>Some red seaweeds are anti-methanogenic, particularly the genus Asparagopsis, due to their capacity to synthesize and encapsulate halogenated CH4 analogues, such as bromoform and dibromochloromethane
It cites studies that suggest the mechanism that's so effective in cattle, and presumably the same in humans, is that the seaweed contains a good combination of compounds which inhibit methane production in anaerobic bacteria in the gut.
