COCOA POLYPHENOLS HEALTH EFFECTS – A RECAP
“Are polyphenols the only important constituent of cocoa?” No cocoa contains carbohydrates, fats, proteins, fiber, vitamins, minerals, methylxanthines and polyphenols. This is why cocoa is regarded as a functional food- provides health benefits beyond basic nutrition. Most of the health effects of cocoa-rich chocolate are due to the high content of nutritional polyphenols. In the last thirty years, polyphenols have attracted much interest owing to their antioxidant capacity (free radical scavenging and metal chelating ability) and their beneficial implications in human health, such as in the treatment and prevention of cancer and cardiovascular disease. Hence, cocoa has the health effects generally ascribed to polyphenol consumption.
Cocoa seeds contain many bioactive compounds including high levels of polyphenols (12–18% of dry weight) as well as fatty acids, vitamins, minerals, fiber, and several methylxanthine alkaloids(4% of dry weight), which are psychoactive dopaminergic substances such as caffeine, theobromine, theophylline, phenylethylamine, and paraxanthine.(Massaro et al. “Effect of Cocoa Products and Its Polyphenolic Constituents on Exercise Performance and Exercise-Induced Muscle Damage and Inflammation: A Review of Clinical Trials.” Nutrients 2019, 11, 1471; doi:10.3390/nu11071471). The compounds that show a significant correlation with the cardiometabolic health effects belong to the polyphenol class. Chemical data for dry seeds in the literature give a range of 6-18% of polyphenols, mainly composed of flavanols.
For many years, chocolate was consumed purely for pleasure, but in the last 20 years researches have shown that polyphenol-rich cocoa (dark chocolate with minimum 70% cocoa solids) and natural cocoa powder have beneficial effect on human health due to high content of polyphenols. Polyphenols are large and heterogeneous group of biologically active secondary metabolites in plants, where they act as cell wall support materials, colourful attractants for birds and insects, and defence mechanisms under different environmental stress conditions (wounding, infection, excessive light, or UV irradiation.
The most important food sources of polyphenols are vegetables and fruits, green and black tea, red wine, coffee, cocoa, olives, and some herbs and spices, as well as nuts and algae. But on weight basis cocoa is the richest source of polyphenols. Many researches have shown that polyphenols and/or polyphenol-rich foods have an important role in health preservation due to antioxidant properties. The antioxidant activity of cocoa was shown to be correlated with their polyphenol content.
Polyphenols can act as proton donor-scavenging radicals, inhibitors of enzymes that increase oxidative stress, chelate metals, bind carbohydrates, and proteins. These properties enable them to act as anticarcinogenic, anti-inflammatory, antihepatotoxic, antibacterial, antiviral, and antiallergenic compounds. This is supported by research of Hollenberg et al. who established relationship between high consumption of cocoa beverages and very low blood pressure levels, reduced frequency of myocardial infarction, stroke, diabetes mellitus, and cancer in Kuna Indians residing in archipelago on the Caribbean Coast of Panama. These health benefits were not seen in Kuna Indians residing on Mainland of Panama.
The fat in cocoa in the main is made up of oleic acid, palmitic acid, and stearic acid. Cocoa is also rich in minerals: potassium, phosphorus, copper, iron, zinc, and magnesium.
Polyphenols abundant in cocoa and dark chocolate, activate endothelial nitric oxide (NO) synthase; that leads to generation of NO,, which lowers blood pressure by promoting vasodilation. Indeed, following the consumption of polyphenol-rich, effects include improvement of the pulse wave speed and of the atherosclerotic score index, with parietal relaxation of large arteries and dilation of small and medium-sized peripheral arteries. . Once released, NO also activates the prostacyclin synthesis pathway, which acts as a vasodilator in synergy with NO, thereby contributing to thrombosis protection. Further, the anti-inflammatory and vasoprotective properties of prostacyclin are enhanced by its ability to reduce plasma leukotrienes (inflammatory mediators).
Cocoa plays also a role in treating cerebral conditions, such as stroke; in fact, cocoa intake is associated with increased cerebral blood flow. Polyphenol-rich cocoa has antiplatelet effects and thus of benefit in infarctive stroke treatment or prevention. Thus, daily polyphenol-rich consumption may reduce the likelihood of a stroke attack.
Cocoa and flavonols improve glucose homeostasis by slowing carbohydrate digestion and absorption in the gu. Indeed, cocoa extracts and procyanidins dose-dependently inhibit pancreatic α-amylase, pancreatic lipase, and secreted phospholipase A2. Cocoa and its flavonols improve insulin sensitivity by regulating glucose transport and insulin signaling proteins in insulin-sensitive tissues (liver, adipose tissue, and skeletal muscle).
The observed effects on glucose homeostasis is strongly dependent on the amount of polyphenols. In fact, a single-blind randomized placebo-controlled cross-over study showed, after 4 weeks, showed positive metabolic effects in subjects consuming polyphenol-rich cocoa. Therefore, the daily consumption of small quantities of flavonols from cocoa or chocolate, associated with a dietary intake of flavonoids, would constitute a natural and economic approach to prevent or potentially contribute to the treatment of type 2 diabetes with minimal toxicity and negative side effects.
There is strong interest in the effect of intestinal microbiota on health. Cocoa with its rich fiber content, polyphenol has impacted positively on gut health and in turn on overall metabolic and cardiovascular effects among others.
Studies have shown that cocoa has regulatory properties on the immune cells implicated in both innate (natural) and acquired immunity. Effects worth pursuing and promoting in light of COVID-19.
The polyphenol-rich cocoa acts on the central nervous system (CNS) and neurological functions through the production of NO. Vasodilation and increased cerebral blood flow provide oxygen and glucose to neurons, leading to increased formation of blood vessels in the hippocampus. The polyphenol-dependent antioxidant potential could contribute to the reduction of some neurodegenerative disorders. This inference is based on the fact that age-related cognitive impairment and disorders, such as Alzheimer’s and Parkinson’s diseases, are related to the accumulation of reactive oxygen species in the brain.
The effect of cocoa bioactives on signaling pathways in neurocytes may provide another support for linking it with regulation of brain function. Cocoa flavonols and methylxanthines can activate the cascade pathways of such molecules as rapamycin that play a crucial role in synaptic function, neuronal growth, memory mechanisms, and the pathogenesis of neurodegenerative disorders.
Polyphenol-rich cocoa exerts several effects on human sexuality, mainly acting as an aphrodisiac. Polyphenol-rich cocoa contains three unsaturated N-acylethanolamines, which, acting as cannabinoid mimics, could activate cannabinoid receptors or increase anandamide concentrations. These together with the methylxanthine components produce a transient feeling of well-being.
Until then daily/regularly consume polyphenol-rich cocoa
DR. EDWARD O. AMPORFUL