Chocolate

What's in the cocoa bean?

Cocoa is a rich source of procyanidin flavonoids, including epicatechins and its derivatives. The antioxidant content is significantly higher than tea. Oligomeric polyphenols in cocoa are stronger antioxidants than monomeric polyphenols in tea. Oligomeric polyphenols inhibit reactive oxygen species which can damage cell membranes leading to diseases such as arteriosclerosis, cancer and the ageing process.

After an acute chocolate meal, plasma concentrations of epicatechin and plasma antioxidant capacity increase compared to an acute white chocolate meal. The increase in antioxidant capacity has been observed by a decrease in lipid oxidation by-products. These results suggest that flavonoids can be absorbed in quantities to influence the body’s defence parameters.

Any health benefits?

Antioxidants

Finally, some good news for chocolate lovers. It is not as bad for us as we think. Recent studies have indicated that certain ingredients in chocolate may play a role in preventing heart disease and cancer. Cocoa beans (one of the main ingredients of chocolate) contain over 600 plant chemicals including anti-oxidants which may protect against such diseases. Most of these studies however, have been conducted on cocoa flavoured beverages, not chocolate, which may be misleading. It is worth considering these studies, however, as the findings prove to be very interesting.

Cocoa beans contain a type of phytochemical (anti-oxidant) called polyphenols, which may have a role in the prevention of certain diseases. Polyphenols help guard the body's cells from damage by free radicals. The particular substances arousing so much interest are catechins which are a type of polyphenol. It is these catechins which aid resistance against degenerative diseases such as cancer and heart disease. Catechins can also be found in fruits and vegetables, but the body needs to capture as many different types of catechins as possible such as those found in tea and chocolate. Dark chocolate has higher concentrations of catechins due to higher levels of cocoa.

Feeding studies in human showed that LDL cholesterol in the blood taken 2 hours post consumption of chocolate was less likely to oxidise. One study demonstrated that chocolate polyphenols affected platelet activation proteins. When platelets which were exposed to chocolate polyphenols were stimulated with epinephrine (known to cause platelet aggregation) aggregation decreased, thus reducing the risk of blood clot formation. More evidence is needed on how these findings translate to heart health. 

Saturated fat

Although chocolate has often been condemned due to it's high saturated fat content, the most predominant saturated fat in chocolate, stearic acid, does not have the same cholesterolaemic effect as other saturated fats. The major lipid in chocolate consists of oleic acid, stearic and palmitic acids. Several studies indicate that stearic acid has a neutral effect on blood lipids. However, stearic acid may activate clotting factor VII, may increase lipoprotein Lp(a) concentration and may impair blood clot break down (fibrinolysis) (AJCN 1999; 70: 951). However, cocoa butter appears to decrease platelet activity, potentially beneficial for cardiovascular health. Stearic acid can be found in meat fat, some margarines, and chocolate.

Dark chocolate versus milk chocolate

A study reported by Vlachopoulos at the 2004 European Society of Cardiology demonstrated for the first time how chocolate improved the function of blood vessels, allowing them to dilate, which would help prevent the formation of potentially damaging clots. The study showed that eating 100 grams of dark chocolate improved vessel function in 17 healthy young adults for at least three hours.
Dark chocolate contains high levels of an antioxidant called flavonoids. This study sheds new light on how the mechanism might work, by protecting blood vessels from the damaging effects of unstable oxygen compounds called free radicals. Free radicals attack other atoms to stabilise themselves by stealing an electron, and in the process can damage cells. The study did not include milk chocolate, but the same benefits might not be gained from eating milk chocolate. In 2003, scientists reported that dark chocolate increased levels of antioxidants in the blood by nearly 20% where as milk chocolate did not have the same effect. It is thought that milk may interfere with the absorption of antioxidants from the chocolate.

An Italian study by Lippi et al published in the March 2005 edition of the American Journal of Clinical Nutrition showed that eating 100g dark chocolate (as opposed to white chocolate) for 15 days improved insulin sensitivity and lowered systolic blood pressure in healthy individuals.If you are trying to lose weight, however, 500g a day of dark chocolate may not help as it will add about 600 calories to your diet!

Conclusion

We must still remember though that chocolate is a high-fat food and must be consumed in moderation as part of an otherwise nutritious diet. Evidence to date suggests that the health benefits are primarily seen with dark chocolate and some healthy eating guides recommend up to 200g dark chocolate a week.
It is also advisable to obtain the benefits of catechins from cocoa (e.g. as hot chocolate, mocha coffee) rather than chocolate because plain cocoa does not have the fat content of chocolate. Traditional Mexican cuisine uses dark chocolate in savoury white meat and vegetable dishes. Chocolate eaten this way has a lower energy density. Tea also contains catechins (although not as many as chocolate and cocoa) and may therefore provide some of the same benefits as consuming cocoa or chocolate without the fat.

More information

Chocolate Information Centre

References
Chocolate Information Centre. Chocolate and Fat.
Chocolate Information Centre. Chocolate and Polyphenols.
Arts, I.C.W., Hollman, P.C.H. & Kromhout, D. Chocolate as a source of tea flavonoids. The Lancet. Vol354; August 7, 1999;pp488.

 

Last Updated: June 2005