Hydrogen breath test as a simple noninvasive method for evaluation of carbohydrate malabsorption during exercise

Abstract

The aim of this study was to examine hydrogen (H2) production with the hydrogen breath test (HBT) after ingesting primarily digestible carbohydrate (CHO) during 3 h of 75% maximal oxygen consumption exercise. This was done to indicate CHO overflow in the colon which may occur when gastric emptying, intestinal transit and CHO absorption are not matched and CHO accumulates in the colon where it is subject to bacterial degradation. Further, this study was designed to assess breath H2 production as a function of the type of CHO ingested and the type of exercise. A group of 32 male triathletes performed three exercise trials at 1-week intervals with either a semisolid (S) intake, an equal energy fluid intake (F) or a fluid placebo (P). Each trial consisted of cycling (sessions 1 and 3) and running (sessions 2 and 4). The mixed-expired H2 concentrations in the resting and "recovery" periods (5 min after each session) did not change significantly in time and did not differ among intakes. There were also no significant differences in H2 concentrations between resting and "recovery" conditions. During exercise, H2 concentrations decreased three to six-fold in comparison to resting and recovery levels and differed among intakes (ANOVA; P < 0.05). The H2 concentrations were almost continuously lower with P than with F and S. The H2 concentrations were significantly higher during running than during cycling. During exercise, we found that CHO overflow could be compared among intakes and between exercise types by using the HBT, provided the influence of other factors on H2 excretion--ventilation and intestinal blood flow--was similar for each condition.

Systematic review: exercise‐induced gastrointestinal syndrome—implications for health and intestinal disease

“…Carbohydrate malabsorption can be measured by breath hydrogen (H 2 ) excretion after the consumption of glucose and/or fructose that is normally absorbed. During 3 hours of alternating running and cycling at 75% VO 2max , breath H 2 was higher during running than cycling, and consumption of both fluid (1.3 g/kgBM/h) and semi‐solid (1.2 g/kgBM/h) glucose‐rich carbohydrates resulted in higher breath H 2 excretion (increase in 2 and 3 ppm, respectively) compared with a non‐carbohydrate placebo. However, such increases are minimal and of uncertain significance.…”

“…There is also evidence that exercise impairs intestinal nutrient absorptive transport mechanisms leading to malabsorption . Malabsorption of carbohydrates consumed during exercise is commonly seen after endurance running . It is, however, unclear if the mechanisms underlying impaired nutrient absorption are due to intestinal ischaemic injury, down‐regulated intestinal transporter activity, or a combination of both.…”

Gut-training: the impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance

“…Breath samples were analysed in duplicate (coefficient of variation: 5.6%) for hydrogen content using a gas sensitive analyser (Breathtracker Digital Microlyzer, Quintron, Milwaukee, Wisconsin, US) (Peters et al 1994). Whole blood haemoglobin and haematocrit values were used to estimate changes in plasma volume relative to baseline and to correct plasma variables, as previously reported .…”

Two weeks of repetitive gut‐challenge reduce exercise‐associated gastrointestinal symptoms and malabsorption

“…Interest in food 17 (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26) 42 .110 11 (9-39) 17 .237…”

“…15,16 Recent preliminary data have clearly shown evidence of exacerbated gastrointestinal symptoms and carbohydrate malabsorption (≥10 ppm breath H 2 increase vs baseline) in response to a carbohydrate challenge during prolonged running 17,18 and supports previous observations of carbohydrate malabsorption during endurance exercise using a semi-solid and liquid carbohydrate formulation. 19 Moreover, considering exercise has the potential to interfere with intestinal carbohydrate transportation, 20 it has recently been suggested that malabsorbed nutrients reaching the ileum, which are subject to bacterial degradation (ie, fermentable monosaccharides such as fructose), may promote lower-gastrointestinal symptoms through increased colonic content (ie, H 2 O, H 2 , CH 4 , CO 2 and H 2 S) and pressure. 21,22 But may also suppress gastric emptying and duodenal-jejunum motility via the "ileal brake" feedback mechanisms, 23 thus potentially exacerbating upper-gastrointestinal symptoms.…”