Sugar from cranberries could fight cancer, say scottish researchers

Mannose, a type of sugar found in cranberries and other fruits, is widely available as an alternative treatment for cystitis and urinary tract infections. It is thought to suppress cancer by

interfering with the ability of tumours to take up glucose. When mice with pancreatic, lung or skin cancer were given mannose in their drinking water, the growth of their tumours slowed

significantly with no obvious side effects. Lead researcher Professor Kevin Ryan, of the Cancer Research UK Beatson Institute in Glasgow, said: “Tumours need a lot of glucose to grow, so

limiting the amount they can use should slow cancer progression. The problem is that normal tissues need glucose, as well, so we can’t completely remove it from the body. “We found a dosage

of mannose that could block enough glucose to slow tumour growth in mice, but not so much that normal tissues were affected. “This is early research, but it is hoped that finding this 

perfect balance means that, in the future, mannose could be given to cancer patients to enhance chemotherapy without damaging their overall health.” To see how mannose might affect cancer,

mice were treated with cisplatin and doxorubicin – two of the most widely used chemotherapy drugs. Prof Ryan’s team found the nutrient enhanced the effects of chemotherapy, slowing the

growth of tumours and reducing their size. It also increased the lifespan of some mice. In further tests, cells from other types of cancer, including leukaemia, osteosarcoma (bone cancer),

ovarian and bowel cancer, were exposed to mannose in the lab. Some cells responded well. Others did not. The anti-cancer potential of mannose appeared to depend on whether an enzyme that

breaks down the sugar was present in cells. Prof Ryan added: “Our next step is investigating why treatment only works in some cells, so that we can work out which patients might benefit the

most from this approach. “We hope to start clinical trials with mannose in people as soon as possible to determine its true potential as a new cancer therapy.” But Cancer Research UK’s head

nurse, Martin Ledwick, warned cancer patients not to treat themselves with mannose. He said: “Although these results are very promising for the future of some cancer treatments, this is very

early research and has not yet been tested in humans. “Patients should not self-prescribe mannose as there is a real risk of negative side effects that haven’t been tested for yet. It’s

important to consult with a doctor before drastically changing your diet or taking new supplements.” Dr George Poulogiannis, from The Institute of Cancer Research, London, said: “This study

highlights how interfering with key characteristics of tumour metabolism can help identify cancer’s Achilles heels, and could lead to more effective therapeutic strategies. “However, there

is a lot of work to do before this research can be translated into the clinic, including clinical trials to test whether the treatment is safe and can slow tumour growth in cancer patients.”

The research is reported in the latest issue of Nature – a multidisciplinary scientific journal.