According to MayoClinic.com, up to 75 percent of all women experience at least one yeast infection at some point in their lives. Although some level of the causative fungus, Candida albicans, exists in a healthy vagina, overpopulation of Candida crowds out the helpful vaginal bacteria Lactobacillus acidophilus and results in a yeast infection. Current medical evidence favors antifungals to cure yeast infections and does not support a role for Lactobacillus treatment.
Yeast Infection
A yeast infection occurs when the fungus Candida---usually Candida albicans---multiplies in the vagina at the expense of the normally dominant bacterial resident, Lactobacillus acidophilus. For this reason, a yeast infection is also called candidiasis. Yeast infections cause redness, swelling and tenderness of the vulva and vagina, intense itching at the vulva and vagina, burning during urination or sexual intercourse, and a characteristic vaginal discharge that is odorless, thick and white, and often compared to cottage cheese.
Lactobacillus
Lactobacillus acidophilus bacteria populate the normal, healthy vagina. The species name of acidophilus indicates that these bacteria thrive in a slightly acidic environment, such as that of the healthy vagina. The presence of lactobacilli prevents the overgrowth of Candida, also often a normal, albeit low-level, resident in healthy vaginas. Any factor that disrupts the health of vaginal lactobacilli, such as use of antibiotics, douching, or a change in acidity can upset the balance of microorganisms in the vagina and allow Candida to grow out of control, causing the symptoms of a yeast infection.
Role
As explained in "Primary Care for Women," doctors and scientists used to believe that vaginal lactobacilli maintained vaginal health by releasing lactic acid to control the levels of other microorganisms in the vagina. Now, however, they believe that lactobacilli produce hydrogen peroxide to control the growth of other organisms and maintain a healthy vaginal environment. The Natural Standard says that lactobacilli also produce antimicrobials like acidolin, acidophilin, lactocidin and bacteriocin.
Treatment
The accepted medical treatment for a yeast infection involves the use of an over-the-counter or prescription antifungal preparation such as miconazole or clotrimazole. Oral, suppository, and cream forms are available. These medications kill Candida albicans and allow the vagina to restore its natural balance of Lactobacilli. In most cases, only a few days of treatment are needed.
Alternatives
Some people believe that using lactobacilli preparations, eating lactobacilli-rich yogurt or applying it to the vagina can prevent or cure yeast infections. The idea is that the supplemental lactobacilli overcome the fungal infection and re-establish the normal environment of the vagina. Natural Standard reports that daily doses of lactobacilli in vaginal suppositories with 10 million to 1 billion colony-forming units have been used to fight vaginal infections. For yogurt, dosages consisted of 8 oz. of yogurt containing 100 million colony-forming units per milliliter.
Strength of Evidence
Although there is good evidence that lactobacilli in tablets or yogurt can help with bacterial vaginosis, evidence is not strong for a similar role in preventing or curing vaginitis, including yeast infections. The Natural Standard gives the present scientific evidence a grade of "C" for lactobacilli treatment of yeast infections and says that more research is needed to form a conclusion about its effectiveness.
References
- MayoClinic.com: Yeast Infection
- Natural Standard: Lactobacillus acidophilus
- "Primary Care for Women"; Phyllis Leppert and Jeffrey Peipert; 2004.
