Nothing excites health journalists (and their readers) more than a story about the latest “superfood”. From pomegranates and watercress to Goji berries and even chocolate, we’re bombarded with tales about cancer-fighting fruit and veg.
Reading the news, you might be led to think that a diet of red wine and jam is all you need. And just this week the media is hailing broccoli juice as the next ‘cure for bladder cancer’.
Ed’s already gone into some detail as to why “superfood” stories are often scientifically misguided, and how it’s unlikely that eating these foods can cut cancer risk. But naturally-occurring chemicals do have their place in the fight against cancer – for example, aspirin (originally derived from willow bark) is being researched as a cancer- preventing drug.
And while we definitely don’t endorse glugging broccoli juice as a treatment for cancer (the Daily Mail doesn’t count as a peer-reviewed journal) and – contrary to the news report – we’re not investigating the specific juice recipe in question, we are funding a study to test whether a chemical found in broccoli can help to curb the development of cervical cancer. And that’s not all – we’re also funding research to get to the scientific root of some of these so-called “superfoods”.
CRISP-1: broccoli and cancer prevention
Professor Peter Sasieni is a highly respected researcher into cancer screening and prevention. Funded by Cancer Research UK, Professor Sasieni is running a large-scale clinical trial called CRISP-1, testing whether di-indolylmethane (DIM) tablets can prevent pre-cancerous changes in cervix from progressing into full-blown cancer.
The trial’s involving around 3,000 women and is placebo-controlled, meaning that women either get DIM or a dummy drug. Once the study is finished, the results will be analysed and published in a scientific journal. Maybe DIM will be useful for cancer prevention, maybe it won’t, but the only way to find out is to carry out a scientifically rigorous study like this.
Phytochemicals and “superfoods”
We’re also funding an internationally respected team of researchers at the University of Leicester, who are looking in detail the chemicals contained in several foods, to find out whether they have potential to prevent cancer.
Professor Will Steward and his team are interested in several phytochemicals – natural chemicals found in fruit and veg. In particular, they’re interested in a family of phytochemicals called flavonoids, which are found in many plants, including cocoa (hence those “chocolate prevents cancer” stories).
Good sources of flavonoids include all citrus fruits, berries, onions, parsley, green tea, red wine, and dark chocolate with a cocoa content of 70 per cent or greater. But the amount of flavonoids found in these foods is relatively low, and it’s doubtful whether eating these foods has any effect on your cancer risk, however much chocolate you eat (sorry girls…). So Professor Will Steward’s carrying out experiments using purified phytochemicals.
His team is studying the effects of purified flavonoids on proteins in the body known as COX enzymes. These enzymes help to make molecules involved in inflammation – a process involved in certain types of cancer.
COX enzymes can also be targeted by nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin, which, as mentioned above, are currently being investigated by Cancer Research UK and other organisations for cancer prevention. But NSAIDs can cause side effects, especially with long-term use. Plant-derived COX-blockers might be a better alternative.
This research is still under way, but so far the Leicester team have published an interesting paper looking at whether three flavonoids – tricin (from rice bran), apigenin (from parsley and celery) and quercetin (found in apples and onions) – can affect COX enzymes.
Milk thistle and cancer prevention
The Leicester team are also investigating a molecule called silibinin, found in the milk thistle plant. They’re currently testing silibinin in mouse models of bowel and prostate cancer. Their latest results, published in April this year, suggest that silipide (a mixture of silibinin and chemicals called phospholipids) might hold promise for preventing these cancers, and could potentially go forward into clinical trials.
Roll out the resveratrol
Finally, Profesor Steward’s team are also looking at resveratrol, a chemical found in red grape skins – and red wine (as discussed by Ed) There’s some evidence from animal tests and experiments on cells grown in the lab that resveratrol may have anti-cancer and other health benefits, but little is known about its effects in humans.
Professor Steward and his team are finding out more about the dosage of resveratrol in foods, compared to the doses that might be useful for preventing cancer. Using people with bowel or prostate cancer, or healthy volunteers, the team will be testing a tiny dose of resveratrol (5 milligrams per day) that mimics food intake and a ‘pharmaceutical’ dose 200 times the size (1 gram per day).
The researchers will use special analytical techniques to discover how the chemical is metabolised by the body, and where it goes, at each dosage level. Again, this work’s still ongoing, but the team have published the results of an early-stage clinical trial looking at dosage and metabolism of resveratrol in human volunteers.
Studies such as these are a hot topic of research at the moment and both Professor Sasieni and Professor Steward are hoping their work will lead to new developments in this area. So although the bad news is that consuming red wine and chocolate will never be an effective cancer prevention strategy, they could lead to new preventative drugs in the future.