Abstract: Short-term consumption of flavanol-rich cocoa has been demonstrated to improve various facets of vascular health. The purpose of the present study was to determine the effect of 4-weeks of natural cocoa consumption on selected cardiovascular disease (CVD) biomarkers in young (19-35 y) women of differing BMI (normal, overweight, or obese). Subjects (N=24) consumed a natural cocoa-containing product (12.7 g natural cocoa, 148 kcal/serving) or an isocaloric cocoa-free placebo daily for 4-weeks in a random, double blind manner with a 2-week washout period between treatment arms. Fasted (>8-h) blood samples were collected before and after each 4-week period. Serum was analyzed to determine lipid profile (chemistry analyzer) and CVD biomarkers (26 biomarkers). EDTA-treated blood was used to assess monocytes (CD14, 16, 11b, & 62L), while citrate-treated blood was used to measure changes in endothelial microparticles (CD42a-/45-/144+; EMP) by flow cytometry. Natural cocoa consumption resulted in a significant decrease in haptoglobin (P=0.034), EMP concentration (P=0.017), and monocyte CD62L (P=0.047) in obese compared to overweight and normal weight subjects. Natural cocoa consumption regardless of BMI group was associated with a 18% increase in HDL (P=0.020) and a 60% decrease in EMPs (P=0.047). Also, obese subjects experienced a 21% decrease in haptoglobin (P=0.034) and a 24% decrease in monocyte CD62L expression in (P=0.047) following 4-weeks of natural cocoa consumption. Collectively, these findings indicate that acute natural cocoa consumption was associated with decreased obesity-related disease risk. More research is needed to assess the stability of the observed short-term changes.
Alex’s Notes: Cocoa has received considerable attention in the last decade for its role in cardiovascular support. Research has shown that cocoa consumption protects vascular function through improving blood flow and reducing LDL-c. However, how the effects of cocoa differ among persons of various BMI categories is not yet known. Therefore, the researchers of the current study set out to investigate the effects of four weeks of daily flavanol-rich natural cocoa consumption on cardiovascular disease (CVD) biomarkers in women of differing BMI. Specifically, 26 different blood-borne CVD risk markers were assessed in addition to the standard blood lipids.
In a double-blind crossover design, 24 women were placed into their respective BMI categories (normal, overweight, obese) and assigned to consume one of two chocolate bars daily for four weeks. The bars were supplied by the Hershey Company and identical in calories and macronutrients, but differed in their cocoa and polyphenol content. The “real” chocolate bar contained about 12.7g of cocoa compared to zero for the placebo chocolate bar. After the first four weeks, the women all began eating the opposite chocolate bar for the following four weeks. Blood-borne measurements were taken before and after each four week intervention.
The benefits for everyone
Of all the tested variables, only two showed significant changes with cocoa consumption that were not affected by the BMI of the participants. The first was HDL-c, which increased by 18% or about 10 mg/dL. The second was a 13% reduction in endocan-1, which is a novel biomarker associated with vascular inflammation.
The benefits for some
A handful of CVD biomarkers differed significantly between the BMI groups at baseline, but cocoa consumption truly leveled the playing field.
- Haptoglobin was 300% greater in the obese compared to overweight or normal weight groups, and was reduced by 17% in the obese only.
- Elevated endothelial microparticles (EMP) was 48% greater in obese compared to normal-weight subjects and cocoa consumption reduced the difference to 4%. Also, EMP was 26% greater in overweight vs normal-weight subjects and cocoa consumption reduced the difference to 9%.
- Baseline total monocyte CD62L expression was about 20% greater in the obese vs the overweight and normal weight subjects and was reduced by 18% following cocoa consumption. Moreover, there was an increase of 12% in the normal weight subjects.
- Baseline proinflammatory monocyte CD62L expression was 15 and 32% greater in the obese vs the overweight and normal weight subjects, respectively, but was reduced by 20% in the obese compared to an increase of 18 and 28% in the overweight and normal weight subjects.
The only other biomarkers that differed significantly between the BMI groups were triglycerides and sE-selectin (greater in the obese group), but these were not altered with cocoa consumption.
A note on atherosclerosis
To help illustrate some of the findings of this study, it may help to explain how plaque build-up occurs using the CVD risk factors from the findings of the current study. The first bodily assault that must occur for atherosclerosis is some form of damage to the vasculature. The authors of the current study have previously used EMP as an index of endothelial wall damage for the simple reason that EMPs are released by endothelial cells when damaged.
With damage done, there is now a possibility for the accumulation of LDL-c. For real problems to occur, this LDL-c must be oxidized (oxLDL), which is easily accomplished within individuals of low antioxidant capacity. This includes anyone with a disease characterized by chronic inflammation, such as simply being obese. As excessive amounts of oxLDL accumulate, monocytes are recruited to the area to try and dispose of the oxLDL. In order to move in and out of the subendothelial space, monocytes must express CD62L. It is important to note that this movement of monocytes is completely normal and occurring all the time; it is only when it is accompanied by the vascular damage and accumulation of oxLDL that problems occur because the ingestion of oxLDL by monocytes causes the formation of foam cells. It is these lipid-laden foam cells that are believed to promote vascular remodeling and a shift in endothelial function.
Putting the benefits in perspective
So with the above process in mind, we can now see how the effects of cocoa consumption played a role in cardiovascular health. It is noteworthy that the obese women had significantly greater EMP and CD62L expression at baseline, indicating vascular damage and increased monocyte movement. Together this suggests some atherosclerosis processes occurring. However, cocoa consumption reduced both these values to levels comparable to normal weight subjects. As mentioned, the monocyte movement and CD62L expression is completely normal, and thus the increase in monocyte CD62L expression without a corresponding increase in EMPs in the normal weight and overweight women suggests the change to be due to circadian variations rather than vascular health. This is supported by the fact that haptoglobin and endocan-1 were decreased and HDL-c was increased following cocoa consumption.
Cocoa consumption equivalent to 12.7g of pure cocoa powder appears to increase HDL-c and reduce vascular inflammation regardless of weight status, but the benefits on vascular health are most pronounced in the obese. How these results translate to men or older individuals (the women in this study were young twenties) has yet to be determined.