Red Wine Polyphenols in Cancer Research
by Dr. Erik Skovenborg
In the eyes of science all alcoholic beverages are created equal,
however, some drinks may be more equal than others. Red wine may be one
of those beverages offering a dual action of alcohol and antioxidants.
The name of the game is Red Wine Polyphenols (RWP) – compounds derived
from grape tannins and anthocyanin pigments that belong to the most
powerful antioxidants in the world. As we absorb polyphenols, they change
the properties of blood lipids making LDL-cholesterol more resistant to
the sort of oxidation that can trigger atherosclerosis and coronary heart
disease. From Coronary Heart Disease to Cancer
For many years the overwhelming evidence that light-to-moderate
alcohol use lowers the risk of coronary heart disease has been in focus.
In 2000 Morten Grønbæk with a study of data
from 257,859 person-years of follow-up (the Copenhagen Centre for
Population Studies) was able to conclude that not only did wine drinkers
have significantly lower mortality from coronary heart disease; with a
consumption of 1-3 glasses a day wine drinkers also reduced their risk of
cancer by 20 percent compared with non-drinkers. As the number of global
cancer deaths are rising there is an urgent need of efficient methods of
cancer prevention and cancer cure. Earlier studies have found a strong
protective effect of intake of fruits and vegetables against cancer. The
potential role of red wine polyphenols in cancer prevention may turn out
to be one of the most exciting areas of current cancer research.
RWP in cancer prevention
In 2000 Elias Castanas, professor of experimental endocrinology at the
University of Crete’s School of Medicine in
Iráklion, published important papers on the inhibitory
action of Red Wine Polyphenols on human breast cancer cells and human
prostate cancer cells. In collaboration with Joseph Vercauteren,
professor of pharmacology at the Université Victor Segalen
in Bordeaux and expert in polyphenols, Elias Castanas added polyphenols
derived from from de-alcoholized red wine to cultures of breast cancer
and prostate cancer cells. The RWP had an antiproliferative effect on the
cancer cell lines in test tube experiments in the laboratory. During a
short stay in Crete in the lovely September weather we had the
opportunity to ask professor Castanas some questions about his important
cancer research.
Assisted cancer cell suicide
To professor Castanas one of the most intriguing discoveries of his
laboratory tests is the very low concentrations of polyphenols needed to
inhibit cancer cell growth. Traditional chemotherapy is based on a group
of cell poisons the success of which depend on whether the poisons kill
the cancer cells before they kill the patient. Polyphenols are non toxic
compounds; as a matter of fact it looks as if the RWP have very few side
effects. So if the polyphenols do not poison the cancer cells, how do
they manage to inhibit and eventually kill them? Castanas has an idea
that includes the phenomenon of apoptosis: programmed cell death. The
general purpose of apoptosis is to have any cell that suffers from
irreparable DNA damage kill itself. Maybe the action of RWP on cancer
cells can be described as “assisted suicide”. Elias Castanas and his
colleagues are working hard to find the answers. His laboratory is doing
some preliminary animal (mice) studies that seems to back his test tube
research on cancer cells. No studies with cancer patients has yet been
performed as far as Castanas knows, and besides he warns that such
studies are premature. “Science is five years away from proving whether
wine’s antioxidant polyphenols do kill breast and
prostate cancer cells in humans”.
Other polyphenols to look for
In his tests professor Castanas has used several different polyphenols
such as quercetin against cancer cell lines. However, an extract of total
RWP is what he favours for his experiments. So far more than 200
polyphenols have been identified in red wine, and Castanas has the
opinion that the combined group of polyphenols is more active than the
single compounds by themselves.
Professor Castanas has conducted some experiments with tea polyphenols
and the results were more or less the same as for RWP. He has not yet had
the opportunity to work with beer polyphenols, however, Castanas is
familiar with some of the polyphenols in beer. In his opinion there is no
substantial mechanistic difference between the polyphenols in wine, beer
and tea, however, based on his experience RWP millimol per millimol have
a higher antioxidant capacity than other polyphenols.
Bioavailability of polyphenols
The question of bioavailability is a crucial question: if you drink a
bottle of full-bodied red wine you consume about 2 grams of RWP; what
part of these healthy compounds is absorbed during the process of
digestion to become available to target tissues like the endothelial
cells of blood vessels or the nerve tissue of the brain? Professor
Castanas has good news to wine drinkers: alcohol protects the RWP, so a
glass of Cabernet Sauvignon is a good vehicle for polyphenols. For those
who want a steak on the plate to go with their Cabernet here is more good
news: proteins have a dual action protecting the RWP from oxidation and
increasing the bioavailability of the healthy compounds. That added bonus
leads directly to Elias Castanas’ favourite advice
concerning a sufficient daily intake of polyphenols: eat a normal meal
with a variety of foods like fruit, vegetables, legumes, olive oil, bread
and fish accompanied by moderate consumption of wine.
Polyphenols on the table or in a capsule?
Who wants to spend hours in the kitchen scraping carrots, cleaning
fish and peeling fruit? Why not relax in the sun with an exciting book
washing down a capsule of RWP with Dry Martini? No, says the Cretan
professor, the antioxidant activity of extracts of polyphenols is poor
compared to the antioxidant power of polyphenols from natural fruits and
vegetables. Besides there is always the problem of protecting the
extracted polyphenols from oxidation. With an ample supply of
antioxidants from various sources like fruit, vegetables, vegetable oils
and wine you arm the cells of your body with heavy antioxidant artillery
to face any oxidant threat.
Professor Castanas is a founder member of the Greek academy of taste.
As a bon vivant with an intimate knowledge of the best restaurants on the
island of Crete the choice between a RWP-capsule and the fine cuisine of
Crete is easy. Raising a glass of fragrant Mirambelo, a red wine from the
grape varieties Kotsifali and Mandilaria picked from the mountain
vineyards of Peza, Castanas toasts the conclusion from the landmark
article on wine and health by St. Leger and A. Cochrane (Lancet
1979;i:1017-21): “If wine is ever found to contain a constituent
protective agent against I.H.D. then we consider it almost a sacrilege
that this consituent should be isolated. The medicine is already in a
highly palatable form”.
Dr. Erik Skovenborg is a founder member of the Scandanavian Medical
Alcohol Board, a specialist in alcohol and health and a member of the AIM
Editorial Board.
