|
04/11/2007
Drink of the Gods
My very first column (5/12/1999) under my nom de plume of Dr.
Bortrum was titled “NO, NO, NO”. Its subject was the emerging
realization that nitric oxide, NO, plays an important role in the
body. In a flagrant attempt to capture an audience, knowing that
sex sells, I cited NO as promoting blood flow as a consequence
of taking Viagra. In a later column (11/27/2003), I discussed hot
cocoa as a drink full of beneficial antioxidants and also
mentioned the use of magnetic resonance imaging, MRI, to look
at blood flow in the brain. Subsequently (9/1/2004), I wrote
about studies suggesting that dark chocolate might be good for
the heart and posing the possibility that nitrates in hot dogs might
actually have some good qualities thanks to the formation of NO
in the stomach.
Last week I noted that the late Paul Lauterbur shared the Nobel
Prize in 2003 with physicist Sir Peter Mansfield of the University
of Nottingham for their MRI work. This past week, I’ve learned
of other studies at Nottingham, at Harvard and in Panama that tie
together MRI, chocolate and nitric oxide. Chocolate has been in
the news recently at least in part due to these studies.
At Nottingham, Ian Macdonald, President-Elect of the UK
Nutrition Society, led a study that focused on the effect of
drinking cocoa on blood flow in the brain. The work was
reported in February at a meeting of the American Association
for the Advancement of Science (AAAS) in San Francisco. The
cocoa used in the study was not the mild type you would make at
home or find at your local coffee shop. It’s not surprising that
Mars, maker of M&Ms and other chocolaty delights, sponsored
the Nottingham work as it has other research on chocolate and
health for some 15 years. I found a wealth of information on
chocolate on the Mars Web site.
“Chocolatl” was the drink imbibed by the Aztec and other
Indians in Mexico dating back a thousand years or so. The hot
cocoa that the Aztecs drank was not your namby-pamby drink of
today. They considered it the food of the gods and combined it
with chili peppers and other spices – not a particularly appealing
drink to me. Montezuma introduced chocolate to Cortez, who
carried it back to Europe, where it evolved into today’s milder
drink and confection. In the process, many or most of the
original flavanols and other beneficial ingredients have been lost
or diluted.
However, the Kuna Indians of Panama have preserved the cocoa
drink in a form that more closely approximates the Aztec drink
of the gods. While the Aztecs were being destroyed by the
Spanish conquerors, the Kuna apparently fled to the coast and a
chain of islands known as the San Blas Archipelago. Today
there are the San Blas Kuna and Kuna that have moved to the
mainland, living in Panama City and its suburbs. The San Blas
Kuna have kept more to their old ways and drink several cups a
day of their cocoa. Mars has analyzed the cocoa and it contains
much larger amounts of flavanols than the processed cocoa
available here in the U.S. or in Europe. Mars has come up with
“Cocoapro”, a cocoa that more closely approximates the cocoa
drunk by the San Blas Kuna. The flavanol-rich Cocoapro has
been used in some of the studies described below.
In the early 1990s, Norman Hollenberg, of Harvard Medical
School and Brigham and Women’s Hospital, was interested in
high blood pressure. He thought there might be genes that
protect against high blood pressure and figured that if he could
find an isolated group of people known to have low blood
pressures, he might find such genes. The Kuna Indians fit the
bill. However, Hollenberg was disappointed to find that the
Kuna who moved to the mainland had blood pressures as high as
others living in urban environments. The Kuna had no special
protective genes. So, what is special about the San Blas Kuna?
Perhaps they eat less salt than their mainland counterparts? It
turned out they might actually eat more salt on the islands.
Hollenberg and his team found that the biggest difference in the
lives of the two Kuna groups was that the islanders still drank
their old-fashioned flavanol-rich cocoa. In a recent issue of the
International Journal of Medical Sciences, Hollenberg and three
colleagues, Vicente Bayard, Fermina Chamorro and Jorge Motta
from the Instituto Commemorative Gorgas de Estudios de la
Salud in Panama, published a very interesting study.
They took the death certificates for the San Blas and the
mainland Kuna for the years 2000 to 2004 and calculated the
death rates for cardiovascular disease, cancer and diabetes
mellitus. The results were startling. Adjusted to a figure of
deaths per 100,000, the rate for heart disease was 83 for the
mainland Kuna and only 9 for the San Blas Kuna! For cancer,
the numbers were 68 mainland and 4 San Blas and for diabetes
mellitus, 24 and 7, respectively. The islanders are doing
something right!
Hollenberg and his colleagues caution that these are
“observational” studies and therefore can’t be considered
“definitive”. But what is the reason for the apparent magical
properties of cocoa? Could it be that the flavanol-rich cocoa is
producing NO? On the Harvard Web site there’s an article by
William Cromie about Hollenberg’s work and it says lab tests
show that the cocoa used by the Kuna does indeed stimulate the
body to produce nitric oxide, which we’ve already said promotes
blood flow.
Lest you think I’ve forgotten Nottingham, Ian Macdonald and his
team of Susan Francis, Kay Head and Peter Morris reported to
the same AAAS meeting in February that they used MRI in work
showing that flavanol-rich cocoa increases blood flow in the
brain for 2-3 hours after drinking it. Macdonald suggests the
flavanols might help to improve cognitive performance after
sleep deprivation or in the elderly. Reduced blood flow has been
associated with various diseases such as Alzheimer’s.
February also saw publication of an article by a team of German
workers in the Journal of Cardiovascular Pharmacology that
proclaimed the benefits of high-flavanol cocoa in a study of male
smokers known to have problems with blood vessel function.
Drinking high-flavanol cocoa improved blood flow by amounts
proportional to the amount of flavanols drunk by the subjects.
With several cups of cocoa a day the blood flow improved so
much as to be similar to that of one with no cardiovascular
problems. This held as long as the subjects drank the cocoa.
When the subjects stopped drinking the cocoa, blood flows
returned to the low values prior to the beginning of the study.
In a paper I found in the Proceedings of the National Academy of
Sciences of January 24, 2006, Hollenberg and some of the same
German authors joined forces to isolate a particular flavanol.
They showed a direct correlation of drinking that flavanol and
improved cardiovascular activity. This paper had two co-authors
from the Mars company and the obvious conflict of interest was
duly noted at the end of the paper. However, I was not aware of
the wealth of research that has been done on cocoa/chocolate and
NO and blood flow. I’m reasonably convinced that all this
recent “chocolate’s good for your health” talk isn’t just hype.
After posting this column, I plan to celebrate with a couple of
raisins covered with dark chocolate – as close as I can get to
flavanol-rich cocoa at the moment.
Allen F. Bortrum
|
