August 11, 2020
Evidence in favor of chocolate consumption
It doesn't need to be Valentine's day to enjoy a heart-shaped chocolate treat. Chocolate is a favorite sweet treat for many people. People put chocolate in their coffee, on their ice cream, and even on their bacon. It is common knowledge that the sugar content of chocolate is not the best for our health. The carbs in sugar can lead to type-2 diabetes and obesity if not consumed in moderation. However, there are a number of studies that actually support the consumption of chocolate for heart health. In this article, we make the case for why chocolate may be good for your heart by covering a few studies with significant findings.
First, positive results were found in a meta-analysis that pooled data from 9 different studies. Altogether, the studies assessed over 150,000 subjects. They compared subjects who reported low chocolate consumption with those who reported high chocolate consumption. Subjects who reported high chocolate consumption had a reduced risk of heart disease as well as a reduced risk of heart disease mortality.
There are a few considerations we must take into account when interpreting this analysis. As with all self-reported data, there is a possibility of bias and, in this case, underreporting. The authors seemed to think that chocolate consumption may have been underreported by those at greater risk for heart disease, such as obese or physically inactive subjects. It is also possible that subjects at greater risk for heart disease due to other factors are advised to eat less chocolate by their friends or providers. In this case, the behavior of chocolate consumption is somewhat dependent on the existing risk of heart disease.
Cumulative evidence suggests that higher chocolate intake is associated with a lower risk of future cardiovascular events, although residual confounding cannot be excluded. There does not appear to be any evidence to say that chocolate should be avoided in those who are concerned about cardiovascular risk.
The next study had a similar number of subjects and measurements. However, the sample came from a US Veterans program and included mostly male seniors. the reduction in heart disease risk was not as dramatic as the first study, but still statistically significant. That is until they ran a secondary analysis for other factors. A subject's age, race, gender, and diabetes status did not alter the findings. However, there was evidence that BMI could be a modifying factor.
After adjusting for age, sex, race and lifestyle factors, corresponding hazard ratios (95% CI) for CAD were 1.0 (ref), 0.93 (0.86, 1.12), 0.91 (0.82, 1.00), 0.91 (0.82, 1.00), and 0.89 (0.80, 0.99), respectively (p for trend=0.037).
Source: Chocolate Consumption and Risk of Coronary Artery Disease, The Million Veteran Program
Lastly, we found a study with similar results from the Clinical Nutrition Journal. The study sample was smaller, but still large enough to allow for significant results. This study had the most dramatic results, stating that consuming chocolate 5 or more times a week was associated with a 57% reduction in the risk of heart disease.
Compared to subjects who did not report any chocolate intake, odds ratios (95% CI) for CHD were 1.01 (0.76-1.37), 0.74 (0.56-0.98), and 0.43 (0.28-0.67) for subjects consuming 1-3 times/month, 1-4 times/week, and 5+ times/week, respectively (p for trend <0.0001) adjusting for age, sex, family CHD risk group, energy intake, education, non-chocolate candy intake, linolenic acid intake, smoking, alcohol intake, exercise, and fruit and vegetables.
This study's results stayed strong when considering smoking status and age. Also, researchers measured dietary cholesterol and saturated fat intake, of which were higher for those with high chocolate consumption.
A factor that none of these studies accounted for the type of chocolate. Specifically, the nutritional properties of dark chocolate and milk chocolate are different. It is known that dark chocolate is healthier than milk chocolate because it has lower sugar content and fewer calories. This distinction would dramatically alter the results of these studies. Unfortunately, it is nearly impossible to control for all the relevant factors in a clinical trial setting. So for now, it is best to consume chocolate along with a balanced diet and regular exercise.