Abstract
d: Exercise and the consumption of sugars result in a dysfunction of the intestinal barrier (IB). Here, we determined the effect of sugar in a natural matrix on the intestinal barrier after moderate (A) and intensive endurance exercise (B). Method: The IB function was determined before (pre) and after running (post), and 120 and 180 min after consuming the drink by measuring serum endotoxin concentrations (lipopolysaccharides—LPS), IL-6, CD14, and i-FABP. In study A, nonspecifically trained participants (n= 24, males and females, age 26±4) ran for one hour at 80% of their individual anaerobic threshold (IAT). After finishing, the runners consumed, in a
function was determined before (pre) and after running (post), and 120 and 180 min after consuming the drink by measuring serum endotoxin concentrations (lipopolysaccharides—LPS), IL-6, CD14, and i-FABP. In study A, nonspecifically trained participants (n= 24, males and females, age 26±4) ran for one hour at 80% of their individual anaerobic threshold (IAT). After finishing, the runners consumed, in a crossover setup, either 500 mL of water, diluted cloudy apple juice (test drink), or an identical drink (placebo) without the fruit juice matrix (FJM). In study B, the participants (n= 30, males and females, age 50±9) completed an ultra-marathon run, were divided into groups, and consumed one of the above-mentioned drinks. Results: Study A: Exercise resulted in a significant increase in serum LPS, i-FABP, and IL-6, which decreased fast after finishing. No impact of the different drinks on LPS i-FABP, or IL-6 could be observed, but there was an impact on CD14. Study B: The ultra-marathon resulted in a strong increase in serum LPS, which decreased fast after finishing in the water and test drink groups, but not in the placebo group. Conclusions: The consumed drinks did not affect the kinetics of IB regeneration after moderate exercise, but impacted CD14 serum concentrations, indicating possible beneficial effects of the FJM on the immune system. After an ultra-marathon, IB function regenerates very fast. The intake of sugar (placebo) seems to have had a negative impact on IB regeneration, which was diminished by the presence of the FJM. Keywords:endotoxin; endurance exercise; health; intestinal barrier; apple juice 1. Introduction The consumption of drinks containing carbohydrates during or after exercise has been described as providing energy (during) and supporting recovery processes after exercise [1,2]. Therefore, such drinks are intensively advertised and their consumption has become very popular among athletes [3]. Unfortunately, both exercise and sugar consumption have been described as resulting in a dysfunction of the intestinal barrier (IB). Impairments of the intestinal barrier function can subsequently lead to elevated bacterial Nutrients2024,16, 1353.
very popular among athletes [3]. Unfortunately, both exercise and sugar consumption have been described as resulting in a dysfunction of the intestinal barrier (IB). Impairments of the intestinal barrier function can subsequently lead to elevated bacterial Nutrients2024,16, 1353.
Nutrients2024,16, 1353 2 of 17 endotoxin levels and inflammation [4,5]. With respect to physical activity, the induction of inflammation is, on the one hand, important for the stimulation of exercise-related physiological adaptations [6,7]; on the other hand, chronic inflammation may result in overtraining scenarios [8] and increase the risk for the development of metabolic diseases (for an overview, see [9]). In several studies, it has been demonstrated that the function of the IB is affected by physical activity and that heavy physical exercise, like marathon running or ultra-marathon running, results in massive endotoxemia [10–12]. It has also been shown that even an acute or short-term intake of specific foods or food compounds, like saturated fats or fructose and sucrose [13–15], may impair IB function and increase bacterial endotoxin levels in humans, thereby adding to the development of so-called post- prandial endotoxemia [16]. However, whether sugars consumed in their natural matrix state, like fruits or fruit juices, affect IB function and the translocation of bacterial wall compounds in the same way, has not yet been clarified in humans. Indeed, in contrast to most soft drinks, fruit juices contain a variety of secondary plant metabolites that are absorbed in the intestine and are also metabolized by intestinal cells. For instance, the results ofin vitroand ex vivo studies have suggested that polyphenols, like those found in apple juice, are absorbed and metabolized [17,18], and may thereby affect inflammatory processes and even DNA damage [19,20]. Information about the combinatory effects of sugar consumption and exercise on the IB is limited. Thus, it was the purpose of this study to analyze the combinatory effects of sug- ars consumed in their natural matrix (diluted cloudy apple juice with a high content of polyphenols (test drink)) or in water (placebo), in comparison to water, and in combination with exercise, on the markers of the IB. In the first study, this was analyzed after moderate exercise in a placebo-controlled, blinded, crossover design (study A). In addition, the effects of the same drinks were tested in a second study after high-volume endurance exercise (study B). Here, the finishers of
in water (placebo), in comparison to water, and in combination with exercise, on the markers of the IB. In the first study, this was analyzed after moderate exercise in a placebo-controlled, blinded, crossover design (study A). In addition, the effects of the same drinks were tested in a second study after high-volume endurance exercise (study B). Here, the finishers of an ultra-marathon were divided into groups and consumed the test drink, the placebo, or water directly after finishing. 2. Methods 2.1. Participants 2.1.1. Study A All the participants in this study were recruited from local running groups or from courses at the German Sport University Cologne. This study was carried out between December 2021 and October 2022. The sample size was calculated with G*Power and a total of 24 participants were considered sufficient for enrollment (Gpower, Version 3.1.9.2, Düsseldorf, Germany), based on the effect sizes of previous studies [2]. A total of 24 men and women were enrolled in this study, of whom a total of 17 partic- ipants completed this study. Participants dropped out of this study due to family reasons (n= 2), illness (n= 2), or unspecified reasons (n= 3). None of the participants smoked, suffered from chronic or acute diseases, or was overweight (BMI between 18.5 kg/m 2 and 24.9 kg/m 2 ). All the participants followed an omnivorous diet. None of the participants re- ported drinking more than a moderate amount of alcohol (no more than one glass of beer or wine, so that a quantity of >10 g/day for women and >20 g/day for men was not exceeded). They were healthy, generally physical active, but not specifically endurance-trained. In addition, the subjects had to be between 18 and 35 years old, have no acute injuries or chronic illnesses, take any medications, and have a running time for 10,000 m of <55 min for women and <50 min for men. High-performance athletes with low body fat and individuals trained specifically for national and international competitions were also excluded. Before the subjects were included in this study, they were informed about the study design and objectives and
or chronic illnesses, take any medications, and have a running time for 10,000 m of <55 min for women and <50 min for men. High-performance athletes with low body fat and individuals trained specifically for national and international competitions were also excluded. Before the subjects were included in this study, they were informed about the study design and objectives and had to give their written consent to participate. All personal data collected were anonymized and in compliance with data protection regulations in Germany. An overview of the subjects’ characteristics is given in Table.
Nutrients2024,16, 1353 3 of 17 Table 1.Overview of subjects characteristics. Shown are mean results±standard deviation (SD). Sex Male (14), Female (3) Age (years) 26 ±4 Height (cm) 178.94 ±7.28 Body mass (kg) 70.94 ±8.17 BMI (kg/m 2 ) 22.12±1.80 2.1.2. Study B Ultra-marathon (TorTour de Ruhr ® ) participation required a medical sports examina- tion conducted less than 6 months before the race and that confirmed the physical resilience of the athlete. The inclusion criteria for study participation were as follows: male/female; endurance athlete and 160.9 km or 230 km participant in the TorTour de Ruhr ® 2022; no previous injuries; and the ability to understand this study’s procedure and to give informed consent. The exclusion criteria included the following: participants in the 100 km race (owing to organizational restrictions); nicotine consumption; diseases of the intestine; blood clotting disorders or intake of blood-thinning medications; acute or chronic vascular (blood flow) disorders; cardiovascular, metabolic, or autoimmune diseases; and non-consenting subjects. An overview of the subjects characteristics is given in Table. Table 2.Anthropometric data, finish time, and nutrition details for this study’s participants. All data are presented as mean±standard deviation. Anthropometry Age (years) Height (cm) Body Mass (kg) Body Mass Index (kg/m 2 ) 160.9 km 230 km 160.9 km 230 km 160.9 km 230 km 160.9 km 230 km 50.20 (7.98) 50.14 (9.74) 174.80 (4.62) 177.43 (8.74) 71.14 (4.18) 71.89 (11.30) 23.30 (1.29) 22.79 (2.93) Finish time (hours) 160.9 km 22.56 (3.31) 230 km 32.28 (2.95) All the subjects received information about this study’s content and the use of the data and provided their written consent. Both study parts were approved in their entire study designs by the local ethics committee of the German Sports University Cologne in October 2021 (reference number: 171/2021) and registered with the DKRS under trial No. DRKS00027860. 2.2. Study Design 2.2.1. Study A This study was designed as a randomized, double-blind trial with a crossover design. To ensure accuracy, there was a washout period of at least 2 weeks between intervention phases to account for possible training adaptations and the effects of the study beverages. The
number: 171/2021) and registered with the DKRS under trial No. DRKS00027860. 2.2. Study Design 2.2.1. Study A This study was designed as a randomized, double-blind trial with a crossover design. To ensure accuracy, there was a washout period of at least 2 weeks between intervention phases to account for possible training adaptations and the effects of the study beverages. The intervention consisted of a one-hour endurance run at an intensity of 80% of the individual anaerobic threshold (IAT). To determine the IAT, a field incremental exercise test was conducted. The test started at a velocity of 2.4 m/s, increasing by 0.4 m/s every 5 min. Each increment was followed by a 30 s rest period that allowed for capillary blood sampling, enabling the analysis of the blood lactate concentration [21]. The test continued until volitional exhaustion was reached, determined when at least two of the following three criteria were met: (1) reaching the age-predicted maximum heart rate, (2) a blood lactate concentration of 8 mmol/L or higher, and (3) a rating of 18 or higher on the Borg Scale [22]. The analysis of the IAT included a mathematical calculation of the lactate concentration
Nutrients2024,16, 1353 4 of 17 with the Dmod method [23]. This method determines the maximum distance between a third-degree polynomial curve—representing the lactate data from the incremental test for each participant—and the line connecting the first point of lactate rise (increase of ≥0.4 mmol/L between two increments) to the final measured lactate concentration. The endurance run was carried out three times, with the test drink, placebo, and water supplementation. The study beverages were ingested immediately after the run. Blood samples were taken at defined time points (T0 (pre-exercise (pre-ex)), T2 (post-exercise (post-ex)), T3 (+80 min), T4 (+120 min), and T5 (+180 min)) throughout the study day and a further blood sample was taken on the following day. Figure study design.Nutrients 2024, 16, x FOR PEER REVIEW 4 of 17 The analysis of the IAT included a mathematical calculation of the lactate concentration with the Dmod method [23]. This method determines the maximum distance between a third-degree polynomial curve—representing the lactate data from the incremental test for each participant—and the line connecting the first point of lactate rise (increase of ≥0.4 mmol/L between two increments) to the final measured lactate concentration. The endurance run was carried out three times, with the test drink, placebo, and wa- ter supplementation. The study beverages were ingested immediately after the run. Blood samples were taken at defined time points (T0 (pre-exercise (pre-ex)), T2 (post-exercise (post-ex)), T3 (+80 min), T4 (+120 min), and T5 (+180 min)) throughout the study day and a further blood sample was taken on the following day. Figure 1 displays the entire study design. Figure 1. Study design of study A. CK = creatine kinase; IAT = individual anaerobic threshold; PBMC = peripheral blood mononuclear cells; pre-ex = pre-exercise; post-ex = post-exercise. On the evening before each of the three study days, the 17 healthy subjects consumed a standard dinner. The meal consisted of pasta in a tomato cream sauce with zucchini and mozzarella with the macronutrients, i.e., the energy derived from carbohydrates at 56 E%, fat at 30 E%, and protein at 14 E%, based on the recommendations of the German,
On the evening before each of the three study days, the 17 healthy subjects consumed a standard dinner. The meal consisted of pasta in a tomato cream sauce with zucchini and mozzarella with the macronutrients, i.e., the energy derived from carbohydrates at 56 E%, fat at 30 E%, and protein at 14 E%, based on the recommendations of the German, Aus- trian, and Swiss nutrition societies (DACH) (see Table 3 for meal composition). Protein levels were adjusted for the higher needs of athletes [24]. The energy content of the meal was based on the ‘normal’ energy intake of each participant, taking gender, physical ac- tivity, and age into consideration. To assess the ‘normal’ energy intake of the participants, two independent 24 h recalls (for one weekday and one weekend day) were performed by a trained nutritionist. The nutritional intake and standardization of the meal were calcu- lated via the computer software EBISpro (Version 2011, Willstätt, Germany). Table 3. Composition of the standardized meal served to the participants on the evening before the intervention day. Meal Compo- nents Energy 唐 (kcal/100 g) Carbohydrates 唐(g/100 g) Fat 唐(g/100 g) Protein 唐 (g/100 g) Fiber 唐 (g/100 g) Egg-based pasta 352.3 68.3 2.8 12.3 5.0 Zucchini 19.1 2.0 0.4 1.6 1.1 Onion 28.0 4.9 0.3 1.3 1.8 Olive oil 881.7 0.2 99.6 - - Tomato 17.4 2.6 0.2 0.9 0.9 Cream 唐(10% fat content) 116.6 3.3 10.0 3.1 - Mozzarella 254.8 - 19.8 19.0 - Salt - - - - - Values were determined using the software EBISpro. The results of the 24 h recalls and the values of the energy and macronutrient com- position of the standard meal are shown in Supplementary Tables S1 and S2. On each study day, all study participants arrived at the German Sport University Cologne in a fasting state in the morning, having fasted for at least 12 h since their last Figure 1.Study design of study A. CK = creatine kinase; IAT = individual anaerobic threshold; PBMC = peripheral blood mononuclear cells; pre-ex = pre-exercise; post-ex = post-exercise. On the evening before each of the three
participants arrived at the German Sport University Cologne in a fasting state in the morning, having fasted for at least 12 h since their last Figure 1.Study design of study A. CK = creatine kinase; IAT = individual anaerobic threshold; PBMC = peripheral blood mononuclear cells; pre-ex = pre-exercise; post-ex = post-exercise. On the evening before each of the three study days, the 17 healthy subjects consumed a standard dinner. The meal consisted of pasta in a tomato cream sauce with zucchini and mozzarella with the macronutrients, i.e., the energy derived from carbohydrates at 56 E%, fat at 30 E%, and protein at 14 E%, based on the recommendations of the German, Austrian, and Swiss nutrition societies (DACH) (see Table were adjusted for the higher needs of athletes [24]. The energy content of the meal was based on the ‘normal’ energy intake of each participant, taking gender, physical activity, and age into consideration. To assess the ‘normal’ energy intake of the participants, two independent 24 h recalls (for one weekday and one weekend day) were performed by a trained nutritionist. The nutritional intake and standardization of the meal were calculated via the computer software EBISpro (Version 2011, Willstätt, Germany). Table 3.Composition of the standardized meal served to the participants on the evening before the intervention day. Meal Components Energy (kcal/100 g) Carbohydrates (g/100 g) Fat (g/100 g) Protein (g/100 g) Fiber (g/100 g) Egg-based pasta 352.3 68.3 2.8 12.3 5.0 Zucchini 19.1 2.0 0.4 1.6 1.1 Onion 28.0 4.9 0.3 1.3 1.8 Olive oil 881.7 0.2 99.6 - - Tomato 17.4 2.6 0.2 0.9 0.9 Cream (10% fat content) 116.6 3.3 10.0 3.1 - Mozzarella 254.8 - 19.8 19.0 - Salt - - - - - Values were determined using the software EBISpro. The results of the 24 h recalls and the values of the energy and macronutrient compo- sition of the standard meal are shown in Supplementary Tables S1 and S2. On each study day, all study participants arrived at the German Sport University Cologne in a fasting state in the morning, having fasted for at least 12 h
the software EBISpro. The results of the 24 h recalls and the values of the energy and macronutrient compo- sition of the standard meal are shown in Supplementary Tables S1 and S2. On each study day, all study participants arrived at the German Sport University Cologne in a fasting state in the morning, having fasted for at least 12 h since their last meal. Upon their arrival, a first blood sample was taken (T0). Subsequently, all the subjects
Description
This study analyzes the effects of sugar-rich apple juice on intestinal barrier function post-exercise.