is a naturally occurring yeast that flourishes in moist areas, such as the digestive tract, the vagina, and skin folds. Ordinarily, its population is kept in check by bacteria that live in the same areas. When normal bacteria are disturbed by antibiotics, however, yeast populations can grow to abnormally high levels.
For women, the most common form of excess
vaginal yeast infection
, as marked by itchiness, redness, burning on urination, and a yeasty odor.
can also overpopulate in the mouth (thrush), in the warm moist environment under a diaper (diaper rash), and in other areas.
usually confines itself to the surface of mucous membranes and does not penetrate deeply into the body. However, in people whose immune systems are severely depressed, such as those with AIDS or leukemia,
can become a dangerous, invasive organism. The medical name for this rare and dire condition is
Besides this official meaning,
has another meaning that was coined in the world of alternative medicine. As used there, it is a loose term connoting a whole syndrome of symptoms proposed as related to candida overgrowth. Equivalent terms are
yeast hypersensitivity syndrome
or just plain
Conventional medicine does not recognize this alternative use of the term
as valid. However, for several years it was practically impossible to walk into an alternative practitioner's office and not walk out with the diagnosis of candida. Fortunately, this excess enthusiasm has cooled in recent years.
The story of "the yeast syndrome" begins in 1983, when Orion Truss published
The Missing Diagnosis.
This was followed by William Crook's much more famous
The Yeast Connection.
These books claim that a person who is chronically colonized by too much
may develop an allergy-like hypersensitivity to it. The symptoms of this allergy are said to be similar to those of other allergies, including sinus congestion, fatigue, intestinal gas, difficulty concentrating, depression, muscle aches, and many other common complaints.
The regimen outlined by Dr. Crook consists of two parts: treatments that tend toward diminishing the total body burden of
candida, and less convincing recommendations that attempt to lessen allergic reactions toward yeast in general.
To decrease the amount of yeast in the body, Dr. Crook recommended avoiding certain substances, including antibiotics, corticosteroids, birth control pills, sugar, and most sweet foods. (It is his contention that dietary sugar "feeds yeast.") He also recommended the use of various supplements and even strong prescription drugs to directly kill yeast or at least interfere with its growth.
Next, Dr. Crook recommended avoiding foods containing yeast of any type, for he believed that those who are allergic to
will also be allergic to other members of the fungus family. Thus Dr. Crook forbade fermented foods, such as beer, cheese, breads containing baker's yeast, tomato paste (which has a significant mold content), and even mushrooms.
Some evidence suggests that individuals diagnosed with this condition do not in fact have excessive growth of
in the digestive tract.
Nonetheless, one study suggests that antifungal treatment might provide some benefits, perhaps through effects on other yeasts. This 4-week, double-blind, placebo-controlled study of 116 individuals with symptoms believed to be characteristic of the yeast syndrome evaluated the effects of treatment with the antifungal drug nystatin.
The results showed that treatment with nystatin modestly improved overall symptoms as compared to placebo. In addition, some participants voluntarily undertook a sugar and yeast-free diet, and reported even better results; how much of this latter effect was due to the power of suggestion cannot be determined. A previous study of 42 women failed to find benefit with nystatin, but the study design was somewhat convoluted.