The effect of a low fibre diet on the lactose hydrogen breath test
Research type
Research Study
Full title
Determining the significance of elevated baseline hydrogen levels in relation to the pre-test diet for the lactose hydrogen breath test
IRAS ID
241435
Contact name
Elisa Skinner
Contact email
Sponsor organisation
Salford Royal NHS Foundation Trust
Clinicaltrials.gov Identifier
N/A, N/A
Duration of Study in the UK
1 years, 0 months, 0 days
Research summary
The lactose hydrogen breath test is commonly used to diagnose lactose intolerance. Primary lactase deficiency is a condition where there is a depletion of the enzyme lactase in the small bowel which breaks down lactose to absorbable products. If lactose enters the large bowel (colon) it is fermented by bacteria which produce hydrogen as a result of this process. The majority of hydrogen freely diffuses into the blood and can be measured in expired air using a hand-held device containing an electrochemical sensor which detects hydrogen. The amount of hydrogen detected is representative of the level of hydrogen produced by bacteria in the large bowel. Foods that are high in fibre are fermented by colonic bacteria and produce hydrogen. In current practice, although this can differ between trusts, patients are advised to adhere to a low fibre (reduced intake of fermentable, non-absorbable carbohydrates) diet one day before the test, plus a 12 hour fasting period, however this does not always produce a low baseline hydrogen level. A low baseline hydrogen level is essential for correct interpretation of the breath test results. This often means that the test cannot be performed until the possibility of small intestinal bacterial overgrowth has been ruled out as a cause of the elevated breath hydrogen level. This is costly and inconvenient for the patient. This study aims to assess the significance of the duration of the pre-test diet on baseline hydrogen levels. Patients attending for a lactose hydrogen breath test will be randomly assigned to follow either a one day, two day or three day low-fibre diet prior to the test. The study will include 30 patients in total (10 per group). Correlation between bowel movement frequency and stool consistency (assessed by questionnaires), and baseline hydrogen levels will also be assessed.
REC name
North East - Newcastle & North Tyneside 1 Research Ethics Committee
REC reference
18/NE/0131
Date of REC Opinion
3 May 2018
REC opinion
Favourable Opinion