1.
Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: Assessment of Causal Relations.
Livesey, G, Taylor, R, Livesey, HF, Buyken, AE, Jenkins, DJA, Augustin, LSA, Sievenpiper, JL, Barclay, AW, Liu, S, Wolever, TMS, et al
Nutrients. 2019;11(6)
-
-
-
Free full text
Plain language summary
It is generally accepted that certain diet and lifestyle choices contribute to a person’s risk of developing type 2 diabetes (T2D). In this meta-analysis, researchers set out to review previous studies and assess whether there is any evidence that the amount and type of carbohydrate (measured by Glycaemic Index (GI) and Glycaemic Load (GL)) in a person’s diet has a direct influence on their risk of developing T2D. The authors concluded with a high level of confidence that eating high GI and GL foods can lead to a higher risk of developing T2D. They suggest that nutrition advice that favours low GI and GL foods could produce significant cost savings for public healthcare.
Abstract
While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.
2.
Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial.
Lean, ME, Leslie, WS, Barnes, AC, Brosnahan, N, Thom, G, McCombie, L, Peters, C, Zhyzhneuskaya, S, Al-Mrabeh, A, Hollingsworth, KG, et al
Lancet (London, England). 2018;391(10120):541-551
-
-
-
Free full text
-
Plain language summary
Most individuals with type 2 diabetes are obese with accumulation of fat around the liver and pancreas. Many studies have demonstrated that dietary induced weight loss can improve type 2 diabetes, however none have assessed whether dietary weight loss can sustain type 2 diabetes remission. This 12-month randomised trial of 306 individuals with type 2 diabetes aimed to determine whether weight management led by doctors would achieve long-term remission of type 2 diabetes. The results showed that weight loss of 15kg or more resulted in significantly higher rates of type 2 diabetes remission after 12 months, with 48% of the weight loss group achieving remission compared to 4% of the individuals who were not assigned a weight loss regimen. It was concluded that nearly half of the participants who were on a dietary weight loss programme achieved type 2 diabetes remission and were able to stop their medications. This study could be used by healthcare professionals to understand that type 2 diabetes remission is a possibility with a supervised dietary weight loss programme.
Abstract
BACKGROUND Type 2 diabetes is a chronic disorder that requires lifelong treatment. We aimed to assess whether intensive weight management within routine primary care would achieve remission of type 2 diabetes. METHODS We did this open-label, cluster-randomised trial (DiRECT) at 49 primary care practices in Scotland and the Tyneside region of England. Practices were randomly assigned (1:1), via a computer-generated list, to provide either a weight management programme (intervention) or best-practice care by guidelines (control), with stratification for study site (Tyneside or Scotland) and practice list size (>5700 or ≤5700). Participants, carers, and research assistants who collected outcome data were aware of group allocation; however, allocation was concealed from the study statistician. We recruited individuals aged 20-65 years who had been diagnosed with type 2 diabetes within the past 6 years, had a body-mass index of 27-45 kg/m2, and were not receiving insulin. The intervention comprised withdrawal of antidiabetic and antihypertensive drugs, total diet replacement (825-853 kcal/day formula diet for 3-5 months), stepped food reintroduction (2-8 weeks), and structured support for long-term weight loss maintenance. Co-primary outcomes were weight loss of 15 kg or more, and remission of diabetes, defined as glycated haemoglobin (HbA1c) of less than 6·5% (<48 mmol/mol) after at least 2 months off all antidiabetic medications, from baseline to 12 months. These outcomes were analysed hierarchically. This trial is registered with the ISRCTN registry, number 03267836. FINDINGS Between July 25, 2014, and Aug 5, 2017, we recruited 306 individuals from 49 intervention (n=23) and control (n=26) general practices; 149 participants per group comprised the intention-to-treat population. At 12 months, we recorded weight loss of 15 kg or more in 36 (24%) participants in the intervention group and no participants in the control group (p<0·0001). Diabetes remission was achieved in 68 (46%) participants in the intervention group and six (4%) participants in the control group (odds ratio 19·7, 95% CI 7·8-49·8; p<0·0001). Remission varied with weight loss in the whole study population, with achievement in none of 76 participants who gained weight, six (7%) of 89 participants who maintained 0-5 kg weight loss, 19 (34%) of 56 participants with 5-10 kg loss, 16 (57%) of 28 participants with 10-15 kg loss, and 31 (86%) of 36 participants who lost 15 kg or more. Mean bodyweight fell by 10·0 kg (SD 8·0) in the intervention group and 1·0 kg (3·7) in the control group (adjusted difference -8·8 kg, 95% CI -10·3 to -7·3; p<0·0001). Quality of life, as measured by the EuroQol 5 Dimensions visual analogue scale, improved by 7·2 points (SD 21·3) in the intervention group, and decreased by 2·9 points (15·5) in the control group (adjusted difference 6·4 points, 95% CI 2·5-10·3; p=0·0012). Nine serious adverse events were reported by seven (4%) of 157 participants in the intervention group and two were reported by two (1%) participants in the control group. Two serious adverse events (biliary colic and abdominal pain), occurring in the same participant, were deemed potentially related to the intervention. No serious adverse events led to withdrawal from the study. INTERPRETATION Our findings show that, at 12 months, almost half of participants achieved remission to a non-diabetic state and off antidiabetic drugs. Remission of type 2 diabetes is a practical target for primary care. FUNDING Diabetes UK.
3.
Acceptability of a very-low-energy diet in Type 2 diabetes: patient experiences and behaviour regulation.
Rehackova, L, Araújo-Soares, V, Adamson, AJ, Steven, S, Taylor, R, Sniehotta, FF
Diabetic medicine : a journal of the British Diabetic Association. 2017;34(11):1554-1567
-
-
-
Free full text
-
Plain language summary
Patients with type 2 diabetes can return to normal blood glucose levels through substantial weight loss. While many studies have addressed this, very few have assessed the effects of adherence to a very-low-energy diet (VLED) on patients’ quality of life. The aim of this study was to evaluate the experiences of adhering to VLED for patients in remission for type 2 diabetes. Fifteen participants were interviewed before and after the 8-week VLED intervention and narratives were analysed. This study identified common barriers, facilitators and strategies used by the participants. Overall, participants found adherence easier than anticipated, and found barriers to be offset by suggested behaviour-regulation strategies. Based on this study, the authors conclude dietary treatment for reversal of type 2 diabetes is acceptable and feasible in motivated patients, and suggest further controlled research be done to confirm the validity and applicability of these findings.
Abstract
AIMS: To evaluate the acceptability of an 8-week very-low-energy diet for remission of Type 2 diabetes, and to identify barriers and facilitators of adherence and behaviour-regulation strategies used by participants in the Counterbalance study. METHODS Eighteen of 30 participants in the Counterbalance study (ISRCTN88634530) took part in semi-structured interviews. Of these, 15 participants were interviewed before and after the 8-week very-low-energy diet intervention. Thematic analysis was used to analyse the narratives. RESULTS The prospect of diabetes remission, considerable weight loss, and long-term health improvement provided participants with substantial initial motivation. This motivation was sustained through the experience of rapid weight loss, improvements in blood glucose levels, social support and increased physical and psychological well-being. Overall, adherence to the very-low-energy diet for 8 weeks was perceived as much easier than anticipated, but required personal effort. Participants addressed challenges by removing food from the environment, planning, avoidance of tempting situations or places, and self-distraction. Weight loss and improvements in blood glucose levels lead to a sense of achievement and improvements in physical and psychological wellbeing. CONCLUSIONS Dietary treatment for reversal of Type 2 diabetes is acceptable and feasible in motivated participants, and the process is perceived as highly gratifying. Research outside of controlled trial settings is needed to gauge the generalisability of these findings.
4.
Glycemic response and health--a systematic review and meta-analysis: relations between dietary glycemic properties and health outcomes.
Livesey, G, Taylor, R, Hulshof, T, Howlett, J
The American journal of clinical nutrition. 2008;87(1):258S-268S
-
-
-
Free full text
-
Plain language summary
All carbohydrates are ranked based on their glycaemic impact, or the response they provoke in blood glucose after consumption. It has been proposed that diets with a low impact on blood glucose are associated with a reduction in disease risk, however the specific dietary factors and degree of influence of this association remains unclear. The aim of this meta-analysis was to assess which glycaemic impact factors are important for affecting the maintenance of health and management of disease. Data from 45 relevant publications were included to investigate various health risk markers of overweight and obesity, diabetes mellitus and coronary heart disease. This review found that diets with a reduced glycaemic impact and higher unavailable carbohydrate are associated with favourable changes for all examined health risk markers. The authors conclude that these interventions led to improved glycaemic control, therefore provide a compelling diet for managing chronic disease.
Abstract
BACKGROUND Reduction of dietary glycemic response has been proposed as a means of reducing the risk of diabetes and coronary heart disease. The impact of glycemic response on markers of health remains to be elucidated. OBJECTIVE We assessed the evidence relating the glycemic impact of foods to measures relevant for health maintenance and management of disease. DESIGN This was a systematic review and synthesis of interventional evidence from literature reported on glycemic index and markers of health through the use of meta-analyses and meta-regression models. RESULTS Data from 45 relevant publications were found to January 2005. Lower glycemic index (GI) diets reduced both fasting blood glucose and glycated proteins independently of variance in available and unavailable carbohydrate intakes. Elevated unavailable carbohydrate added to improvements in both blood glucose and glycated protein control. These effects were greater in persons with poor fasting blood glucose control. No effects were seen on fasting insulin<100 pmol/L; above this, study numbers were few but consistent with prevention of hyperinsulinemia in some but not all overweight persons. Insulin sensitivity according to a variety of measurement methods was improved by lower GI, higher unavailable carbohydrate interventions in persons with type 2 diabetes, in overweight and obese persons, and in all studies combined. Fasting triacylglycerol in addition to body weight reduction related more to glycemic load than to GI. Glycemic load reduction by >17 g glucose equivalents/d was associated with reduced body weight. CONCLUSIONS Consumption of reduced glycemic response diets are followed by favorable changes in the health markers examined. The case for the use of such diets looks compelling. Unavailable carbohydrate intake is equally important.