Yeast in the Digestive System

[Charlotte_0'Neil]

Yogurt contains bacteria that are good for you. They create B vitamins
in the intestines, which can be absorbed into the bloodstream. So, it
is given fact that microorganisms can survive in the human digestive
tract, and that humans can absorb the products that the microorganisms
produce. Eat yogurt and you are a symbiot with bacteria.

OK -- so what about the micro-organisms in ale? There's always some
live yeast swimming around in real ale. Yeast eats sugar and produces
Vitamin C and other esters, and quinones. So why shouldn't that yeast
continue to eat sugar when it's inside you, and continue to produce
Vitamin C and other vitamin-like substances? I know it sounds bizarre
to suggest that you can drink beer with your candy bar and the beer
will turn the sugar into Vitamin C, but I can't figure out where there
is any problem with that scenario.

It is true that yeast will reproduce other yeast in the presence of
oxygen, and not make alcohol and vitamins, but whatever small amount of
oxygen you gulp in with your food will be quickly used up by the yeast
and once the oxygen is gone, they will start making vitamin C and
esters and quinones.