07 April 2010
Chocolate lowers heart disease and stroke risk
Research suggests eating chocolate can lower heart disease and stroke risk, partly by lowering blood pressure.
Research published in the European Heart Journal has linked chocolate with a reduced risk of heart disease and stroke in middle-aged people. It suggests chocolate may lower blood pressure, which is likely to contribute to the reduced risk of heart disease and stroke seen in the study.
German researchers looked at 19,350 men and women aged between 35 and 65, who were from the Potsdam area in Germany and had taken part in the European Prospective Investigation into Cancer (EPIC). The researchers wanted to see if chocolate is linked to lower blood pressure and a lower risk of heart disease and stroke. They specifically thought that chocolate intake would reduce stroke risk more than heart disease risk.
This study included a questionnaire about food intake, blood pressure measurements, body measurements (including waist circumference and body mass index) socio-demographics, lifestyle and incidence of chronic diseases. The people were first questioned and examined between 1994 and 1998 and questionnaires were sent every two to three years to find out if they had developed any chronic diseases. The researchers monitored these people for about eight years. None were taking any medication for high blood pressure.
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Dr Annabel Bentley, Assistant Medical Director, Bupa |
This does not mean that we can start saying 'a chocolate a day keeps the doctor away'. 
In the group of people with the lowest intake of chocolate, 59 people had a heart attack and 47 had a stroke. In the group of people with the highest chocolate intake, the numbers were lower. In this group 34 people had a heart attack and 22 had a stroke.
On average, the low chocolate intake group ate about 1.5g of chocolate per day and the high chocolate intake group had about 7.5g per day - about one small bar of chocolate a week. A 6g increase of chocolate per day was linked to a 39 percent lower risk of heart attack and stroke. Lowering of blood pressure was thought to be partly responsible for reduced risk and the link was seen to be stronger for stroke than heart disease.
The majority of people in the study ate milk rather than dark chocolate and a few ate white chocolate. Cocoa contains chemicals called flavanols that are thought to have beneficial health properties and may improve the health of blood vessels and how well blood clots; these properties may have contributed to the results too. The researchers suggest that eating chocolate, particularly chocolate with higher amounts of cocoa (darker chocolate), may be beneficial for health, but only in small amounts.
However, the researchers only measured chocolate intake once at the start of the study. Diet can change over time and this was not taken into account. Other factors that were not measured or adjusted for may have caused the decrease in heart disease and stroke risk.
Bupa's Assistant Medical Director, Dr Annabel Bentley, said: "This rigorous cohort study gives some interesting insight into foods that are linked with a lower rate of stroke and heart disease. However, it does not mean that we can start saying 'a chocolate a day keeps the doctor away'. Understanding the links between diet and health are complex, and even well conducted research can only give us pointers."
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Related topics
- Haemorrhagic stroke health factsheet
- Heart attack health factsheet
- High blood pressure health factsheet
- Ischaemic stroke health factsheet
- Stroke health factsheet
- Transient ischaemic attack health factsheet
Read the study
Buijsse B, Weikert C, Drogan D, et al. Chocolate consumption in relation to blood pressure and risk of cardiovascular disease in German adults. Eur Heart J 2010. doi: 10.1093/eurheartj/ehq068
