Is There a Diet That Can Control or Prevent Yeast Vaginitis?

Are there any foods that would help alleviate the symptoms of recurrent yeast vaginitis and also keep it under control?  I find that conventional medicine relieves symptoms, but does not cure. Also, should soaps be avoided? 

You bring up several excellent issues.  The role of foods in yeast vaginitis is very controversial and many statements made about this topic are unproven.  There are many "old wives tales" about this issue, especially regarding the benefits of acidophilus.  Basically, there is no food that has been scientifically established to decrease the risk of recurrent yeast infections.  So, this is all unknown territory.  Some doctors react to the lack of knowledge by saying it sounds like harmless advice to use acidophilus, go ahead.  While other doctors say it is a real hassle and not worth doing given the lack of proof that it works.  We have no evidence that this practice is harmful in pregnancy.  I feel if a woman really swears it works go ahead, but I personally don't believe it is worth doing for most women, thus I do not generally recommend it.  

Regarding the role of soaps, it is a culprit in many vaginal irritations.  While soap doesn't cause yeast infections per se, it should be avoided in all women, but most especially in those with problems with frequent vaginal discharge or irritation. 

Almost all the yeast vaginitis medications are now available by prescription.  Many women do not use them properly.  In order to work well, they need to be used for a long enough time.  While some women can get away with a short course, like a single dose or a 3-day treatment, many women will require 2 weeks, or even 2 months of therapy.  If the short therapy fails, before longer therapy is undertaken, the diagnosis needs to be confirmed, and also the woman needs to try more that one brand to be sure she is not having an irritation/allergic reaction form one particular brand.  Once she finds a brand that suits her, she should stick with it

Of course, any irritation or discharge needs to be thoroughly evaluated by a doctor until the cause is determined as clearly as possible.  Also, diabetes should be looked for in women with frequent yeast infections because diabetes can predispose women to frequent yeast infections.  However, the majority of women who have frequent yeast infections test negative for diabetes.