Data from a double-blind, randomized, placebo-controlled control may go some way to explaining the conflicting results seen in other cocoa studies, wrote the Unilever scientists in the American Journal of Clinical Nutrition .
“To our knowledge, this is the first study to show that a daily intake of 850 mg theobromine independently and significantly increases HDL-cholesterol concentrations by 0.16 mmol/L in healthy subjects,” wrote the researchers, led by Nicole Neufingerl.
“Together with the lack of a significant main effect of cocoa and interaction effect, this result suggests that theobromine is the major active compound in cocoa that is responsible for the beneficial HDL-cholesterol–increasing effect.”
The health benefits of polyphenols from cocoa have been gathering increasing column inches in the national media. To date studies have reported potential benefits for cardiovascular health, skin health, and even brain health.
The majority of science into the potential benefits of cocoa have revolved around cardiovascular benefits of the flavanols (also known as flavan-3-ols or catechins), and particularly the monomeric flavanol (-)epicatechin.
Scientists from the University of Reading in England and Mars have also reported that cocoa may also affect gut microflora and possess prebiotic potential.
While the majority of the science has focused on the flavanols, the new study indicates that the theobromine content may be responsible for any HDL cholesterol-boosting benefits.
Neufingerl and her co-workers recruited 152 healthy men and women to participate in their 2-center, double-blind, randomized, placebo-controlled, parallel study. The participants were randomly assigned to consume a daily 200-mL drink for four weeks, which contained cocoa (150 mg theobromine and 325 mg flavonoids), pure theobromine (850 mg), cocoa and added theobromine (1000 mg theobromine and 325 mg flavonoids), or neither cocoa nor theobromine (placebo).
Results showed that there was a significant effect of the pure theobromine beverage on HDL cholesterol (+0.16 mmol/L), but no effect was observed for the cocoa-only beverage, said the researchers.
No significant interaction effect between cocoa and theobromine was observed for the combination group, they added.
In addition, the researchers also observed a significant effect of theobromine on rising apolipoprotein A-I, which is the main protein component of HDL, while LDL-cholesterol levels decreased, as did apolipoprotein B, the main apolipoprotein of LD cholesterol and responsible for the transport of cholesterol to tissues.
What’s going on?
The researchers note that the metabolism of HDL-cholesterol is complex, and several biological mechanisms have already been proposed, but their study did not examine the actual mechanism of theobromine.
“A number of epidemiologic studies, including prospective observation studies, have shown that a 1% increase in HDL cholesterol is linked to a 1–3% reduction in CVD risk, even when controlled for other risk variables,” they wrote.
“Although elevated LDL cholesterol is the most important lipid target in the prevention and treatment of CVD, and despite powerful treatment options to lower LDL-cholesterol concentrations, there remains substantial residual cardiovascular risk, which can be further reduced by targeting other blood lipids such as raising HDL cholesterol.”
Source: American Journal of Clinical Nutrition
June 2013, Volume 97, Number 6, Pages 1201-1209, doi: 10.3945/ajcn.112.047373
“Effect of cocoa and theobromine consumption on serum HDL-cholesterol concentrations: a randomized controlled trial”
Authors: N. Neufingerl, Y.E.M.P. Zebregs, E.A.H. Schuring, E.A. Trautwein