Endothelial Function as a New Target for Health Claims
BY DAVID DESPAIN
The endothelium, a fine layer of cells that lines blood vessel walls, has emerged as a new focus of health claims for functional foods. Its intricate role in maintaining vascular tone and blood flow is increasingly being recognized as a “barometer” of vascular health, its dysfunction as a serious contributor to atherosclerosis and cardiovascular risk.
Fortuitously, several studies have found that dietary and lifestyle approaches could positively influence endothelial function. On Tuesday, June 26, a session at the 2012 IFT Annual Meeting served to cover the growing body of research and to review the regulatory environment of pursuing related health claims.
Walnuts, for example, have been awarded a health claim recently by the European Food Safety Authority (EFSA). The approved wording—“Walnuts contribute to the improvement of elasticity of blood vessels”—may be used for foods that provide 30 grams or more of walnuts daily.
Cargill global nutrition and regulatory manager Peter Decock shared that EFSA requires that the claim be “specific as the science that supports it.” For example, a claim of “improves artery health” was not approved for walnuts.
Foods containing high amounts of polyphenols (such as tea, chocolate, red wine, grape juice, and cranberry juice) may also be future candidates for endothelial function claims.
These, originally thought to deliver improvements to cardiovascular health through antioxidant activities, explained Joseph Vita, M.D., of Boston University, act on endothelial function by stimulating increased nitric oxide release.
The dysfunction of the endothelium, Vita said, is linked to decreased nitric oxide combined with increased constriction of blood vessels. The polyphenols stimulate expression of enzymatic pathways—SIRT1, AMP kinase, and eNOS—to increase nitric oxide and dilation of blood vessels.
“In a setting of risk factors such as hypercholesterolemia, you have a loss of nitric oxide, a shift in thrombotic factors, inflammatory factors, and adhesion molecules,” Vita said. “If you can make an intervention that improves a healthy phenotype, you’ll get a reversal of cardiovascular risk.”
Regular exercise and nutritional dietary compounds including omega-3 fatty acids, antioxidant vitamins, B vitamins (folic acid), and l-arginine have also been indicated in improving nitric oxide regulation and endothelial function.
The sugar alcohol erythritol (often used as a sugar substitute) has also been found to provide additional protection to endothelial cells. Recent evidence suggests a mechanism through antioxidant activity and by inhibiting production of pro-inflammatory signaling molecules (eicosanoids).