Heart-Protective Dark Chocolate
Reduces Blood Pressure and Improves Insulin Sensitivity
Nov 11, 2008
Cocoa teems with phytochemicals that confer health benefits to animals including humans. In this recent study, Grassi and his colleagues tested the effects of flavonoids on endothelial function, insulin sensitivity, and blood pressure in 19 hypertensive and glucose-intolerant subjects.
For 15 days, each participant received 100 grams of flavanol-rich dark chocolate or flavanol-free white chocolate. After a washout period, the subjects switched chocolates. Throughout the investigation, their blood pressure, insulin sensitivity, C-reactive protein, and plasma homocysteine levels were monitored. Results showed that dark chocolate reduced blood pressure, improved sensitivity and reduced markers of inflammation. However, similar results were not observed when flavanol-free white chocolate were consumed. Their study was published in the September 2008 issue of The Journal of Nutrition.
"Xocoacatl" - Aztec for the "watery" beverage made from the beans of "Theobroma cacao "or chocolate is one of the most concentrated sources of polyphenols. Polyphenols are plant substances that give fruits, vegetables, seeds, nuts, and herbs their color and flavour. Some polyphenols confer health advantages. Cacao contains the following nutrients and phytochemicals:
- 6 nutrients: Carbohydrates, Fats, Proteins, Minerals, Vitamins, and Water
- 6 vitamins: Thiamine (vit.B1), Riboflavin (vit.B2), Niacin (vit. B3), Pyridoxine (vit. B6), Biotin (vit. H),and Ascorbic Acid (vit. C).
- 5 minerals: Calcium ,Chlorine, Copper, Iron, and Phosphorus
- 171 phytochemicals, 92 have strong biological properties.
In this study, phytochemicals improved blood pressure by working with body synthesized vasodilators prostacyclins and nitric oxide. Vasodilators expand blood vessels thereby improving blood flow. Vasoconstrictors constrict blood vessels reducing blood flow, raising blood pressure, causing coronary spasm, and systemic vascular resistance. The polyphenols reduced blood clotting by preventing platelets from "clumping" together, thereby inhibiting thrombosis. They also reduced edema and inflammation by blocking their metabolic pathways. Inflammation activates cytokins, thromboxane A2, and endothelins - potent platelet aggregants and vasoconstrictors. Antioxidants in chocolate prevented LDL cholesterol from oxidation. Oxidized LDL attracts macrophages that evolve into "foam" cells which eventually migrate and adhere to arterial walls., facilitating the formation of plaques.
Twelve powerful antidiabetic/hypoglycemic agents improved insulin sensitivity, beta cell function, endothelial integrity, and reduced inflammation. Most phytochemicals have multiple biologic properties. For example, Chlorogenic Acid, Ferulic Acid, Quercetin, Quercitrin, and Trigonelline are not only potent anti-inflammatory and antioxidant agens, they're also antihyperglycemic compounds.
Points to Consider
- Health benefits from chocolate consumption is "dose" dependent, and "cumulative." Persons who regularly eat chocolates get more benefits than those who consume them periodically.
- The amount believed to be therapeutic is unknown.
- Sugar added to chocolate offsets health benefits. Sugar promotes the formation of toxic substances in the body that hastens "aging" (AGEs - Advanced Glycated End Products) and cell death.
- Milk binds phytochemicals that reduces their efficacy.
- Sugar-sweetened confections and baked goods contain significant amounts of fat and calories that may contribute to obesity.
- Best way to eat chocolates? Low-calorie, high-potency products with about 60% or more cocoa.
References
- Grassi D et al. " Blood Pressure is Reduced and Insulin Sensitivity Increased in Glucose-Intolerant Hypertensive Subjects after 15 Days of Consuming High Polyphenol Dark Chocolate" The Journal of Nutrition Sept.1, 2008;138(9):1671-1676
- McPhee SJ et al. 'Cardiovascular Disorders' Pathophysiology of Diseases, McGraw-Hill 2006; pp. 307-308
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