Short-term effects of alterations in dietary fat on metabolic control in IDDM

Dietary treatment of type 1 diabetes: Beyond carbohydrate counting to fight cardiovascular risk

AIMS

Type 1 diabetes (T1D) is tied to an increased risk of cardiovascular morbidity and mortality. Dietary treatment would be an elective therapeutic strategy to fight this risk. However, it is not known what the best dietary approach is. We revisited the currently available literature on the nutritional treatment of T1D in the light of their potential comprehensive effects on the management of cardio-metabolic risk factors (body weight, fasting and postprandial glucose and lipid metabolism).

DATA SYNTHESIS

Nutritional research in T1D is mainly focused on blood glucose control, with most of the trials aiming at evaluating the acute effects of nutrients on postprandial glycemic response. The effects of the quantity and quality of nutrients and some specific foods on other metabolic risk factors have been explored mainly in cross-sectional analysis. Very few well-designed nutritional trials evaluated the best dietary approach to comprehensively manage cardiovascular risk by targeting along with blood glucose control, overweight, fasting and postprandial dyslipidemia. Therefore, the current best practice guidance for the dietary management of cardiovascular risk in T1D is generally based on evidence from patients with type 2 diabetes.

CONCLUSIONS

Well-conducted nutritional trials specifically designed for T1D are needed to identify the best dietary treatment to fight cardiovascular risk in these patients.

The beneficial short-term effects of a high-protein/low-carbohydrate diet on glycaemic control assessed by continuous glucose monitoring in patients with type 1 diabetes

AIM

To compare the effects of three different but isocaloric dietary patterns, high-protein/low-carbohydrate (HPD) with 20% of calories as carbohydrates, Mediterranean/low glycaemic index (MED) with 40% carbohydrates, and a reference diet (REF) with 50% carbohydrates, in patients with type 1 diabetes (T1D).

MATERIALS AND METHODS

In a randomized crossover study, 15 patients with T1D were assigned to the three dietary patterns for three separate weeks, with 7-day washout periods in between. Continuous glucose monitoring was applied during the intervention periods. The primary outcome was glycaemic control, as measured by the percentage of time patients spent within the euglycaemic range (TIR_{70-140   mg/dl} ). Other key glycaemic metrics were also investigated as secondary outcomes.

RESULTS

TIR_70-140 was not statistically different between HPD, MED and REF (p = .105). Pairwise analysis revealed a statistically significant difference between HPD and REF at the .05 level, which was not retained after applying Bonferroni correction (54.87% ± 14.11% vs. 48.33% ± 13.72%; p = .018). During the HPD period, 11 out of 15 participants spent more time within TIR_70-140 compared with either the REF or MED. The HPD performed significantly better than the REF in terms of TIR_70-180 (74.33% ± 12.85% vs. 67.53% ± 12.73%; p = .012), glycaemic variability (coefficient of variation: 36.18% ± 9.30% vs. 41.48% ± 8.69%; p = .016) and time spent in the hypoglycaemic range (TBR_{70   mg/dl} ; median: 12, IQR: 16 vs. median: 14, IQR: 20; p = .007), whereas no statistically significant differences were observed between MED and HPD or REF.

CONCLUSIONS

Compared with REF and MED, an HPD plan may have a positive impact on glycaemic control in patients with T1D. During the HPD, patients spent a shorter time in hypoglycaemia and exhibited lower glycaemic variability.

Association Between a Low Carbohydrate Diet, Quality of Life, and Glycemic Control in Australian Adults Living With Type 1 Diabetes: Protocol for a Mixed Methods Pilot Study

BACKGROUND

Globally, the prevalence of type 1 diabetes mellitus (T1DM) is rising. In 2020, a total of 124,652 Australians had T1DM. Maintaining optimal glycemic control (hemoglobin A_1c ≤7.0%, ≤53 mmol/mol) on a standard carbohydrate diet can be a challenge for people living with T1DM. The Diabetes Complications and Control Trial established that macrovascular and microvascular complications could be reduced by improving glycemic control. Recent studies have found that a very low or low carbohydrate diet can improve glycemic control. However, the overall evidence relating to an association between a very low or low carbohydrate diet and glycemic control in people living with T1DM is both limited and mixed. In addition, research has suggested that a reduced quality of life due to anxiety and depression adversely influences glycemic control. Despite a potential link between a very low or low carbohydrate diet and optimal glycemic control, to our knowledge, no research has examined an association between a low carbohydrate diet, quality of life, and glycemic control, making this study unique in its approach.

OBJECTIVE

The study aims to develop a validated diabetes-specific quality of life questionnaire for use in Australian adults with T1DM and to determine if an association exists between a low carbohydrate diet, quality of life, and glycemic control in Australian adults living with T1DM.

METHODS

This cross-sectional study will be conducted in a tertiary hospital outpatient setting and will consist of 3 phases: phase 1, online Australian diabetes-specific quality of life questionnaire development and piloting (25-30 adults with T1DM); phase 2, questionnaire validation (364 adults with T1DM); and phase 3, a 12-week dietary intervention to determine if an association exists between a low carbohydrate diet, quality of life, and glycemic control in adults with T1DM (16-23 adults with T1DM). The validation of the study-developed Australian diabetes-specific quality of life questionnaire, and changes in hemoglobin A_1c and quality of life in adults with T1DM while undertaking a low carbohydrate diet over 12 weeks will be the primary outcomes of this study.

RESULTS

Phase 1 of the study is currently open for recruitment and has recruited 12 participants to date. It is anticipated that the first results will be submitted for publication in November 2021. Presently, no results are available.

CONCLUSIONS

This study is the first of its kind in that it will be the first to generate a new validated instrument, which could be used in evidence-based practice and research to understand the quality of life of Australian adults with T1DM. Second, the low carbohydrate dietary intervention outcomes could be used to inform clinicians about an alternative approach to assist T1DM adults in improving their quality of life and glycemic control. Finally, this study could warrant the development of an evidence-based low carbohydrate dietary guideline for adults living with T1DM with the potential to have a profound impact on this population.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04213300; https://clinicaltrials.gov/ct2/show/NCT04213300.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/25085.

Lipidomic profiling of plasma free fatty acids in type-1 diabetes highlights specific changes in lipid metabolism

Type-1 diabetes mellitus (T1DM) is associated with metabolic changes leading to alterations in glucose and lipid handling. While T1DM-associated effects on many major plasma lipids have been characterised, such effects on plasma free fatty acids (FFA) have not been fully examined. Using gas chromatography–mass spectrometry, we measured the plasma concentrations of FFA species in individuals with T1DM (n = 44) and age/sex-matched healthy controls (n = 44). Relationships between FFA species and various parameters were evaluated. Plasma concentrations of myristate (14:0), palmitoleate (16:1), palmitate (16:0), linoleate (18:2), oleate (18:1c9), cis-vaccenate (18:1c11), eicosapentaenoate (20:5), arachidonate (20:4) and docosahexanoate (22:6) were reduced in the T1DM group (p < 0.0001 for all, except p = 0.0020 for eicosapentaenoate and p = 0.0068 for arachidonate); α-linolenate (18:3) and dihomo-γ-linolenate (20:3) concentrations were unchanged. The saturated/unsaturated FFA ratio, n-3/n-6 ratio, de novo lipogenesis index (palmitate (main lipogenesis product)/linoleate (only found in diet)) and elongase index (oleate/palmitoleate) were increased in the T1DM group (p = 0.0166, p = 0.0089, p < 0.0001 and p = 0.0008 respectively). The stearoyl-CoA desaturase 1 (SCD1) index 1 (palmitoleate/palmitate) and index 2 (oleate/stearate) were reduced in T1DM (p < 0.0001 for both). The delta-(5)-desaturase (D5D) index (arachidonate/dihomo-γ-linolenate) was unchanged. Age and sex had no effect on plasma FFA concentrations in T1DM, while SCD1 index 1 was positively correlated (p = 0.098) and elongase index negatively correlated with age (p = 0.0363). HbA1c was negatively correlated with all plasma FFA concentrations measured except α-linolenate and dihomo-γ-linolenate. Correlations were observed between plasma FFA concentrations and cholesterol and HDL concentrations, but not LDL concentration or diabetes duration. Collectively, these results aid our understanding of T1DM and its effects on lipid metabolism.

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Plasma concentrations of major FFA species are lower in T1DM compared to controls.

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Plasma FFA concentrations negatively correlates with HbA1c in T1DM.

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The SCD1 index is reduced in T1DM.

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Lipogenesis, elongase, n3/n6, saturated/unsaturated indices are increased in T1DM.

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Collectively, the data highlight specific changes in lipid metabolism in T1DM

Low-Carbohydrate and Very-Low-Carbohydrate Diets in Patients With Diabetes

Low-carbohydrate diets have been advocated as an effective method for promoting weight loss in overweight and obese individuals and preventing and treating type 2 diabetes. This article reviews the differences between various low-carbohydrate eating plans and discusses the benefits and drawbacks of such a diet based on available evidence. It also offers practical pointers for clinicians.

Low-carbohydrate diets for type 1 diabetes mellitus: A systematic review

Type 1 diabetes is an autoimmune condition characterised by pancreatic beta cell destruction and absolute insulin deficiency. The strongest predictor of diabetes complications is glycaemic control and achieving HbA1c ≤ 7.0% is the primary management target. However, standard treatment appears to be lacking and adjunctive strategies require consideration. A systematic review was conducted to examine the effect of low-carbohydrate diets on type 1 diabetes management. Four databases were searched from inception until 28 March 2017: MEDLINE; CINAHL; Cochrane Library; and EMBASE. All primary studies containing a methods section (excluding cross-sectional) were included. Reports had to quantitatively measure the effect(s) of a dietary intervention or observed intake over at least two weeks where carbohydrate is below 45% total energy in adults and/or children with type 1 diabetes. The primary outcome was HbA1c and secondary outcomes were severe hypoglycaemia, total daily insulin, BMI, quality of life and mean daily glucose. Seventy-nine full-text articles were assessed for eligibility and nine were included (two randomised controlled trials, four pre-post interventions, two case-series, one case-report). Eight studies reported a mean change in HbA1c with a low-carbohydrate diet. Of these, four reported a non-significant change (P ≥ 0.05) and three reported statistically significant reductions (P < 0.05). Two studies reported severe hypoglycaemia, five reported total insulin, three reported BMI, and one reported blood glucose. Due to the significant heterogeneity of included studies, an overall effect could not be determined. This review presents all available evidence on low-carbohydrate diets for type 1 diabetes and suggests an urgent need for more primary studies.

Nutritional therapy for diabetes mellitus

Dietary therapy affects diabetes management in the dog and cat directly through control of blood glucose and indirectly through control of obesity and lipid abnormalities. Caloric intake, the feeding schedule, food form, macronutrient composition of the diet, and the presence of any concurrent problems must all be considered when planning the dietary regime. Generally, the healthy diabetic dog or cat should be fed a diet with increased fiber and moderate carbohydrate in a quantity sufficient to attain and maintain optimal body weight; whenever possible, the daily food allotment should be divided into multiple small meals that are fed through the day and evening when the physiologic effects of administered insulin are present. Once established, the dietary regime should be kept constant from day to day. Following these guidelines will help minimize postprandial hyperglycemia and may lead to a decreased exogenous insulin requirement. However, if a concurrent disorder has dietary requirements that conflict with those for the diabetic pet, nutritional management of the other disorder should usually take precedence.