Dark chocolate is widely studied for its health benefits, which stem from the high concentration of bioactive compounds within the cacao bean. Research focuses on whether consuming dark chocolate can influence the body’s natural regenerative processes, particularly by affecting the levels of circulating stem cells. These compounds are primarily investigated for their effects on the cardiovascular system and vascular network repair.
The Active Compounds in Cacao
The health effects of dark chocolate originate from its rich composition of polyphenols, a large family of plant-based compounds. These polyphenols are dominated by flavonoids, which are responsible for cacao’s high antioxidant capacity. Epicatechin is the most studied flavonoid, considered the primary bioactive component linked to vascular and regenerative health effects.
The concentration of epicatechin varies significantly based on processing methods. Processes like fermentation, roasting, and alkalization (Dutch-processing) can drastically lower the final flavanol content. Therefore, a higher cacao percentage generally indicates a greater presence of these beneficial compounds.
Endothelial Progenitor Cells and Vascular Health
The regenerative capacity being investigated involves Endothelial Progenitor Cells (EPCs), a specific type of adult stem cell. These circulating cells originate primarily from the bone marrow. Their primary function is to maintain the integrity and repair the lining of blood vessels, known as the endothelium.
When the endothelium is damaged, such as by high blood pressure or cholesterol, EPCs are mobilized into the bloodstream. They travel to the injury site, differentiate into mature endothelial cells, and repair the vessel wall, promoting new blood vessel formation (neovascularization). A reduced number or impaired function of EPCs is often seen in individuals with cardiovascular risk factors, highlighting their importance as a marker for vascular health.
Mechanism of Stem Cell Mobilization
The connection between the compounds in dark chocolate and the body’s repair cells lies in the ability of epicatechin to enhance the bioavailability of nitric oxide (NO). NO is a gaseous molecule produced by endothelial cells, acting as a potent vasodilator that signals blood vessels to relax and widen, thus improving blood flow. Epicatechin is believed to stimulate the enzyme endothelial nitric oxide synthase (eNOS), which synthesizes NO.
This increase in nitric oxide plays a direct role in mobilizing EPCs from the bone marrow. Mechanistically, NO increases the activity of an enzyme called matrix metalloproteinase-9 (MMP-9) within the bone marrow. This enzyme is responsible for cleaving certain adhesion molecules that anchor the EPCs, resulting in the release of EPCs into the peripheral circulation.
Several human studies have demonstrated that consuming high-flavanol dark chocolate leads to a temporary, but significant, increase in the number of circulating EPCs. This temporary boost suggests that the flavanols in dark chocolate translate the NO-mediated vascular signal into a regenerative response by triggering the release of these repair cells from their bone marrow reservoir.
Guidelines for Consumption
To maximize potential stem cell and cardiovascular benefits, select dark chocolate with a cacao percentage of 70% or higher. Lower percentage products often contain more sugar and fat, and fewer beneficial flavanols.
The effective daily intake, based on human studies, corresponds to a flavanol content of around 200 milligrams. This amount is typically found in a small portion, such as 10 grams of high-flavanol dark chocolate. Consumers should avoid chocolate labeled as “Dutch-processed” or “alkalized,” as this treatment severely diminishes the flavanol content. Since dark chocolate is calorie-dense, moderation is necessary.