hydrogen breath tests (hbt) rafał seredyński, katarzyna

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)