Cranberry: polyphenols against cancer?

Polyphenols, bioactive compounds found in many plants, are attracting growing interest for their antioxidant and anti-inflammatory properties. Among these plant sources, the cranberry(Vaccinium macrocarpon) stands out for its high content of polyphenols, particularly flavonoids and proanthocyanidins. These molecules are recognised for their potential to inhibit certain stages of carcinogenesis, the complex process involved in the development of cancer.

What is cancer?

Living organisms, whether plants or animals, are made up of fundamental elements called cells. Each cell contains genes that control its function and characteristics. During their life cycle, cells divide. They pass on their genetic information to two new daughter cells and then die. However, genetic abnormalities can occur, disrupting the way certain cells function.

These mutations can be repaired or cause the defective cell to die. However, some damaged cells escape these control mechanisms and survive. This is how cancer can develop. A normal cell changes and begins to multiply uncontrollably, producing abnormal cells. This uncontrolled proliferation gradually forms a malignant tumour.

Under normal circumstances, mechanisms such as the cell cycle and apoptosis (programmed cell death) regulate cells, balancing cell production and destruction. If a cell fails to correct its genetic errors, they accumulate over the course of divisions. This increases the risk of cancer.

Cancer refers to all diseases caused by the uncontrolled growth of abnormal cells. These cells can form tumours. They are also capable of invading neighbouring tissues and spreading to other parts of the body via blood or lymph vessels. These secondary tumours are known as metastases. These metastases are responsible for the majority of cancer-related deaths. Although some cancers can be treated successfully, others are more aggressive and can recur. In these cases, regular monitoring is required. Early detection remains crucial to improving the chances of recovery.

Cranberries and their properties

Oxycoccus, a subgenus of the genus Vaccinium in the Ericaceae family, includes the cranberry. This perennial plant grows in peat bogs in cold regions, where the soil is acidic and waterlogged.

The cranberry grows as an evergreen shrub . They grow to less than 30 cm in height, with creeping branches that can reach 80 cm. Bumblebees pollinate its small pink flowers, while its bright red berries are packed with bioactive compounds.

The composition of the cranberry makes it a particularly interesting fruit from a nutritional and medicinal point of view. It contains various organic acids (citric, malic, ascorbic and benzoic), tannins, flavonoids and, above all, proanthocyanidins (PACs), which are responsible for its beneficial properties. These PACs, type A, play a key role. They prevent bacteria, particularly Escherichia coli, from adhering to the walls of the urinary tract. In this way, they help prevent urinary tract infections.

In addition to PACs, cranberries are rich in antioxidants, such as flavonoids, which protect cells against oxidative damage and boost the immune system. Its vitamin C content also gives it anti-infectious and revitalising properties. Studies have shown that cranberries can also inhibit the Helicobacter pylori bacteria involved in gastric ulcers.

In addition to its benefits for urinary health, cranberries contribute to cardiovascular health by reducing the oxidation of LDL cholesterol and increasing HDL levels. It is consumed in the form of juice, dried fruit or food supplements. It is a major asset in preventing infections and maintaining general well-being.

What are the mechanisms of action of cranberries against cancer?

Cranberries may have anti-cancer properties, according to a study conducted by researchers at the University of Massachusetts. The results, published in The Global Source for Science News, show that cranberries contain compounds capable of selectively eliminating tumour cells in the colon. The researchers treated mice with colon cancer with three types of cranberry extract: a complete extract, one containing only polyphenols and another without polyphenols. After 20 weeks, the mice treated with the full extract showed a 50% reduction in the number of tumours, a reduction in their size, and a reduction in inflammatory markers.

Proanthocyanidins and flavonols, phytochemical components of cranberries, induce apoptosis (programmed death) in cancer cells, particularly in colon and prostate cancers. These compounds trigger the release of cytochrome-C from the mitochondria, leading to the destruction of tumour cells. They also impact genes associated with cell survival, such as those controlling the production of anti-apoptotic proteins like caspase-8 and FLIP.

At the same time, studies on prostate cancer have shown that cranberries can improve the effectiveness of treatments such as radiotherapy, by reducing side-effects such as bladder inflammation. One study found that daily intake of proanthocyanidins reduced urinary symptoms in 65% of patients treated for prostate cancer.

Research into cranberries shows promising potential as a supplement in the prevention and treatment of certain cancers. Their richness in polyphenols and antioxidants could play an important role in the fight against tumours.

However, further studies are still needed to confirm these effects in humans.