Dark chocolate is believed to have many health benefits, from protecting against cardiovascular disease to lowering blood pressure. Now, a new study published in the British Medical Journal (BMJ) suggests that eating dark chocolate could also reduce the risk of developing type 2 diabetes.
Scientists and medical professionals believe this could be important because diabetes has become increasingly widespread since the 1990s.
According to the latest data from the World Health Organization on diabetes, the number of people living with type 1 or 2 diabetes worldwide quadrupled to 830 million between 1990 and 2022, and the vast majority of them have type 1 diabetes. 2.
The consequences of this can be significant: diabetes can cause blindness, kidney failure, heart attacks, strokes and require amputation of lower limbs.
So what did this latest study reveal about dark chocolate and type 2 diabetes?
What is the difference between type 1 and type 2 diabetes?
Although type 1 diabetes and type 2 diabetes share a name, there are marked differences between how each of these chronic diseases of the body regulates blood sugar, known as glucose.
Type 1 diabetes occurs when the body's immune system fails and launches an autoimmune response against its own healthy cells. This occurs when the immune system incorrectly identifies these healthy cells as a foreign threat to the body, leading to the destruction of insulin-producing cells in the pancreas. As a result, the body loses its ability to effectively regulate blood sugar levels.
It is still unclear how type 1 diabetes develops, but most research points to a combination of a genetic predisposition in the individual and environmental triggers, such as certain viruses, that can trigger an autoimmune response.
According to a 2023 study published by several Greek medical institutions, 8.4 million people worldwide were suffering from type 1 diabetes in 2021. By 2040, the number of people living with type 1 diabetes worldwide is expected to range between 13.5 million and 17.4 million.
People diagnosed with type 2 diabetes experience insulin resistance, a condition that causes their bodies to continue producing insulin but unable to use it efficiently. This altered insulin function prevents proper regulation of blood sugar levels.
Type 2 diabetes is a chronic disease that usually develops gradually over several years. It is strongly associated with lifestyle factors, particularly physical inactivity and obesity. While it can occur at any age, this form of diabetes is most commonly diagnosed in adults.
What did the study reveal about dark chocolate and type 2 diabetes?
About 192,000 adults in the U.S. participated in three studies over 34 years conducted by Harvard researchers: the Nurses' Health Studies I and II and the Health Professionals Follow-up Study.
Not all subjects had type 2 diabetes at the start of the study. Participants reported their diabetes status (if they had it), eating habits, overall weight, and chocolate consumption over time.
People who consumed dark chocolate regularly (specifically five or more servings per week) experienced a 21 percent reduction in the risk of developing type 2 diabetes. The risk was measured by comparing the incidence of type 2 diabetes among participants who consumed different amounts of chocolate.
Over the course of the studies, approximately 19,000 people who previously did not have diabetes were diagnosed with type 2 diabetes.
However, among the nearly 112,000 participants who reported consuming chocolate, only 5,000 developed type 2 diabetes.
Studies revealed that while dark chocolate had beneficial effects, other types of chocolate did not.
“Higher consumption of dark chocolate, but not milk, was associated with a lower risk of type 2 diabetes [type 2 diabetes]. “Increased consumption of milk, but not dark chocolate, was associated with long-term weight gain,” the report states of the three studies.
“Our findings suggest that not all chocolate is created equal,” lead researcher Binkai Liu, a doctoral student in Harvard's Department of Nutrition, said in a statement.
“For anyone who loves chocolate, this is a reminder that making small decisions, like choosing dark chocolate over milk chocolate, can make a positive difference to your health.”
Why is dark chocolate good for us?
Dark chocolate has been found to offer several health benefits, largely due to its rich concentration of flavonoids, especially flavanols. These are powerful antioxidants found in cocoa solids and are key to understanding the scientific basis for the positive health effects of dark chocolate.
According to research, the flavanols in dark chocolate help improve cardiovascular health by improving blood flow and lowering blood pressure.
“Chocolate contains high levels of flavanols, which promote cardiometabolic health and reduce the risk of type 2 diabetes (T2D), as shown in randomized controlled trials,” the study report found.
Additionally, these compounds have been shown to reduce LDL cholesterol levels while increasing HDL cholesterol, promoting a healthier lipid profile.
HDL, known as “good cholesterol,” collects excess cholesterol from the bloodstream and tissues, while LDL, known as “bad cholesterol,” can accumulate in arterial walls, forming plaque that narrows and hardens them. In some cases, this can lead to atherosclerosis, hardening of the arteries, which can lead to coronary artery disease, heart attacks, strokes, and poor blood circulation in the extremities.
The antioxidant properties of dark chocolate also play a role in fighting oxidative stress and inflammation in the body. This can potentially reduce the risk of chronic diseases and support overall cellular health. Additionally, research suggests that the flavanols in dark chocolate may improve cognitive function and mood, possibly due to their effect on cerebral blood flow and neurotransmitter activity.
“Higher consumption of total dietary flavonoids, as well as specific flavonoid subclasses, has been associated with a lower risk of type 2 diabetes [type 2 diabetes]. In randomized controlled trials, these flavonoids exerted antioxidant, anti-inflammatory, and vasodilatory effects that could confer cardiometabolic benefits and reduce the risk of type 2 diabetes. [type 2 diabetes]”wrote the report's authors.
Dark chocolate also has a high concentration of minerals such as iron, magnesium and zinc, further enhancing its nutritional value. Research suggests that these minerals support various bodily functions, from oxygen transport to enzyme activity and regulation of the immune system.
The health benefits are most pronounced in dark chocolate with a high percentage of cocoa solids, usually 70 percent or more. As cocoa content increases, the concentration of beneficial compounds also increases, while higher sugar content generally decreases them.
“Although dark chocolate and milk chocolate have similar levels of calories and saturated fat, it appears that the rich polyphenols in dark chocolate could offset the effects of saturated fat and sugar on weight gain and diabetes. “It is an intriguing difference worth exploring further,” report author Qi Sun, associate professor in the Departments of Nutrition and Epidemiology, said in a statement.
What else can reduce the risk of developing type 2 diabetes?
In a study conducted in Brazil this year, researchers from the Department of Internal Medicine at the State University of Rio de Janeiro and the Lagoa Federal Hospital in Rio de Janeiro found that following a plant-based diet not only reduces the risk of developing type 2 diabetes but it also reduces our carbon footprint.
“A plant-based diet may be important not only to prevent T2DM [Type 2 Diabetes Mellitus – the scientific name for diabetes] and obesity and to improve other cardiovascular risk factors (high blood pressure and dyslipidemia), but also to alleviate the impact on the environment,” state the authors of the study. “A sustainable diet in which animal products, especially red meat and milk/dairy products, are replaced by plant-based products, has the potential to reduce greenhouse gas emissions.”
In general, according to research, a diet focused on high-fiber foods such as fruits, vegetables, nuts, seeds and whole grains can help reduce the risk of developing type 2 diabetes.
A 2020 study coordinated by the Epidemiology Unit of the Medical Research Council at the University of Cambridge found that consuming a diet rich in fruits and vegetables could reduce the risk of developing type 2 diabetes by up to 50 percent.
“This study suggests that even a modest increase in fruit and vegetable intake could help prevent type 2 diabetes, as indicated by objective biomarkers of consumption, regardless of whether the increase occurs among people with initially low or high intake,” the authors stated.
