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Autor: Snežana Feletar



Cranberry as a powerful antioxidant: medicinal properties, use and action


Cranberry is the name that includes several species of evergreen shrubs of the genus Vaccinium, family Ericaceae, the most common of which are the Norh American species (Vaccinium macrocarpon) and European cranberry (Vaccinium vitis-idaea). Cranberry fruit is a red hard berry with a sour and acidic taste. It can be found in the colder parts of the northern hemisphere, and grows in Gorski kotar and Lika. It is very resistant to cold, can withstand temperatures up to -40°C. 

Cranberry is grown in the areas with colder climates and require moist, acidic soil. It is mostly grown in North America – 98% of the world’s total production is generated in Canada and the US.


Medicinal properties of cranberry

Cranberry is healthy low-calorie food, rich in fiber, vitamins and minerals, dominated by vitamins C, A, E, minerals calcium, potassium, magnesium and iron. It is rich in antioxidants, owing to its strong medicinal properties. It has antibacterial, antiseptic, anti-inflammatory and diuretic effects. 

Cranberries are attributed many medicinal properties when administered in a correct form and in an appropriate dose:

  • Helps with urinary tract infections
  • Helps with edema
  • Protects against gum disease
  • Reduces risk of cancer
  • Strengthens the immunity, microbial flora of the stomach and intestines
  • Helps with dyspepsia, especially caused by Helicobacter pylori 
  • Helps prevent cardiovascular diseases
  • Lowers cholesterol levels
  • Has a positive effect on eye health
  • Helps with rheumatism and gout
  • Reduces blood sugar
  • Improves the quality of hair, skin, nails


Despite all these medicinal properties, caution should be exercised when using cranberry products. In higher concentration, cranberry has side effects for patients with kidney stones. Due to the higher concentration of oxalate, it can also have a laxative effect. Caution should be exercised in patients on warfarin therapy, people highly sensitive to salicylate, and people using medicines to treat prostate and urinary obstructions.


Cranberry use and action

The medicinal parts of the cranberry are the fruit and the leaf. Cranberry fruit is commonly used is, which contains proanthocyanidins (PAC), anthocyanins, flavonoids, catechins, organic acids, carbohydrates (fructose and dextrose), tannins. Most commonly mentioned is a positive effect in the treatment of bladder infection. The most potent effect is the proanthocyanidins, which prevent the bacteria from adhering to the walls of the bladder and affect the bacterial biofilm. 

For better effect in the treatment of bladder infections, standardized cranberry extracts containing significant concentrations of proanthocyanidins are recommended. Cranberry nutrition supplements have proven successful as they can reduce the need for frequent antibiotic therapy in the treatment of recurrent urinary infections and thus reduce side effects such as vaginal candidiasis. 


Cranberry is a powerful antioxidant

Many in vitro and in vivo studies have shown that cranberry is a plant rich in many antioxidants, which is the reason why it is attributed its positive effects, in addition to the one best known for urinary infections. The aforementioned phenolic glycosides and anthocyanins protect against the enhanced effect of lipoprotein oxidase. Flavonoids and organic acids reduce the oxidation of LDL which mostly affects the cardiovascular system. It has a positive effect on both metabolism and the immune system due to its high dose of antioxidants. 


Tea and cranberry juice

Cranberry leaf is most commonly used for tea, but a mixture of leaf and fruit can also be found. Cranberry leaf tea has primarily uroantiseptic properties due to its higher concentration of phenolic glycosides. Cranberry tea contains a lower concentration of tannin and can be also used by children under 12 years of age. Tea is prepared by pouring one teaspoonful of 2.5 dl of boiling water, leaving it covered for up to 15 minutes, followed by straining and drinking up to three times a day. 

For more than 30 years, the inhibitory effect of cranberry juice on bacterial adherence has been studied for potential use in the treatment of urinary tract diseases. Caution is to be taken by people who have a predisposition to develop stones, where larger amounts of juice can have a laxative effect. Caution is, of course, also to be taken by diabetics. It is best to prepare fresh cranberry juice so that well-washed and picked ripe berries are mixed and a small amount of water is added. It is important that purchased cranberry juice contains as much cranberry fruit and as little sugar as possible.


Cranberry in pregnancy

Pregnant women and breastfeeding women are not recommended to take cranberry leaf tea in the first weeks because it contains substances that cause uterine tone, increasing the risk of bleeding. Many studies have shown that fruit and leaf tea is safe for use in pregnant women if a right dose is taken, but not longer than 14 days. Tea is suitable in the last quarter for the relief of edema, for colds and viruses, as a mild analgesic, aid in dyspepsia, in regulating sugar levels.



The term superfood refers to foods that are rich in extremely high concentrations of phytonutrients, active compounds in plants that contribute to human health. Because of all these medicinal and nutritional values, cranberries can be classified as superfood. Cranberry products are an excellent nutritional supplement for everyone, provided they are taken in a correct form and in a proper dose.