Studies on breath methane: the effect of ethnic origins and lactulose.

Abstract

SUMMARY The prevalence of methane production in an adult population of 256 subjects was 41%, but it was significantly higher in females (49 %), than males (33 %). When the population was subdivided into ethnic groups, Caucasians (48 %) and Blacks (45 %) had significantly more methane producers than Orientals (24%) and Indians (32 %). When the ethnic groups were analysed by sex, female Caucasians had the highest prevalence (58 %), significantly more than Caucasian males, Oriental males, and females and Indian males. In contrast with previous studies, a single dose of lactulose was found to significantly increase breath methane concentrations in six out of 12 methane producers, but not in 25 non-methane producers from the population study. In conclusion, any studies on breath methane must take into consideration the ethnic origin of the subjects and, contrary to previous advice, substrate intake, especially undigestible carbohydrates. Furthermore, a single breath sample may miss up to one-fifth of methane producers.A proportion of intestinal methane produced by anaerobic methanobacteria in the colon is excreted into the breath.' In one series methane was found in the breath in only one-third of a population of 280 adults.' There appeared to be a familial tendency and environmental factors were also thought to play a part. The ingestion of non-absorbable carbohydrates, such as lactulose and raffinose,' 2 appeared not to influence methane production. In this paper we report a study on the prevalence of methane production in a population consisting of four different ethnic groups, together with the acute effect of a single dose of the non-absorbable disaccharide, lactulose, on methane production. Methods SUBJECTSThe pulmonary excretion of methane was studied in a population of 256 healthy volunteers from the staff of two hospitals. The subjects were enrolled by two of us (PP, MFB) touring wards and laboratories asking for volunteers. One hundred and eighteen *Address for reprint requests: Dr L M Blendis, 9th Floor, Eaton Wing, Toronto General Hospital, 585 University Avenue, Toronto, Ontario, M5G 1L7, Canada.Received for publication 29 July 1980 were male and 138 female, with ages ranging from 19 to 59 years with an average of 34 years. None of these subjects was taking antibiotics or laxatives for at least seven days before the sampling. The group was investigated as a whole and then divided into subgroups according to their ethnic origin. This was established by the ethnic characteristics of their appearance and their place of birth. Only three of the 256 subjects (Indians) were related. Duplicate endexpiratory breath samples were collected via a modified Haldane-Priestly tube into 20 ml plastic syringes attached to the side arm of the tube by a three-way stopcock.3 The methane content of both syringes was measured by gas chromatography, using a Carle AGC-311 equipped with a hydrogen flame detector. Breath components were separated at room temperature on a 2 m X 6-10-3 m (length X inner diameter) column, packed ...

Dose dependence of breath hydrogen and methane in healthy volunteers after ingestion of a commercial disaccharide mixture, Palatinit®

“…CH, exhalation occurs at relatively constant rates (Bond et al 1971 ;Tadesse & Eastwood, 1978;Pitt et al 1980;Tadesse et al 1980;Bjnrneklett & Jenssen, 1982), as was also observed in the present investigation ( Fig. 3(a)) during 10 h when no sharp meal-related peak was found.…”

Pan-genome of the dominant human gut-associated archaeon, Methanobrevibacter smithii , studied in twins

“…Methane excretion phenotyping of 274 Australian families containing adolescent twin pairs indicated that environmental exposures play a deterministic role in methanogen carriage, with similar concordance and correlations between MZ and DZ co-twins, and less concordance between parents and their offspring (17). As in other studies (18), more females than males had positive methane breath tests. Studies of intergenerational transfer of a positive methane excretion phenotype in rats demonstrated the critical effects of environmental factors during the weaning period; however, colonization through adulthood varied between strains of rats (17), suggesting that host genetic factors affect carriage.…”

Shared and unique environmental factors determine the ecology of methanogens in humans and rats

“…A female bias (p ϭ 0.012) for methanogenesis (63% females vs 37% males), which has been found in most studies (6,17,21,22,32), is unlikely to be a chance finding. The modeling, although distinguishing genetic and environmental effects within same sex subjects, cannot discriminate between genetic and behavioral effects that associate with the Y chromosome (or conversely with the X chromosome).…”