Nicola Guess

Dietary Fatty Acids Differentially Associate with Fasting Versus 2-Hour Glucose Homeostasis: Implications for The Management of Subtypes of Prediabetes

Over-nutrition has fuelled the global epidemic of type 2 diabetes, but the role of individual macronutrients to the diabetogenic process is not well delineated. We aimed to examine the impact of dietary fatty acid intake on fasting and 2-hour plasma glucose concentrations, as well as tissue-specific insulin action governing each. Normoglycemic controls (n = 15), athletes (n = 14), and obese (n = 23), as well as people with prediabetes (n = 10) and type 2 diabetes (n = 11), were queried about their habitual diet using a Food Frequency Questionnaire. All subjects were screened by an oral glucose tolerance test (OGTT) and studied using the hyperinsulinemic/euglycemic clamp with infusion of 6,62H2-glucose. Multiple regression was performed to examine relationships between dietary fat intake and 1) fasting plasma glucose, 2) % suppression of endogenous glucose production, 3) 2-hour post-OGTT plasma glucose, and 4) skeletal muscle insulin sensitivity (glucose rate of disappearance (Rd) and non-oxidative glucose disposal (NOGD)). The %kcal from saturated fat (SFA) was positively associated with fasting (β = 0.303, P = 0.018) and 2-hour plasma glucose (β = 0.415, P<0.001), and negatively related to % suppression of hepatic glucose production (β = -0.245, P = 0.049), clamp Rd (β = -0.256, P = 0.001) and NOGD (β = -0.257, P = 0.001). The %kcal from trans fat was also negatively related to clamp Rd (β = -0.209, P = 0.008) and NOGD (β = -0.210, P = 0.008). In contrast, the %kcal from polyunsaturated fat (PUFA) was negatively associated with 2-hour glucose levels (β = -0.383, P = 0.001), and positively related to Rd (β = 0.253, P = 0.007) and NOGD (β = 0.246, P = 0.008). Dietary advice to prevent diabetes should consider the underlying pathophysiology of the prediabetic state.

Adherence to NICE guidelines on diabetes prevention in the UK: Effect on patient knowledge and perceived risk

BACKGROUND NICE Guidelines for prevention of diabetes include identifying people at risk followed by cost-effective intervention if necessary. Based on assessment of risk via a questionnaire and/or blood test the intervention may comprise a brief discussion of risk factors and preventive advice or referral to intensive lifestyle intervention. DESIGN AND SETTING In this cross-sectional study 59 subjects recruited from local GP practices were invited by letter to attend a screening for a diabetes prevention study. METHOD Following a telephone screening during which subjects were asked whether they had been informed if they were at high-risk of type 2 diabetes, eligible subjects completed a Risk Perception Survey for Developing Diabetes (RPS-DD), a validated diabetes risk score and underwent an oral glucose tolerance test (OGTT) at a medical screening. RESULTS As measured by the Diabetes UK Risk Score, 44.1% were at high risk, 42.4% moderate risk and 13.6% at increased risk. 42% of patients had been informed they were at high-risk by a health professional. Those who had been informed of their risk had significantly higher perceived risk scores (p<0.001), higher knowledge scores (p<0.001) and decreased optimism scores (p=0.004), but were not more aware that diet (p=0.42) and weight management (p=0.57) can play a role in preventing diabetes. CONCLUSIONS People at high-risk of diabetes are not being informed of their risk status as recommended by NICE guidelines. There is scope for education for health professionals and the public.

A Randomised Crossover Trial: The Effect of Inulin on Glucose Homeostasis in Subtypes of Prediabetes

Background: Fermentable carbohydrates (FCHO) have been shown to improve insulin sensitivity in normoglycaemic and insulin-resistant subjects. However, there are no data on subjects with prediabetes. We aimed to investigate the effect of the FCHO inulin, on glucose homeostasis in subjects with prediabetes. Methods: In a double-blind and placebo-controlled crossover study, 40 volunteers with prediabetes were randomly allocated to take 30 g/day of inulin or cellulose for 2 weeks in a crossover trial, following a 4-week dose-escalation run-in. Fasting insulin and glucose were measured for all subjects. Fifteen of the 40 subjects also underwent a meal tolerance test to assess insulin sensitivity, free fatty acids and glucagon-like peptide-1 concentrations. A subanalysis was carried out to examine any differences between the prediabetes subtypes. Results: Inulin was associated with a significant increase in (0-30 min)incremental AUC (iAUC) for insulin (treatment: p < 0.04) and (0-60 min)iAUC for insulin (treatment: p < 0.04) compared to control. There was a significant reduction in insulin resistance measured by the homeostatic model assessment in the isolated-impaired fasting glucose (p < 0.05) but not in the isolated-impaired glucose tolerance groups (p = 0.59). Conclusion: The FCHO, inulin, may have unique metabolic effects that are of particular benefit to people at risk of diabetes, which warrant further investigation.

Dietary intake in people consuming a reduced-carbohydrate diet in the National Diet and Nutrition Survey

BACKGROUND Diets reduced or low in carbohydrates are becoming increasingly popular. The replacement foods and their accompanying nutrients determine the health effects of such diets. However, little is known about the dietary intake of people consuming reduced or low carbohydrate diets. METHODS In this cross-sectional study, the dietary and nutrient intake of individuals aged 16-75 years consuming less than 40% of energy from carbohydrate (n = 430) was compared with individuals consuming equal to or more than 40% energy from carbohydrate (n = 1833) using the UK National Diet and Nutrition Survey. RESULTS Those consuming less than 40% of total energy from carbohydrate reported a higher consumption of red and processed meat, butter, oily fish and vegetables, as well as a lower consumption of soft drinks and pulses, than those with a normal carbohydrate intake. After adjusting for socio-economic status, only red meat intake was different between the groups, and reached the maximum recommended daily intake daily intake. There were no significant differences in micronutrient intakes between the groups, although magnesium, selenium and potassium, along with fibre, were lower than recommended amounts across the cohort. CONCLUSIONS Individuals consuming reduced or low carbohydrate diets could benefit from replacing some red meats with white meats and vegetable sources of protein, and increasing vegetable intake.

Insulin-associated weight gain in obese type 2 diabetes mellitus patients – what can be done?

Insulin therapy (IT) is initiated for patients with type 2 diabetes mellitus when glycaemic targets are not met with diet and other hypoglycaemic agents. The initiation of IT improves glycaemic control and reduces the risk of microvascular complications. There is, however, an associated weight gain following IT, which may adversely affect diabetic and cardiovascular morbidity and mortality. A 3 to 9 kg insulin‐associated weight gain (IAWG) is reported to occur in the first year of initiating IT, predominantly caused by adipose tissue. The potential causes for this weight gain include an increase in energy intake linked to a fear of hypoglycaemia, a reduction in glycosuria, catch‐up weight, and central effects on weight and appetite regulation. Patients with type 2 diabetes who are receiving IT often have multiple co‐morbidities, including obesity, that are exacerbated by weight gain, making the management of their diabetes and obesity challenging. There are several treatment strategies for patients with type 2 diabetes, who require IT, that attenuate weight gain, help improve glycaemic control, and help promote body weight homeostasis. This review addresses the effects of insulin initiation and intensification on IAWG, and explores its potential underlying mechanisms, the predictors for this weight gain, and the available treatment options for managing and limiting weight gain.

The effect of dietary changes on distinct components of the metabolic syndrome in a young Sri Lankan population at high risk of CVD

South Asian populations are predisposed to early onset of the metabolic syndrome. Lifestyle intervention programmes have demonstrated a reduction in the metabolic syndrome and CVD risk; however, the most effective components of the multi-faceted lifestyle interventions are unknown. We studied 2637 Sri Lankan males (n 1237) and females (n 1380), with a mean BMI of 23·9 (sd 4·2) kg/m2, aged 22·5 (sd 10·0) years, who had participated in a 5-year lifestyle-modification programme to examine the effect of dietary changes on distinct components of the metabolic syndrome. The dietary intervention comprised advice to replace polished starches with unpolished starches, high-fat meat and dairy products with low-fat products and high-sugar beverages and snacks with low-sugar varieties. For the purposes of this analysis, data from the control and intensive lifestyle groups were combined. Anthropometric and biochemical data were recorded, and a FFQ was completed annually. Multiple regression was used to determine the effect of the dietary changes on distinct components of the metabolic syndrome. The ratio unpolished:polished rice was inversely related to change in fasting glucose (β=-0·084, P=0·007) and TAG (β=-0·084, P=0·005) and positively associated with change in HDL-cholesterol (β=0·066, P=0·031) at the 5-year follow-up after controlling for relevant confounders. Red meat intake was positively associated with fasting glucose concentrations (β=0·05, P=0·017), whereas low-fat (β=-0·046, P=0·018) but not high-fat dairy products (β=0·003, P=0·853) was inversely related to glucose tolerance at the follow-up visit. Replacement of polished with unpolished rice may be a particularly effective dietary advice in this and similar populations.

NHS Diabetes Prevention Programme is vital but criteria need reviewing

I agree with Barry and colleagues that we will not sustainably reduce the incidence and prevalence of type 2 diabetes (T2D) without major changes to our working and living environments.1 However, I fully support the principles of the NHS Diabetes Prevention Programme for the following reasons.

Improvements in stage of change correlate to changes in dietary intake and clinical outcomes in a 5-year lifestyle intervention in young high-risk Sri Lankans

The objectives of a stage-matched approach to lifestyle change are that individuals progress forward through the stages of change. It also posits that progression through the stages of change is associated with positive changes in lifestyle behaviours. Measuring the relationship between stage of change and food intake is challenging due to the plurality of dietary behaviours. Furthermore, it is not clear whether changes in behaviour are sustained long-term. In this study we assess the movement through stages of change in the intensive (visits every 3months) and control groups (visits annually) of a large-scale primary prevention study in cardiovascular disease, carried out in 2637 children and young adults in Sri Lanka between 2007 and 2012. We also examine their relationship to dietary behaviours and clinical outcomes. We demonstrate that individuals in both groups continue to progress through stages of change over the course of the study and that measures of dietary behaviours improved from baseline to final follow-up. We also demonstrate that stage of change positively correlates to dietary behaviours including the ratio of recommended:not-recommended items, unpolished:polished starches and low-fat:high-fat food items throughout each year of the study. Finally, participants in the later stages of change at Y2, Y3 and Y4, had a significantly attenuated increase in weight and waist circumference at the final visit in both groups. We therefore demonstrate the usefulness of stage-matched approach in modifying complex dietary behaviours, and that stage of change is a valid measure of dietary behaviours across a large population over time.

Dairy products and fish intake and the progression of type 2 diabetes: an update of the evidence

In general, replacement of saturated fat with monounsaturated and polyunsaturated fat reduces the risk of type 2 diabetes, with the evidence stronger for polyunsaturated fat. However, recent research studies have highlighted the importance of the source of dietary fat in prevention of type 2 diabetes. For example, saturated fats found in dairy products are associated with a reduction in risk in large epidemiological studies. Similarly, while polyunsaturated fats in vegetable oils and nuts appear to reduce the risk of type 2 diabetes, polyunsaturated fats in fish do not.

11. The Impact of Dietary Fatty Acids on Fasting vs. Postprandial Glucose Homeostasis (87-OR)

SamenvattingWe examined the impact of dietary fatty acids on measures of fasting and postprandial glucose homeostasis. Habitual dietary intake was collected in controls (n = 15), athletes (n = 14), obese (n = 23) and subjects with prediabetes (n = 10) and type 2 diabetes (n = 11) using the National Institutes of Health Diet History Questionnaire II. All subjects underwent an OGTT and a hyperinsulinemic-euglycemic clamp with infusion of [6,6-2H2]-glucose. Multiple regression was performed to examine age- and BMI-adjusted relationships between dietary fatty acids and measures of fasting plasma glucose (FPG) and postprandial glucose (2hPG).