Cranberry is a shrub native to northern parts of the United States. It can be found in bogs and swamps.
A popular food, cranberry is rich in polyphenols, which have antioxidant, antibacterial, and anti-inflammatory effects.
Cranberry has traditionally been used for stomach, liver, and bladder disorders. Today it's most often used for urinary tract infections (UTIs).
Cranberry can be consumed as fresh or dried berries, juice, or found in supplement form.
This article reviews the latest evidence for cranberry's uses and its nutritional profile to help you decide if it's right for you. It also discusses some ways to incorporate cranberry into your diet and important side effects and drug interactions to keep in mind.
Uses of Cranberry
The vast majority of clinical trials of cranberry have studied its effects on UTIs.
It's also been investigated for its role in the following:
Here's the latest research.
Fresh cranberries.
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Urinary Tract Infections
There is some evidence that cranberry may help prevent recurring UTIs, though there's not enough evidence to support using it for active infections.
UTIs are common in females over 18. About 60% of females have at least one UTI, and up to 30% have subsequent ones.
The following populations are especially susceptible to UTIs:
Components of cranberries called proanthocyanidins (PACS) are credited with cranberry's beneficial effect on UTIs.
PACS keep bacteria that commonly cause UTIs, such as Escherichia coli, from attaching to cells in the urinary tract and causing infection.
Recent guidelines suggest cranberry products reduce the risk of recurrent UTIs in the following populations:
Cranberry is associated with an average 30% decreased risk of recurrent UTIs in these groups.
Some studies show that cranberry may be as effective as antibiotics in preventing recurrent UTIs in children.
Cranberry juice appears to be more effective than other dosage forms, like capsules, tablets, or powders, in preventing UTIs.
Cranberry is likely ineffective in preventing UTIs in the following populations:
GI Tract Infections
PACS found in cranberries may also play a role in suppressing stomach or intestinal infections caused by a bacteria called Helicobacter pylori (H. pylori).But the evidence is conflicting.
A study of 522 adults with H. pylori showed that those who drank cranberry juice with a high amount of PACS twice a day for eight weeks had a 20% lower infection rate than those who took cranberry powder or placebo (sugar pill).
But a review of five studies found that while cranberry helped eradicate H. pylori in adults, the results were not statistically significant. This means that results could be due to chance rather than reflecting cranberry's true effects. More data is needed to determine the role of cranberry in these infections.
Diabetes
A review of 22 studies concluded that cranberry may lower fasting blood sugar and hemoglobin A1c (a test that measured average blood sugar levels over the past three months) in people with type 2 diabetes. It's thought that the polyphenols in cranberry are responsible for this blood sugar-lowering effect.
Interestingly, cranberry had no effect on the blood sugar of people without diabetes, suggesting it's unlikely to prevent the development of the disease.
Heart Protection
Cranberry may improve some risk factors for heart disease, such as blood pressure and body mass index (BMI). It may also increase high-density lipoprotein (HDL, or "good" cholesterol) in people under 50 years old.
Additional Uses
Cranberry has also been studied in clinical trials for the following conditions, but more data is needed before it can be recommended:
Before taking cranberry, involve a registered dietitian (RD) or registered dietitian nutritionist (RDN), pharmacist, or healthcare provider to help you safely achieve your health goals.
What Are Side Effects of Cranberry?
For most healthy people, cranberry isn't associated with many side effects.
Due to the high sugar content, however, drinking large amounts of sweetened cranberry juice may cause stomach upset or diarrhea, particularly in children.
Nutrition
A 100 gram (g) serving, equal to about one-half cup of cranberry juice, provides the following nutrients, according to the U.S. Department of Agriculture (USDA).
Cranberry juice has a similar sugar content as other juices, which may be problematic for people monitoring their sugar intake.
Low-calorie juices made with artificial sweeteners are also available.
These may be an alternative for people with diabetes or low-carbohydrate diets.
Discuss the use of cranberry juice with your healthcare provider or a RD or RDN for more details.
How to Use Cranberry
Cranberry can be easily incorporated into your eating pattern in lots of ways.
Fresh cranberries are not typically consumed raw due to their acidity and tartness, though they can be added to recipes.
Cranberry is most often sweetened and consumed as a juice or sauce.
Sweetened dried cranberries can be found in some dairy products, chocolates, and cereals.
Cranberry extracts and powders may be added to food, or cranberry can be consumed as a dietary supplement. It's available in capsule and tablet form.
Most research into cranberry's effects on UTI prevention has come from studies of cranberry juice.
Precautions
Do keep the following precautions in mind when using cranberry:
Avoid cranberry if you have a known allergy to it or its components (ingredients or parts). If you're unsure, ask an RD or RDN, pharmacist, or healthcare provider for more information.
Interactions
Cranberry is considered to have a low risk of drug interactions. That said, there are a few to be aware of:
It is essential to carefully read a supplement's ingredients list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review the supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.
How to Store
Store food or juice that contains cranberries according to package directions. Juices should be refrigerated once opened and discarded according to the package label.
Cranberry supplements should also be stored according to the manufacturer's directions. These should be kept at room temperature, out of the reach of children and pets.
Discard supplements after one year or according to the expiration date on the package.
Summary
Cranberries may be a good choice for preventing recurrent UTIs in females, children, and people with catheters.
There's not enough evidence to recommend it for UTI prevention in pregnant people, older adults living in institutional settings, or treating active UTIs in any population. And it shouldn't replace advice from a healthcare provider who may recommend antibiotics or another treatment plan.
Some evidence also supports the use of cranberry for diabetes, intestinal infections caused by H. pylori, or diabetes.
Most of the research comes from clinical trials of cranberry juice rather than any other forms of cranberry.
If you decide to use it, remember that cranberry may interact with prescriptions of warfarin and tacrolimus and isn't advised for people at risk of kidney stones or during pregnancy or breastfeeding.
Is cranberry juice good for you?
Cranberry juice is appropriate for most healthy people because of its anti-inflammatory and antioxidant effects.
Remember that sweetened cranberry juice can be relatively high in sugar, so it may not be right for everyone. If you are on a low-carbohydrate diet or have diabetes, look for juice made with artificial sweeteners.
And due to a lack of safety data, discuss using cranberry with your healthcare provider or pharmacist before taking it if you are pregnant or breastfeeding.
Does cranberry juice help UTIs?
Cranberry juice may help prevent recurrent UTIs in females, children, and people with catheters or who have undergone bladder interventions.
There's not enough evidence to support cranberry for UTI prevention for pregnant females, older adults, or people with bladder-emptying disorders.
There's also not enough evidence to support the use of cranberry for active UTIs.
Is cranberry juice good for kidney stones?
Cranberry juice shouldn't be used in people who have kidney stones or are at risk for them. This is because cranberry can increase the levels of urinary oxalate, which can lead to the development of kidney stones.
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