Effects of acute caffeine supplementation on reducing exercise-associated hypoglycaemia in individuals with Type 1 diabetes mellitus

Caffeine: A Multifunctional Efficacious Molecule with Diverse Health Implications and Emerging Delivery Systems

Natural caffeine is found in many plants, including coffee beans, cacao beans, and tea leaves. Around the world, many beverages, including coffee, tea, energy drinks, and some soft drinks, have this natural caffeine compound. This paper reviewed the results of meta-studies on caffeine's effects on chronic diseases. Of importance, many meta-studies have shown that regularly drinking caffeine or caffeinated coffee significantly reduces the risk of developing Alzheimer's disease, epilepsy, and Parkinson's disease. Based on the health supplements of caffeine, this review summarizes various aspects related to the application of caffeine, including its pharmacokinetics, and various functional health benefits of caffeine, such as its effects on the central nervous system. The importance of caffeine and its use in alleviating or treating cancer, diabetes, eye diseases, autoimmune diseases, and cardiovascular diseases is also discussed. Overall, consuming caffeine daily in drinks containing antioxidant and neuroprotective properties, such as coffee, prevents progressive neurodegenerative diseases, such as Alzheimer's and Parkinson's. Furthermore, to effectively deliver caffeine to the body, recently developed nanoformulations using caffeine, for instance, nanoparticles, liposomes, etc., are summarized along with regulatory and safety considerations for caffeine. The U.S. Department of Agriculture (USDA) and the Food and Drug Administration (FDA) recommended that healthy adults consume up to 400 mg of caffeine per day or 5~6 mg/kg body weight. Since a cup of coffee contains, on average, 100 to 150 mg of coffee, 1 to 3 cups of coffee may help prevent chronic diseases. Furthermore, this review summarizes various interesting and important areas of research on caffeine and its applications related to human health.

A very low carbohydrate diet for minimising blood glucose excursions during ultra-endurance open-water swimming in type 1 diabetes: a case report

Carbohydrate-restricted diets are used by people with type 1 diabetes (T1D) to help manage their condition. However, the impact of this strategy on blood glucose responses to exercise is unknown. This study describes the nutritional strategies of an athlete with T1D, who follows a very low carbohydrate diet to manage her condition during an ultra-endurance open-water swimming event. The athlete completed the 19.7 km distance in 6 h 43 min. She experienced minimal disruptions to glycaemia, reduced need for supplemental carbohydrate, and no episodes of symptomatic hypoglycaemia. This case report will hopefully encourage further experimental studies that inform and expand current clinical practice guidelines.

Nutritional Management of Athletes with Type 1 Diabetes: A Narrative Review

Type 1 diabetes mellitus (T1DM) represents a complex clinical challenge for health systems. The autoimmune destruction of pancreatic beta cells leads to a complete lack of insulin production, exposing people to a lifelong risk of acute (DKA, coma) and chronic complications (macro and microvascular). Physical activity (PA) has widely demonstrated its efficacy in helping diabetes treatment. Nutritional management of people living with T1DM is particularly difficult. Balancing macronutrients, their effects on glycemic control, and insulin treatment represents a complex clinical challenge for the diabetologist. The effects of PA on glycemic control are largely unpredictable depending on many individual factors, such as intensity, nutrient co-ingestion, and many others. Due to this clinical complexity, we have reviewed the actual scientific literature in depth to help diabetologists, sport medicine doctors, nutritionists, and all the health figures involved in diabetes care to ameliorate both glycemic control and the nutritional status of T1DM people engaging in PA. Two electronic databases (PubMed and Scopus) were searched from their inception to January 2024. The main recommendations for carbohydrate and protein ingestion before, during, and immediately after PA are explained. Glycemic management during such activity is widely reviewed. Micronutrient needs and nutritional supplement effects are also highlighted in this paper.

Blood glucose response to running or cycling in individuals with type 1 diabetes: A systematic review and meta-analysis

AIMS

The aim of this systematic review and meta-analysis was to assess how running and cycling influence the magnitude of blood glucose (BG) excursions in individuals with type 1 diabetes.

METHODS

A systematic literature search was conducted in EMBASE, PubMed, Cochrane Central Register of Controlled Trials, and ISI Web of Knowledge for publications from January 1950 until February 2021. Parameters included for analysis were population (adults and adolescents), exercise type, intensity, duration and insulin preparation. The meta-analysis was performed to estimate the pooled mean with a 95% confidence interval (CI) of delta BG levels. In addition, sub-group and meta-regression analyses were performed to assess the influence of these parameters on delta BG.

RESULTS

The database search identified 3192 articles of which 69 articles were included in the meta-analysis. Due to crossover designs within articles, 151 different results were included for analysis. Data from 1901 exercise tests of individuals with type 1 diabetes with a mean age of 29 ± 4 years were included. Overall, exercise tests BG decreased by -3.1 mmol/L [-3.4; -2.8] within a mean duration of 46 ± 21 min. The pooled mean decrease in BG for running was -4.1 mmol/L [-4.7; -2.4], whilst the pooled mean decrease in BG for cycling was -2.7 mmol/L [-3.0; -2.4] (p < 0.0001). Overall results can be found in Table S2.

CONCLUSIONS

Running led to a larger decrease in BG in comparison to cycling. Active individuals with type 1 diabetes should be aware that current recommendations for glycaemic management need to be more specific to the mode of exercise.

Association of HbA1c with VO2max in Individuals with Type 1 Diabetes: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to evaluate the association between glycemic control (HbA1c) and functional capacity (VO2max) in individuals with type 1 diabetes (T1DM). A systematic literature search was conducted in EMBASE, PubMed, Cochrane Central Register of Controlled Trials, and ISI Web of Knowledge for publications from January 1950 until July 2020. Randomized and observational controlled trials with a minimum number of three participants were included if cardio-pulmonary exercise tests to determine VO2max and HbA1c measurement has been performed. Pooled mean values were estimated for VO2max and HbA1c and weighted Pearson correlation and meta-regression were performed to assess the association between these parameters. We included 187 studies with a total of 3278 individuals with T1DM. The pooled mean HbA1c value was 8.1% (95%CI; 7.9−8.3%), and relative VO2max was 38.5 mL/min/kg (37.3−39.6). The pooled mean VO2max was significantly lower (36.9 vs. 40.7, p = 0.001) in studies reporting a mean HbA1c > 7.5% compared to studies with a mean HbA1c ≤ 7.5%. Weighted Pearson correlation coefficient was r = −0.19 (p < 0.001) between VO2max and HbA1c. Meta-regression adjusted for age and sex showed a significant decrease of −0.94 mL/min/kg in VO2max per HbA1c increase of 1% (p = 0.024). In conclusion, we were able to determine a statistically significant correlation between HbA1c and VO2max in individuals with T1DM. However, as the correlation was only weak, the association of HbA1c and VO2max might not be of clinical relevance in individuals with T1DM.

Altered Caffeine Metabolism Is Associated With Recurrent Hypoglycemia in Type 2 Diabetes Mellitus: A UPLC-MS-Based Untargeted Metabolomics Study

Background

Recurrent hypoglycemia (RH) is well known to impair awareness of hypoglycemia and increase the risk of severe hypoglycemia; the underlying mechanism requires further understanding. We aimed to investigate the metabolic characteristic profile for RH in type 2 diabetes mellitus (T2DM) patients and explore the potential metabolic mechanism and prevention strategies.

Methods

We screened 553 community-based T2DM patients. T2DM with RH (DH group, n=40) and T2DM without hypoglycemia (DC group, n=40) were assigned in the case-control study, matched by propensity score matching. Non-targeted, global metabolite profiling was conducted using ultra-high performance liquid chromatography-mass spectrometry. Principal component analysis and supervised projections to latent structures-discriminant analysis were constructed to evaluate the potential biomarkers. Metabolites with a fold change of >2.0 or <0.5, a t-test q-value <0.05, and variable importance in projection value of >1 were identified as significantly differential metabolites. MetaboAnalyst was performed to analyze the related metabolic pathways.

Results

We identified 12 significantly distinct metabolites as potential biomarkers of RH, which were enriched in five pathways; the caffeine metabolic pathway was the most dominant related one. Caffeine and its main downstream metabolites (theophylline and paraxanthine, all q <0.05) were significantly lower during RH. The combination of these metabolites can serve as a reliable predictor biomarker for RH (area under the curve = 0.88). Regarding lipid metabolism, triglyceride was upregulated (P=0.003) and the O-Acylcarnitine was downregulated (q < 0.001). Besides, RH was accompanied by lower phenylalanine (q=0.003) and higher cortisone (q=0.005) levels.

Conclusions

RH in T2DM is accompanied by caffeine, lipolysis, phenylalanine, and cortisone metabolism abnormalities. Caffeine might be a reliable candidate biomarker and potential prevention strategy for RH, but further validation studies are needed.

Clinical Trial Registry

Chi CTR 1900026361, 2019-10-3.

Digital Solutions to Diagnose and Manage Postbariatric Hypoglycemia

Postbariatric hypoglycemia (PBH) is an increasingly recognized late metabolic complication of bariatric surgery, characterized by low blood glucose levels 1-3 h after a meal, particularly if the meal contains rapid-acting carbohydrates. PBH can often be effectively managed through appropriate nutritional measures, which remain the cornerstone treatment today. However, their implementation in daily life continues to challenge both patients and health care providers. Emerging digital technologies may allow for more informed and improved decision-making through better access to relevant data to manage glucose levels in PBH. Examples include applications for automated food analysis from meal images, digital receipts of purchased food items or integrated platforms allowing the connection of continuously measured glucose with food and other health-related data. The resulting multi-dimensional data can be processed with artificial intelligence systems to develop prediction algorithms and decision support systems with the aim of improving glucose control, safety, and quality of life of PBH patients. Digital innovations, however, face trade-offs between user burden vs. amount and quality of data. Further challenges to their development are regulatory non-compliance regarding data ownership of the platforms acquiring the required data, as well as user privacy concerns and compliance with regulatory requirements. Through navigating these trade-offs, digital solutions could significantly contribute to improving the management of PBH.

Nutritional support for a person with type 1 diabetes undertaking endurance swimming

Long distance and open water swimming have increased in popularity over recent years. Swimming a long distance in lakes, rivers and the sea present numerous challenges, including cold water exposure and maintaining adequate nutritional intake to fuel exercising muscles. Guidelines exist outlining issues to consider and potential solutions to overcome the difficulties in feeding athletes. Exercising with type 1 diabetes adds further complexity, mostly around matching insulin to the recommended high carbohydrate intake, but also because of the way in which higher circulating insulin levels affect glucose utilisation and fat oxidation. This paper describes the nutritional considerations for people with type 1 diabetes intending to undertake long distance open water events, and insulin management suggestions to trial alongside. In addition, we include personal testimony from a swimmer with type 1 diabetes describing the challenges and considerations he faced when undertaking marathon swimming.

Post-exercise recovery for the endurance athlete with type 1 diabetes: a consensus statement

There has been substantial progress in the knowledge of exercise and type 1 diabetes, with the development of guidelines for optimal glucose management. In addition, an increasing number of people living with type 1 diabetes are pushing their physical limits to compete at the highest level of sport. However, the post-exercise recovery routine, particularly with a focus on sporting performance, has received little attention within the scientific literature, with most of the focus being placed on insulin or nutritional adaptations to manage glycaemia before and during the exercise bout. The post-exercise recovery period presents an opportunity for maximising training adaption and recovery, and the clinical management of glycaemia through the rest of the day and overnight. The absence of clear guidance for the post-exercise period means that people with type 1 diabetes should either develop their own recovery strategies on the basis of individual trial and error, or adhere to guidelines that have been developed for people without diabetes. This Review provides an up-to-date consensus on post-exercise recovery and glucose management for individuals living with type 1 diabetes. We aim to: (1) outline the principles and time course of post-exercise recovery, highlighting the implications and challenges for endurance athletes living with type 1 diabetes; (2) provide an overview of potential strategies for post-exercise recovery that could be used by athletes with type 1 diabetes to optimise recovery and adaptation, alongside improved glycaemic monitoring and management; and (3) highlight the potential for technology to ease the burden of managing glycaemia in the post-exercise recovery period.

Nutrition and Exercise Performance in Adults With Type 1 Diabetes

The best nutritional practices for exercise and sports performance are largely activity specific. The presence of type 1 diabetes undeniably bestows additional factors to consider to manage exercise and ensure adequate nutrients and fuels are available for optimal performance. Whether participating in sports or physical activity on a recreational basis or striving to achieve a high level of athletic performance, individuals with type 1 diabetes must pay attention to their nutritional and dietary patterns, including intake of macronutrients, micronutrients, fluids and supplements, such as caffeine to maintain metabolic and glycemic balance. Performance aside, nutritional recommendations may also differ on an individual basis relative to exercise, glycemic management and body weight goals. Balancing all these dietary factors can be challenging for individuals with type 1 diabetes, and many related aspects have yet to be fully researched in this population.

Use and abuse of dietary supplements in persons with diabetes

The dietary supplement industry has estimated sales of over $30 billion in the US and over $100 billion globally. Many consumers believe that dietary supplements are safer and possibly more effective than drugs to treat diabetes. The sheer volume of the literature in this space makes compiling them into one review challenging, so much so that primarily narrative reviews currently exist. By applying the interactive database supplied by the Office of Dietary Supplements at the National Institutes of Health, we identified the top 100 ingredients that appeared most often in dietary supplement products. One-hundred different keyword searches using the ingredient name and the word diabetes were performed using a program developed to automatically scrape PubMed. Each search was retained in a separate Excel spreadsheet, which was then reviewed for inclusion or exclusion. The studies that met the inclusion criteria were evaluated for effect of reducing and controlling diabetes. The PubMed scrape resulted in 6217 studies. For each keyword search only the most recent 100 were retained, which refined the total to 1823 studies. Of these 425 met the screening criteria. The ingredients, fiber, selenium and zinc had the most studies associated with improvement in diabetes. Several popular supplement ingredients (phosphorus, pantothenic acid, calcium, magnesium, glutamine, isoleucine, tyrosine, choline, and creatine monohydrate) did not result in any studies meeting our screening criteria. Our study demonstrates how to automate reviews to filter and collapse literature in content areas that have an enormous volume of studies. The aggregated set of studies suggest there is little clinical evidence for the use of dietary supplements to reduce or control diabetes.

Continuous Glucose Monitoring and Exercise in Type 1 Diabetes: Past, Present and Future

Prior to the widespread use of continuous glucose monitoring (CGM), knowledge of the effects of exercise in type 1 diabetes (T1D) was limited to the exercise period, with few studies having the budget or capacity to monitor participants overnight. Recently, CGM has become a staple of many exercise studies, allowing researchers to observe the otherwise elusive late post-exercise period. We performed a strategic search using PubMed and Academic Search Complete. Studies were included if they involved adults with T1D performing exercise or physical activity, had a sample size greater than 5, and involved the use of CGM. Upon completion of the search protocol, 26 articles were reviewed for inclusion. While outcomes have been variable, CGM use in exercise studies has allowed the assessment of post-exercise (especially nocturnal) trends for different exercise modalities in individuals with T1D. Sensor accuracy is currently considered adequate for exercise, which has been crucial to developing closed-loop and artificial pancreas systems. Until these systems are perfected, CGM continues to provide information about late post-exercise responses, to assist T1D patients in managing their glucose, and to be useful as a tool for teaching individuals with T1D about exercise.

The effect of acute caffeine intake on insulin sensitivity and glycemic control in people with diabetes

The prevalence of diabetes is growing globally, and with no current cure for the disease, management is focused on optimizing blood glucose control to limit complications. The purpose of this review was to examine the effect of caffeine intake on blood glucose levels in people with diabetes. Electronic searches were completed using Pub Med, CINAHL, and Web of Science using the search terms "coffee and insulin," "caffeine and insulin," "caffeine and diabetes," "caffeine and type 1 diabetes," "caffeine and type 2 diabetes," and "caffeine and glycemia." Seven trials were found to meet the search criteria. Five of the 7 studies suggest caffeine intake increases blood glucose levels, and prolongs the period of high blood glucose levels. Future research should focus on larger clinical trials to confirm the relationship and mechanism of action related to caffeine intake and glycemic control in individuals with diabetes.

Exercise management in type 1 diabetes: a consensus statement

Type 1 diabetes is a challenging condition to manage for various physiological and behavioural reasons. Regular exercise is important, but management of different forms of physical activity is particularly difficult for both the individual with type 1 diabetes and the health-care provider. People with type 1 diabetes tend to be at least as inactive as the general population, with a large percentage of individuals not maintaining a healthy body mass nor achieving the minimum amount of moderate to vigorous aerobic activity per week. Regular exercise can improve health and wellbeing, and can help individuals to achieve their target lipid profile, body composition, and fitness and glycaemic goals. However, several additional barriers to exercise can exist for a person with diabetes, including fear of hypoglycaemia, loss of glycaemic control, and inadequate knowledge around exercise management. This Review provides an up-to-date consensus on exercise management for individuals with type 1 diabetes who exercise regularly, including glucose targets for safe and effective exercise, and nutritional and insulin dose adjustments to protect against exercise-related glucose excursions.

Basal insulin delivery reduction for exercise in type 1 diabetes: finding the sweet spot

Exercise poses significant challenges to glucose management in type 1 diabetes. In spite of careful planning and manipulation of subcutaneous insulin administration, increased risk of hypoglycaemia and glycaemic variability during and after exercise may occur as a result of inherent delays in insulin action and impaired counter-regulatory hormone responses. Various strategies to mitigate this issue have been advocated in clinical practice, including ingestion of supplementary carbohydrate prior to exercise, reducing background and pre-meal insulin bolus and performing bouts of resistance/high intensity exercise before aerobic exercise. Insulin pump therapy, considered the most physiological form of insulin replacement for type 1 diabetes allows modulation of basal insulin delivery before, during and after exercise. However uncertainty remains regarding the optimal strategy to reduce basal insulin delivery and its efficacy. In this issue of Diabetologia, McAuley and colleagues (DOI: 10.1007/s00125-016-3981-9 ) report on the impact of a 50% reduction of basal insulin delivery before, during and after moderate-intensity aerobic exercise. Results from this study may contribute to a better understanding of the effects of basal insulin delivery manipulation and may aid in devising therapeutic approaches for glucose management during exercise.