a trial with and without a diet restricted to 75 g of carbohydrate per day.

METHODS

Eight participants were interviewed by focus group or interview 12 weeks after a carbohydrate counting course with individual dietary choice or the same course with information on restricted carbohydrate eating and a daily maximum intake of 75 g of carbohydrate. Data were analysed using a qualitative thematic analysis approach.

FINDINGS

Themes included the need for insulin management skills, impact of the dietary experience, and need for dietary knowledge. The restricted-carbohydrate group encountered mealtime insulin resistance and difficulty managing insulin dosages when transitioning on and off the low-carbohydrate diet. The diet impacted on mood, feelings of satiety and it was reported that food changed from being 'a pleasure to chemistry'. Both groups described feeling empowered to manage their diabetes as a result of the carbohydrate counting course.

CONCLUSION

Participants reported increased knowledge and challenging insulin management. The restricted-carbohydrate group reported mealtime insulin resistance and a strong dietary impact. Extra health professional support may be required, especially at dietary transition periods. More research is warranted into the reported mealtime insulin resistance.

The effect of a cinnamon-, chromium- and magnesium-formulated honey on glycaemic control, weight loss and lipid parameters in type 2 diabetes: an open-label cross-over randomised controlled trial

PURPOSE

This randomised controlled trial assessed the acute and long-term effects of daily supplementation of kanuka honey, formulated with cinnamon, chromium and magnesium on glucose metabolism, weight and lipid parameters in individuals with type 2 diabetes.

METHODS

Twelve individuals with type 2 diabetes received 53.5 g of a formulated honey and a control (non-formulated) kanuka honey in a random order for 40 days, using cross-over design. Fasting glucose, insulin, HbA1c, lipids and anthropometric measures were measured at baseline and end of treatment. A meal tolerance test was performed at baseline to assess acute metabolic response.

RESULTS

There was no statistically significant difference in acute glucose metabolism between treatment groups, as measured by the Matsuda index and AUC for glucose and insulin. After the 40-day intervention with honey, fasting glucose did not differ significantly between the two treatments (95 % CI -2.6 to 0.07). There was no statistically significant change in HbA1c or fasting insulin. There was a statistically significant reduction in total cholesterol by -0.29 mmol/L (95 % CI -0.57 to -0.23), LDL cholesterol by -0.29 mmol/L (95 % CI -0.57 to -0.23) and weight by -2.2 kg (95 % CI -4.2 to -0.1). There was a trend towards increased HDL and reduced systolic blood pressure in the intervention treatment.

CONCLUSION

The addition of cinnamon, chromium and magnesium supplementation to kanuka honey was not associated with a significant improvement in glucose metabolism or glycaemic control in individuals with type 2 diabetes. Use of the formulated honey was associated with a reduction in weight and improvements in lipid parameters, and should be investigated further.

Should support for obesity interventions or perceptions of their perceived effectiveness shape policy?

OBJECTIVES

Most studies suggest the public locate responsibility for the 'obesity epidemic' with individuals themselves and support measures promoting greater personal responsibility in the belief these will reduce obesity prevalence. We compared estimates of policy support with estimates of perceived policy effectiveness to test this assumption.

METHODS

In an on-line survey of 534 New Zealanders, we tested support for 15 potential measures to reduce overweight and obesity and compared this with estimates of the effectiveness of these policies, determined by a Best-Worst choice experiment.

RESULTS

Respondents gave strongest support to measures encouraging people to undertake more exercise and adopt a better diet. However, they saw greater personal responsibility as less effective in reducing obesity than environmental interventions that reduced the costs of healthy food and exercise, and decreased the availability of unhealthy foods.

CONCLUSIONS

Potentially important differences exist between the measures the general public say they support to address obesity, which favour personal responsibility and education, and those they believe will be effective, which include more environmental interventions.

IMPLICATIONS

Simply measuring the popularity of measures to reduce obesity produces an incomplete picture of public opinion. Examining the perceived efficacy of different interventions offers a complementary perspective that policy makers should also consider.

The prevalence of low vitamin B12 status in people with type 2 diabetes receiving metformin therapy in New Zealand--a clinical audit

AIM

Metformin, the most common hypoglycaemic agent used in type 2 diabetes, is associated with reduced serum vitamin B12 concentrations. This cross sectional observational study determines the prevalence of low vitamin B12 status in people with type 2 diabetes on metformin therapy in both primary and secondary care in New Zealand.

METHOD

All eligible patients seen in a secondary-care clinic over a 15-month timeframe were screened for low serum vitamin B12 concentrations. Additionally, patients from four primary health care providers were identified using metformin prescription data and offered the chance to participate in the audit.

RESULTS

Prevalence of serum Vitamin B12 level <220 pmol/L was 18.7%. Positive correlations were observed between B 12 concentration, age and dosage and duration of metformin treatment. Maori and Pacific Islanders had higher mean serum B12 concentrations than Europeans but no difference in prevalence of low serum B12 concentrations.

CONCLUSION

Low serum B12 concentration is a common occurrence in people with type 2 Diabetes treated with Metformin. Age is an important factor which explains some of this association. Systematic screening in those receiving metformin is advisable, particularly for patients older than 50 years.

Improvements in glucose metabolism and insulin sensitivity with a low-carbohydrate diet in obese patients with type 2 diabetes

OBJECTIVE

The optimal diet for weight loss in type 2 diabetes remains controversial. This study examined a low-carbohydrate, high-fat diet with detailed physiological assessments of insulin sensitivity, glycemic control, and risk factors for cardiovascular disease.

METHODS

Fourteen obese patients (body mass index [BMI] 40.6 ± 4.9 kg/m(2)) with type 2 diabetes were recruited for an "Atkins"-type low-carbohydrate diet. Measurements were made at 0, 12, and 24 weeks of weight, insulin sensitivity, HbA1c, lipids, and blood pressure.

RESULTS

Twelve completers lost a mean of 9.7 ± 1.8 kg over 24 weeks attributable to a major reduction in carbohydrates and resultant reduction in total energy intake. Glycemic control significantly improved (HbA1c -1.1 ± 0.25%) with reductions in hypoglycemic medication. Fasting glucose, homeostasis model assessment (HOMA), and area under the curve (AUC) glucose (intravenous glucose tolerance test [IVGTT]) were significantly reduced by week 12 ( p < 0.05). There were nonsignificant improvements in insulin sensitivity (SI) at week 12 ( p = 0.19) and week 24 ( p = 0.31). Systolic blood pressure was reduced (mean -10.0 mmHg between weeks 0 and 24, p = 0.13). Mean high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol all increased. The ratio of total: HDL cholesterol and triglycerides was reduced.

CONCLUSION

A low-carbohydrate diet was well tolerated and achieved weight loss over 24 weeks in subjects with diabetes. Glycemic control improved with a reduction in requirements for hypoglycemic agents.

Therapeutic options in the management of obesity

In New Zealand 28.4% of adults now classify as obese, whilst a total of 63.8% are overweight or obese (BMI >25 kg/m²). This presents an ever increasing social and economic burden to individuals, families and the healthcare system. Obesity is a major risk factor for cancer, cardiovascular, metabolic, and respiratory disorders. Preventing obesity is the optimal long-term population strategy and must be a government priority. There are many approaches which could be taken to facilitate this, however it is important not to forget those who are currently overweight or obese. This review addresses the current therapeutic options in the treatment of obesity, focusing on lifestyle changes, medications, and surgery in New Zealand. It also presents a suggested algorithm for the clinician assessing and managing obese patients in New Zealand.

A structured, group-based diabetes self-management education (DSME) programme for people, families and whanau with type 2 diabetes (T2DM) in New Zealand: an observational study

BACKGROUND

Group-based diabetes self-management education (DSME) programmes have been shown to be effective. A programme tailored for the unique social and ethnic environment of New Zealand (NZ) was developed using concepts from internationally developed programmes.

AIM

To assess the effectiveness of a 6 week New Zealand specific DSME programme.

METHODS

In this observational study people with type 2 diabetes (aged 18-80 years) from diverse cultural backgrounds were recruited from primary care. Seventeen groups of six education sessions were run. Clinical data were collected from primary care at baseline, 3, 6 and 9 months. Participants also completed a self-administered questionnaire on diabetes knowledge, and self-management behaviours.

RESULTS

107 participants, mean age 56.7±11.3 years and mean duration of diabetes 7.5±7 years (NZ European (44%), Maori (24%), Pacific (16%) and Indian (16%)), were enrolled. Confidence in self-managing diabetes, regular examination of feet, physical activity levels and smoking rates all improved. Glycaemic control improved between baseline and 6 months (HbA1C 64.9±20.0 mmol/mol to 59.9±13.9 mmol/mol (p<0.05) (baseline 8.07%±1.80, 6 months 7.62%±1.25)), but was no different to baseline at 9 months. Systolic BP reduced from 131.9±16.4 to 127.4±18.2 mmHg (p<0.05) at 6 months, but increased to baseline levels by 9 months. Diastolic BP, triglycerides and urine microalbumin:creatinine ratio were significantly reduced at 3, 6 and 9 months.

CONCLUSION

A group-based DSME programme designed specifically for the NZ population was effective at improving aspects of diabetes care at 6 months. The attenuation of these improvements after 6 months suggests a refresher course at that time may be beneficial.

Is there an optimal diet for patients with type 2 diabetes? Yes, the one that works for them!

Diet is fundamental in the aetiology and management of type 2 diabetes. The optimal diet remains unclear and the EASD and ADA have recently adopted increased flexibility with dietary composition, whilst maintaining a focus on reduced energy, reduced saturated fat and increased dietary fibre. This review draws three conclusions on the current evidence for three dietary approaches; high protein diets, very low carbohydrate diets and the Mediterranean diet, specifically for the management of weight, glycaemic control and cardiovascular risk in patients with type 2 diabetes. First, unless energy intake is reduced below energy expenditure over a sustained period of time, weight loss will not occur. Second, weight loss achieved with any dietary approach over the long-term is modest, though compared with the natural history of weight gain in obesity is clinically important. Third, the evidence supports flexibility in dietary composition with no approach superior to another for weight loss, glycaemic control or cardiovascular risk management. Most importantly there is evidence that adherence to any given dietary approach is more important than the macronutrient prescription. So the best diet for those with type 2 diabetes is the one that works for them, and critically the one that they can maintain in the long term.

A cross-over study of the acute effects of espresso coffee on glucose tolerance and insulin sensitivity in people with type 2 diabetes mellitus

The objective was to determine the effect of a single dose of espresso caffeinated coffee, decaffeinated coffee, or water on glucose tolerance and insulin sensitivity in people with type 2 diabetes mellitus. Eighteen participants who were habitual coffee drinkers, were studied using a random-order cross-over design. After a fasting blood sample participants consumed either a double-shot black espresso coffee, decaffeinated coffee, or hot water. The main outcomes were area under the curve (AUC) glucose and insulin, and insulin sensitivity (Matsuda index) during a 75 g oral glucose tolerance test (OGTT) performed one hour later. Other outcomes were change in glucose and insulin and also the insulinogenic index (IGI) and disposition index (DI). AUC glucose was marginally different between beverages (P=.06) being greater following caffeinated coffee than water, mean difference 104 mmol/L/180 min (95% CI 0.1 to 198.1, P=.031), or decaffeinated coffee, mean difference 92.1 mmol/L/180 min (95% CI -1.9 to 186.1, P=.055). There was no difference in AUC insulin (P=.87) or insulin sensitivity (P=.47), nor in change in glucose or insulin over the hour following beverage consumption. There was a marginal difference in IGI between beverages (P=.097) with coffee having a lower incremental increase in insulin/glucose than water (P=.037) though no difference between coffee and decaffeinated coffee (P=.54) and no difference in DI (P=.23). Black espresso coffee in people with type 2 diabetes mellitus results in a marginally greater excursion of glucose during a following OGTT compared with water or decaffeinated coffee. This effect does not appear to be mediated by changes in insulin sensitivity.

The Diabetes Excess Weight Loss (DEWL) Trial: a randomised controlled trial of high-protein versus high-carbohydrate diets over 2 years in type 2 diabetes

AIMS/HYPOTHESIS

To compare the effectiveness of low-fat high-protein and low-fat high-carbohydrate dietary advice on weight loss, using group-based interventions, among overweight people with type 2 diabetes. Study design Multicentre parallel (1:1) design, blinded randomised controlled trial.

METHODS

Individuals with type 2 diabetes aged 30–75 years and a BMI >27 kg/m2 were randomised, by an independent statistician using sequentially numbered sealed envelopes, to be prescribed either a low-fat high-protein (30% of energy as protein, 40% as carbohydrate, 30% as fat) or a low-fat high carbohydrate(15% of energy as protein, 55%as carbohydrate,30% as fat) diet. Participants attended 18 group sessions over 12 months. Primary outcomes were change in weight and waist circumference assessed at baseline, 6 and 12 months.Secondary outcomes were body fatness, glycaemic control,lipid profile, blood pressure and renal function. A further assessment was undertaken 12 months after the intervention.Research assessors remained blinded to group allocation throughout. Intention-to-treat analysis was performed.

RESULTS

A total of 419 participants were enrolled (mean±SDage 58±9.5 years,BMI 36.6±6.5 kg/m2 and HbA1c 8.1±1.2%(65 mmol/mol)). The study was completed by 70%(294/419).No differences between groups were found in change in weight or waist circumference during the intervention phase or the 12-month follow-up. Both groups had lost weight (2–3 kg, p<0.001) and reduced their waist circumference (2–3 cm, p<0.001) by 12 months and largely maintained this weight loss for the following 12 months. By 6 months, the difference in self-reported dietary protein between groups was small (1.1%total energy; p<0.001). No significant differences between groups were found in secondary outcomes: body fatness, HbA1c, lipids, blood pressure and renal function.There were no important adverse effects.

CONCLUSIONS/INTERPRETATION

In a 'real-world' setting, prescription of an energy-reduced low-fat diet, with either increased protein or carbohydrate, results in similar modest losses in weight and waist circumference over 2 years