Women who eat at least two chocolate bars each week appear to have a 20% lower risk of stroke, compared to females of the same age and weight who rarely or never eat chocolate, researchers from the Karolinska Institute, Sweden, reported in the Journal of the American College of Cardiology. The researchers explained that cocoa has flavonoids – powerful antioxidants that can suppress oxidation of bad cholesterol (LDL, low-density lipoprotein). LDL can cause stroke and other cardiovascular diseases.

As background information, the authors explained that several studies have clearly demonstrated that chocolate can be good for the cardiovascular system – the circulatory system which comprises the heart and blood vessels. The consumption of chocolate has been demonstrated to reduce diastolic and systolic blood pressure in randomized, short-term trials. Chocolate has also been shown to improve endothelial and platelet function, and to improve insulin resistance.

Chocolate typically comes in dark, milk and white varieties. Its brown coloration comes from cocoa solids

Susanna Larsson Ph.D. and team set out to determine whether chocolate consumption might have an impact on the risk of stroke. They used the population-based Swedish Mammography Cohort. 39,227 adult females had completed a questionnaire that asked 350 questions regarding lifestyle and diet factors.

Some participants were excluded from their list, such as those whose total energy intake values did not make sense, women with a history of stroke, coronary heart disease, stroke, or diabetes before baseline. The list was then reduced to 33,372 adult females aged from 49 to 83 years.

A self-administered food questionnaire was used to assess their chocolate intake. They were asked to indicate with what frequency they ate chocolate and 95 other foods during the previous 12-month period. The women were divided into 8 categories, ranging from no chocolate intake to at least 3 times daily.

During the 1990s, nine out of every ten Swedish women ate milk chocolate with a cocoa solids content of about 30%. Cocoa content of chocolates in Europe is generally considerably higher than in the USA.

They gathered data on first stroke occurrence from the Swedish Hospital Discharge Registry, dated from January 1st, 1998, to December 31st, 2008.

Events of stroke were classified as:

  • Cerebral infarction (ischemic stroke)
  • Intracerebral hemorrhage
  • Subarachnoid hemorrhage
  • Unspecified stroke

They gathered dates of death from the Swedish Cause of Death Registry. They also collected data on incidence of atrial fibrillation.

Below is some highlighted data from their findings:

  • During a follow-up period of 10.4 years, there were 1,549 strokes, of which 1,200 were cerebral infarctions (ischemic stroke), 224 were hemorrhagic strokes, and the remaining 125 were unspecified strokes.
  • The women who ate the most chocolate (average 2.3 ounces per week) had the lowest risk of stroke, about 20% lower compared to those who rarely or never ate chocolate.

The authors found that their (large) study was broadly similar to previous smaller ones – with an inverse association between chocolate consumption and total stroke.

For risk to be significantly impacted, the authors add, chocolate consumption needs to be high. It was only the females in the highest quartile of chocolate consumption who had a significant drop in stroke risk.

Dark (plain) chocolate has a much higher concentration of cocoa, and consequently flavonoids than milk chocolate, and less sugar too, the authors wrote. They also warn against eating too much chocolate, because it has sugar, fats and many calories. Chocolate also contains caffeine.

The authors concluded:

“In summary, results from this cohort of women suggest that a high chocolate consumption is associated with a lower risk of stroke.”

Written by Christian Nordqvist