Abstract
Deuterium is a natural heavy isotope of hydrogen, having a neutron as well as a proton. Deuterium disrupts ATP synthesis in mitochondria, causing increased production of reactive oxygen species and reduced synthesis of ATP. Gut microbes likely play a significant role in providing deuterium depleted short chain fatty acids (SCFAs) to human colonocytes through hydrogen gas recycling. The production of deuterium depleted (deupleted) nutrients necessarily leaves behind deuterium enriched water, unless there is a process that can sequester deuterium in small molecules that are excreted through the feces. Here, we provide evidence that a small number of classes of uniquely structured carbon-nitrogen rings and bis-allylic carbon atoms in certain biologically active small molecules may play a crucial role in sequestering deuterium for export into feces or urine. Specifically, we have identified the imidazole ring present in histidine, histamine, and microbial derivatives of histidine, the tetraterpenoid lutein, bilirubin and the derivatives urobilinogen and stercobilinogen produced by gut microbes, and the bis-allylic carbons in polyunsaturated fatty acids as likely candidates for sequestering deuterium and thereby reducing the deuterium levels in the water-based medium. Normally, carbon atoms never exchange their bound protons with deuterons from the medium, but all the above classes of molecules are important exceptions to this rule, as has been shown experimentally.