Cranberry
A tart, antioxidant-rich berry used to support urinary tract health.
Cranberry (Vaccinium macrocarpon) is a small, tart berry native to North America, noted for a high concentration of polyphenols and vitamin C. Traditionally used by Native Americans for food preservation, wound care and to address digestive and urinary complaints, the fruit is valued for its antioxidant properties and firm, acidic flesh.
Cranberries are consumed fresh, dried, as juice or in standardized extracts and supplements; they contain proanthocyanidins (PACs) that have been studied for their ability to inhibit bacterial adhesion in the urinary tract. Some sources cite an effective intake of about 36 mg per day of PACs for prevention of recurrent urinary tract infections, but clinical evidence is mixed and individual responses vary; common adverse effects include gastrointestinal irritation and prolonged high intake may be inadvisable in people prone to oxalate kidney stones.
At a Glance
A low-growing bog plant that yields small, firm red berries, cranberry is native to North America and noted for a high content of polyphenols and vitamin C. It was traditionally used by Native American peoples for food preservation, wound dressings and to address digestive and urinary complaints.
These berries are consumed fresh, dried, as juice or in standardized extracts; research has examined proanthocyanidins for their capacity to inhibit bacterial adhesion in the urinary tract, while antioxidant properties are associated with other proposed benefits and individual responses may vary.
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| Scientific name | Vaccinium macrocarpon |
| Plant family | Ericaceae |
| Origin | North America |
| Parts used | Fruit |
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Origin & History
Cranberry (Vaccinium macrocarpon) is native to the cold, wet regions of North America and typically grows in bogs, peatlands and acidic, sandy soils where it tolerates very low temperatures. The plant is a low-growing perennial with small leaves and round red berries; today most commercial production is concentrated in the United States and Canada.
Native American peoples used cranberries both as a preservative ingredient in pemmican and as a trade good, and they applied the berries in poultices and wound dressings. Early European settlers adopted many of these uses and cranberries also became incorporated into regional food traditions; historically the berries have been used for food preservation, as a dye, and in folk remedies for digestive, urinary and kidney complaints.
Composition & Active Compounds
Cranberry fruits are small, round and red, typically 1–2 cm in diameter, with a firm, crisp texture and an acidic, astringent taste driven by tannins. Chemically the berry is mostly water with sugars and fiber, and it contains a high proportion of phenolic constituents: polyphenols including proanthocyanidins (PACs), phenolic acids (malic, citric, benzoic), quercetin and tannins, together with vitamins and trace minerals.
Proanthocyanidins (PACs), and particularly PAC A, are the compounds most studied for effects on bacterial adhesion, and the fruit is the part most commonly used in supplements.
- Polyphenols: broad class of antioxidant compounds
- Proanthocyanidins (PACs): condensed tannins including PAC A and PAC B; PAC A associated with inhibition of bacterial adhesion
- Phenolic acids: malic, citric and benzoic acids contributing to acidity and antioxidant activity
- Quercetin: flavonoid with antioxidant properties
- Tannins: astringent phenolic compounds that affect taste and can irritate mucosa
Related Herbs
Properties & Effects
Cranberry is traditionally known for supporting urinary and digestive concerns and has been used in food and folk medicine for preservation and topical applications. Evidence is strongest for its traditional role in helping to prevent recurrent urinary tract infections.
- Prevention of urinary tract infections: research suggests cranberry may help reduce the risk of recurrent urinary tract infections in susceptible individuals.
- Antioxidant: may support protection against oxidative damage and contribute to cardiovascular health.
- Oral health: may help reduce dental plaque formation and support gum health.
Dosage & How to Use
Dosage guidance from available research is specific for prevention of urinary tract infections and is presented below.
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Safety, Side Effects & Contraindications
People who are sensitive to acidic or astringent foods should use cranberry products with caution; the most commonly reported adverse effects are gastrointestinal and can include mucosal irritation, reflux, moderate nausea and intestinal cramping. Individual tolerance varies and effects depend on dose and formulation.
Prolonged or high intake may increase oxalate exposure; anyone with a history of kidney stones or other chronic health conditions should consult a healthcare professional before beginning regular cranberry supplementation, and people taking multiple medications should seek personalized advice.
- Oxalate kidney stones: prolonged consumption not recommended in individuals prone to calcium oxalate stones.
Consult a healthcare professional before use if prone to oxalate kidney stones or taking multiple medications; cranberry can cause gastrointestinal irritation in some people.