Abstract:
Background: Fructose is a simple sugar found naturally in fruits, vegetables and honey.
Fructose and glucose together constitute sucrose sugar, commonly used to sweeten everyday
food and beverages. Unlike glucose, the ability to absorb fructose varies between individuals
and the mechanism behind this is unclear. Hydrogen breath testing is a non-invasive method
used to diagnose individuals by their fructose absorption capacity. Understanding the
variability in fructose absorption, relationships between fructose absorption capacity, dietary
behaviour and anthropometry could be characterised.
Aim: To investigate the variability in fructose absorption in healthy school children over two
years and characterise the relationships between fructose absorption, anthropometry (fat
composition and BMI), and dietary intake.
Methods: Participants provided breath samples at baseline and every 15 minutes after
ingesting 25 g fructose solution for 105 minutes. Two hydrogen breath tests took place on
separate occasions by the same participants (n = 93) 5 – 6 months apart. Anthropometric
measurements, including height, weight, waist circumference, % fat mass, and BMI were taken,
and dietary data were collected via the Monash Comprehensive Nutrition Assessment
Questionnaire. A secondary study of three weekly hydrogen breath tests took place involving
a small sample size (n=11). Data were analysed using non-parametric unpaired t-tests and
paired t-tests. Statistical significance was set up as p < 0.05.
Results and Discussion: There were more fructose absorbers (60.7%, n = 88) than nonabsorbers (39.3%, n = 54) in the first test. Absorbers had greater % fat mass (p < 0.0068), waist
circumference (p < 0.0035) and BMI (p < 0.0053). Furthermore, absorbers consumed greater
excess fructose (p < 0.0127), galacto-oligosaccharide (p < 0.0083) and fructo-oligosaccharide
(p < 0.0130). Of the 93 participants, 35 participants (37.6%) showed a change in fructose
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absorption status when comparing test 1 and test 2. In the secondary test, 4 participants (36.4%)
changed fructose absorption status at least once during the three tests. There were no significant
changes in the participants' characteristics that could explain the fructose absorption status
change.
Conclusion: Inter-individual variability in fructose absorption is seen in healthy school
children. A notable proportion of individuals also change fructose absorption capacity on a
week-to-week basis. However, the mechanism behind these findings remains unclear. Further
research involving larger groups undertaking week-to-week (ideally day-to-day) fructose
testing is needed to confirm these findings, and daily dietary intake assessments are required
to identify the potential cause of the change in fructose absorption status.