From the Rare Fruit Club WA
by John H Weisburger
Cocoa, chocolate and the food processors
"Eat to Live, Not Live to Eat"
We've all been told in
health documentaries, magazines, news reports etc. that chocolate in
moderation is good for you. It's delicious and the problem for almost
everybody is that it can be hard to stop at only a few squares without
eating the whole block in one go. It's a high calorie food because of
the high fat content and the usual addition of milk products and sugar.
Dark chocolate, where these additives are reduced or absent is
healthier but is far less popular because of the reduced sweetness - to
many it just tastes unpleasantly bitter. Chocolate is made from ground
cacao bean kernels that come from the fruit tree Theobroma cacao. World production is centred in tropical countries, mainly west Africa.After
harvesting, the pods are broken, much of the flesh is removed and the
seeds are then fermented, dried and exported worldwide. Kernels are
roasted and pressed to extrude the cocoa butter primarily for chocolate
production, and the remaining solid cocoa cake is dried and ground to
produce cocoa powder. Separation of the two is not complete, but the
powder contains a much higher concentration of health-promoting
flavonoids (variable but average of 261mg/100g compared to 53 and 15
mg/100g in dark and milk chocolate respectively) and has lower calories
(370 and 550kcal/100g respectively). There is also evidence that the
milk products and sugars added to chocolates reduce flavonoid activity,
and a further consideration is that the average serving size for cocoa
powder is 3g, while the size for dark and milk chocolate is 17g and
32g, respectively. So if cacao products are eaten from a nutritional
viewpoint rather than straight enjoyment, cocoa powder has the best of
both worlds – higher effective flavonoids and lower calories. What does
the research say about consuming cocoa powder? The following is a
summary of a study published in the International Journal of Medical
Sciences (2007), 4, 53-58.
| Substantial
data suggest that flavonoid-rich food could help prevent cardiovascular
disease (CVD) and cancer. Cocoa is the richest source of flavonoids,
but current processing reduces the content substantially. The
indigenous Kuna Indians living in the Panamanian San Blas islands drink
a natural flavanol-rich cocoa as their main beverage. This provides
more than 900 mg/day and probably means they have the most
flavonoid-rich diet of any population worldwide. We used diagnosis on
death certificates to compare cause-specific death rates from year 2000
to 2004 on the mainland and San Blas islands where only Kuna live. In
this period there were 77,375 deaths on the mainland and 558 deaths in
the San Blas. As anticipated on the mainland, CVD was the leading cause
of death (83 age adjusted deaths/100,000) and cancer was second (68).
In contrast, the age-adjusted rate of CVD and cancer among
island-dwelling Kuna was much lower, 9 and 4 respectively. Similarly,
deaths due to diabetes mellitus were much more common on the mainland
(24) than in the San Blas (6). This comparatively lower risk among Kuna
in the San Blas from the most common causes of morbidity and mortality
in much of the world possibly reflects a very high flavanol intake.
However, many other risk factors could possibly be involved and an
observational study such as the present cannot provide definitive
evidence. |
The authors are
commendably cautious in recognising their study is not the last word on
this topic, and recommend further work in the field. But given such a
major impact on the common western chronic diseases, the question for
individuals is – should I include some cocoa in my diet now while
waiting for more exhaustive studies, or is it best to wait till the
story has been overwhelmingly settled in perhaps the next 10 years? The
authors of the above study did consider or evaluate some of the more
obvious possible contributing factors. For example, genetic differences
in the two populations are unlikely to be responsible because when the
Kuna migrate to the mainland they rapidly acquire the same disease
incidence as the mainlanders, they are an older population than the
mainlanders which normally would lead to increased disease rates
whereas theirs were lower, diet components in the two locations are not
significantly different apart from cocoa, and so on. In addition to
this study there are now many others focussed on different aspects and
using different approaches, and generally they all point in the same
direction – cocoa is good for you. The 900mg/day intake of the Kuna
compares with average flavonoid intakes in the US, UK, Ireland and
Australia of 190, 182, 177 and 130mg/day respectively.
A very
common intermediate step in cocoa kernel processing is called
alkalisation. This raises the pH, causes colour changes, reduces
bitterness and improves water miscibility, but most importantly can
destroy a lot of the beneficial flavonoids. If heavily alkalised, less
than 5% of what was initially there may be left. Food processors
accommodate the dominant sweet preference of consumers by alkalising,
so that almost all retail supplies of cocoa powder will have been
treated. The US requires alkalised cocoa products to be labelled as
such, but here some dogged detective work will be required to track
down ‘natural' cocoa powder if you want the full nutritional benefits.
After bean fermentation which we have little/no control over,
alkalisation is the principal cause of flavonoid loss. Most of the
5000-odd flavonoids known in plant materials are heat labile, but
fortunately the main ones in cocoa are more resistant. This means cocoa
powder can be incorporated into baked products such as biscuits,
muffins and cakes without causing significant loss of nutrient
benefits. However if some degree of rising is required, baking soda
should be avoided, as it is alkaline and will result in major flavonoid
breakdown.
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