Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

Dietary Changes Don't Show Any Effect on UTIs

Dear Doctor: I have a lot of urinary tract infections. My doctor told me not to drink anything with caffeine, but surely there must be something else I can do. Are there foods I should eat? Not eat?

Dear Reader: First, let me say that you have my sympathies. Urinary tract infections, though they have no outward signs, can be quite painful. Such infections are common, especially in women, who have a short urethra compared to men, meaning bacteria don't have far to travel in order to cause a problem. The majority of bacteria that cause these infections reside in the colon. These bacteria can colonize the area at the exit of a woman's urethra and, from there, move up the urinary tract to cause infections in the upper urethra, bladder or even kidney. These infections usually require antibiotics.

In younger women, sexual intercourse is a substantial risk factor for urinary tract infections, or UTIs, as are spermicide use and having a new sexual partner. Genetics likely play a role as well; daughters born to mothers with a history of UTIs have a greater likelihood of such infections. Further, those who have a UTI before age 15 have a greater chance of recurrent infections later in life.

After menopause, problems with bladder emptying, incontinence and bladder position increase the risk of UTIs. For post-menopausal women, vaginal estrogen can reduce infections, because it improves the natural bacterial flora in the vaginal area and decreases colonization of harmful bacteria. If you develop UTIs after sexual activity, urinating and increasing fluid intake after intercourse may decrease your chances of infection because these actions help flush the bacteria from the urethra.

If these measures -- not proven by any study -- don't reduce intercourse-related UTIs, a dose of antibiotics after intercourse might be warranted. But take care: With increased exposure comes a greater likelihood of bacterial resistance to that antibiotic.

Another alternative is the use of the probiotic Lactobacillus, which helps protect the vaginal area from the bacteria associated with urinary tract infections. It's not as effective as prophylactic antibiotics, but it can decrease infection frequency.

Cranberry extracts have shown an ability in the laboratory to stop bacteria from attaching to urinary tract cells, but studies of cranberry juice and tablets have been mixed. A combined study in 2012 did show a reduced risk of UTIs among women taking cranberry products, but many studies within the larger study showed no benefit.

Studies on caffeine intake and UTIs have been limited. Although caffeine does cause bladder irritability and may worsen the symptoms of urinary frequency and urgency that are seen with a UTI, the polyphenols in tea and coffee may create antibacterial activity within the urine.

A 2003 Finnish study showed that women who had a higher intake of yogurt containing probiotics and berry juice, like cranberry juice, had a lower rate of urinary tract infections. But the data have not been replicated, and the study did not adjust for confounding factors.

Overall, although some people advise women to avoid alcohol, sodas, spicy foods or citrus, I'm afraid there is no good research on specific diets to help stop recurrent UTIs. The best that science can support is cranberry extract tablets; probiotics or yogurt with Lactobacillus; some of the behavioral changes mentioned above; and doses of antibiotics.

(Send your questions to, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)