A yeast for all reasons or is candidiasis the hidden enemy?

A yeast for all reasons or is candidiasis the hidden enemy?

Carole A. Palmer

Increasing interest and concern about women’s health issues in this country have led to an upsurge in nutritional remedies that are reported to cure various female complaints. One such common gynecologic problem is vaginal yeast infection (candidiasis) caused by Candida albicans (monilia). This is not the same type of yeast that is used to leaven bread, a critical point to consider in assessing the validity of “yeast connections” to food. More than half of all women suffer from vaginal yeast infections at some time in their lives, and about 10% have frequent recurrences.


C. albicans is a yeast microorganism, spread from person to person, that is found in warm, moist areas of the body, usually at harmless levels and with no ill effects.

Half of all adults have C albicans in their gut or oropharynx, 5% as part of their skin flora, and a fifth of all women–and even more pregnant women–have C. albicans in their vaginal flora. Candida infection is most common among diabetics, pregnant women, oral contraceptive users, individuals being treated with glucocorticoids and antibiotics and persons with immunosuppressive disease.

Overgrowth of C. albicans may occur in the vagina,usually because the secretions bathing these mucosal surfaces contain higher than normal amounts of glucose and glycogen, which serve as food for yeast cells. This happens in diabetes, during pregnancy and among individuals taking oral contraceptives or glucocorticoids. Also, when high doses of broad spectrum antibiotics are used, normal bacterial flora such as vaginal Lactobacillus are suppressed, and more nutrients are available for the candida.

If both Candida overgrowth and a break in the mucocutaneous surfaces occur together, the infection may reach the bloodstream and become invasive. The lactobacilli that normally grow in the vagina antagonize Candida overgrowth, but if they are eliminated, the Candida can grow freely (Redondo-Lopez et al., 1990). If immune response is severely compromised, as it is in acquired immune deficiency syndrome or during some types of chemotherapy, yeast infection may spread throughout the body (Schwab, 1991).

The symptoms of vaginal yeast infection include itching and irritation of the vagina and burning upon urination. However, about a third of women who have yeast infections exhibit no symptoms and may go untreated (McCormack et al., 1988).


The best protection against C. albicans is a normally functioning immune system and intact mucosal defenses. The usual treatment of vaginal candidiasis is to correct the underlying condition predisposing to overgrowth and invasion by such measures as stopping broad-spectrum antibiotic use or controlling the causes of hyperglycemia and by chemotherapy to treat the Candida itself. The chemotherapy is typically applied to the vaginal area or affected skin in a cream or lotion containing nystatin, clotrimazole or miconazole.

If the yeast infection does not respond to topical therapy, systemic therapy is employed, using drugs such as ketoconazole, fluconazole or amphotericin B (Rubin, 1986).

Many other treatments, both traditional and nontraditional, have been proposed to relieve the discomfort of yeast infections. However, victims often find conventional medical approaches ineffective. In pursuit of relief, they may embrace home remedies, some of which involve diet.

Although dietary approaches to treating candidiasis are not new, one which has become quite popular in recent years is the yeast-free diet. This dietary approach received a boost in popularity when William G. Crook, M.D. first published The Yeast Connection in 1983. He aggressively promoted the book in seminars and interviews. It is now in its 3rd edition and 16th printing, and has sold close to a million copies (Schwab, 1991).

Crook claims that a sugar-free (lacking food for the yeast), yeast-free diet (lacking a dietary source: of the offending organism) along with antifungal medications such as oral or topical nystatin (Mycostatin) or ketoconazole (Nizoral) will cure most, if not all, yeast infections. Further, he asserts that C albicans infections and the “candidiasis hypersensitivity syndrome” play a far greater role in causing human illness than has been previously recognized. Crook is one of several “clinical ecologists” who claim that yeast infections are a hidden pathogen causing the syndrome. Further, they hold the view that this syndrome is an underlying cause of “environmental hypersensitivity” or “immune system dysregulation” (Barrett, 1987a).

Dr. Crook asserts that Candida infections are associated with, if not directly responsible for, a wide array of medical problems. Indeed, it seems that there is a “yeast for all reasons.” To enthusiasts, these reasons include: urinary tract infections, multiple sclerosis, headaches, fatigue, digestive and respiratory disorders, joint pain, menstrual disorders, bladder and urinary infections, arthritis, schizophrenia, premenstrual syndrome, sexual dysfunction, suicidal depression and mitral valve prolapse.

In Crook’s book, he also claims that w. omen with yeast infections may be at increased risk of developing adverse reactions to some chemical odors, additives and to silver/mercury dental fillings. He also links these yeast infections with increased risk of complications from AIDS. He asserts that yeast infections of the gastrointestinal tract may play a role in the development of psoriasis (Rosenberg et al., 1983), of mood and behavior disorders and alcoholism (Iwata, 1976). In Crook’s view, the role of yeast infections is so pervasive and significant that if only others would embrace his views on the importance of yeast-associated illnesses, the advance in health science would be so great that in a hundred years this view of C. albicans as an infectious agent would be regarded as a medical revolution.


The rationale proposed for the connection between yeast and these multiple diseases is based upon a valid and recognized association between immune function and opportunistic infections. In fact, yeast infections are often able to take hold when the immune system becomes impaired. Such impairment may arise from disease, infection with other organisms or disease, or as a result of antibiotic therapy. Crook postulates that this immune system depression then allows overgrowth of C. albicans and that toxins are produced as a result (Schwab, 1991). Supposedly, the toxins. further suppress immune function and predispose the individual to recurrent infection (Crook, 1989). Crook claims that yeast overgrowth is stimulated not only by immunosuppression but also by sugar in the diet (which presumably appears in mucosal secretions), birth control pills, cortisone and other drugs. Sugar consumption, nutritional deficiencies and exposure to molds and chemicals such as tobacco, perfume, petrochemicals and formaldehyde are other factors he claims further compromise immune function. This results in additional medical problems including allergies and other adverse reactions. The vicious cycle allegedly continues when these allergies cause further disease and infection, and these in turn may require more antibiotic therapy. Figure 1 is a diagram of the interactions claimed. Promoters of the Candida hypersensitivity theory claim that even when signs of infection are absent, the yeast can cause or trigger multiple symptoms. Indeed, they report that 30% of Americans suffer from candidiasis hypersensitivity (Barrett, 1987b).


To manage C. albicans overgrowth, Crook advocates the use of antifungal therapy, herbs and special supplements and a sugar-free, yeast-free dietary regimen among other measures. Foods to be avoided are those that either contain yeast or mold or are high in sugar and thought to stimulate yeast growth. The list of “forbidden foods” includes yeast-risen bread, sugar, cheese, mushrooms, white flour and milk. In addition, sufferers are urged to supplement the yeast-free diet with garlic capsules, linseed oil, evening primrose oil, Lactobacillus acidophilus and antioxidant vitamins and mineral supplements.

Other Proposed Anti-C. albicans Therapies Involving Food and Diet. In addition to proponents of the yeast connection, other individuals suggest less extensive manipulations of dietary intake to control vaginal yeast infections. Such recommendations include eating garlic to “kill” the yeast, drinking cranberry juice in the hopes that so doing will acidify the urine and decrease yeast growth and using yoghurt douches to change the acidity of the vaginal milieu.

Candidiasis Hypersensitivity Syndrome: Myth or Reality? The medical community is dubious about the candidiasis hypersensitivity syndrome (Bennett, 1990). Although experts agree that vaginal candidiasis exists, most question the existence of a far-reaching candidiasis hypersensitivity syndrome. First, the syndrome lacks precise definition. Signs and symptoms attributed to it are nonspecific and overlap with those of many other disorders. Moreover, the proponents of the syndrome have not published findings that are rigorous enough to be accepted in peer-reviewed medical journals. To date, prospective randomized studies that eliminate other possible causes and control for placebo effects have not been attempted. Proponents of the syndrome thus rely heavily on anecdotal evidence, which is notoriously unreliable. The assertions that dietary sugar intake encourages vaginal yeast proliferation and that yeast itself weakens the immune system enough to cause multiple organ system damage are also unsupported (Bennett, 1990). Table 1 lists some of the concerns of the Practice Standards Committee of the American College of Allergy and Immunology (Journal of Allergy and Clinical Immunology, 1986). At present the treatment of the candidiasis hypersensitivity syndrome using Crook’s diagnostic laboratory tests and special aspects treatments, including diet, is considered to be unorthodox, unconventional and experimental at best. John Renner, M.D., director of the National Council Against Health Fraud, states that “While systemic candidiasis does exist, one needs to be cautious about ascribing generalized symptoms to the yeast” (Schwab, 1991). The California Medical Association’s Scientific Board Task Force on Clinical Ecology, the Ad Hoc Committee on Environmental Hypersensitivity Disorders (established by the Ministry of Health, in Ontario Canada) and The American Academy of Allergy and Immunology have all concluded that the basic premises of clinical ecology are speculative and unproven and do not constitute a valid medical discipline. (Barrett, 1987a, p. 82).


Herbalists claim that C. albicans “hates garlic.” Some studies do show that the allicin in garlic is an antimicrobial agent and that it inhibits the growth of C. albicans in the test tube. However, whether it does so in humans is questionable (Odds, 1988).

Drinking cranberry juice does change urine pH. However, very large amounts (e.g., a quart) a day or more may be needed to do so. If changes in urine pH are needed, an easier way to bring this about is by the use of urinary acidifying agents (drugs) (Dwyer et al., 1985).

Yoghurt and yoghurt douches have also been suggested to help to control yeast activity. The supposed mechanism of action is that they alter vaginal pH. Some yeast proponents contend that yoghurt, when taken orally, may have a preventive effect on yeast infections. In the only existing study that we found on this topic, yoghurt consumption was shown to be associated with significantly reduced incidence of yeast infections. (Hilton et al., 1992). Women suffering from chronic yeast infections were studied for a year and randomly assigned to two treatments. For 6 months they followed a yoghurt-free diet. During the other 6 months they consumed a cup of yoghurt a day. During the yoghurt consumption period, the women had only a third of the incidence of yeast infections that they had during the yoghurt-free period. It was theorized that the L. acidophilus in the yoghurt was absorbed in the gut and colonized the vaginal tract of the patients, where it overtook the infection-causing organisms.

These results have not been replicated; thus, they cannot be accepted as validating yoghurt as a treatment for yeast infections. Furthermore, many commercially available brands of yoghurt do not contain live L. acidophilus, so that the whole rationale, if based on the ability of this organism to produce an acid environment, is dubious.


Pros and Cons of the Yeast-Free Diet. Table 2 summarizes Crook’s dietary recommendations. Many of these are confusing or conflicting. Some, if followed religiously, could result in dietary deficiencies or toxicities. Some may be harmless, and some are simply silly. The recommendation to decrease consumption of sugar is practical, particularly if dental hygiene is poor and many foods high in sugar and starch are eaten. However, it is not possible to eliminate all sources of sugar without also eliminating fruits and many other nutritious and enjoyable foods as well.

It is also difficult to determine if foods actually contain live yeasts and molds. Obviously moldy cheeses such as Blue Cheese, yeast and yeast-raised breads all contain yeasts and/or molds. But the yeast in bread is not Candida, and furthermore, after performing its leavening function, it is killed during baking. However, other foods contain yeasts and molds simply because they have been inadvertently contaminated. Primrose oil ([gamma]-linolenic acid) is considered hazardous and a Food and Drug Administration regulation in 1985 ruled it illegal to be sold in the United States (Barrett, 1987). However, it is still marketed in health food stores. Vitamins, when consumed in large megadose amounts, 10 to 100 times the Recommended Daily Allowances, can also cause harmful toxicity. Silver-amalgam toxicity is mentioned as one potential result of decreased resistance resulting from yeast overgrowth. However silver-amalgam toxicity was exposed as a nonexistent syndrome in a report by the American Council on Science and Health (Dodes, 1991).

Pros and Cons of Mycostatic Drug

Use. Crook claims that mycostatic drugs, which control fungi and yeast are safe and effective. However, others report that they are expensive, frequently ineffective and, if used indiscriminately, are potentially toxic (Quinn and Venezio, 1986). The drugs can also be easily misused. This is a major risk because many such drugs are now being sold over the counter rather than by prescription. Nystatin (Mycostatin, Nilstat) is the drug most often prescribed by proponents of candidiasis hypersensitivity syndrome. Fortunately, it seldom has significant side effects. However, the unsupervised, long-term use of such antifungal agents may produce antimycostatic-resistant species of C. albicans and other fungi.

Also, ketoconazole (Nizoral) can cause liver toxicity. An incidence of hepatitis of between 1 in 10,000 to 1 in 15,000 has been reported in individuals taking. ketoconazole, as well as several deaths (Tabor, 1985).

Moreover, there is little evidence that these antifungal drugs help patients with certain symptoms. A randomized, double-blind study of nystatin therapy for presumed candidiasis hypersensitivity syndrome found that mycostatin did not reduce either the systemic or psychological symptoms more than did a placebo (Dismukes et al., 1990). This study has been questioned, however, because it lacked dietary control and also had several other design flaws (Bennett, 1990).

Of the four patients in one study whose primary physicians prescribed ketoconazole or nystatin and who were subsequently treated by specialists, one developed symptomatic hepatitis associated with ketoconazole therapy (Quinn and Venezio, 1986). None developed disseminated candidiasis, but all had nonspecific complaints including chronic fatigue, anxiety and depression. All of the patients had read the book The Yeast Connection and had shown it to their primary physicians. Thus, these readers of the book, who in fact may not have been ill, may have concluded that they suffered from a serious fungal disease and may have self-treated or convinced their physician to treat them with these mycostatic agents. The result of such drug use may be iatrogenic illness.

Also, there is a danger in inappropriate treatments of candidiasis. One 2-year-old child with severe disseminated candidiasis underwent several days of unproven diagnostic tests from a “candidia doctor” (e.g., a proponent of the candidiasis syndrome) and was being prepared for a costly trip to Mexico for sheep cell infusions, when he finally received proper treatment at a reputable medical center (Haas and Stiehm, 1986).

Eradication of the yeasts most often identified as C albicans does not prevent relapses of recurrent vaginitis (Davidson and Mould, 1978; Sobel, 1986). Also, colonization by C. albicans may be a secondary consequence rather than a primary underlying cause of the disease (Witkin, 1987). Pregnancy, steroids, chemotherapy, diabetes’ and other factors all predispose to subsequent depression of cell-mediated immunological defenses. Thus, vaginitis should be recognized as a disorder that may sometimes be due to a transient and localized immunodeficiency rather than a permanent problem (Witkin, 1987).


Vaginal yeast infections are real and bothersome afflictions. However, there is little evidence that the so-called “candidiasis hypersensitivity syndrome” is actually a disease. Moreover, dietary measures do not appear to cause or cure either yeast infections or any of the many other diseases and illnesses that have been attributed to yeasts. Diets low in yeast or in substances that stimulate yeast growth in vitro do not necessarily do so in vivo. Several antiyeast and fungal treatments, formerly sold only by prescription, now are sold as over-the-counter drugs. Chronic use of these preparations, even as specified on the label, is risky without medical supervision. The development of antifungal-resistant strains may result. Both the consumption of yoghurt and the use of vaginal douches with yoghurt is interesting but unsubstantiated. Women with vaginal infections should consult their gynecologists and never rely on self-medication with over-the-counter remedies. Thus, while candidiasis may truly be a hidden enemy in rare instances, dietary remedies for it are poorly supported.

So, the theory of a yeast for all reasons and seasons just will not fly.


We thank Dr. Charlotte C. Campbell, Professor Emeritus of Microbiology, Harvard School of Public Health, and Dr. Beth Goldbaum and Dr. Barry Goldin of Tufts University School of Medicine for their help in reviewing this manuscript.

We acknowledge Grant MCJ9120 from the Maternal and Child Health Service, U.S. Department of Health and Human Services, J. Dwyer, Principal Investigator.


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Dr. Palmer is Associate Professor and Co-Chair, Division of Nutrition and Preventive Dentistry, Tufts University School of Dental Medicine. She is also staff nutritionist at the Frances Stern Nutrition Center at the New England Medical Center Hospital in Boston.

Dr. Dwyer is Professor of Medicine (nutrition) in the Schools of Medicine and Nutrition at Tufts University, and Director of the Frances Stern Nutrition Center at the New England Medical Center Hospital in Boston.

Table 1

Criticism of the Alleged Candidiasis Hypersensitivity Syndrome

(American Academy of Allergy and Immunology)*

Specific criticisms

* Concept is speculative end unproven

* Basic elements end complaints are universal and would apply to almost all sick patients at some time in their illness

* The treatment program is so broad end general that it would produce improvement in most illnesses regardless of cause

* No published proof that Candida albicans is responsible

* No published demonstration that treatment of the Candida infection with specific antifungel agents benefits the syndrome

* No proof that immunotherapy, provocation, and/or neutralization with Candida albicana allergenic extracts benefits patients who are supposedly suffering from the syndrome

* No proof that the special studies and diagnostic tests are effective

Dangers of the proposed treatment program

* Long-term oral use of the major antifungal agents may produce resistent species of Candida albicans and of other yeasts and fungi

* Untoward side effects from oral use of antifungal agents

* From Anderson JA, Chai H, Claman HN, et al. Candidiasis hypersensitivity syndrome. J. Allergy Clin Immunol 1986;78:271-3.

Table 3

Topical Drugs for Vaginal Candidiasis*

Over the

Compound Brand Manufacturer Counter

Butoconazole Femstat Syntex

Clotrimazole Lotrimin Schering OTC

Mycelex-G Miles

Miconazole Monistat 7 Ortho OTC

Monistat 3 Ortho

Nystatin Mycostatin Squibb

Nilstat Lederie

Terconazole Terazol 7 Ortho

Terazol 3 Ortho

Ticonazole Vagistat Mead Johnson

Effectiveness: all are effective.

Adverse effects: burning and itching, contact dermatitis, vulval edema, dysuria, some headache, fever and chills may occur with those which are slightly absorbed (all but nystatin). Conclusion: all topical antifungals are safe and effective for treatment of vulvovaginal candidiasis in most people. Some are available over the counter.

* Adapted and reprinted with permission from the Medical Letter Vol 33 (851) August 23, 1991, p. 81.

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