Flavanols, the Kuna, cocoa consumption, and nitric oxide

Abstract

The Kuna Indians, who reside in an archipelago on the Caribbean Coast of Panama, have very low blood pressure (BP) levels, live longer than other Panamanians, and have a reduced frequency of myocardial infarction, stroke, diabetes mellitus, and cancer-at least on their death certificates. One outstanding feature of their diet includes a very high intake of flavanol-rich cocoa. Flavonoids in cocoa activate nitric oxide synthesis in healthy humans. The possibility that the high flavanol intake protects the Kuna against high BP, ischemic heart disease, stroke, diabetes mellitus, and cancer is sufficiently intriguing and sufficiently important that large, randomized controlled clinical trials should be pursued.

Figure 1

Vascular responses to cocoa and N^G-nitro-L-arginine methyl ester (LNAME). (a) 5 minutes of baseline assessment in a volunteer. The baseline demonstrated normal variability in pulse wave amplitude. (b) After 4 days of ingestion of flavanol-rich cocoa by this volunteer, there was a clear increase in pulse wave amplitude measured in the morning more than 12 hours after the last dose of cocoa. (c) On that day, exposure to an additional 230 ml dose of flavanol-rich cocoa led to a further increase in pulse wave amplitude 90 minutes later. (d) After ingestion of cocoa on day 5, the nitric oxide synthesis inhibitor L-NAME had a dramatic effect in reversing dilatation. *Reproduced from Fisher NDL, et al, J Hypertension 2003; 21:2281–6 (reference 10).

Figure 2

The generic 3 ring (A, B, and C) carbon backbone structures (C₆-C₃-C₆) of the major flavonoid subclasses found in foods (flavone, isoflavone, flavonol, anthocyanidin, flavanone, and flavanol) are depicted. The flavanol generic structure is highlighted. *Reproduced from Robbins RJ, et al, J Cardiovascular Pharmacology 2006: 47 (Suppl 2):S110–S118 (reference 41).