CRANBERRY Overview Information
Cranberry is a type of evergreen shrub that grows in wet areas, such as bogs or wetlands. Cranberry is native to northeastern and northcentral parts of the United States. The shrub has small, dark green leaves, pink flowers, and dark red fruit 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, neurogenic bladder (a bladder disease), to deodorize urine in people with difficulty controlling urination, to prevent urine catheters from becoming blocked, and to heal skin around surgical openings in the stomach that are used to eliminate urine. Some people use cranberry to increase urine flow, kill germs, and reduce fever.
Some people use cranberry for type 2 diabetes, chronic fatigue syndrome (CFS), enlarged prostate, common colds, flu, heart disease, memory, metabolic syndrome, ulcers caused by Helicobacter pylori (H. pylori), scurvy, inflammation of the lining around the lung (pleurisy), and cancer.
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 making the urine acidic and, therefore, unlikely to support the growth of bacteria. But researchers don't believe this explanation any more. They now think that some of the chemicals in cranberries keep bacteria from sticking to the cells that line the urinary tract where they can multiply. Cranberry, however, does not 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.
Possibly Effective for:
- Preventing urinary tract infections (UTIs). Some research shows that drinking cranberry juice or taking certain cranberry extracts can lower the risk of repeated UTIs in some people, such as women, children, older people, and people who are hospitalized. But cranberry juice and cranberry extracts don't seem to prevent repeated UTIs in all people. Also, research comparing cranberry to standard antibiotic treatments used for UTIs is not consistent. Some research shows that cranberry extract works as well as the antibiotic trimethoprim at preventing UTIs. But other evidence shows that cranberry less effective at preventing UTIs compared to antibiotic treatment.
Despite the conflicting results, cranberry products might be an option for PREVENTING recurrent UTI. But it is not clear what the most effective dose is, or if drinking cranberry juice or taking supplements of cranberry extract is more effective.
While cranberry may be effective for PREVENTING UTIs, there is no evidence showing that cranberry is effective for TREATING UTIs.
Possibly Ineffective for:
- Diabetes. Research shows that taking cranberry supplements by mouth does not lower blood sugar in people with diabetes.
- Benign prostatic hyperplasia (BPH). Early research shows that taking dried cranberry capsules three times daily for 6 months might improve urinary symptoms and reduce levels of certain biomarkers associated with BPH.
- Common cold. Research suggests that drinking cranberry juice daily for 70 days does not reduce the risk of cold or flu, but might reduce cold and flu symptoms.
- Clogged arteries (coronary artery disease). Early evidence suggests that drinking cranberry juice daily for 4 weeks does not improve blood flow in people with clogged arteries.
- Stomach ulcers caused by Helicobacter pylori (H pylori) infection. There is inconsistent evidence regarding the ability of cranberry juice to eliminate a certain bacteria (H. pylori) in the stomach that can cause stomach ulcers. Some research suggests 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 while taking conventional medication used to treat H. pylori infections does not improve healing time compared to taking the medication alone.
- Flu. Research suggests that drinking cranberry juice daily for 70 days does not reduce the risk of cold or flu, but might reduce cold and flu symptoms.
- Kidney stones (nephrolithiasis). There is inconsistent evidence on the use of cranberry to lower the risk of kidney stones. Some early evidence suggests that drinking cranberry juice might lower the risk of kidney stones forming. However, other early evidence suggests that drinking cranberry juice or taking cranberry extracts might actually increase the risk of kidney stones.
- Memory. Early research suggests that drinking cranberry juice twice daily for 6 weeks does not improve memory in older people.
- Metabolic syndrome. Early research suggests 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.
- Urine odor. Early research shows that drinking cranberry juice might reduce the odor of urine in people with difficulty controlling urination.
- Wound healing.
- Chronic fatigue syndrome (CFS).
- Other conditions.
CRANBERRY Side Effects & Safety
Cranberry is LIKELY SAFE for most people when taken by mouth appropriately. Cranberry juice and cranberry extracts have been used safely in people. However, drinking too much cranberry juice can cause some side effects such as mild stomach upset and diarrhea. Drinking more than 1 liter per day for a long period of time might increase the chance of getting kidney stones.
Special Precautions & Warnings:Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking cranberry for therapeutic reasons if you are 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.
Inflammation of the stomach lining (Atrophic gastritis): Cranberry juice might increase how much vitamin B12 the body absorbs for people with atrophic gastritis.
Diabetes: Some cranberry juice products are sweetened with extra sugar. If you have diabetes, stick with cranberry products that are sweetened with artificial sweeteners.
Low stomach acid (hypochlorhydria). Cranberry juice might increase how much vitamin B12 the body absorbs for people with low levels of stomach acid.
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 by as much as 43%. Since kidney stones are made primarily from oxalate combined with calcium, healthcare providers worry that cranberry might increase the risk of kidney stones. To be on the safe side, avoid taking cranberry extract products or drinking a lot of cranberry juice if you have a history of kidney stones.
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.
The following doses have been studied in scientific research:
- For preventing urinary tract infections (UTIs): 10-16 ounces of a cranberry juice cocktail providing 26% cranberry juice daily has been used. 30-300 mL of cranberry juice daily has also been used. 50 mL of a drink containing both cranberry juice and lingonberry juice, taken daily for 6 months, has been used. Capsules containing 400-500 mg of dried cranberry, taken twice daily for 6 months to 1 year, has been used. 500 mg of a specific cranberry extract (Cran-Max, Proprietary Nutritionals) daily, and 800 mg cranberry capsules (Natural Cranberry Extract with Vitamin C, Solgar) twice daily for 6 months has also been used.
- For preventing urinary tract infections (UTIs): 50 mL of a cranberry and lingonberry concentrate taken daily for 6 months has been used. Also, 2 mL/kg of cranberry juice taken daily for one year has been used.