Chocolate and health

• Introduction to chocolate
• History of chocolate
• How is chocolate made?
• Types of chocolate
• Nutritional content of chocolate
  • Nutrients derived from cocoa
• Health risks associated with consuming chocolate
• Dental health and chocolate
• Health benefits of consuming chocolate
  • Improved endothelial function and cardiovascular parameters and chocolate
  • Cancer and chocolate
  • Cognitive performance and chocolate
  • Photoprotection (protection from light) and chocolate
  • General health and well-being and chocolate
  • Sexual health and chocolate
• The health benefits without the chocolate
• How much and which chocolate is best consumed?
• Healthy chocolate recipes

Introduction to chocolate

Chocolate is a food typically associated with pleasure and indulgence. It is a sugary food, high in fat and energy, which should be consumed in moderation. Many individuals consume chocolate as a treat or share chocolate at special occasions like birthdays and Christmas. Boxes of chocolates may be given as gifts on special occasions and in Australia it is common to exchange chocolate eggs to celebrate Easter.

There is considerable temptation to also buy chocolate at other times. The confectionary industry in Australia, which monitors chocolate sales, reports that some 70% of confectionary is purchased on impulse and encourage sellers to display confectionary prominently to tempt customers. Australians spend more money on chocolate confectionary products (including chocolate blocks, bars, boxes of chocolates and novelty chocolates like Easter eggs) than on other type of confectionary combined. In 2002, Australians spent $1,550 million on chocolate products (compared to $950 million and $220 million on sugar confectionary and gum).

History of chocolate

The consumption of cocoa, which gives chocolate its flavour, has a long history. Since as early as 1500BC, ancient Olmec and Mayan civilisations of South America have consumed cocoa (usually as bitter, aromatic drinks) and associated cocoa with the gods.

Cocoa has been consumed in many cultures for medicinal purposes. The word ‘chocolate’ (derived from the Mayan cacauatol) was coined by Spanish colonisers of South American in the 16^th century and since that time chocolate preparation has changed considerably. Cocoa is now usually consumed as sweet beverages or snacks. Mass production of chocolate sweets dates back to the 1800s.

How is chocolate made?

Chocolate is made from cocoa beans which are derived from the cacao tree, a tropical rainforest plant. The cacoa tree is native to Latin America, but is now grown in other tropical areas of the world, mostly to meet the demand for chocolate production. It grows brightly colours pods of seeds, roughly the size of a football. The 30-50 seeds (sometimes called beans) contained within each pod are the key ingredients from which chocolate is made. The seeds are harvested, fermented and dried or roasted to enhance their aroma, before being heated and mixed with other ingredients (e.g. sugar, milk, cocoa butter) to make chocolate. These typically include cocoa or cocoa liquor (non-alcoholic), milk and/or milk solids, sugar and cocoa butter (or vegetable fats).

Types of chocolate

There are many different types of chocolate, which can be broadly classified as white chocolate, milk chocolate and dark chocolate, depending on the relative proportions of cocoa and milk they contain.

White chocolate contains milk but no cocoa, while dark chocolate contains cocoa (in higher concentrations than milk chocolate) but no milk. Milk chocolate contains both milk and cocoa.

White, milk and dark chocolate can be manufactured in different ways and may therefore take different forms. For example, they may be sold as blocks of plain chocolate, as chocolate bars with additional ingredients such as nuts and wafers or as sauces or drinks.

Another means of classifying chocolate is as either block or compound chocolate. Compound chocolate, most often used for cooking, is made from cocoa and vegetables fats. Block chocolate (white, milk and dark) mixes cocoa with cocoa butter. The distinct compositions of compound compared to block chocolate have an effect on the relative proportions of saturated, mono-unsaturated and poly-unsaturated fat levels in each (see Table 1).

Nutritional content of chocolate

Chocolate contains a variety of ingredients which contain different nutrients and affect the body’s functioning in different ways. Depending on the relative proportions of cocoa, milk and other ingredients, the overall nutritional content of a bar or piece of chocolate varies considerably. For example, chocolate containing greater quantities of milk or milk solids (white or milk chocolate) has a higher calcium content, while chocolate containing greater concentrations of cocoa (dark chocolate) is higher in caffeine. Adding nuts, fruit or other ingredients to chocolate changes its nutritional composition (see Table 1). Chocolate also contains over 400 chemicals including micronutrients which protect the body and its function in various ways. These include Vitamin E, phosphorous, magnesium, iron, copper and plant chemicals.

Cocoa and cocoa butter also contains three types of fat, a monounsaturated fat known as oleic acid, and two saturated fats, stearic acid and palmitic acid. Oliec acid, like other monounsaturated forms of fat including olive oil, does not affect cholesterol levels. There is also evidence that stearic acid, despite being a saturated form of fat has a neutral effect on cholesterol. While palmitic acid (which comprises about one third of chocolate’s fat content) is a saturated fat which is known to affect cholesterol levels, there is no evidence that eating chocolate raises cholesterol levels.

Please note that the values in the table are a general guide and that the nutritional value of a particular brand of chocolate may vary, depending on the relative proportions of cocoa and other ingredients and the manufacturing process used to make the chocolate.

Table 1 – Nutritional composition of chocolate (all per 100g)

Click here to view the table.

Nutrients derived from cocoa

In terms of the health benefits which may be derived from chocolate consumption (discussed below) the cocoa content is of key importance. Cocoa contains high concentrations of a powerful type of antioxidant known as polyphenols. Flavanoids, the most common subclass of polyphenols, are found in higher concentrations in chocolate than in other flavanoid rich substances (e.g. red wine). A further subclass of flavanoids, flavanols (or flavan-3-ols), are also found in particularly high quantities in cocoa.

Flavanol in chocolate is derived from its cocoa content, and thus the quantity of flavanol varies depending on the amount of cocoa in the chocolate. White chocolate does not contain cocoa and presumably contains no flavanol, while dark chocolate contains more flavanol than milk chocolate. The flavanol content of various types of milk and dark chocolate also varies depending on the quantity of cocoa contained (some types of dark chocolate contains more cocoa than other types), the agricultural environment in which the cocoa was grown and the method used to process the chocolate. Heating of ingredients and other steps in the chocolate production process can reduce the flavanol content by as much as 90%.

The extent to which flavanol from chocolate is absorbed by the body after consumption also varies depending on the type of chocolate. Dark chocolate flavanol is absorbed more readily by the body than milk chocolate flavanol. However, this does not appear to result from the differing milk content of milk and dark chocolate.

For more information on nutrition, including information on types and composition of food, nutrition and people, conditions related to nutrition, and diets and recipes, as well as some useful videos and tools, see Nutrition.

Health risks associated with consuming chocolate

There is no conclusive evidence linking chocolate consumption to a higher risk of any health conditions, although chocolate is widely perceived to cause migraines, acne and obesity. Evidence suggests that chocolate consumption alone cannot cause any of these health conditions. However, acne is associated with high glycaemic index diets and high intakes of refined carbohydrates, and consuming large quantities of chocolates could considerably increase the glycaemic index and refined carbohydrate content of a diet. Similarly, chocolate consumption alone does not cause obesity, which is a disease that arises from excessive calorie intake. However, consuming large quantities of chocolate can considerably increase an individual’s calorie intake and may lead to weight gain and obesity, which in turn increase the risk of cardiovascular disorders including high blood pressure (hypertension), diabetes and dyslipidaemia.

Dental health

Consumption of chocolate may also increase the risk of dental health problems. Dental caries (cavities) are associated with high sugar intakes, so chocolate products with high concentrations of sugar increase the risk of dental caries. There is also evidence that regular intake of chocolate can cause tooth discolouration.

Health benefits of consuming chocolate

Improved endothelial function and cardiovascular parameters and chocolate

Proposed mechanism

Evidence suggests that consuming chocolate can improve cardiovascular health by improving endothelial function, that is, by increasing the amount of nitric oxide produced by the endothelium. The endothelium is the layer of tissue which lines the inside of the arteries. It regulates the flow of blood through the arteries, by producing (or not producing) a substance called nitric oxide. Nitric oxide causes the arteries to expand to facilitate blood flow. The more nitric oxide produced by the endothelium, the more easily blood can flow through the arteries and the less likely an individual is to experience cardiovascular problems such as stroke and heart attack. This may also influence a man’s erectile function and the orgasmic function of men and women, as erection and orgasm are nitric oxide dependent processes (see sexual health and chocolate).

The cardiovascular health benefits of chocolate consumption are related to the activity of the polyphenols (and particularly flavanol) found in the cocoa content of chocolate. Flavanols stimulate nitric oxide secretion and thus consumption of cocoa and flavanol-containing chocolate enhances nitric oxide secretion and widens the arteries. This in turn enhances blood flow and improves a range of cardiovascular parameters. Nitric oxide also has anti-platelet effects (meaning it protects against the formation of blood clots), anti-inflammatory and anti-atheroschlerotic effects (protects against hardening of the walls of the blood vessels).

The anti-oxidant effect of flavanols is also thought to provide cardiovascular protection. Antioxidants are compounds which scavenge and neutralise free radical molecules, or molecules which contain unpaired oxygen atoms. The unpaired oxygen atoms react with and can damage other chemical compounds and cells in the body and also reduce the production of nitric oxide (and thus impair endothelial function). Antioxidants also react with the unpaired oxygen atoms on free radical molecules, and in doing so they neutralise the oxygen atoms and prevent them from damaging the body’s cells. The antioxidant effects of flavanols are thought to underlie the association between chocolate consumption and improved cholesterol. Flavanols assist in the oxidation of low density lipoproteins (LDLs) which are “bad” forms of cholesterol. In doing so, they reduce blood concentrations of LDLs.

Anti-oxidants also counter the nitric oxide suppressing effects of free radical molecules and stimulate nitric oxide secretion. There is also evidence that the flavanols contained in chocolate improve glucose metabolism (and thus reduce insulin sensitivity and other markers of diabetes), by stimulating nitric acid production. Insulin sensitivity is regulated by the availability of nitric oxide concentrations.

Evidence

Endothelial function

There is considerable evidence that cocoa consumption improves endothelial function. One study in which participants consumed either dark chocolate (containing 22g of cocoa) or cocoa-free chocolate daily, reported significantly improved endothelial function (increased arterial blood flow) in the dark chocolate group. Participants who consumed the dark chocolate then tested a cocoa beverage (containing 22g of cocoa). They also experienced improved endothelial function compared to participants who drank a cocoa free beverage. Evidence shows that endothelial function improves after both short-term and long-term consumption of chocolate.

Cardiovascular disease

There is also evidence that chocolate consumption protects against ill-health and death associated with cardiovascular disease. One large study reported that men with high cocoa intake were 50% less likely to die of cardiovascular causes than men with the low cocoa intake. Another study reported a dose-response relationship between cocoa consumption and cardiovascular mortality, meaning that the more chocolate an individual consumed, the less chance they had of dying from cardiovascular complications. Individuals who consumed chocolate more than once a week were 66% less likely to die of cardiovascular causes compared to those who never ate chocolate, while those who consumed chocolate less than once a month were 27% less likely to experience cardiovascular mortality.

Studies have also reported a protective effect regarding cardiovascular ill health. One reported that elderly individuals (aged 70-74) who consumed chocolate in the previous year were significantly less likely to have a history of cardiovascular disease compared to those who did not.

Blood pressure

There is also considerable evidence that chocolate consumption can reduce blood pressure. For example, a study of Dutch men reported that those who consumed high quantities of cocoa had lower blood pressure than those with low chocolate consumption. Another compared blood pressure in healthy individuals consuming 100 grams of dark chocolate everyday for 15 days, with blood pressure of subjects consuming 90 grams of white chocolate everyday. It reported significantly lower blood pressure amongst the dark chocolate consumers. Evidence suggests that consuming chocolate can reduce blood pressure as much as some medications used to reduce blood pressure, and chocolate consumption could reduce the risk of stroke and cardiovascular disease by 20% and 10% respectively.

Inflammatory markers

There is also some evidence that cocoa consumption reduces inflammation which contributes to vascular ill-health. For example, one study showed consumption of dark chocolate was inversely associated with c-reactive protein levels. High levels of c-reactive protein are a marker of inflammation and an indicator of coronary heart disease. However, the study found that the relationship was only present when chocolate was consumed in moderation (~20 grams of dark chocolate every three days). The association disappeared when greater quantities of dark chocolate were consumed. The authors of this study concluded that moderate consumption of dark chocolate could reduce the risk of coronary events in men by 26% and in women by 33%.

Platelet activity

Evidence that cocoa consumption positively effects platelet activity, that is reduces the risk of platelets forming clots in the blood and causing blockages in arteries, is also growing. Studies have shown that cocoa consumption can reduce platelet clotting and thin an individual’s blood, in a similar way to which aspirin does.

Diabetes

Evidence also suggests that chocolate consumption can improve insulin sensitivity and reduce the risk of diabetes. A Norwegian study reported a significantly lower prevalence of diabetes amongst elderly subjects (70-74) who consumed chocolate in the previous year compared to those who did not. A study of healthy individuals (average age 34 years) reported improved insulin sensitivity in subjects who consumed polyphenol-rich dark chocolate compared to those who consumed polyphenol-free white chocolate. Insulin sensitivity improved after just 15 days of consuming 100 grams of dark chocolate per day.

Improved cholesterol

Studies have also shown that consumption of dark chocolate improves cholesterol. One study, in which healthy individuals consumed either a flavanol-enriched dark chocolate bar or a dark chocolate bar with no added flavanols, reported significant reductions in total cholesterol and LDLs (bad cholesterol) amongst flavanol-enriched chocolate consumers. As high cholesterol is a significant risk factor for heart disease, dark chocolate consumption therefore also indirectly reduces the risk of cardiovascular disease, by improving cholesterol.

For more information on cholesterol, including the health effects of high cholesterol and ways to lower cholesterol levels, as well as some useful tools, see Cholesterol.

Cancer and chocolate

Proposed mechanism

The anti-oxidant properties of cocoa are thought to protect against cancer by protecting cells from oxidative damage which contributes to the growth of cancerous cells. Flavanoids in cocoa appear to interrupt the cell cycle of cancerous cells (the process through which cancerous cells replicate themselves and grow excessively to form tumours). Effectively, they impair the growth of cancerous tumours, however the way in which flavanoids exert this effect is not yet well understood.

Evidence

Evidence regarding the effect of chocolate or flavanoid consumption on cancer risk is somewhat contradictory. While test tube/laboratory studies have shown that cocoa-derived flavanoids interrupt the replication of cancer cells, there is no evidence from studies of cocoa consumption and incidence of cancer amongst humans to indicate whether or not flavanoids exert the same effect in the human body.

For more information on cancer, including breast, prostate, kidney and stomach cancer, see Cancer: Overview.

Cognitive performance and chocolate

Proposed mechanism

The proposed mechanism through which increased chocolate intake improves cognitive performance is via increasing blood flow to the cerebral grey matter (grey matter in the brain which regulates sensory responses).

Evidence

Evidence suggests that elderly individuals who consume chocolate have better cognitive function than those who do not. A study of Norwegian 70-74 year olds reported that chocolate intake in the past year was associated with better performance on numerous cognitive tests. The best cognitive performance was achieved with consumption of 10 grams of chocolate per day.

Photoprotection (protection from light) and chocolate

Proposed mechanism

Photoprotection refers to protection from light. In the human body, the skin provides photoprotection by absorbing the sun’s rays. This results in the production of free radical molecules (molecules with unpaired oxygen atoms which can break away and damage or alter other molecules and cells in the body). Free radical molecules can cause damage to skin cells and result in the growth of cancerous cells.

The properties of skin vary between individuals according to their genes (e.g. pigmentation of their skin) and the extent to which the skin is exposed to sunlight (e.g. use of sunscreen or a hat), and these factors influence the extent to which the skin is photoprotective. Nutritional intake is one factor affecting skin photoprotection and dietary antioxidants (including flavanols in cocoa) are thought to exert a photoprotective effect. The proposed mechanism by which they exert this effect is by reducing the sensitivity of skin cells to UV exposure.

Evidence

One study which compared the effect of UV-exposure on the skin of women who had consumed high and low flavanol cocoa drinks daily prior to UV exposure, reported increased photoprotection (reduced sunburn) and improved skin condition (greater blood flow to skin, increased skin density and hydration) amongst women who consumed the high flavanol cocoa drink.

General health and wellbeing and chocolate

One study of elderly European men found that those who preferred chocolate had better general health than those who preferred other types of confectionary. For example, men who preferred chocolate were significantly less likely to be lonely or depressed and more likely to feel happy and have plans for the future. However, the mechanisms by which chocolate preference improves wellbeing are not well understood.

Sexual health and chocolate

Chocolate has also been proposed to have an aphrodisiac effect (increase sexual desire) because it stimulates the release of serotonin (a mood regulating hormone which also regulates blood flow) and phenylethylamine (a stimulant which regulates mood). However, there is currently limited scientific evidence to support this theory.

Chocolate may also enhance sexual response in men and women (e.g. improve erectile function and vaginal lubrication) because chocolate consumption stimulates the release of nitric oxide which plays an important role in regulating sexual function. As mentioned above, nitric oxide regulates blow flow through the arteries, and the more nitric oxide released, the more blood that flows through the arteries. As erectile function depends on increased blood flow to the penis, the availability of nitric oxide can affect a man’s ability to get an erection. Nitric oxide also plays a role in regulating the movement of smooth muscles, that is, muscles which expand and contract involuntarily. Smooth muscles in the genitals of men and women are involved in genital arousal and orgasm, and thus chocolate may also affect an individual’s genital arousal and orgasmic ability. However, research studies are yet to be undertaken investigating the effect of eating chocolate on sexual response.

The health benefits without the chocolate

While there is a growing body of evidence that some nutritional components of chocolate have beneficial health effects, it is important to remember that consumption of other anti-oxidant containing foods (particularly fresh fruit and vegetables) also produces these beneficial effects and individuals consuming a healthy balanced diet can obtain sufficient antioxidants without adding chocolate.

There is a risk of weight gain (and associated cardiovascular ill-health which accompanies weight gain) from increasing chocolate consumption and so chocolate should be consumed with caution.

How much and which chocolate is best consumed?

Chocolate is an energy rich food which is high in fat and sugar and the National Health and Medical Research Council recommend that such foods are consumed in moderation.

People who enjoy consuming chocolate will benefit most from dark varieties of chocolate which have cocoa or cocoa liquor listed first (and before sugar) in the ingredients. Chocolate should be consumed in small quantities (e.g. 10-15 grams per day). It is also important to bear in mind that over consumption of chocolate is likely to lead to weight gain and obesity, due to its high energy content. Individuals who wish to consume chocolate may need to reduce their calorie intake from other components of their diet, or increase their physical activity to offset the energy gained from consuming chocolate.

Healthy chocolate recipes

A quick and easy low-fat slice packed with dates, walnuts and chocolate. For more information, see Chocolate Date Slice.

Enjoy a healthy, easy to make chocolate sultana cake. For more information, see Chocolate Sultana Cake.

Indulge in a deliciously low-fat dark chocolate brownie. Serve warm from the oven with fresh berries for a great dessert. For more information, see Dark Chocolate Brownies.

A quick and easy low-fat oat slice packed with dried fruits, nuts and chocolate. For more information, see Fruit and Nut Chocolate Slice.

 

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