Overview

Cranberry is a type of evergreen shrub that grows in bogs or wetlands. Cranberry is native to northeastern and northcentral parts of North America. The shrub has small, dark green leaves, pink flowers, and dark red fruits that are egg-shaped.

Cranberry is most commonly used for the prevention and treatment of urinary tract infections (UTIs). Cranberry is also used for kidney stones, enlarged prostate, the common cold, and many other conditions, but there is no good scientific evidence to support these uses

In foods, cranberry fruit is used in cranberry juice, cranberry juice cocktail, jelly, and sauce.

How does it work ?

People used to think that cranberry worked for urinary tract infections by slowing the growth of bacteria. But this doesn't seem to be true. Instead it seems that some of the chemicals in cranberries keep bacteria from sticking to the cells that line the urinary tract. But cranberry doesn't seem to have the ability to release bacteria which are already stuck to these cells. This may explain why cranberry is possibly effective in preventing urinary tract infections, but possibly ineffective in treating them.

Cranberry, as well as many other fruits and vegetables, contains significant amounts of salicylic acid, which is an important ingredient in aspirin. Drinking cranberry juice regularly increases the amount of salicylic acid in the body. Salicylic acid can reduce swelling, prevent blood clots, and can have antitumor effects.

Uses & Effectiveness ?

Possibly Effective for

  • Infections of the kidney, bladder, or urethra (urinary tract infections or UTIs). Some research shows that taking certain cranberry juices, capsules, or tablets can help prevent UTIs in people who have had UTIs in the past. Taking certain cranberry products or drinking cranberry juice might prevent UTIs in some older people living in nursing homes, pregnant patients, and children who have had UTIs in the past. But cranberry does not appear to help prevent UTIs in people undergoing surgery near the bladder or urinary tract, as well as people with a bladder condition (neurogenic bladder) caused by an injury to the spinal cord.

    While cranberry may help prevent UTIs in some people, it should not be used to treat UTIs.

Insufficient Evidence for

  • Enlarged prostate (benign prostatic hyperplasia or BPH). Early research shows that taking dried cranberry daily for 6 months might improve urinary symptoms and reduce levels of certain chemicals associated with BPH.
  • Heart disease. Some research shows that drinking cranberry juice or taking cranberry capsules might slightly improve blood pressure and body mass index (BMI). But cranberry does not seem to improve other risk factors like cholesterol levels, blood sugar levels, or waist size.
  • Diabetes. Early research shows that taking cranberry supplements by mouth does not lower blood sugar in people with diabetes.
  • A digestive tract infection that can lead to ulcers (Helicobacter pylori or H. pylori). There is inconsistent evidence regarding the ability of cranberry juice to eliminate bacteria (H. pylori) in the stomach. Some research shows that drinking cranberry juice daily for up to 90 days can help eliminate H. pylori in adults and children. But other early research shows that drinking cranberry juice along with taking conventional medication used to treat H. pylori infections is not better than taking the medication alone.
  • Kidney stones. Some early research shows that drinking cranberry juice might lower the risk of kidney stones forming. But other early research shows that drinking cranberry juice or taking cranberry extracts might actually increase the risk of kidney stones.
  • Memory. Early research shows that drinking cranberry juice twice daily for 6 weeks does not improve memory in older people.
  • A grouping of symptoms that increase the risk of diabetes, heart disease, and stroke (metabolic syndrome). Early research shows that drinking cranberry juice twice daily for 8 weeks can benefit some antioxidant measurements in the blood, but it does not appear to affect blood pressure, blood sugar, or cholesterol levels in people with metabolic syndrome.
  • Build up of fat in the liver in people who drink little or no alcohol (nonalcoholic fatty liver disease or NAFLD). Early research shows that taking cranberry extract tablets might help improve some blood levels, but not others, in people with NAFLD.
  • Overactive bladder. Early research shows that taking dried cranberry powder capsules daily for 24 weeks can reduce the number of times people with overactive bladder urinate. It can also reduce the number of sudden urges to urinate each day.
  • Prostate cancer. Some research shows that taking dried cranberry might reduce levels of certain chemicals in patients with prostate cancer. But it is unclear if it slows down cancer development.
  • Irritation of the bladder caused by radiation therapy. Some early research shows that cranberry juice might reduce the risk for this type of irritation in men who are receiving radiation therapy for prostate cancer. But not all research agrees. Also, some research shows that it is not helpful in people who are receiving radiation therapy for bladder cancer or cancer of the cervix.
  • Upper airway infection. Research shows that drinking cranberry juice daily for 70 days does not reduce the risk of getting a cold or flu. But it might reduce cold and flu symptoms.
  • Urinary odor. Early research shows that drinking cranberry juice might reduce the odor of urine in people with difficulty controlling urination.
  • Cancer.
  • Chronic fatigue syndrome (CFS).
  • Infections in people with catheters.
  • Skin breakdown around a stoma (peristomal lesions).
  • Other conditions.
More evidence is needed to rate cranberry for these uses.

Side Effects

When taken by mouth: Cranberry juice and cranberry extracts are LIKELY SAFE for most adults. Drinking too much cranberry juice may cause some side effects such as mild stomach upset and diarrhea in some people. Taking large amounts of cranberry products might increase the risk of kidney stones.

Special Precautions and Warnings

Pregnancy and breast-feeding: There isn't enough reliable information to know if cranberry is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.

Children: Cranberry juice is LIKELY SAFE for children when taken by mouth as a food or drink.

Aspirin allergy: Cranberries contain significant amounts of salicylic acid. Salicylic acid is similar to aspirin. Avoid drinking large quantities of cranberry juice if you are allergic to aspirin.

Diabetes: Some cranberry juice products are sweetened with extra sugar. If you have diabetes, stick with cranberry products that are sweetened with artificial sweeteners.

Kidney stones: Cranberry juice and cranberry extracts contain a large amount of a chemical called oxalate. In fact, there is some evidence that some cranberry extract tablets can boost the level of oxalate in the urine. Since oxalate is found in kidney stones, healthcare providers worry that cranberry might increase the risk of kidney stones. If you have a history of kidney stones, stay on the safe side and avoid taking cranberry extract products or drinking a lot of cranberry juice.

Interactions ?

    Moderate Interaction

    Be cautious with this combination

  • Warfarin (Coumadin) interacts with CRANBERRY

    Warfarin (Coumadin) is used to slow blood clotting. Cranberry might increase how long warfarin (Coumadin) is in the body, and increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

    Minor Interaction

    Be watchful with this combination

  • Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates) interacts with CRANBERRY

    Some medications are changed and broken down by the liver.

    Cranberry might decrease how quickly the liver breaks down some medications. Taking cranberry along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking cranberry, talk to your healthcare provider if you take any medications that are changed by the liver.

    Some medications that are changed by the liver include amitriptyline (Elavil), diazepam (Valium), zileuton (Zyflo), celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), irbesartan (Avapro), losartan (Cozaar), phenytoin (Dilantin), piroxicam (Feldene), tamoxifen (Nolvadex), tolbutamide (Tolinase), torsemide (Demadex), warfarin (Coumadin), and others.

Dosing

The following doses have been studied in scientific research:

ADULTS

BY MOUTH:
  • For preventing infections of the kidney, bladder, or urethra (urinary tract infections or UTIs): Capsules or tablets containing 120-800 mg of dried cranberry taken once or twice daily have been used. Drinking cranberry juice 120-300 mL 1-3 times daily has also been used.
CHILDREN

BY MOUTH:
  • For preventing infections of the kidney, bladder, or urethra (urinary tract infections or UTIs): 50 mL of a cranberry and lingonberry concentrate taken daily for 6 months has been used. Also, 5 mL/kg of cranberry juice taken daily for 6 months has been used. A standardized cranberry extract (Anthocran) 120 mg taken daily for 60 days has been used in children 12-18 years of age.
View References

CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version. © Therapeutic Research Faculty 2018.