Written by James C. Morton Jr., Staff Writer. In a randomized placebo-controlled, double-blinded, crossover trial, clinical research study, epicatechin and quercetin significantly decreased endothelial dysfunction (10.5%) and inflammation (10.1%) serum biomarkers compared to the baseline and placebo groups.
Endothelial dysfunction is one of the most pathological disorders that leads to chronic inflammation, hypertension, coronary atherosclerosis, and cardiovascular disease 1. It is characterized by an impaired or imbalanced ability of the endothelium to regulate the dilation and constriction of the vascular smooth muscle in blood vessels or a diminished production of nitric oxide 2. The latest statistics on the U.S. healthcare costs of cardiovascular disease related to endothelial dysfunction is $315.4 billion. An estimated 78 million adults in the U.S. have hypertension 3.
The alterations of endothelial cellular function can cause an increase in platelet development and changes to its metabolic state, which leads to chronic inflammation. This is due to the increased activation of inflammatory cytokines and the increase of adhesion molecules that can lead to atherosclerosis. Adhesion molecules (E-selectin for the endothelial, VCAM-1 for vascular cells, and ICAM-1 for intercellular) are used to induce leukocytes to attach to the endothelium for initiation of repair due to damage and activation of the immune system 4.
The most common treatment approach for endothelial dysfunction patients is the use of prescription medication such as an ACE inhibitor (ramipril), L-arginine therapy, estrogen replacement therapy, and other chemical drugs. It is a direct method to prevent constriction of the blood vessels, increase vascular dilation, and decrease plaque build-up in the vessels 5. Unfortunately, these therapies and methods can be costly and have side effects.
Fortunately, a 2015 study 6 reveals that epicatechin (in cocoa and tea) and quercetin (in tea) reduces biomarkers that can lead to endothelial dysfunction and inflammation. The study involved 37 healthy, prehypertensive patients (25 males, 12 females) aged 40 to 80 with pre-hypertension and was conducted as a 3-armed, randomized, double-blind, placebo-controlled, crossover study. Participants ingested equimolecular amounts of epicatechin (100 mg/d), quercetin-3-glucoside (160 mg/d), or placebo capsules for a period of 4 wk, in random order, separated by 4-wk washout periods. Plasma biomarkers of endothelial dysfunction and inflammation were measured at the start and end of each 4-wk intervention period.
After 4 weeks, researchers noted the following: (p-value <0.05 = significant)
| Biomarkers | Epicatechin Group | Quercetin-3-glucoside Group |
|---|---|---|
| Endothelial Dysfunction E-selectin(ng/mL) | 10.5% Decrease (from 73.6 to 65.9) p-value = 0.03 | 10.1% Decrease (from 73.6 to 66.2) p-value = 0.03 |
| Inflammation IL-1(beta)(pg/mL) | 8.9% Decrease (from 0.78 to 0.71) p-value = 0.42 (not Significant) | 29.5% Decrease (from 0.78 to 0.55) p-value = 0.009 |
In addition, other endothelial dysfunction serum biomarkers (VCAM, ICAM, and z-score) and other inflammatory biomarkers (IL-6, IL-8, TNF-alpha, and CRP) showed a decrease, but were not significant.
When suggesting how epicatechin and quercetin benefits patients with endothelial dysfunction and inflammation, the researchers pointed to epicatechin’s and quercetin’s ability as strong flavonoid-rich foods to decrease plasma concentration of biomarkers by preventing inflammatory stimulation 7,8.
Researchers also stated that cocoa and tea have anti-inflammatory and other properties that help endothelial function by decreasing the risk of atherosclerosis caused by plaque build-up in the vessels 9-11. Because of the study’s small size and the possibility of false-positive findings, more research should be conducted with pure epicatechin and quercetin to test all serum biomarkers that lead to endothelial dysfunction and inflammation.
Source: Dower, James I., Johanna M. Geleijnse, Lieke Gijsbers, Casper Schalkwijk, Daan Kromhout, and Peter C. Hollman. “Supplementation of the pure flavonoids epicatechin and quercetin affects some biomarkers of endothelial dysfunction and inflammation in (pre) hypertensive adults: a randomized double-blind, placebo-controlled, crossover trial.” The Journal of nutrition 145, no. 7 (2015): 1459-1463.
© 2015 American Society for Nutrition
Posted December 5, 2016.
References:
- CDC. Endothelial Dysfunction cytokines and their Genetic Variations. Endothelium: molecular aspects of metabolic disorders. 2013; https://www.cdc.gov/niosh/nioshtic-2/20042829.html.
- Vanhoutte P. Endothelial Dysfunction: The First Step toward coronary arterosclerosis. In: Vol 73. Circulation Journal; 2009: https://www.jstage.jst.go.jp/article/circj/73/4/73_CJ-08-1169/_pdf/-char/en.
- Association AH. Endothelial Dysfunction and Cardiovascular Disease Statistics. 2016.
- Hadi H. Endothelial Dysfunction: Cardiovascular Risk Factors, Therapy, and Outcome. In: Vol 1. Vascular Health Manag; 2005.
- CDC. Endothelial Dysfunction Treatment.
- Dower JI, Geleijnse JM, Gijsbers L, Schalkwijk C, Kromhout D, Hollman PC. Supplementation of the pure flavonoids epicatechin and quercetin affects some biomarkers of endothelial dysfunction and inflammation in (pre) hypertensive adults: a randomized double-blind, placebo-controlled, crossover trial. The Journal of nutrition. 2015;145(7):1459-1463.
- Wang-Polagruto JF, Villablanca AC, Polagruto JA, et al. Chronic consumption of flavanol-rich cocoa improves endothelial function and decreases vascular cell adhesion molecule in hypercholesterolemic postmenopausal women. Journal of cardiovascular pharmacology. 2006;47 Suppl 2:S177-186; discussion S206-179.
- Monagas M, Khan N, Andres-Lacueva C, et al. Effect of cocoa powder on the modulation of inflammatory biomarkers in patients at high risk of cardiovascular disease. Am J Clin Nutr. 2009;90(5):1144-1150.
- Mathur S, Devaraj S, Grundy SM, Jialal I. Cocoa products decrease low density lipoprotein oxidative susceptibility but do not affect biomarkers of inflammation in humans. J Nutr. 2002;132(12):3663-3667.
- Steptoe A, Gibson EL, Vuononvirta R, et al. The effects of chronic tea intake on platelet activation and inflammation: a double-blind placebo controlled trial. Atherosclerosis. 2007;193(2):277-282.
- Oyama J, Maeda T, Sasaki M, et al. Green tea catechins improve human forearm vascular function and have potent anti-inflammatory and anti-apoptotic effects in smokers. Internal Medicine. 2010;49(23):2553-2559.
