Diet patterns are widely recognized as contributors to hypertension. Widely studied potential contributors include intake of sodium, potassium, magnesium, calcium, soluble fiber, ω-3 fatty acids, alcohol, protein, and calories. We add to that list the effect of dietary flavanols present in certain cocoas, which have sufficient activity on vascular nitric oxide to influence blood pressure control. Kuna Indians who live on islands near Panama have little age-related rise in blood pressure or hypertension. On migration to Panama City, blood pressure rises with age, and the frequency of essential hypertension matches urban levels elsewhere. We have identified a specific food that probably makes an important contribution to cardiovascular status. Island-dwelling Kuna drink more than 5 cups of flavanol-rich cocoa per day and incorporate that cocoa into many recipes. Mainland Kuna ingest little cocoa, and what they take is commercially available and flavanol-poor. The flavanol-rich cocoa activates nitric oxide synthase in vitro and in intact humans in the doses that the Kuna employ. Vasodilator responses to flavonoid-rich cocoa are prevented or reversed by the arginine analog, N-nitro-L-arginine methyl ester. Island-dwelling Kuna have a 3-fold larger urinary nitrate:nitrite than do Mainland dwellers. As endothelial dysfunction is central to current thinking on cardiovascular pathophysiology, a food that enhances endothelial function could have broad implications. The list of candidate conditions that might be influenced is impressive, ranging from atherosclerosis and diabetes mellitus to hypertension and preeclampsia, to vascular dementias and end-stage renal disease. The next decade will be interesting.
Browse Scientific Research by Tag
Epidemiologic studies have linked flavonoid-rich foods with a reduced risk of cardiovascular mortality. Some cocoas are flavonoid-rich and contain the monomeric flavanols (-)-epicatechin and (+)-catechin and oligomeric procyanidins formed from these monomeric units. Both the monomers and the oligomers have shown potential in favorably influencing cardiovascular health in in vitro and preliminary clinical studies. Although previous investigations have shown increasing concentrations of (-)-epicatechin in human plasma after cocoa consumption, no information is available in the published literature regarding the presence of procyanidins in human plasma. OBJECTIVE: This study sought to determine whether procyanidins can be detected and quantified in human plasma after acute consumption of a flavanol-rich cocoa. DESIGN: Peripheral blood was obtained from 5 healthy adult subjects before (baseline, 0 h) and 0.5, 2, and 6 h after consumption of 0.375 g cocoa/kg body wt as a beverage. Plasma samples were analyzed for monomers and procyanidins with the use of reversed-phase HPLC with coulometric electrochemical array detection and liquid chromatography-tandem mass spectrometry. RESULTS: Procyanidin dimer, (-)-epicatechin, and (+)-catechin were detected in the plasma of human subjects as early as 0.5 h (16 +/- 5 nmol/L, 2.61 +/- 0.46 micro mol/L, and 0.13 +/- 0.03 micro mol/L, respectively) after acute cocoa consumption and reached maximal concentrations by 2 h (41 +/- 4 nmol/L, 5.92 +/- 0.60 micro mol/L, and 0.16 +/- 0.03 micro mol/L, respectively). CONCLUSION: Dimeric procyanidins can be detected in human plasma as early as 30 min after the consumption of a flavanol-rich food such as cocoa.
Sir Ilya Arts and colleagues (Aug 7, p 488) report that chocolate and tea may contribute significantly to total dietary catechin intake (20% and 55%, respectively).
However, their methods only took into account the monomeric catechins and neglected the more abundant oligomers found in chocolate,2 which are present in only minor concentrations in tea.
Indeed, Arts and colleagues' method to determine catechin content illustrates a commonly encountered difficulty when trying to assess total dietary intake of flavonoids. The commonly used reverse-phase high-performance liquid chromatography techniques are superior for the separation of simple flavonoids, such as those found in tea. However, they are insufficient for analysis of larger oligomeric procyanidins, such as those found in cocoa and chocolate, and normal-phase chromatography is better suited.3 Adamson and colleagues have shown that the monomers (−)-epicatechin and (+)-catechin, are only a fraction of the total quantifiable procyanidins in cocoa and chocolate.4 Hence, the total concentrations of procyanidins in chocolate may have been substantially underestimated by Arts and colleagues.
