cranberry

Cranberry is the fruit of an evergreen shrub (Vaccinium macrocarpon and Vaccinium oxycoccos) that grows in wet habitats in the northeastern and north-central parts of North America. As a supplement it is sold as juice, dried fruit, and concentrated extracts in tablets or capsules, and it contains compounds called proanthocyanidins (PACs).

According to NCCIH, cranberry products may decrease the overall risk of symptomatic, recurrent UTIs in women by about 25 percent, and in some cases by more than 30 percent. However, NCCIH cautions that cranberry's effectiveness "is still in question because of inconsistent findings." Cranberry is not recommended as a treatment for an existing UTI in any population. Results have been inconsistent in some groups (such as older adults in long-term care and pregnant women), and studies have not found cranberry to be beneficial for people undergoing gynecological surgery or for people with multiple sclerosis. NCCIH notes there is little research on cranberry for any other condition.

There is no established standard dose. NCCIH notes that processing cranberry into products such as tablets or capsules can reduce the concentration of PACs, which may reduce its potential effectiveness. Because the evidence is mixed and the most effective form and amount are uncertain, talk to your doctor or pharmacist before using cranberry supplements, and seek medical care for a suspected infection rather than self-treating.

According to NCCIH, cranberry taken by mouth is generally considered safe. Some studies suggest it is safe during pregnancy and breastfeeding in amounts commonly found in food, but the evidence is not conclusive for larger, supplement-level amounts. Cranberry should not be relied on to treat an active UTI in place of medical care.

NCCIH reports that if consumed in very large amounts, cranberry can cause stomach upset and diarrhea, and that young children may be particularly affected.

NCCIH describes conflicting evidence about whether cranberry interacts with the anticoagulant (blood thinner) warfarin. If you take warfarin or other blood thinners, check with your clinician before using cranberry supplements.