However consuming chocolate every day can eliminate its positive benefits, says the study.
Lead researcher Dr Murray Mittleman of Harvard Medical School said: “You can’t ignore that chocolate is a relatively calorie-dense food and large amounts of habitual consumption is going to raise your risks for weight gain.
“But if you’re going to have a treat, dark chocolate is probably a good choice, as long as it’s in moderation.”
In fact in the nine-year study, conducted among 31,823 Swedish women, researchers looked at the relationship between the amount of high-quality dark chocolate eaten and the risk of heart failure.
The researchers found that women who ate an average of one to two servings of the high-quality chocolate per week had a 32 per cent lower risk of developing heart failure. Those who had one to three servings per month had a 26 per cent lower risk, but those who ate at least one serving daily or more didn’t seem to benefit from a protective effect against heart failure.
Dr Mittleman said the lack of a protective effect among women eating chocolate every day was probably due to the additional calories gained from eating chocolate instead of more nutritious foods.