Study to strengthen bilberry-cancer link

The studies, led by Professor Andy Gescher of the University of Leicester, will use the commercial product Mirtoselect (Indena) and will look at the potential benefits of bilberry extract against colorectal and liver cancer.

"We are interested in agents, many of them derived from diet, which may prevent cancer or delay its onset," said Gescher.

"Our current research, funded by Hope Against Cancer, involves berries, coloured blue or red, which contain chemicals called anthocyanins.

These have long been suspected to have a beneficial effect in this sense.

"We take an individual chemical out of its context and investigate it.

Instead of asking people to eat a punnet of bilberries, we ask them to take Mirtoselect, which contains anthocyanins.

We also study whether anthocyanins are more efficacious when they are part of a dietary mixture.

There is some evidence to say that this may be the case," he added.

The research project builds on previous laboratory studies with animals that found Mirtoselect decreased the development of colorectal cancer.

The next stage is to quantify how much of the bilberry extract actually gets into human tissue and whether there are changes in the tissue that may have been caused by the substance.

If so, then that indicates that taking the extract over a long period may be beneficial.

If not, then the researchers have to decide whether it is feasible to increase the dose and whether it is right to go forward to a major clinical trial.

By comparing results with their laboratory model, the research team will have an indication as to how effective the bilberry extract is likely to be in preventing cancer.

This will help them to design a protocol for a future clinical trial that will test whether it really does interfere with the onset of colorectal or liver cancer.

Co-researcher Sarah Thomasset said: "Modern medicine is increasingly trying to find ways to prevent diseases from developing.

You can see this in the Public Health Warnings on tobacco products.

Our research project is looking at substances which can be taken as tablets and which may slow down the development of a cancer, or even prevent it from occurring in the first place."

Bilberries are closely related to the North American blueberry but contain a very distinct anthocyanin profile.

Bilberry extracts are relatively expensive, with the price per kilo now estimated at around €600.

Concerns are rife within the industry of lower-price extracts reported to be mixed with mulberry or black bean skins or azo-dyes.

Concerns were raised last year when Australian scientists discovered that azo dyes were used to mimic the colour of bilberries in a commercial product ( J. Agric.

Food Chem 2006, Vol. 54, Issue 19, pp. 7378 -7382).

This has since expanded to reports of mulberry or black bean skins being used to increase the anthocyanin content of the extracts.

The anthocyanins content is used as the standard for bilberry, and UV spectrometry is needed to verify the 25 per cent anthocyanins.

However, according to unconfirmed reports, this has led to extracts masquerading as bilberry but actually containing mulberry (22-24 per cent), or black bean skin (20 per cent).

The bilberry project is the latest in a long line of research carried out by Professor Gescher and with the team having investigated the potential anti-cancer properties of curcumin, the yellow constituent of curry.