Hydrogen breath tests (HBT)
Background
Nowadays, human gut microflora is considered a key regulatory factor of numerous
physiological and pathological processes. Its quality and quantity disturbances (dysbioses) are linked to the development of diabetes, gut
inflammation, cancers, asthma, coronary artery disease, and many others.
Background
Gut microbes are also found related to the fat tissue distribution and the development of
obesity, including connections with insulin and leptin resistance.
Background
Bacterial metabolites, including short-chainfatty acids, play role in the blood pressure
regulation. Receptors for these metabolites are located in vascular endothelium, sympatheticganglia and on the surface of carotid glomus cells; their stimulation affects the blood flux,
renal filtration intensity and muscle sympathetic nerve activity.
Basics
Hydrogen is only generated during anaerobic metabolism.
As the human body at rest does not have anaerobic metabolism, all the exhaled
hydrogen originate from anaerobic bacteria.
Basics
Anaerobic bacteria prefer to metabolize sugar molecules, which, as part of fermentation
reaction, are initially broken down into short-chain fatty acids (SCFA), carbon dioxide and
hydrogen.
Hydrogen generated in the intestine ends up in the bloodstream, and then is transported to
the lungs and excreted as part of exhaled breath.
Basics
Hydrogen level measured in the exhaled air reflects the quantity and the metabolic activity
of anaerobic bacteria in the gut.
Bacterial concentration
Small intestine 102 – 105 CFU#/ml
Large intestine 1015 CFU#/ml
CFU – colony forming unit#
Basics
If the bacterial concentration in small intestine exceeds 105 CFU/ml, we speak of a small intestine bacterial overgrowth
(SIBO).
Types of hydrogen breath tests:
→ glucose load test (GLT)→ lactose tolerance test (LTT)→ lactulose breath test (LT)→ fructose tolerance test (FTT)→ sorbitol tolerance test (STT)→ xylitol tolerance test (XTT)
Comparison:glucose load test vs lactulose
breath test
Lactulose breath test: example results
HBT contraindications:
→ hereditary fructose intolerance→ hypoglycaemia→ administration of antibiotics (in the last
month)→ colonoscopy (in the last month)
HBT: preparations
One week prior to test
→ no stool hardeners/softeners→ no supplements containing fructose or
lactose→ no fiber supplements→ avoid pre- and probiotics→ avoid PPI (proton pump inhibitors) and
hydrogen blockers
Three days prior to test– foods to avoid:
→ grains and cereals→ milk and dairy products
→ fruit and fruit derivatives→ vegetables
→ nuts, seeds and beans→ any foods containing high fructose corn
syrup (ketchup, mustard, mayo…)
12 hours prior to test
→ fasting – nothing should be consumed apart from water
→ exercises should be avoided
Day of test
→ do not take any medication→ no smoking→ no exercise
→ no chewing gum→ brush teeth thoroughly 2h before the
test
How to conduct HBT?
HBT measurements are always conducted on a a sitting subject
(hydrogen is distributed differently depending on the body position).
(1) Volunteers rinse mouth with a fluid containing chlorhexidine1.
(2) Volunteers give a basal breath:at first, they need to hold their breath for
15 seconds (without any deeper inspiration before);
then, they exhale slowly and completely via the device.
1 to reduce oral bacteria fermentation
� 10 g of glucose in 200 ml of water(for GLT)
� 10 g of lactulose in 200 ml of water(for LT)
� 25 g of lactose in 200 ml of water(for LTT)
(3) Subsequently, each volunteer isrequired to drink a substrate solution:
(4) After substrate administration, volunteers once again rinse their mouth
with chlorhexidine fluid.(5) Volunteers give subsequent breaths after 30, 60, 90, 120 and (optionally)
150 minutes, according to the instructions on the previous slides.
(6) Obtained results can be plotted with Microsoft Excel or the HBT device
dedicated software.
Interpretation of the results
Glucose load test: indications
→ suspected SIBO→ exocrine pancreatic insufficiency
→ cirrhosis of the liver→ irritable bowel syndrome
→ intolerance of sugar and sweets
Glucose load test: interpretation
Any increase of more than 10 ppm above the basal value is to be considered as significant
regarding the bacterial overgrowth of the proximal part of the small intestine.
No increase in hydrogen level indicates the lack of SIBO, but can be also related to the
bacterial overgrowth of the distal part of the small intestine (false-negative result).
Lactulose breath test: indications
→ establishing oro-cecal transit time2
→ establishing non-hydrogen-producers→ suspected SIBO
→ investigation of constipation
2 according to the current recommendations, however, the reference
method is scintigraphy of the GI tract
Lactulose breath test:”non-hydrogen-producers”
Lactulose is a non-absorbable disaccharide and should therefore always lead to the
increase in hydrogen level. If no increase is obtained within 120 minutes, a subject is
classified as non-hydrogen-producer.
The lack of hydrogen production can be due to a predominance of methanogenic bacteria,
metabolizing hydrogen to methane.
Lactulose breath test: oro-cecal transit time
Normally, lactulose reaches the large intestine within 70 to 90 minutes; in this
timeframe, the hydrogen level should increase at least 20 ppm above the basal
value.
Extended oro-cecal trasit time is a sign of disturbed motility affecting the entire
digestive system.
Lactulose breath test: SIBO
Test results are considered positive, if:
ΔH2$ [ppm]
Lack of symptoms 10Presence of symptoms$$ 5
$$ abdominal pain, bloating, constipation, diarrhea
$ increase in hydrogen level above basal value within 30 minutes of the test
Lactose tolerance test: interpretation
Bibliography (1)→Ugidos-Rodriguez S., Matallana-Gonzalez M.C., Sanchez-Mata M.C.
(2018) Lactose malabsorption and intolerance: a review. Food and Function, 15;9(8): 4056-4068.
→Pawłowska K., Seredyński R., Umławska W., Iwańczak B. (2018) Hydrogen excretion in pediatric lactose malabsorbers: relation to symptoms and the dose of lactose. Archives of Medical Science, 14(1): 88-93.
→Marques F.Z., Mackay C.R., Kaye D.M. (2018) Beyond gut feelings: How the gut microbiota regulates blood pressure. Nature Reviews Cardiology 15(1): 20-32.
→Koliada A., Syzenko G., Moseiko V., Budovska L., Puchkov K., Perederiy V., Gavalko Y., Dorofeyev A., Romanenko M., Tkach S., Sineok L., Lushchak O., Vaiserman A. (2017) Association between body mass index and firmicutes/bacteroidetes ratio in an adult ukrainian population. BMC Microbiology 17(1): 120.
→Yang T., Santisteban M.M., Rodriguez V., Li E., Ahmari N., Carvajal J.M., Zadeh M., Gong M., Qi Y., Zubcevic J., Sahay B., Pepine C.J., Raizada M.K., Mohamadzadeh M. (2015) Gut dysbiosis is linked to hypertension. Hypertension (Dallas, Tex : 1979) 65(6): 1331-1340.
→Ledochowski M., Ledochowski L. (2011) Hydrogen breath tests. Akadmed-Verlag, Akademie fur Ernahrungsmedizin GmbH, Salzburg-Innsbruck, Austria.
Bibliography (2)