Eating yeast will make you healthy

Partly true. The yeast used by brewers and bakers is called Saccharomyces cerevisiae, which uses sugar to produce carbon dioxide and alcohol. Flavoursome compounds are also produced. This single-cell fungus is rich in nutrients, especially water-soluble vitamins, like thiamin and folic acid, and some trace elements, like zinc and copper. The yeast contributes to the nutritional quality of a product like bread or beer.

Alone, yeast is nothing but cells and their nuclei - there is no intervening tissue, as in a plant or animal. This means that the relative concentration of material from the nuclei, like nucleic acid and purines, is high. As a consequence yeast can increase the production of uric acid, the gout factor, after it has been eaten. This usually does not matter, since the body's capacity to handle it is adequate. Moreover, the associated alcohol in beer, for example, causes relatively more uric acid production in the body than would the nucleic acid from yeast.

Much has been written about food sensitivity arising from yeast. A few people may be sensitive to yeast. However, sensitivity to yeast has been confused with a yeast-like infection, Candida, which occurs in people from time to time. There is no good evidence that yeast sensitivity leads to candidiasis or that excluding yeast from the diet helps control the infection. Increasingly, many people are being diagnosed as having candidiasis. Candidiasis, when it occurs, may present as thrush in the mouth, balanitis (whitish material about the glans of the penis), as a vaginal infection, or sometimes affect fingernails or toenails. The situations in which these infections occur are mostly where the body's immune defence is not functioning well - as in a person with newly diagnosed or poorly controlled diabetes, or someone given treatment to deliberately suppress the immune system. It is unlikely that food intake contributes significantly to the development of candidiasis.