James Lind Alliance research priorities: what role do carbohydrates, fats and proteins have in the management of Type 2 diabetes, and are there risks and benefits associated with particular approaches?

Is glycaemic control associated with dietary patterns independent of weight change in people newly diagnosed with type 2 diabetes? Prospective analysis of the Early-ACTivity-In-Diabetes trial

BACKGROUND

It is unclear whether diet affects glycaemic control in type 2 diabetes (T2D), over and above its effects on bodyweight. We aimed to assess whether changes in dietary patterns altered glycaemic control independently of effects on bodyweight in newly diagnosed T2D.

METHODS

We used data from 4-day food diaries, HbA1c and potential confounders in participants of the Early-ACTivity-In-Diabetes trial measured at 0, 6 and 12 months. At baseline, a 'carb/fat balance' dietary pattern and an 'obesogenic' dietary pattern were derived using reduced-rank regression, based on hypothesised nutrient-mediated mechanisms linking dietary intake to glycaemia directly or via obesity. Relationships between 0 and 6 month change in dietary pattern scores and baseline-adjusted HbA1c at 6 months (n = 242; primary outcome) were assessed using multivariable linear regression. Models were repeated for periods 6-12 months and 0-12 months (n = 194 and n = 214 respectively; secondary outcomes).

RESULTS

Reductions over 0-6 months were observed in mean bodyweight (- 2.3 (95% CI: - 2.7, - 1.8) kg), body mass index (- 0.8 (- 0.9, - 0.6) kg/m2), energy intake (- 788 (- 953, - 624) kJ/day), and HbA1c (- 1.6 (- 2.6, -0.6) mmol/mol). Weight loss strongly associated with lower HbA1c at 0-6 months (β = - 0.70 [95% CI - 0.95, - 0.45] mmol/mol/kg lost). Average fat and carbohydrate intakes changed to be more in-line with UK healthy eating guidelines between 0 and 6 months. Dietary patterns shifting carbohydrate intakes higher and fat intakes lower were characterised by greater consumption of fresh fruit, low-fat milk and boiled/baked potatoes and eating less of higher-fat processed meats, butter/animal fats and red meat. Increases in standardised 'carb/fat balance' dietary pattern score associated with improvements in HbA1c at 6 months independent of weight loss (β = - 1.54 [- 2.96, - 0.13] mmol/mol/SD). No evidence of association with HbA1c was found for this dietary pattern at other time-periods. Decreases in 'obesogenic' dietary pattern score were associated with weight loss (β = - 0.77 [- 1.31, - 0.23] kg/SD) but not independently with HbA1c during any period.

CONCLUSIONS

Promoting weight loss should remain the primary nutritional strategy for improving glycaemic control in early T2D. However, improving dietary patterns to bring carbohydrate and fat intakes closer to UK guidelines may provide small, additional improvements in glycaemic control.

TRIAL REGISTRATION

ISRCTN92162869 . Retrospectively registered on 25 July 2005.

Therapeutic developments in metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) has become one of the most prevalent chronic liver diseases worldwide, bringing risk of multiorgan disfunctions including cardiovascular events, complications of cirrhosis, and even malignance. In terms of health burden management, screening patients with high risk of MAFLD and providing individual comprehensive treatment is critical. Although there are numerous agents entering clinical trials for MAFLD treatment every year, there is still no effective approved drug. The nomenclature of MAFLD highlighted the concomitant metabolic disorders and obesity. MAFLD patients with type 2 diabetes had higher risk of developing liver cirrhosis and cancer, and would benefit from anti-hyperglycemic agents; overweight and obese patients may benefit more from weight loss therapies; for patients with metabolic syndrome, individual comprehensive management is needed to reduce the risk of adverse outcomes. In this review, we introduced the current status and advances of the treatment of MAFLD based on weight loss, improving insulin resistance, and management of cardiometabolic disorders, in order to provide individualized therapy approaches for patients with MAFLD.

Proximal and distal influences on dietary change among a diverse group with prediabetes participating in a pragmatic, primary care nurse-led intervention: a qualitative study

OBJECTIVE

To understand motivators, facilitators and challenges to dietary change amongst a diverse sample of New Zealanders with prediabetes participating in a primary care nurse-led individualised dietary intervention.

DESIGN

A qualitative study involving semi-structured, face-to-face interviews with a stratified sample of adults with prediabetes and BMI ≥ 25 kg/m2, purposefully selected from a larger 2-year primary care-based prediabetes dietary intervention study. Thematic analysis was undertaken. A socio-ecological model guided interpretation.

SETTING

Hawke's Bay, Aotearoa/New Zealand, April 2018-March 2020.

PARTICIPANTS

Fifty-eight people aged 28-69 years, with similar numbers of men and women, indigenous Māori and non-Māori, and those who had and had not regressed to normoglycaemia at 6 months.

RESULTS

Motivators for wanting to make dietary changes were determination not to progress to diabetes; wanting to be healthy and contribute to others and encouragement by others. Facilitators for adopting and maintaining changes were a strong desire to be healthy; personal determination and feeling supported. Challenges were compromised control over life and environmental factors; feeling unsupported by others; social occasions; financial constraints and living with other health conditions. Developing their own strategies to overcome challenges was empowering, enabling a sense of control. These factors were similar across demographic and glycaemic outcome groups.

CONCLUSIONS

Influences on dietary change involved personal, interpersonal, organisational, environmental and policy factors. Although findings appeared similar across groups, dietary interventions need to address the specific ways motivators, facilitators and challenges manifest for individuals and social groups and be tailored accordingly within the context of the wider obesogenic and socio-economic environment.

Exploring dietitians' practice and views of giving advice on dietary patterns to patients with type 2 diabetes mellitus: A qualitative study

BACKGROUND

Dietary guidelines for type 2 diabetes mellitus (T2DM) emphasise weight management and individualised total carbohydrate intake. Evidence on the most effective dietary patterns (DPs) for T2DM management is mixed, potentially leading to variations in the advice that dietitians provide. The present study aimed to explore dietitians' practice of DP advice provision to adults with T2DM, as well as understand their views when advising their patients on the DPs deemed effective for glycaemic management or recommended by current guidelines.

METHODS

Semi-structured interviews were conducted with 12 UK-registered dietitians, with experience in consulting adults with T2DM. Dietitians were asked for their views on five DPs recommended for glycaemic management of T2DM. Interview transcripts were analysed using deductive and inductive thematic analysis.

RESULTS

Nine themes were identified that draw attention to DP advice provision practices, the five DPs (low-carbohydrate, low-fat, low-glycaemic index, Mediterranean diet and Dietary Approaches to Stop Hypertension diet), other DPs, the barriers and facilitators to DP advice provision and following this advice, and the factors affecting the provision of DP advice. Participants' current practice of DP advice provision to patients with T2DM was perceived to be individualised and patient-centred. Participants discussed their current practice and perceptions of available evidence and how patients respond to advice on the DPs shown to be effective for glycaemic management. Several barriers to providing advice on specific DPs, including safety and compliance challenges, were identified. Participants also highlighted factors that would facilitate the provision of advice on specific DPs and would help patients to follow this advice, including social support, educational resources and more robust scientific evidence.

CONCLUSIONS

The findings of the present study provide important insights regarding dietitians' views of promoting whole DPs to patients with T2DM. Emerged barriers and facilitators should be considered when developing future guidance for dietetic practice to support patients with following whole DPs for T2DM management.

Lifestyle interventions affecting hepatic fatty acid metabolism

PURPOSE OF REVIEW

Prevalence of metabolic-associated fatty liver disease (MAFLD) is increasing, and as pharmacological treatment does not exist, lifestyle interventions (i.e. diet and exercise) represent the cornerstone management and treatment strategy. Although the available data clearly demonstrate that changes in lifestyle influence intrahepatic triglyceride (IHTG) content, the mechanisms through which this is achieved are seldom investigated. Here, we review recent evidence demonstrating the influence of lifestyle interventions on hepatic fatty acid metabolism and IHTG content.

RECENT FINDINGS

Diet and exercise influence IHTG content through various, and often interrelated factors. These include alterations in whole-body and tissue-specific insulin sensitivity, which may influence the flux of fatty acid and lipogenic substrates to the liver, and changes in intrahepatic fatty acid synthesis and partitioning. Notably, there are only a few studies that have investigated intrahepatic fatty acid metabolism in vivo in humans before and after an intervention.

SUMMARY

Lifestyle interventions represent an effective means of influencing hepatic fatty acid metabolism. IHTG content is decreased without weight-loss either through exercise or by changing the macronutrient composition of the diet, although what the optimal macronutrient composition is to achieve this has yet to be defined.

Lower carbohydrate and higher fat intakes are associated with higher hemoglobin A1c: findings from the UK National Diet and Nutrition Survey 2008-2016

PURPOSE

Evidence of low-carbohydrate, high-fat diets (LCHF) for type 2 diabetes (T2DM) prevention is scarce. We investigated how carbohydrate intake relates to HbA1c and T2DM prevalence in a nationally representative survey dataset.

METHODS

We analyzed dietary information (4-day food diaries) from 3234 individuals aged ≥ 16 years, in eight waves of the UK National Diet and Nutrition Survey (2008-2016). We calculated LCHF scores (0-20, higher score indicating lower  %food energy from carbohydrate, with reciprocal higher contribution from fat) and UK Dietary Reference Value (DRV) scores (0-16, based on UK dietary recommendations). Associations between macronutrients and diet scores and diabetes prevalence were analyzed (in the whole sample) using multivariate logistic regression. Among those without diabetes, analyses between exposures and %HbA1c (continuous) were analyzed using multivariate linear regression. All analyses were adjusted for age, sex, body mass index, ethnicity, smoking status, total energy intake, socioeconomic status and survey years.

RESULTS

In the overall study sample, 194 (6.0%) had diabetes. Mean intake was 48.0%E for carbohydrates, and 34.9%E for total fat. Every 5%E decrease in carbohydrate, and every 5%E increase in fat, was associated with 12% (95% CI 0.78-0.99; P = 0.03) and 17% (95% CI 1.02-1.33; P = 0.02) higher odds of diabetes, respectively. Each two-point increase in LCHF score is related to 8% (95% CI 1.02-1.14; P = 0.006) higher odds of diabetes, while there was no evidence for association between DRV score and diabetes. Among the participants without diagnosed diabetes (n = 3130), every 5%E decrease in carbohydrate was associated with higher %HbA1c by + 0.016% (95% CI 0.004-0.029; P = 0.012), whereas every 5%E increase in fat was associated with higher  %HbA1c by + 0.029% (95% CI 0.015-0.043; P < 0.001). Each two-point increase in LCHF score is related to higher  %HbA1c by + 0.010% (0.1 mmol/mol), while each two-point increase in the DRV score is related to lower  %HbA1c by - 0.023% (0.23 mmol/mol).

CONCLUSIONS

Lower carbohydrate and higher fat intakes were associated with higher HbA1c and greater odds of having diabetes. These data do not support low(er) carbohydrate diets for diabetes prevention.

James Lind Alliance research priorities: should diet and exercise be used as an alternative to drugs for the management of type 2 diabetes or alongside them?

AIM

To review evidence on whether diet and exercise should be used as an alternative to drug therapy for the management of type 2 diabetes or alongside.

METHOD

We present a narrative review that draws on evidence from other systematic reviews and meta-analyses, narrative reviews, trials and cohort studies. We focused mainly on glycaemic control rather than control of blood pressure or cholesterol.

RESULTS

Good-quality dietary advice that results in weight loss of >5% and physical activity interventions of >150 min/week of moderate to vigorous physical activity, combined with resistance exercise, can produce improvements in HbA_1c similar to those produced by the addition of glucose-lowering drugs. These improvements can be seen at all stages of the disease. There are recognized interactions between glucose-lowering drugs and physical activity which may not be synergistic, but these are not well understood, and it is not clear if they are considered in clinical practice. Studies that explicitly compare drugs with diet or physical activity or control for drug use found that lifestyle could delay or reduce medication use, but most people eventually needed to progress to drug treatment. There are few studies, however, that provide strategies for the long-term maintenance of weight loss or physical activity.

CONCLUSION

Diet and physical activity are of key importance in type 2 diabetes management, and attention to them improves glycaemic control and cardiovascular disease risk, but it is not yet known whether maintained lifestyle changes provide an alternative to drug therapy in the long term.

Low and reduced carbohydrate diets: challenges and opportunities for type 2 diabetes management and prevention

Low-carbohydrate diets (LCD) have been promoted for weight control and type 2 diabetes (T2D) management, based on an emerging body of evidence, including meta-analyses with an indication of publication bias. Proposed definitions vary between 50 and 130 g/d, or <10 and <40 % of energy from carbohydrate, with no consensus on LCD compositional criteria. LCD are usually followed with limited consideration for other macronutrients in the overall diet composition, introducing variance in the constituent foods and in metabolic responses. For weight management, extensive evidence supports LCD as a valid weight loss treatment, up to 1-2 years. Solely lowering carbohydrate intake does not, in the medium/long term, reduce HbA1c for T2D prevention or treatment, as many mechanisms interplay. Under controlled feeding conditions, LCD are not physiologically or clinically superior to diets with higher carbohydrates for weight-loss, fat loss, energy expenditure or glycaemic outcomes; indeed, all metabolic improvements require weight loss. Long-term evidence also links the LCD pattern to increased CVD risks and mortality. LCD can lead to micronutrient deficiencies and increased LDL-cholesterol, depending on food selection to replace carbohydrates. Evidence is limited but promising regarding food choices/sources to replace high-carbohydrate foods that may alleviate the negative effects of LCD, demanding further insight into the dietary practice of medium to long term LCD followers. Long-term, high-quality studies of LCD with different food sources (animal and/or plant origins) are needed, aiming for clinical endpoints (T2D incidence and remission, cardiovascular events, mortality). Ensuring micronutrient adequacy by food selection or supplementation should be considered for people who wish to pursue long-term LCD.

Effect of Rice Processing towards Lower Rapidly Available Glucose (RAG) Favors Idli, a South Indian Fermented Food Suitable for Diabetic Patients

The Asian food pattern primarily embraces rice and rice-based products, which mainly comprise 90% starch. Among these various food products, Idli is mostly prepared through fermentation. It has high palatability, and the rapid and highly digestible nature of the food product results in a higher post-glucose level in diabetic patients. A heat-treated Idli rice sample was prepared by roasting parboiled rice at the temperature range of 155 to 165 °C for 65 to 75 s. Idli/rice-based Dokala made from heat-treated rice is better when compared to untreated rice in terms of its microbiological profile and physiochemical properties. The proximate composition of heat-treated parboiled rice Idli/Rice Dokala showed slightly higher values than the untreated parboiled rice Idli/Rice Dokala, which reveals that it has marginally higher nutritive value. Determination of the Rapidly Available Glucose (RAG) and Slowly Available Glucose (SAG) values, SEM analysis, resistant starch analysis, microbial assay, and in vivo studies were performed to determine the glycemic index (GI) and glycemic load in normal and diabetic persons. Sensory analysis also proved that heat-treated Idli/Rice Dokala is superior to untreated based on the color, flavor, appearance, taste, and texture.