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An Interview With Denis Gingras

Denis Gingras, researcher in the Molecular Medicine Lab of UQAM and co-writer, with Dr. Beliveau, of Foods That Fight Cancer, in conversation with Pan Pantziarka of LondonBookReview.com.

PP: For many cancer patients the dietary advice they recieve remains 'eat what you like so long as your weight stays up'. Even patients who go into remission but who have signficant risk of recurrence are told that what they eat doesn't make a difference. Why is the message not changing?

DG: Well, first of all the science was not conclusive until very recently. Reports on the impact of diet on cancer recurrence have only begun to be published in the last 2-3 years. Now, in its last report, the World Cancer Research Fund presents the first clear-cut recommendations for cancer survivors i.e. that after treatment, people should follow the general recommandations for cancer prevention (http://www.wcrf.org/research/expert_report/recommendations.php). It may take a few years from now but we believe that these concepts will gradually be integrated in the medical practice.

PP: For many people anti-oxidants are the be all and end all of diet and cancer. Why has this idea taken such a hold?

DG: I would say that this situation most likely reflect our tendancy to oversimplify complex issues. A few years ago, vitamins were the "stars" of nutrition ; minerals such as selenium came next and now, its antioxidants' turn. Of course, food is much more complex than that but most people do not have the scientific basis that is needed to understand this complexity.

I think that the concept of antioxidants took hold mainly because it is relatively simple to understand : people see what oxygen can do to their cars (rust) and can imagine how detrimental these processes may be for their bodies. Supplement makers also greatly contribute to this "antioxidant buzz" by aggressively promoting a variety of "miracle" products supposed to be active against the development of most diseases. That is not to say that antioxidants do not play an important role in disease prevention, they do. But this picture is incomplete : for example, two of the most potent antioxidant foods in our diet are coffee and chocolate but these are clearly not the most important things to eat in order to prevent cancer.

PP: Your book, (and your research), shows that inflamatory pathways are a key part of cancer development and metastases. But it is also the case that cancer cell metabolism, particularly with regards to glucose, is also important. Do you have any views on anti-cancer diets and glucose restriction?

DG: The scientific term for this phenomenon is the "Warburg effect" i.e. that cancer cells degrade glucose to lactic acid instead of using the usual metabolic pathway present in mitochondria. To the best of my knowledge, it is still not known if this altered metabolism is a cause or a consequence of cancer but some molecules that interfere with glucose metabolism have been proposed as cancer therapeutics. For example, a molecule named DCA came out a few years ago and it will be interesting to see its efficacity in clinical trials.

PP: While there is lots of excellent research on natural agents against cancer, much of this is still in vitro or early stage animal trials. Why the long wait for human trials?

DG: Basically one word : money. Natural molecules cannot be patented and so the industry is not very interested in such trials.

PP: Of the countless number of anti-cancer agents from food (curcumin, resveratrol, ellagic acid, EGCG, etc) which are the ones that hold most promise in your view?

DG: No doubt that curcumin is the most interesting. Phase I studies show that the molecule is extremely well tolerated even at high dosage. It also seems to be biologically active in some cancer patients (Clin Cancer Res. 2008 Jul 15;14(14):4491-9)

PP: Your book is clear that the emphasis should be on diet and not supplements. But it doesn't have to be either/or. How much value is there in adopting the kind of diet you propose and then supplementing judiciously as well?

DG: Several reports published during the last few years have clearly shown that supplements are ineffective in preventing cancer (as well as other chronic diseases). Meta-analyses of these studies have even show that high doses of some of these supplements (vitamins A and E, folate) actually increases the risk of cancer. A diet rich in foods of natural origin (fruits, vegetables, whole grains) contain sufficient amounts of vitamins, minerals and phytochemicals for maintaining a good health. Too much of a good thing is not necessarly a good idea.

PP: There is much research now on increasing bioavailability of natural agents, such as curcumin and resveratrol, by combing with synergistic substances or changing the delivery mechanism (liposomal encapsulation, nano or micronised formulations etc). Do you have any views on this area of research and development?

DG: Our main strategy is to sensibilize people to the need of eating well as a mean to prevent cancer. These are interesting approaches but, as for supplements, the underlying rationale is that it would be possible to achieve this goal without significant modifications in our lifestyles. So on a chemopreventive point of view, this does not seem to us to represent a promising approach. However, the therapeutic potential of these methods may be interesting and certainly warrants future investigation.

Contents © London Book Review 2010. Published March 03 2010