- Nirusha Pahladi ANutr
Chocolate [Theobroma cacao tree (cocoa, cacao)]
Chocolate is best known as an indulgent confection, but historically it has also been consumed for its purported healing properties. Cocoa contains more phenolic antioxidants than most foods. The phenolic compounds in cocoa are mainly flavanols (catechins (37%), proanthocyanidins (58%), and anthocyanins (4%).
Cocoa, or cacao, is the dried and fully fermented fatty seed of the fruit of the cocoa tree, Theobroma cacao. Cocoa liquor is the paste made from ground, roasted, shelled, and fermented cocoa beans, called nibs. It contains both nonfat cocoa solids and cocoa butter. Cocoa liquor is what is referred to as “percent cacao” on food packaging. Cocoa powder is made by removing some of the cocoa butter from the liquor. Chocolate is a solid food made by combining cocoa liquor with cocoa butter and sugar. The proportion of cocoa liquor in the final product determines how dark the chocolate is. Milk chocolate is made with the addition of condensed or powdered milk to the chocolate mixture. Semisweet or bittersweet chocolate is often referred to as dark chocolate and must contain no less than 35% by weight of cocoa liquor. Most of the health benefits attributable to chocolate are associated with consuming the dark type.
The processing of chocolate from cocoa beans.
Picture adapted from Montagna et al. (2019)
White chocolate contains only cocoa butter (at least 20% by weight) combined with sweeteners and dairy ingredients. Cocoa butter contains significant amounts of fatty acids, whereas the nonfat cocoa solids contain vitamins, minerals, fiber, and polyphenols. Therefore, only dark chocolate, with high percentages of cocoa, flavonoids, and theobromine and low content of sugar, differently from milk chocolate or other types of chocolate, would be associated with health-promoting effects.
Some Health Benefits
Chocolate’s antioxidant potential may have a range of health benefits. The higher the cocoa content, as in dark chocolate, the more benefits there are. Dark chocolate may also contain less fat and sugar, but it is important to check the label.
Eating chocolate may have the following benefits:
● lowering cholesterol levels
● preventing cognitive decline
● reducing the risk of cardiovascular problems
Effects on lowering cholesterol levels
A 2010 research by meta-analysis of eight trials summarised the short-term impact of cocoa consumption on blood lipids. The data from these trials indicated that cocoa may significantly reduce low-density lipoprotein (LDL) cholesterol and total cholesterol when consumed in low quantities by overweight and obese individuals. Intervention studies suggest that cocoa can inhibit LDL oxidation. Decreased levels of plasma-oxidized LDL have been observed in subjects after long-term daily consumption of cocoa powder and dark chocolate.
Effects on preventing cognitive decline
Flavonoids in cocoa have demonstrated a variety of effects in central nervous processes, and there is promising preliminary evidence for protection from neurodegradation, increased perfusion, decreased neuroinflammation, and modulation of neuronal function through interaction with a number of signaling pathways.
Neuroinflammation is involved in the pathogenesis of Parkinson's disease, Alzheimer's disease, and neuronal injury associated with stroke. Flavonoids interact with a variety of neuronal protein kinase and lipid kinase signaling cascades and can possibly prevent excitotoxic death in neurons.
The consumption of flavonoid-enriched cocoa affects cerebral blood flow; magnetic resonance MR imaging studies demonstrate increased blood flow to gray matter 3 h after consuming cocoa as well as other changes to regional blood flow. Increased blood flow to the cerebral gray matter induces angiogenesis and new nerve cell growth in the hippocampus, a key region involved in the processing of memory.
Increased blood flow velocity in the middle cerebral artery has been demonstrated, providing insights to possible protective effects against dementia and stroke. Cocoa can increase cerebral blood flow, which can be neuroprotective.
Effects on the cardiovascular system
Cocoa polyphenols modulate the activity of NF-κB, a protein complex involved in DNA transcription that is a pivotal factor in a number of inflammatory processes. NF-κB activation in leukocytes (as well as in endothelial cells and macrophages) results in leukocyte adhesion to the endothelium, tissue invasion, and the secretion of mediating factors leading to tissue injury. Cocoa polyphenols can reduce the activity of NF-κB, down regulating leukocyte activation and attenuating the production of inflammatory mediators and reactive oxygen species ROS. Further, polyphenols act synergistically with other nutrients, such as vitamin C and selenium, to increase endogenous antioxidant capacity.
Cocoa flavanols can affect oxidant enzymes such as lipoxygenases, involved in arachidonic acid metabolism and the biosynthesis of leukotrienes. High-procyanidin chocolate was found to increase plasma prostacyclin and decrease plasma leukotrienes, reflecting anti-inflammatory and vasoprotective properties.
Flavanols (particularly epicatechin), in cocoa have anti-inflammatory properties that inhibit the production of reactive oxygen species ROS, and have antihypertensive and vasoprotective effects.
Please note chocolate bars do not contain only cocoa. The benefits and risks of other ingredients such as sugar and fat need to be considered. Scientists raised the concern about chocolate's caloric density in commercial products and its potential to contribute to weight gain, which may counteract any small benefits of cocoa's polyphenol content. The possibility of weight gain when overindulging in chocolate or cocoa-based foods is real, but certainly not attributable to the cocoa content. The bioactive components of cocoa (i.e., flavanols) are found in the nonfat portion of the cocoa bean and can be readily isolated in a low-energy-dense form, that is, cocoa powder. Cocoa powder contains up to 50 mg of polyphenols per gram; a single serving of cocoa and cocoa products contain more phenolic antioxidants than most foods.
Nutritional values per 100 g of cocoa and two types of chocolate.
Table adapted from Montagna et al. (2019)
Interest in chocolate has grown, owing to its physiological and potential health effects, such as regulation of blood pressure, insulin levels, vascular functions, oxidation processes, prebiotic effects, glucose homeostasis, and lipid metabolism. Cocoa plays a role in healing conditions such as stroke; in fact, cocoa intake is associated with increased cerebral blood flow. In the same way, daily dark chocolate consumption may reduce the likelihood of a stroke attack. In agreement with other findings, dark chocolate exerts prebiotic effects, as evidenced by its ability to restructure the diversity and abundance of intestinal bacteria; thus, it may improve negative emotional states via the gut-brain axis. However more research is needed in this area of study.