Can eating chocolate help ward off Type 2 diabetes? Yes, suggests a new Harvard study | Canada Voices

From advent calendars and yule logs to Hanukkah chocolate coins and boxed chocolates, it’s the time of year many of us love to indulge in the rich flavour and velvety mouthfeel of chocolate.

Turns out, there may be another reason to celebrate chocolate over the holidays (and beyond).

According to a large study from the Harvard T.H. Chan School of Public Health, including chocolate in your regular diet may guard against Type 2 diabetes.

There’s a caveat, however. The benefit of chocolate depends on which type you eat. Here’s what to know.

The new research findings

The study, published this month in the BMJ, investigated the association between milk, dark and total chocolate (both types) and risk of Type 2 diabetes.

The researchers looked at data from three large observational studies initiated in the mid-1970s and 1980s involving 192,208 healthy male and female health professionals.

Participants were followed for three decades, during which time their diet was assessed every four years, including chocolate consumption. Information on lifestyle factors and medical conditions was collected every two years.

During the follow up period 18,862 people developed Type 2 diabetes.

People who consumed at least five one-ounce servings of any type of chocolate each week were 10 per cent less likely to develop Type 2 diabetes compared to those who rarely or never ate chocolate.

When the researchers looked at specific types of chocolate they found that participants who consumed at least five weekly one-ounce servings of dark chocolate had a 21 per cent lower risk of diabetes than those who rarely or never ate dark chocolate.

There was no association between milk chocolate intake and diabetes risk.

To arrive at the findings, other diabetes risk factors were accounted for including age, body weight, diet quality, physical activity, smoking status, alcohol intake and family history of diabetes.

Strengths, limitations

The study is credited for examining the association between different types of chocolate and diabetes risk. Previous studies have mostly focused on total chocolate intake.

The study’s repeated diet measurements, large sample size and long follow up duration are other strengths.

The main limitation is the study’s observational design. It found a correlation between chocolate intake and diabetes risk, which does not prove that eating chocolate results in a lower risk of developing diabetes.

The researchers stated that randomized controlled trials are needed to replicate the findings.

Even so, the study’s finding that total chocolate intake reduces diabetes risk align with results from three previous observational studies.

Plus, there are plausible ways in which dark chocolate may guard against Type 2 diabetes.

How dark chocolate may protect

Dark chocolate is an excellent source of flavanols, phytochemicals in cocoa beans that have antioxidant and anti-inflammatory effects that may protect insulin-producing cells in the pancreas.

Flavanols also have blood-vessel-relaxing effects. One small clinical study showed that flavanols lowered blood pressure and improved insulin sensitivity in people with prediabetes.

Compared to other types of chocolate, dark chocolate has the highest cocoa content (50 to 90 per cent) and, as such, contains the most flavanols.

Milk chocolate has a lower cocoa content (about 35 per cent) and one-fifth of the flavanols of dark chocolate. White chocolate, which isn’t made from cocoa beans, has no flavanols.

The higher sugar content of milk chocolate may also contribute to why it doesn’t deliver the same metabolic health benefits as dark chocolate. One ounce of milk chocolate delivers 15 g of sugar (nearly four teaspoons worth), while an ounce of 70 per cent dark chocolate has 9 g (two teaspoons worth).

The higher the per cent cocoa solids, the lower the sugar content. An ounce of 85 per cent dark chocolate, for example, contains 4 g of sugar.

Although dark and milk chocolate have a similar calorie and saturated fat contents – 170 calories and 7 g saturated fat per ounce – dark chocolate’s abundant flavanols may offset the effects of sugar and saturated on diabetes risk.

Takeaways

If you love dark chocolate, enjoy it as part of a healthy diet but don’t overdo it. Stick to a one-ounce portion.

To lower your risk of Type 2 diabetes, prioritize lifestyle and diet strategies supported by strong evidence.

A modest weight loss of 5 to 7 per cent combined with 150 minutes of exercise per week, especially brisk walking, has been proven to prevent diabetes in people who are overweight and have prediabetes.

Eating too few whole grains, too many refined grains and too much red and processed meats are believed to be key dietary drivers of Type 2 diabetes cases globally.

Replace foods made with refined (white) grains with ones made with whole grains.

Avoid sugar-sweetened beverages such as soft drinks, fruit drinks, iced tea and energy drinks.

Eat little, if any, processed meats (e.g., deli meats, sausage, bacon, hot dogs).

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD