The Cardiovascular Benefits of Plant Flavonoids: Insights from Cocoa and Chocolate

The Biological Effects of Plant Flavonoids
Plant flavonoids, a group of natural substances found in fruits, vegetables, and certain beverages, have garnered significant attention due to their wide-ranging and substantial biological effects. Flavonoids encompass various subgroups, including flavanols, which are notably present in cocoa and chocolates. These compounds have demonstrated specific activities in vitro that are crucial for vascular health, particularly concerning endothelial function, the synthesis of endothelium-derived nitric oxide, platelet function, and cellular processes influenced by reactive oxygen and nitrogen species.

Flavanols and Vascular Health
In vitro studies have highlighted that flavanols can significantly impact vascular health. They promote the synthesis of nitric oxide, a molecule that plays a vital role in maintaining endothelial function. This effect is crucial as endothelial dysfunction is a precursor to various cardiovascular diseases. Additionally, flavanols influence platelet function and cellular processes modulated by reactive oxygen and nitrogen species, further contributing to cardiovascular health.

Epidemiological Evidence and the French Paradox
Epidemiological evidence linking flavonoid consumption to heart disease and mortality in humans is impressive yet often conflicting. A well-known example is the 'French paradox,' which refers to the observation that the French population, despite having a high-fat diet, does not exhibit a corresponding high rate of myocardial infarctions. Researchers have attempted to attribute this paradox to the consumption of red wine, rich in flavonoids. However, the evidence remains inconclusive.

Flavanols in Cocoa and Chocolate
Epidemiological studies examining the impact of flavanols consumed through cocoa and chocolate on cardiovascular risk are limited. Despite this, certain studies have indicated a significant influence of flavonoid-rich foods on cardiovascular health. For instance, a prospective study on mortality determinants after acute myocardial infarction (MI) revealed that patients consuming an average of 14 or more cups of black tea per week experienced a 39% reduction in mortality during a median follow-up of 3.8 years. Even moderate tea drinkers, averaging two cups per week, showed a 31% reduction. These associations persisted even after adjusting for usual risk factors.

Conflict in Study Results
The conflicting results in studies exploring the cardiovascular benefits of flavonoids can be attributed to various factors. These inconsistencies necessitate a focused review on the potential cardiovascular health benefits of flavanols in cocoa and chocolate. Identifying the mechanisms responsible for these effects can substantially aid in resolving the discrepancies observed in different studies.

Endothelial Dysfunction and Flavanols
Endothelial dysfunction is a critical factor in cardiovascular diseases. Studies conducted in vitro, in animal models, and in humans have provided growing evidence that flavonoids can positively influence endothelial dysfunction. The activation of nitric oxide synthesis appears to be the common pathway through which these natural products exert their beneficial effects. This discovery has its roots in the study of the Kuna Indians in Panama. These indigenous people, living on Caribbean islands, do not exhibit the typical rise in blood pressure with age, and hypertension is rare among them. Initially, researchers speculated a genetic protection; however, migration to Panama City, which led to the loss of this protection, pointed towards an environmental factor.

The Kuna Indians and Flavanol-Rich Cocoa
Further investigation revealed that the Kuna Indians consumed large amounts of flavanol-rich cocoa. Subsequent in vitro studies demonstrated that cocoa extracts could induce endothelium-dependent relaxation, prompting further research in healthy volunteers and patients with vascular risk or disease. One study showed that consuming flavanol-rich cocoa increased flow-mediated vasodilation of the brachial artery after five minutes of ischemia, correlating with biochemical evidence of increased nitric oxide bioavailability.

In another study, flavanol-rich cocoa induced significant dilation of the finger vessels in normal volunteers, an effect completely reversed by an arginine analogue that blocks nitric oxide synthesis. These findings underscore the potential of flavanol-rich cocoa in improving vascular function through mechanisms involving nitric oxide synthesis.

Conclusion
In summary, the biological effects of plant flavonoids, particularly flavanols found in cocoa and chocolates, are substantial and multifaceted. Despite conflicting epidemiological evidence, studies highlight their potential cardiovascular benefits, especially through mechanisms enhancing endothelial function and nitric oxide synthesis. These insights not only advance our understanding of flavonoids' health benefits but also underscore the importance of dietary choices in cardiovascular health.
The Cardiovascular Benefits of Plant Flavonoids: Insights from Cocoa and Chocolate

Flavanols: Boosting Vascular Health

Flavanols, a class of phytochemicals abundantly present in various foods such as chocolate, fruits, and vegetables, exhibit promising potential in mitigating the detrimental effects of smoking on vascular health. Studies have shown that flavanols, particularly those found in cocoa products, can enhance the levels of nitric oxide in the bloodstream of smokers, thereby counteracting some of the impairments in blood vessel function associated with smoking.

The cardiovascular benefits of flavanol-rich foods extend beyond chocolate, encompassing a wide array of dietary sources. Notably, green and black teas, especially Ceylon tea, red wine, sweet cherries, apples, apricots, purple grapes, blackberries, raspberries, and broad beans also contain significant amounts of flavonoids like epicatechin and catechin, akin to those present in cocoa and dark chocolate.

Moreover, research indicates that consuming a flavanol-rich beverage can elevate nitric oxide levels in smokers' blood, potentially reversing the adverse effects of smoking on vascular adaptation. However, whether this acute improvement translates into long-term cardiovascular benefits, such as attenuating or preventing atherosclerosis development, remains an area warranting further investigation.

In essence, the findings underscore the potential of flavanols in promoting cardiovascular health, offering insights into dietary interventions that could mitigate the deleterious consequences of smoking on vascular function. Continued research into the long-term effects of flavanol consumption holds promise for developing strategies to combat smoking-related cardiovascular diseases effectively.
Flavanols: Boosting Vascular Health

Flavonoids in chocolate

Cocoa contains more phenolic antioxidants than most foods. Flavonoids, including catechin, epicatechin, and procyanidins predominate in antioxidant activity. The tricyclic structure of the flavonoids determines antioxidant effects that scavenge reactive oxygen species, chelate Fe2+ and Cu+, inhibit enzymes, and upregulate antioxidant defenses.

Cocoa has the highest flavanol contents of all foods on a per-weight basis and is a significant contributor to the total dietary intake of flavonoids. The main subclasses of flavonoids found in cocoa are flavanols, particularly the flavanol monomers catechin and epicatechin, and their oligomers, also known as procyanidins.

Epidemiological evidence supports the notion that long-term flavanol intake provides a number of health benefits, including neurocognitive enhancement and neuroprotective effects.

A large-scale, longer duration study in the Netherlands recruited men aged 65-84 years. The subjects were asked about their dietary intake when they enrolled in the study and again at five-year intervals. Over the next 15 years, men who consumed cocoa regularly had significantly lower blood pressure than those who did not.

Iron (Fe) deficiency is one of the most important nutritional problems in the world (50). Milk chocolate contains 5% of the RDA for iron for adult men and postmenopausal women (0.42 mg) per 100 kcal; dark chocolate provides 25% of the RDA (1.90 mg).

Dietary intake of chocolate

Flavonoids in dark chocolate

The beneficial plant compounds in chocolate are called flavonoids, which contribute to the dark pigment in chocolate. Flavonoids are polyphenolic compounds found abundantly in cocoa.

Dark chocolate contains a high percentage (equal to 70 percent) of cocoa solids, and little or no added sugar. As a result, dark chocolate contains more health benefits. At the contrary, milk chocolate contains less flavonoids as evidenced by its lighter color.

Cocoa flavonoids are classified as flavanols and include the monomers, (-)-epicatechin, (+)-catechin, and procyanidins, the oligomers of these monomeric units. Flavonoids occur naturally in the cocoa plant as a way of protecting the plant. Their presence affects the taste of chocolate and they are responsible for the astringency in the unprocessed cocoa bean.

The flavonoid found in dark chocolate has been linked to decreases in blood pressure, improvements in endothelial dysfunction that promote vascular homeostasis, improvements in antiplatelet activity, improvements in insulin sensitivity, increases in high-density lipoprotein (HDL) cholesterol concentrations, improvements in cognitive, and antioxidant properties.

Furthermore, an increase in plasma antioxidant capacity and a decrease in plasma oxidation products are associated with elevated epicatechin concentrations. Research recently reported that the cocoa flavonoids decrease plasma leukotriene-prostacyclin ratios in human plasma and aortic endothelial cells (Journal of the American College of Nutrition, Vol. 23, No. 3, 197–204, 2004).
Flavonoids in dark chocolate

Dark chocolate can help lower high blood pressure

Dark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease.

Recent studies indicate that regular intake of chocolate, particularly dark chocolate, has beneficial effects on cardiovascular disease risk by lowering blood pressure, insulin resistance, serum triglycerides, vascular reactivity, endothelial dysfunction, oxidative stress, indicators of inflammation, and anti-platelet activity (Corti R, Flammer AJ, Hollenberg NK, Luscher TF. Cocoa and cardiovascular health. Circulation. 2009;119:1433–1441).

According to the study, participants who enjoyed 100 grams of dark chocolate daily for 15 days had reduced blood pressure and become more sensitive to insulin than they were prior to the "experiment".

It has been hypothesized that flavonoid compounds found in foods, including epicatechin found in high-cocoa-solid chocolates, decrease the risk of death from coronary heart disease, cancer and stroke.

Polyphenols, in particular flavanols in cocoa products, have been shown to increase the formation of endothelial nitric oxide, which promotes vasodilation and consequently may lower blood pressure (Fisher ND, Hollenberg NK. Aging and vascular responses to flavanol-rich cocoa. J Hypertens. 2006;24:1575–1580).

Short-term administration of dark chocolate was followed by a significant increase in insulin sensitivity and a decrease in blood pressure in healthy subjects. Therefore, the daily consumption of chocolate (25 g daily) containing polyphenol-rich; high-cocoa solids for 8 weeks would improve cardiovascular risk factors in patients with diabetes and hypertension (ARYA Atheroscler. 2015 Jan; 11(1): 21–29).
Dark chocolate can help lower high blood pressure

What nutrients are in dark chocolate?

Many studies show that beneficial nutrients can be found in dark chocolate. Dark chocolate is made up of cocoa solids and sugar but no milk solids (prevalent in milk chocolate) and white chocolate, although referred to as chocolate had no cocoa solids, but instead is made of cocoa butter (the fat in chocolate), milk solids and sugar.

One of the nutrients in dark chocolate is called a polyphenol. Polyphenols are apart of a large family of natural compounds found in a wide variety of plant foods. They are helpful in assisting the human body protect itself from free radicals that cause oxidation.

Researchers believe that the benefits of dark chocolate are because of the flavonoids it contains, which are associated with the ability to lower the risk of heart disease and some cancers.

The heart may be vulnerable to damage by oxidation and flavonoids of dark chocolate hold potential for positive heart health effects.

Dark chocolate contains small amounts of B-complex vitamins (thiamin, or B1; riboflavin, or B2; niacin; vitamin B6’ and folate), needed for releasing energy and creating the body’s building blocks. Bone-enhancing vitamin D and antioxidant E are found in dark chocolate, which are important nutrients, too.

According to some studies done in Italy, dark chocolate has many of the same benefits as vitamin C helping the body use insulin more effectively and lower blood pressure. According to the study, participants who enjoyed 100 grams of dark chocolate daily for 15 days had reduced blood pressure and become more sensitive to insulin than they were prior to the "experiment".

Dark chocolate is plentiful in magnesium, important for brain functioning. It also boasts other nutrients, such as copper, iron, manganese and zinc.
What nutrients are in dark chocolate?

Production of dark chocolate

Dark chocolate goes to the essence of what chocolate is because dark chocolate has a wealth of cocoa solids, and these gave chocolate its flavor and color.

Dark chocolate also contains cocoa butter, which carries that wonderful flavor to taste buds and makes it linger.

Dark chocolate processing
It is crucial that the plant flavonoids in dark chocolate stay intact while processing. Since the native form of coca seeds is quite unpalatable, it undergoes many manufacturing processes.

Cocoa pods are harvested, fermented, dried, cleaned and roasted. After the roasting and grinding processes, cocoa beans become a thick, dark, bitter paste called ‘cocoa liquor’: the most important component of chocolate.

Dark contains a high percentage (equal to 70%) of cocoa solids, and little or no added sugar. The compounds, not only confer to dark chocolate its typical astringent and bitter taste, but also significantly contribute to its antioxidant activity.

The ideal processing temperatures after melting and pre-crystallization are different for the different types of chocolate (dark, milk and white). For dark chocolate, processing temperature is 31-32 °C.

The industry has monitored the flavonoids losses over the whole chocolate process including the tree genotype, fermentation, drying and industrial process in order to be able to obtain a high flavonol concentration in the final dark chocolate.
Production of dark chocolate

Blood Clots Risk Lowered by Dark Chocolate

Blood Clots Risk Lowered by Dark Chocolate
Eating a little bit of dark chocolate each day you could be reducing your chances of developing a blood clot. The researchers said that dark chocolate helps thin the blood, in pretty much the same way as aspirin does.

The research team had started studying aspirin's effect on platelets. Platelets are tiny particles in the blood that stick to each other, eventually forming clumps which make a clot. The scientists compare the blood of the chocoholics to those who had stopped eating chocolate. They found that the chocoholics' platelets clotted at 130 seconds (when taken out), compared to 123 seconds for the other people. In other words, the platelets of the chocoholics were taking longer to clot.

They concluded that chemicals, perhaps flavonoids, in the cocoa bean have a biochemical effect similar to aspiring in reducing platelet clumping. Platelet clumping can block a blood vessel and cause heart attacks.

The scientists say people could benefit from either having a bit of dark chocolate each day or a chocolate drink. It is important its sugar and butter content is minimal. The ideal amount would be about two tablespoons of dark chocolate each day.

Blood Clots Risk Lowered by Dark Chocolate

Chocolate A Healthy Food

Chocolate A Healthy Food
Chocolate actually is good for us. This is the nutrition news we have all been waiting for. And chocolate actually have a health benefits.

Recent studies show that cocoa and dark chocolate with a high cocoa content contain many heart-healthy antioxidants. They contain a compound called flavonoids which may help prevent the oxidation of LDL cholesterol and raise HDL cholesterol levels in the blood. There is also some evidence that these flavonoids may prevent certain cancers.

However, not all chocolate have these health benefits. The healthy flavonoids found in chocolate are found in the cocoa butter and cocoa solids. Milk chocolate is diluted with milk and sugar and contains little amounts of these substances, therefore providing fewer health benefits.

The darker the chocolate, the higher the cocoa content and the more antioxidants it contains. The cocoa butter is quite pricey so less expensive brands will replace the cocoa butter with milk fats and hydrogenated oils which are bad for health. Look for high quality chocolates with their main ingredients being cocoa butter and cocoa solids. Unsweetened cocoa powder is one of the purest forms of chocolate can be eaten and is lower in fat and calories than other chocolates.

Although this is great news for all chocolate lovers, don’t forget that most chocolate does still contain sugar and saturated fat. An ounce of chocolate contains around 135 calories. Therefore, enjoy a cup of hot cocoa or an ounce of chocolate once in awhile to contribute to health and not to waistline.
Chocolate A Healthy Food

Flavonol and health

There has been a long-standing interest in the relation between what we eat and cardiovascular risk. Over the years, attention has been given to calories, total fat, saturated fat, cholesterol, omega-3 polyunsaturated fatty acids, trans fatty acids, folic acid, antioxidants and, most recently, flavanols. Flavanol concentrations can be moderately high in a number of foods that have been associated with a reduction in cardiovascular risk including red wine, and black and green tea. Some cocoa and chocolate products are extraordinarily rich in flavanols but, as with other flavanol-containing foods, certain post-harvesting and processing procedures can have a striking influence on the flavanol content of chocolate and cocoa.

Endothelial dysfunction with a consequent reduction in nitric oxide production has achieved a central conceptual role in the pathogenesis of atherosclerosis and coronary artery disease, diabetes mellitus and hypertension. Recent evidence that flavanol-rich cocoa activates vascular nitric oxide synthesis in the intact human raises an interesting possibility of a therapeutic potential.

Among the most recent candidates that have drawn important attention are the flavonoids - polyphenolic compounds found in a variety of foods of vegetable origin, including tea, cocoa, chocolate, red wine, purple grapes, apples, onions and cranberries. In particular, a specific subclass of flavonoids - known as flavanols - has attracted increasing interest as a result of recent epidemiological, mechanistic and human intervention studies. Among the wide variety of dietary flavanol sources, some cocoas and chocolates can be extraordinarily rich in certain flavanols.

A possible confounder in epidemiological studies is a contribution from sources of flavonoids that were not part of the analysis. One striking example in this area is cocoa and chocolate, which can contain flavonoid, specifically flavanol, profiles and concentrations very different from those of other sources. Equally important is the fact that foods recognized as being flavonoid-rich vary in their flavonoid content substantially, largely due to common techniques used during post-harvest handling of raw materials and processing during food production.

The biological effects of plant flavonoids are wide-ranging and sometimes substantial. In vitro, flavanols found in cocoas and chocolates have shown specific activities related to vascular health and, in particular, mechanisms associated with endothelial function, endothelium-derived nitric oxide synthesis, platelet function, and cellular processes modified by reactive oxygen and nitrogen species.

Epidemiological evidence linking flavonoid consumption to heart disease or mortality in humans is impressive but has often been conflicting. For example, there has been enormous interest in the 'French paradox' reflecting the interesting finding that the French do not have a myocardial infarction rate to match their fat intake. Attempts have been made to implicate red wine as a contributor via its flavonoid content. Regarding flavanols consumed as cocoa and chocolate and their potential influence on cardiovascular risk in epidemiological studies, there is a paucity of data. Such studies examining the potential health effects of foods rich in flavonoids have, at times, shown a very large influence on cardiovascular risk. For example, researchers reported the findings in a prospective study on the determinants of mortality after acute MI. Patients who consumed an average of 14 or more cups per week of black tea showed a 39% reduction in mortality during a median follow-up of 3.8 years. Perhaps more striking was the fact that the moderate tea drinkers who averaged only two cups of tea per week showed a 31% reduction. Adjustment for the usual risk factors did not alter this association. Why should the results of studies be in conflict given such a robust influence? There are several reasons: indeed, they provide the rationale for this review focusing on the potential cardiovascular health benefits of flavanols in cocoas and chocolates. Sometimes identifying the responsible mechanism(s) can have a substantial influence on the attempt to resolve such issues.

The clinical processes of interest are characterised by endothelial dysfunction. Studies in vitro, in animal models, and in intact humans have provided growing evidence for an action of this class of natural products on endothelial dysfunction. The final common pathway appears to be activation of nitric oxide synthesis. This story has at least one of its beginnings a long way from the issue of phytochemicals in foods. The Kuna Indians in Panama, living in their indigenous island home in the Caribbean, do not show the typical rise in blood pressure with age, and hypertension is very rare. In a study that began with the search for protective genes, the observation that migration to Panama City led to a loss of the protection against hypertension made it clear that an environmental factor was involved. Examination of their diet uncovered the fact that they drank large volumes of a flavanol-rich cocoa. Subsequent in vitro studies suggesting that cocoa extracts can induce endothelium-dependent relaxation led to studies in healthy volunteers, and in patients with vascular risk or disease. In one study researchers found that ingestion of flavanol-rich cocoa led to an increase in flow-mediated vasodilation of the brachial artery following five minutes of ischaemia, a response that correlated with biochemical evidence of increased nitric oxide bioavailability. In the normal volunteers studied flavanol-rich cocoa induced striking dilatation of the vessels of the finger, which was reversed completely by an arginine analogue that blocks nitric oxide synthesis.