Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus Oxycoccus of the genus Vaccinium. In Britain, cranberry may refer to the native species Vaccinium oxycoccos, while in North America, cranberry may refer to Vaccinium macrocarpon. Vaccinium oxycoccos is cultivated in central and northern Europe, while Vaccinium macrocarpon is cultivated throughout the northern United States, Canada and Chile. In some methods of classification, Oxycoccus is regarded as a genus in its own right. They can be found in acidic bogs throughout the cooler regions of the Northern Hemisphere.

Cranberries are low, creeping shrubs or vines up to 2 meters (7 ft) long and 5 to 20 centimeters (2 to 8 in) in height; they have slender, wiry stems that are not thickly woody and have small evergreen leaves. The flowers are dark pink, with very distinct reflexed petals, leaving the style and stamens fully exposed and pointing forward. They are pollinated by bees. The fruit is a berry that is larger than the leaves of the plant; it is initially light green, turning red when ripe. It is edible, but with an acidic taste that usually overwhelms its sweetness.

In 2020, the United States, Canada, and Chile accounted for 97% of the world production of cranberries. Most cranberries are processed into products such as juice, sauce, jam, and sweetened dried cranberries, with the remainder sold fresh to consumers. Cranberry sauce is a traditional accompaniment to turkey at Christmas and Thanksgiving dinners in the United States and Canada, and at Christmas dinner in the United Kingdom.

Raw cranberries are 87% water, 12% carbohydrates, and contain negligible protein and fat (table). In a 100 gram reference amount, raw cranberries supply 46 calories and moderate levels of vitamin C, dietary fiber, and the essential dietary mineral manganese, each with more than 10% of its Daily Value. Other micronutrients have low content.

Dried cranberries are commonly processed with up to 10 times their natural sugar content. The drying process also eliminates vitamin C content.

Raw cranberries, cranberry juice and cranberry extracts are a source of polyphenols – including proanthocyanidins, flavonols and quercetin. These phytochemical compounds are being studied in vivo and in vitro for possible effects on the cardiovascular system, immune system and cancer. However, there is no confirmation from human studies that consuming cranberry polyphenols provides anti-cancer, immune, or cardiovascular benefits. Potential is limited by poor absorption and rapid excretion.

Cranberry juice contains a high molecular weight non-dializable material that is under research for its potential to affect formation of plaque by Streptococcus mutans pathogens that cause tooth decay. Cranberry juice components are also being studied for possible effects on kidney stone formation.

Common Names: cranberry, American cranberry, bearberry

Latin Names: Vaccinium macrocarpon (also known as Oxycoccus macrocarpos), Vaccinium oxycoccos

Background

• Cranberry is an evergreen shrub that grows in wet habitats in the Northeastern and North Central parts of the United States.
• Historically, cranberry fruits or leaves were used for bladder, stomach, and liver disorders, as well as diabetes, wounds, and other conditions.
• Today, cranberry is most commonly promoted for urinary tract infections (UTIs).

How Much Do We Know?

• There have been many studies in people of cranberry for UTIs, but there’s little research on cranberry for other conditions.

What Have We Learned?

• ​​​​In general, studies in people who are at increased risk for UTIs or those who have had recurrent UTIs show that cranberry products decrease the risk of UTIs by about one-third. However, there’s still some uncertainty about the effectiveness of cranberry because some of the research has not been of high quality. Also, studies in certain populations at increased risk of UTIs, such as elderly people in long-term care and pregnant women, have had inconsistent results, and studies in other high-risk populations, such as women undergoing gynecological surgeries or people with multiple sclerosis, have not found cranberry to be beneficial.
• In 2020, the U.S. Food and Drug Administration announced that it would permit manufacturers to claim on product labels that there is “limited” evidence that daily consumption of specified amounts of cranberry dietary supplements may reduce the risk of recurrent UTI in healthy women who have had a UTI. A similar claim may be made for cranberry juice beverages, but the evidence must be described as “limited and inconsistent.”
• Cranberry hasn’t been shown to be effective as a treatment for an existing UTI.
• NCCIH-supported research is looking at the effects of polyphenols from cranberry and other fruits and vegetables on the gut microbiome, to see whether these effects may play a role in the association between consumption of these foods and reduced risk of chronic diseases.

What Do We Know About Safety?

• Cranberry products are generally thought to be safe. However, if consumed in very large amounts, they can cause stomach upset and diarrhea, particularly in young children.
• Little is known about whether it’s safe to use cranberry for health purposes during pregnancy or while breastfeeding.
• There is conflicting evidence about whether cranberry interacts with the anticoagulant (blood thinner) warfarin.
• People who think they have a UTI should see a health care provider for diagnosis and treatment. Don’t use cranberry products in place of proven treatment for a UTI.

Keep in Mind

• Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.

Maybe. Studies on whether cranberry juice or products prevent or treat UTIs show mixed results.

Cranberries may help prevent bacteria from attaching to cells in the wall of the urinary tract and causing infection. If you get recurrent UTIs, talk to your doctor or nurse about taking cranberry products to prevent UTIs.

• Botanists estimate that blueberries burst onto the scene more than 13,000 years ago, in what is now North America. Native Americans enjoyed blueberries year-round. They dried blueberries in the sun and added them whole to soups, stews and meat, and even crushed them into a powder to use on meat as a preservative.

• Cranberries were first used by Native Americans, who discovered the wild berry’s versatility as a food, fabric dye and healing agent.

• In the USA, Cranberries were first cultivated in the early 1800s and blueberries in the early 1900s.

• Cranberries contain bacteria-blocking compounds that are believed to be helpful in preventing urinary tract infections, and scientists now think this same function may be useful in blocking the bacteria responsible for ulcers and certain oral bacteria that can lead to gum disease.

• Native Americans called blueberries “star berries” because the blossom end of each berry – the calyx – forms a perfect five-pointed star. Tribal elders recounted how the Great Spirit sent “star berries” to ease the children’s hunger during a famine. And according to legend, Native Americans gave blueberries to the pilgrims to help them make it through their first winter.