Según una nueva investigación publicada en Journal of Clinical Endocrinology & Metabolism, el contenido de la respiración de una persona podría indicar su grado de susceptibilidad para ganar peso y acumular grasas.

Los resultados apuntan que las personas cuya respiración contiene altas concentraciones de hidrógeno y metano tienen mayor riesgo de tener un índice de masa corporal y un porcentaje de grasas mayores. La presencia de los dos gases señala la presencia de un microorganismo que favorece la obesidad.

Cuando el microorganismo M. smithii coloniza en tracto digestivo, la persona exhala grandes cantidades de hidrógeno y metano. Estudios previos demostraron que el M. smithii es el microorganismo predominante en tracto gastrointestinal responsable de la producción de metano.

"Normalmente, los microorganismos que habitan en el tracto digestivo se presentan en equilibrio y beneficia a la persona convirtiendo los alimentos en energía", comentó Ruchi Mathur, director del Departamento de Endocrinología del Centro Cedars-Sinai de Los Ángeles y autor principal del estudio. "Sin embargo, cuando este microorganismo aparece en exceso, puede alterar este equilibrio y provocar un aumento de peso y una mayor acumulación de grasa en el huésped".

Para la investigación, los científicos analizaron la respiración de 792 personas estableciendo cuatro patrones básicos: sujetos con respiración normal, con altas concentraciones de metano, con altas cantidades de hidrógeno y los que tenían tasas elevadas de ambos gases. Aquellas cuyos análisis respiratorios mostraron niveles elevados de los dos gases, tuvieron tendencia a presentar índices de masa corporal más altos y mayores porcentajes de grasa corporal.
marzo 27/2013 (Diario Médico.com)

R. Mathur, M. Amichai, K. S. Chua, J. Mirocha, G. M. Barlow, M. Pimentel. Methane and Hydrogen Positivity on Breath Test Is Associated With Greater Body Mass Index and Body Fat. The Journal of Clinical Endocrinology & Metabolism 2013, doi: 10.1210/jc.2012-3144.

Resumen:

Context: Colonization of the gastrointestinal tract with methanogenic archaea (methanogens) significantly affects host metabolism and weight gain in animal models, and breath methane is associated with a greater body mass index (BMI) among obese human subjects.

Objective: The objective of the study was to characterize the relationship between methane and hydrogen on breath test (as a surrogate for colonization with the hydrogen requiring methanogen, Methanobrevibacter smithii), body weight, and percent body fat in a general population cohort.

Design and Subjects: This was a prospective study (n = 792) of consecutive subjects presenting for breath testing.

Setting: The study was conducted at a tertiary care center.

Outcome Measurements: BMI and percent body fat were measured.

Results: Subjects were classified into 4 groups based on breath testing: normal (N) (methane <3 ppm and hydrogen <20 ppm at or before 90 minutes); hydrogen positive only (H+) [methane <3 ppm and hydrogen =20 ppm); methane positive only (M+) (methane =3 ppm and hydrogen <20 ppm), or methane and hydrogen positive (M+/H+) (methane =3 ppm and hydrogen =20 ppm]. There were significant differences in age but not in gender across the groups. After controlling for age as a confounding variable, M+/H+ subjects had significantly higher BMI than other groups (N: 24.1 ± 5.2 kg/m2; H+: 24.2 ± 4.5 kg/m2; M+: 24.0 ± 3.75 kg/m2; M+/H+: 26.5 ± 7.1 kg/m2, P < .02) and also had significantly higher percent body fat (N: 28.3 ± 10.0%; H+: 27.5 ± 9.0%; M+: 28.0 ± 8.9%; M+/H+; 34.1 ± 10.9%, P < .001).

Conclusions: The presence of both methane and hydrogen on breath testing is associated with increased BMI and percent body fat in humans. We hypothesize that this is due to colonization with the hydrogen-requiring M smithii, which affects nutrient availability for the host and may contribute to weight gain.