Bacterial cystitis (BC) can feel like it runs your life when attacks keep coming back. While antibiotics treat active infections, what you eat and drink between episodes may genuinely influence how often you get them. I say “may” deliberately here because the evidence varies wildly depending on which dietary factor we’re discussing.

Let me walk through what we actually know about diet and bladder health, separating the well-supported advice from the folk wisdom that’s been passed down without much scrutiny.

The case for staying well-hydrated

This one’s actually solid. Drinking plenty of fluids helps dilute your urine and makes you urinate more frequently, which physically flushes bacteria out of your bladder before they can multiply and cause an infection. A 2018 randomised controlled trial published in JAMA Internal Medicine found that women who increased their daily water intake by 1.5 litres had 48% fewer UTI episodes than those who didn’t change their fluid intake 1.

That’s a pretty impressive result for something as simple as drinking more water.

What counts as adequate hydration? Most guidelines suggest around 6-8 glasses of fluid daily, but this varies based on your activity level, climate, and body size. The simplest check is your urine colour: pale straw is ideal. If it’s dark yellow, you’re probably not drinking enough.

Best fluids for bladder health:

Plain water (obviously)
Diluted squash or cordial
Herbal teas (though see the section on irritants below)
Milk

Water remains the gold standard. It’s calorie-free, cheap, and won’t irritate your bladder like some other drinks might.

Drinks that may irritate your bladder

Here’s where things get more individual. Some people with bacterial cystitis find certain drinks trigger symptoms or make attacks worse, while others notice no difference at all.

Alcohol

Alcohol poses several problems for bladder health. It’s a diuretic, meaning it makes you urinate more while simultaneously dehydrating you. This sounds contradictory but makes sense when you consider that alcohol suppresses the hormone (vasopressin) that normally helps your body retain water. You lose more fluid than you take in.

Alcohol may also increase urine acidity and irritate the bladder lining directly. Some women report that a night of drinking reliably triggers a UTI within a day or two.

My practical suggestion: I’m not going to tell you to never drink alcohol again—that’s unrealistic for most people. Instead, try alternating alcoholic drinks with water, which reduces dehydration and dilutes any irritating effects. If you notice a pattern between drinking and subsequent infections, that’s valuable information worth acting on.

Caffeine

Tea, coffee, and caffeinated soft drinks present similar issues. Caffeine is a mild diuretic and may irritate the bladder in some individuals. Research on whether caffeine actually increases UTI risk is mixed, but many people with recurrent UTIs report that reducing caffeine intake helps.

If you’re drinking six cups of coffee daily and getting frequent infections, cutting back might be worth trying. If you have one morning coffee and no obvious correlation with your symptoms, I wouldn’t stress about it.

Acidic fruit juices

Orange juice, grapefruit juice, and other citrus drinks are highly acidic and may irritate an already-sensitive bladder. Some people also find tomato juice problematic. However, there’s little research specifically linking these drinks to increased UTI rates in healthy people—the concern is more about symptom exacerbation during or after an infection.

Cranberry: the complicated success story

Cranberry probably comes up more than any other food when discussing UTI prevention, and with good reason. A 2023 Cochrane systematic review of 50 trials involving nearly 9,000 participants found that cranberry products reduced the risk of symptomatic UTIs by about 25% in women with recurrent infections 2.

The mechanism involves proanthocyanidins (PACs) in cranberries that appear to prevent certain bacteria (particularly E. coli) from adhering to the bladder wall. If bacteria can’t attach, they get flushed out before they can colonise.

The catch: Not all cranberry products are equal. Sweetened cranberry juice cocktails often contain as much sugar as fizzy drinks, which brings its own problems. Look for unsweetened juice (quite tart) or cranberry supplements that specify their PAC content. The Cochrane review noted that capsules and tablets showed similar effectiveness to juice.

For more detail on cranberry’s benefits and limitations, see our full article on cranberry supplements.

Sugar and bacterial growth

Here’s a theoretical concern that makes intuitive sense but lacks robust clinical evidence. Bacteria love sugar—this is why high blood glucose levels in diabetes increase infection risk across the body. The reasoning goes that dietary sugar feeds bacteria and encourages their growth.

In practice, the sugar you eat gets processed by your body before reaching your bladder in any meaningful concentration (unless you have uncontrolled diabetes). The direct link between dietary sugar and UTI risk in healthy people hasn’t been conclusively demonstrated.

That said, reducing added sugar has numerous other health benefits, so there’s no harm in cutting back. Read labels carefully—sugar hides in unexpected places like baked beans, pasta sauces, and “healthy” breakfast cereals.

D-Mannose: a promising supplement

D-mannose is a simple sugar that doesn’t get absorbed the way table sugar does. Instead, it passes largely unchanged into your urine, where it may interfere with bacterial adhesion to the bladder wall—similar to how cranberry works, but through a different mechanism.

A 2020 systematic review found moderate evidence that D-mannose supplements reduce UTI recurrence, though the authors noted that more high-quality trials are needed 3. Some women swear by it; others notice no difference.

We have a dedicated article on D-mannose if you want to explore the research further.

Supporting your immune system through diet

Your ability to fight off bacterial infections depends partly on having a well-functioning immune system. While no specific food dramatically boosts immunity, chronic nutritional deficiencies can impair it.

Key nutrients for immune function:

Vitamin C (citrus fruits, berries, peppers, broccoli)
Vitamin D (oily fish, eggs, fortified foods, sunlight exposure)
Zinc (meat, shellfish, legumes, seeds)
Iron (red meat, leafy greens, fortified cereals)
Vitamin A (liver, sweet potatoes, carrots, leafy greens)

A varied diet with plenty of vegetables, some fruit, adequate protein, and whole grains generally provides what you need. Supplements are worth considering if you have a restricted diet, limited sun exposure (for vitamin D), or known deficiencies.

Regular exercise also supports immune function, though this is beyond diet strictly speaking. Moderate physical activity is beneficial; excessive intense training can temporarily suppress immunity.

Foods that may help bladder health

Beyond cranberry and D-mannose, a few other foods have been studied for bladder health, though the evidence is generally weaker.

Probiotic-rich foods

Fermented foods like natural yoghurt, kefir, sauerkraut, and kimchi contain beneficial bacteria that may help maintain a healthy microbiome, including in the urogenital tract. The vaginal and bladder microbiome is increasingly recognised as playing a role in UTI susceptibility. Whether eating more yoghurt actually prevents UTIs remains unclear from current research, but it’s unlikely to cause harm.

For more on probiotics and urinary health, see our article on probiotics.

Garlic

Garlic contains allicin, a compound with antibacterial properties in laboratory settings. Whether eating garlic translates to meaningful antibacterial effects in the urinary tract is another question entirely. It’s a stretch to claim garlic prevents UTIs based on current evidence, but it’s a tasty addition to meals with no downside.

Alternative and herbal remedies

Several traditional herbal remedies are used for bladder health, though scientific support varies considerably.

Uva ursi (bearberry)

Uva ursi contains arbutin, which converts to hydroquinone in the body—a compound with antibacterial properties. Some studies suggest short-term use may help treat mild UTI symptoms, but the evidence isn’t strong enough to recommend it as a first-line treatment. It shouldn’t be used long-term due to potential liver toxicity.

Nettle leaf

Nettle has traditional use as a diuretic and is sometimes recommended for urinary symptoms. There’s limited clinical evidence specifically for UTI prevention. Our article on nettle covers what’s known about its effects and safety.

Oregano oil

Oregano oil has demonstrated antibacterial activity against various organisms in laboratory studies, including some UTI-causing bacteria. Clinical trials in humans are lacking, however. If you try it, use a diluted form appropriate for internal use—the concentrated essential oil is quite potent and can cause irritation.

Identifying your personal triggers

Everyone’s bladder is different. Some people can drink coffee all day without issues; others get symptoms after a single cup. The same applies to spicy foods, artificial sweeteners, carbonated drinks, and various other potential irritants.

If you’re getting frequent infections or flare-ups, consider keeping a food and drink diary alongside your symptoms. After a few weeks, patterns may emerge. This approach is more useful than blanket advice to avoid twenty different foods, most of which might not affect you at all.

When diet isn’t enough

Dietary modifications are just one piece of the puzzle. If you’re having recurrent UTIs (typically defined as two or more infections in six months, or three or more in a year), discuss this with your GP. Other strategies that may help include:

Post-coital voiding (urinating after sex)
Appropriate wiping technique (front to back)
Avoiding spermicides if you use them
Prophylactic low-dose antibiotics in some cases
Vaginal oestrogen for post-menopausal women

For more comprehensive information about UTIs, see our overview article on urinary tract infections.

Summary

Diet and hydration can genuinely influence your risk of bacterial cystitis, though they’re unlikely to eliminate it entirely if you’re prone to infections. The evidence is strongest for adequate fluid intake (particularly water) and cranberry products. D-mannose shows promise but needs more research. Reducing alcohol, caffeine, and sugar may help some people but isn’t universally necessary.

The most sensible approach is to stay well-hydrated, eat a balanced diet that supports immune function, try cranberry if you haven’t already, and pay attention to any personal triggers you notice. Beyond that, work with your healthcare provider on a comprehensive prevention strategy rather than relying on diet alone.

References

Hooton TM, et al. Effect of Increased Daily Water Intake in Premenopausal Women With Recurrent Urinary Tract Infections: A Randomized Clinical Trial. JAMA Intern Med. 2018;178(11):1509-1515.
Williams G, et al. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2023;4(4):CD001321.
Lenger SM, et al. D-mannose vs other agents for recurrent urinary tract infection prevention in adult women: a systematic review and meta-analysis. Am J Obstet Gynecol. 2020;223(2):265.e1-265.e13.