Saccharomyces cerevisiae

Since ancient times, this form of yeast has been used in brewing and baking and can also be found in human bodies acting as a sort of probiotic. Research has suggested that it originated on the skin of grapes (think of it as a kind of mould!).

Through fermentation, Saccharomyces cerevisiae helps to turn sugars into carbon dioxide and alcohols. While found in the human intestine, it is not thought to cause major issues to humans unless severely ill or immunocompromised. It is mainly used for industrial purposes such as beer and wine making and baking. It can also be known as:

• baker's yeast

• brewer's yeast

• ale yeast

• top-fermenting yeast

• budding yeast

It is also the main form of nutritional yeast and yeast extract.

Candida Albicans

This yeast is commonly found in the human gut and is known to cause the human infection, Candidiasis, when there is an overgrowth in the body. It doesn't just appear, it is always present in low amounts within the gastrointestinal tract and mouth. It is responsible for those itchy yeast infections, known as thrush, when there is an overgrowth.

The human body needs some amount of Candida in the body to help with digestion and nutrient absorption. Within the gastrointestinal tract however, it can cause havoc and produce symptoms such as bloating, indigestion and gas among others when there is a lot of the yeast present. The human body is naturally very good at using bacteria to keep candida under control however, there are occasions where it can become out of control such as:

• Taking antibiotics: this is due to the antibiotics not only killing off "bad" bacteria from another infection but also "good" bacteria causing an imbalance

• Diets high in sugar and carbs: more on this later

• High alcohol consumption

• Weakened immune system

• Diabetes

• High levels of stress