[Shawna]

Betsy wrote
“Can you tell me the difference between brewer’s yeast and yeast culture; and how they differ from the type of yeast that that makes up a yeast overgrowth?”

Brewers yeast and nutritional yeast are made from the same strain of yeast, Saccharomyces cerevisiae, but are grown on different mediums. Brewers yeast is a by-product from the brewing industry and is said to have a bitter or “yeasty” taste. Nutritional yeast is often grown on molasses and is described to have a nutty or cheesy taste. Depending on what they are grown on will vary the nutritional content of the final product to a degree. The yeast in these products are deactivate (killed) so they can not colonize the system.

It is my understanding that it is the deactivation process that frees the amino acids and creates the MSG like issues in these supplements. Fermentation, which is what the yeast does to the sugar mediums they are grown on, also creates some freed glutamic and aspartic acids. I think the amounts are relatively small but because freed glutamic and aspartic acids bioaccumulate, when added to other sources it definitely could be enough to cause illness. For those that are sensitive to MSG or aspartame, I would avoid nutritional and brewers yeasts.

There are also a few types of yeast that are considered probiotics Saccromyces boulardi is one and can be found in some probiotic products. Saccromyces is a “non-colonizing” yeast.

Candida yeast is the type that are normal to the colon and can grow out of proportion when the good bacteria are not in correct proportion.

There is another type of yeast, Malassezia, that grows on a dogs skin when the immune system is not up to par. I beleive Malassezia can infect the ears as well.