Sorry, No Proof Chocolate Prevents Stroke

Just shy of Valentine's Day, a holiday known for the sale and consumption of copious amounts of chocolate, Canadian researchers have released a review of studies to assess whether eating chocolate is associated with a lower risk of stroke.

They looked through 88 publications and narrowed them down to three that were relevant.

But even after that, Dr. Gustavo Saposnik, a self-described chocoholic and neurologist at St. Michael's Hospital in Toronto, said, "You can't draw conclusions."

The review was released Thursday and will be presented at the American Academy of Neurology's annual meeting in Toronto in April.

"More research is needed to determine whether chocolate truly lowers stroke risk, or whether healthier people are simply more likely to eat chocolate than others," said study author Sarah Sahib of McMaster University in Hamilton, who worked alongside Saposnik.

One study published in 2007 in the American Journal of Clinical Nutrition looked at more than 34,000 postmenopausal women in the Iowa Women's Health Study, and found that those who ate one serving of chocolate per week were 22 per cent less likely to have a stroke than people who ate no chocolate.

Another study published last year in the Journal of Internal Medicine involved more than 1,100 people in Sweden, and found that those who ate 50 grams of chocolate once a week were 46 per cent less likely to die following a stroke than people who did not eat chocolate.

A third study found no link between eating chocolate and risk of stroke or death.

In the first two studies, the findings are associations, not cause-and-effect. And there's an important caveat, Saposnik cautioned.

"There is some confounding issue here ... you can't control in these studies for what people may also eat outside of a study."

As well, subjects did not identify what kind of chocolate they had eaten, and Saposnik notes there are differences.

"Milk chocolate or white chocolate or dark chocolate have completely different compositions," he said, and probably have a completely different profile on risk of stroke.

Chocolate - in particular dark chocolate - contains flavonoids, compounds known for their antioxidant properties, and also found in varying degrees in fruit, vegetables, tea and red wine. They've been linked to potential benefits for human health.

In terms of long-term cardiovascular risk, Saposnik said there are some components of chocolate, such as saturated fat, that are associated with an increase of bad cholesterol, the LDL cholesterol.

"The recommendation is do not eat chocolate," he said, adding he tries to consume it only "in moderation" and chooses dark chocolate that's low-fat.

To reduce stroke risk, the Heart and Stroke Foundation of Canada recommends, among other things, eating a balanced diet that's higher in fruit and vegetables, reducing saturated and trans fats, reducing sodium consumption and increasing fiber.