Cranberry supplements: what are the proven benefits of cranberries?

The cranberry in botany

The cranberry (Vaccinium microcarpon) is a perennial plant from the Ericaceae family which also includes the lingonberry and the blueberry. Native to North America, it grows wild in the acid, moist soil of peaty bogs and marshes. Today, it is cultivated on a large scale in the United States(especially Wisconsin and Massachusetts) and Canada, where it is known as ‘atoca’ or ‘atoka’. In France, it is more commonly known as ‘cranberry’ or ‘large North American cranberry’ (1).

Growing to no more than 30cm in height, this evergreen, groundcover shrub is distinct from other species of the genusVaccinium in that it has small, pink, oval, open flowers which bloom in the spring.

These are replaced in autumn by red berries, 2cm in diameter, with a tart, astringent flavour, which are usually consumed in the form of dried fruit, juice or jelly. Extracts of these tiny fruit are also used in the production of dietary supplements.

What health benefits are offered by cranberries?

Cranberries have a remarkable nutritional profile. The fresh berries provide a significant amount of antioxidant vitamin C (100g of raw cranberries provides 12% of our recommended daily intake) and manganese, while also being low in sugar and calories (2). The dried form has more calories, but also more fibre and vitamin E. The fruit also contains various organic acids (including citric, malic and phosphoric acids), pectin, tannin and glucosides (3).

In traditional medicine, cranberries were much prized by Native Americans for treating any condition related to the kidneys, blood and digestive system (4). They were also applied to wounds in the form of poultices or powder for their disinfecting and healing properties. However, the primary indication was for preventing and relieving urinary tract infections (5-6).

When European colonists arrived in the New World, they too came to appreciate cranberries’ many benefits. They were used, in particular, during the ‘Age of Discovery’ to combat scurvy on Atlantic voyages. Cranberry use fell out of favour after the Second World War, with the advent of synthetic antibiotics, and it was only in the early 1960s that this small red berry returned to the forefront of the scientific arena.

It was long thought that cranberries’ effects on the urinary tract were due to their acidifying action on urine. However, a totally different explanation has now been suggested. The cranberry is actually the only fruit to contain specific flavonoids called type A proanthocyanidins, which create an anti-adhesion environment hostile to bacteria (7-8).

Scientists are actively engaged in trying to confirm this theory. The results so far are generally promising. For example, one study has examined the efficacy of cranberry juice compared with a placebo in preventing recurrent urinary tract infections (UTIs) in a cohort of girls aged between 3 and 14 (9).

In a randomised controlled trial, 137 older women suffering from recurrent UTIs were given either 500mg of cranberry extract, or 100mg of an antibiotic called trimethoprim, for a period of six months. The antibiotic was found to have only a very limited advantage over the cranberry extract in preventing recurrence (25 cases in the cranberry group and 14 in the trimethoprim group), and it also had more adverse side-effects (10).

In view of their ‘anti-adhesion’ potential, cranberries are already being considered by the scientific community for other areas of application, including oral hygiene and combatting H. pylori (the most common cause of stomach ulcers) (11-12).

Innovative cranberry capsules

If you’re looking for a tried-and-tested cranberry supplement, the product Cran-Max® contains a cranberry extract supported by various clinical studies, and comes in capsule form (13). In particular, it is standardised to 7.2% type A proanthocyanidins, its most recognised active compound, for maximum efficacy.

It also benefits from the use of patented Bio Shield® technology for slow release of the active principles once they have reached the lower GI tract. This cutting-edge delivery system ensures complete and optimal absorption of the capsules’ precious substances.