Effect of an alcohol-free beer enriched with isomaltulose and a resistant dextrin on insulin resistance in diabetic patients with overweight or obesity

Summary

Background & aims

The quality of carbohydrates has an essential role in nutritional management of type 2 diabetes mellitus (T2DM) because of its substantial impact on glucose homeostasis. Alcohol-free beer has beneficial bioactive components but it has a relatively high glycemic-index so its consumption is restricted in diabetic subjects. We aimed to explore the effect of an alcohol-free beer with modified carbohydrate composition almost completely eliminating maltose and adding isomaltulose (16.5 g/day) and a resistant maltodextrin (5.28 g/day) in comparison to a regular alcohol-free beer on glycemic control of diabetic subjects with overweight or obesity.

Design

We randomized 41 subjects into two groups: a) consumption of 66 cL/day of; regular alcohol-free beer for the first 10 weeks and 66 cL/day of alcohol-free beer with modified carbohydrate composition for the next 10 weeks; b) the same described intervention in opposite order. There was a washout period for 6–8 weeks between the two interventions. Participants were counseled to adhere to a healthy diet for cardiovascular health and to increase physical activity. Clinical, biochemical, anthropometric, lifestyle and satiety assessments were performed at the beginning and at the end of each period.

Results

Subjects showed significantly weight loss after the two ten weeks periods (−1.69 ± 3.21% and −1.77 ± 3.70% after experimental and regular alcohol-free beers, respectively, P = 0.881). Glucose and glycated hemoglobin did not significantly change after any period. Insulin concentrations and HOMA-IR significantly decreased (−11.1 [–21.3−4.64]% and −1.92 ± 32.8% respectively) after the intake of experimental alcohol-free beer but not after regular alcohol-free beer. Reductions remained statistically significant after adjusting for weight loss, energy intake, physical activity and intervention order. Subjects reported higher satiety scores after consuming experimental alcohol-free beer.

Conclusions

An alcohol-free beer including the substitution of regular carbohydrates for low doses of isomaltulose and the addition of a resistant maltodextrin within meals led to an improvement in insulin resistance in subjects with T2DM and overweight or obesity.

Clinical trial registration

The clinical trial has been registered in ClinicalTrials.gov (Identifier: NCT03337828).

Introduction

Diabetes mellitus burden is becoming a cause of concern due to its rapidly increasing global prevalence, complications and the excessive mortality rate which follows from its diagnosis [1], [2]. Lifestyle intervention is a key issue in diabetes management and includes, among other aspects, medical nutrition therapy [3]. In the presence of overweight or obesity, weight loss constitutes one of the key objectives of treatment. However, there is limited evidence on the optimal diet to control hyperglycemia and obesity in type 2 diabetes mellitus (T2DM). The amount and type of carbohydrate is one of the cornerstones in nutrition therapy of T2DM patients since they commonly comprise fifty percent or more of all calories consumed, and they have a substantial impact on glucose homeostasis [4]. The effect of low-carbohydrate diets in patients with T2DM remains unclear [3], [5], [6]. Beyond the quantity, carbohydrate composition directly impacts postprandial glucose control [7]. The metabolic effects of carbohydrate-containing foods are determined, mainly, by their content of sugars, dietary fiber, glycemic responses to digestion, processing and whole-grain content. Several clinical trials have documented the beneficial effect of low-glycemic index (GI) diets on glycemic control in T2DM [8]. More recently, several studies have demonstrated that the impact of carbohydrates on insulin secretion and postprandial glycemia can substantially change depending on the types of foods with which the carbohydrates are consumed [9].

Isomaltulose, a disaccharide composed of α-1,6–linked glucose and fructose, was recently introduced as an alternative sugar with delayed digestion and absorption resulting in a low GI of 32 [10]. A relatively high isomaltulose consumption (over 20 g per day) leads to cardiometabolic benefits including glycemic control, macronutrient oxidation and improved lipid profile, both in healthy and in diabetic patients [11]. Resistant dextrin is a glucose polymer (rich in α-1,4 and α-1,6 linkages) derived from wheat or maize [12]. It is incompletely hydrolyzed and absorbed in the small intestine, while the majority is fermented in the colon. High doses (≥10 g) of resistant dextrin induce beneficial effects on glycemic status, systemic inflammation, body weight, and body composition in humans [13], [14], [15]. To the best of our knowledge, no study has previously explored the potential synergistic beneficial effect of isomaltulose and resistant dextrin in glucose homeostasis of subjects with prediabetes or T2DM.

Beer is over 90% water while the rest of components are mainly carbohydrates (glucose polymers) and alcohol. As a product of cereals fermentation of cereals, beer has B-complex vitamins, in particular folate and choline, and trace amounts of minerals such as potassium, calcium and magnesium [16]. Beer composition also includes a range of polyphenols such as flavonoids and phenolic acids that have protective effects on cardiovascular health as measured by inflammatory biomarkers, among other biomarkers [17], [18], [19], [20]. Beer is widely consumed and it is often a preferred drink both in social events and on a daily basis. However, beer is usually restricted in T2DM patients because of its high content of carbohydrates and alcohol [3], [5]. Alcohol-free beer has the same bioactive compounds (although in lower concentrations) than regular beer, excluding the alcohol [16], [21]. GI is estimated as 119 in regular beer and 80 in alcohol-free beer, which is similar to that of potatoes, white bread or rice. In this context, we aimed to explore the effects of an alcohol-free beer with modified carbohydrates (almost completely eliminating maltose and adding isomaltulose (16.5 g/day) and a resistant maltodextrin (5.28 g/day)) on glycemic control (HOMA-IR as main outcome) in diabetic subjects who are overweight or obese, in comparison to an alcohol-free beer with regular composition to overcome the restrictions to regular beer for T2DM. A secondary and exploratory objective of the study was to address the effect of modified alcohol-free beer on satiety.