Cranberry juice for cystitis: does it work?

Is cranberry juice good for cystitis?

Cystitis is a urinary tract infection (UTI) that's very common in women and people assigned female at birth (AFAB). According to Dr Melanie Bone, female health specialist and Daye medical board member, 1 in 3 women will have a UTI by age 24 and more than half will get one at least once in their lifetime.

With a condition this widespread, home prevention and remedy tips often spread by word of mouth rather than evidence. Many women believe in the healing powers of cranberry juice, and some who get repeated bouts of cystitis keep a carton in the fridge at all times - just in case.

Yet, although there have been many studies on cranberry for the treatment and prevention of cystitis and other UTIs, the evidence hasn't always been clear cut. However, there have been some developments in recent years.

So, the current understanding is that cranberry juice may indeed help cystitis - in some people. However, Dr Bone warns that this

home remedy

should only be used alongside, and never instead of, prescribed medical treatment:

"If you suspect you have cystitis, it's important to consult your doctor for an accurate diagnosis and appropriate treatment. The only recognised treatment for UTIs is antibiotics, which can clear up the infection and prevent it from developing into a more serious problem."

Different studies also research cranberries or various cranberry extracts - but be wary that shop-brought cranberry juice may not produce the same results.

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Why is cranberry juice good for cystitis?

Cystitis means you may have a bacterial infection in your urinary tract - the system that allows urine to pass from your bladder out of your body. These bacteria, the most common being E. Coli, causes your bladder to become inflamed, which leads to painful and disruptive symptoms.

"There are certain compounds in cranberries called proanthocyanidins (PACs). PACs can help prevent harmful bacteria from attaching to the walls of your urinary tract, including the bladder," says Dr Bone.

Cranberries also contain a naturally occurring sugar called D-mannose, which binds to E. coli bacteria in your urinary tract so it can more easily flush out your system. D-mannose is recommended by the National Institute for Health and Care Excellence (NICE) for women who experience recurrent UTIs but are not pregnant - although it's not classed as a medicine, and evidence is inconclusive.

But before you reach for the carton of cranberry juice, Dr Bone advises that most commercially available cranberry juices are pasteurised and preserved with added sugars. In fact, there is a lot of sugar in store bought cranberry drinks. "This makes them unlikely to contain the beneficial proanthocyanidins found in whole cranberries."

Likewise, D-mannose is also a sugar, and so anyone considering taking cranberry juice, other cranberry products, or D-mannose need to read the label and make sure they don't exceed the recommended maximum 30g daily sugar intake. This is especially true for people with diabetes, who should always ask their doctor before taking these products for cystitis.

How much cranberry juice for cystitis?

The scientific evidence for cranberries and their benefits may be growing, but it's less clear how effective and healthy it is to drink commercial cranberry juice for cystitis. Therefore, there's no recommended amount of cranberry juice for cystitis.

One alternative is supplementing your diet with extracts from cranberries. For example, D-mannose and PACs can both be extracted from cranberries and taken as a tablet or a powder mixed with water. This means you can avoid the added sugars in cranberry juice.

Dr Bone says: "The typical dosage for D-mannose is 1 to 2 grams (1000 to 2000 mg) per day. A 2014 study found D-mannose to be as effective in preventing UTIs as antibiotic treatment⁴."

This said, it remains unclear whether cranberry juice or cranberry extract supplements, like D-Mannose and PACs, are more effective for cystitis³.

If you do decide to try cranberry juice, Dr Bone has this advice: "Drink pure, unsweetened and cold-pressed cranberry juice. At the very least, pure cranberry juice won't have added sweeteners that can do you any harm - but there's also no guarantee that it will do any good, either."

Further reading

1. Jepson et al: Cranberries for preventing urinary tract infections.

2. Mantzorou and Giaginis: Cranberry consumption against urinary tract infections: clinical state of- the-art and future perspectives.

3. Williams et al: Cranberries for preventing urinary tract infections.

4. Kranjčec et al: D-mannose powder for prophylaxis of recurrent urinary tract infections in women: a randomized clinical trial.