Chocolate: Indulgence or Superfood (Part 2)April 5th, 2010
Although chocolate has been shown to have a variety of impressive health benefits, there are a number of concerns to consider before consuming it specifically for this reason. Contrary to what you might think, the majority of these concerns aren’t related to the unhealthy characteristics of candy and other sweets that often lead people to classify chocolate as an indulgence food.
The previous article presented the many impressive health benefits of chocolate including a remarkably high antioxidant capacity, a reduced risk of heart disease and diabetes, a reduced growth rate of several cancers, and even improved skin health. However, since each of these benefits can be obtained in other ways, the remaining question that needs to be answered is if chocolate should be consumed specifically to promote good health despite having some potentially harmful characteristics. The following issues provide some of the insight needed to answer this question.
Chocolate Can Impair Digestion and Absorption
Chocolate can be a rich source of minerals including calcium, copper, iron, magnesium, phosphorous, potassium, and zinc.1,2 However, as with most seeds, the cacao bean also contains phytic acid3 and enzyme inhibitors.4 Phytic acid allows seeds to maintain the nutrients they need to germinate by binding to minerals such as iron, calcium, magnesium, and zinc. However, research has shown that phytic acid impairs our ability to absorb these minerals.5,6,7,8,9,10,11 The protease inhibitors that exist in cacao beans cause another problem by inactivating digestive enzymes in the human digestive tract which reduces the efficiency of protein digestion. This also puts an additional burden on the pancreas to produce more enzymes which has the potential to impair its function and cause it to enlarge.12,13
The potential for phytic acid and enzyme inhibitors to interfere with mineral absorption and protein digestion applies to the nutrients found in chocolate as well as any other foods eaten with it. If phytic acid and enzyme inhibitors are consumed frequently in high enough concentrations, they can impair overall digestion and increase the potential for nutrient deficiencies and subsequent health issues. As such, this is an important consideration. In most cases, the amount of phytic acid and enzyme inhibitors can be reduced by soaking and cooking. However, because chocolate manufacturers are very unlikely to do so, phytic acid and enzyme inhibitors may very well exist in their final products. Although enzyme inhibitors are likely to at least be partially inactivated by the heating involved in the processing of chocolate,16 this is not the case with phytic acid which has been found in chocolate at relatively high levels.14,15
Oxalate, another substance that can interfere with digestion, has also been found in chocolate.14 Oxalate impairs the absorption of calcium17 and can therefore increase the risk of developing osteoporosis.18 Foods that contain oxalate are also thought to increase the risk of kidney stones,19 and this risk is believed to be made even worse by the combination of sugar and oxalate that exists in chocolate.20 Although steaming and especially boiling can reduce the oxalate content in food, baking has been shown to not have this effect.21 As such, the heat that chocolate is exposed to during processing is unlikely to have much of an impact on its oxalate content. This has been made evident by the detection of oxalate in chocolate products that have already been processed.14
Some Chocolate is Contaminated with Heavy Metals
Plants are extremely effective at absorbing minerals from the soil. In some cases, the roots of plants can contain mineral concentrations that are 10,000 times that of the soil, and this is an important aspect of their survival. Because of this absorption capability, plants are often used to remove environmental contamination through a process called phytoremediation.22 Unfortunately, this absorption capacity can also result in the contamination of plants that are used for food.
Potentially toxic heavy metals including lead, cadmium, and arsenic have been found in chocolate products from a variety of origins.23,24,25,26 These metals can be absorbed directly by the Theobroma cacao tree or be introduced during the manufacturing process, but either way, they can still exist in the final product. Although the levels of these metals are often within acceptable ranges, it’s important to realize that they accumulate in the body and can become quite toxic over an extended period of exposure to small amounts. Many chocolate manufacturers claim that the amounts are small enough to not be a concern,27 but the American Environmental Safety Institute considered it a large enough concern to file suit against a number of manufacturers in 2002 and petition for required contaminant labeling.28
The concentration of heavy metals may very well be too low to be of significant concern, but it’s definitely a legitimate reason to avoid eating sizable portions of chocolate on a regular basis. Furthermore, because the cacao beans used to make chocolate come from all over the world, the amounts of heavy metals that they contain can vary widely. Although there’s no guarantee, certified organic chocolate is less likely to be produced from cacao beans that have been grown in a contaminated environment or exposed to contaminants during processing.
Chocolate can Alter Your Mood
Chocolate is the most commonly craved food in North America by a large margin, especially among women.29 As such, it shouldn’t be much of a surprise that it can alter your mood considerably. Although some people might consider this a benefit, it’s often a compensatory measure that can have undesirable long term effects, just like relying on coffee for energy.
Despite the amount of research that’s been done on this aspect of chocolate, a lot of questions remain unanswered and there’s quite a bit of disagreement regarding the mechanisms through which the cravings and mood alterations associated with it might occur.
Chocolate as a Stimulant
Chocolate often contains a substance called phenylethylamine (PEA)30 which is believed to act as a stimulant that can increase energy, elevate mood, and promote aggression.31 This substance is one of the most common explanations for the mood alterations and intense cravings that are often associated with chocolate. However, there’s some doubt about this because other foods such cheese and sausage contain greater quantities of PEA and aren’t associated with cravings.29
Another somewhat common explanation for chocolate’s addictive properties is its caffeine content, but because chocolate contains such a small amount of caffeine, it’s unlikely to have much of an influence. However, chocolate does contain much larger quantities of a substance called theobromine which is similar to caffeine and is therefore believed to be a stimulant with addictive properties, but to a lesser extent.32,29 As such, theobromine is believed to possibly play a role in the cravings and mood alterations associated with chocolate.
In addition to their energizing effects, many stimulants are believed to be a potential trigger for migraine headaches, and there’s evidence suggesting that this may be the case for chocolate as well.33
Chocolate as a Mood Enhancer
Dopamine is a neurotransmitter that’s associated with feelings of euphoria and satisfaction and is well known for having a significant influence on mood. Chocolate contains a derivative of dopamine named salsolinal which is naturally produced in the brain of humans and has been shown to have a strong affinity for dopamine receptors. As such, it’s believed to play a role in the reinforcement and reward system associated with addiction. Salsolinal has also been shown to decrease the production of the neurologically influential substances β-endorphin and ACTH which is a common characteristic of addiction34 and can have an undesirable long term effect on mood.
Chocolate contains a notable amount of magnesium1,2 which is another reason why it’s believed to influence mood and cravings. A deficiency in magnesium can cause a depletion of dopamine, and based on this, it’s believed that the magnesium in chocolate may induce cravings because of its potential to alleviate the deficiency. However, this too is uncertain because similar amounts of magnesium are found in a variety of nuts that generally aren’t associated with cravings.29
Chocolate as a Drug
Chocolate has been found to contain several compounds constituting a lipoprotein called anandamide. This substance naturally exists in the human brain and is known to produce the heightened sensitivity and sense of euphoria associated with cannabinoid drugs such as marijuana.29 As such, these compounds are believed to be another potential cause of the addictive and mood altering characteristics of chocolate, but other researchers disagree and believe that chocolate doesn’t contain enough of these compounds to have such an effect.35,36
Just Another Sweet Craving?
Sweet and palatable foods in general are believed to invoke an immediate opiate response, which includes the release of β-endorphin, and this is believed to be a possible explanation for the satisfaction associated with eating certain foods.37,38,39,40 Sweet foods are also believed to influence mood through the neurotransmitter serotonin which is known to provoke a general sense of wellbeing. When carbohydrates are consumed, especially those which cause a rapid rise in blood sugar, the resulting release of insulin causes more amino acids to be absorbed by cells. However, tryptophan is left behind which results in a higher concentration that can enter the brain more easily and be used to produce serotonin.41,42
Whether the potential for chocolate to alter mood and cause cravings is because of one or more of its ingredients, the simple fact that it’s sweet and tastes good, or if it’s just a matter of psychology is still up for debate.29,35 Regardless of the actual cause, research has clearly acknowledged the existence of these effects, and it would be prudent to regard them as more of a potential concern than a benefit.
A Combination of Good and Bad
Although the impressive health benefits associated with chocolate have been getting a lot of attention, it’s arguable that these benefits are negated by issues relating to digestion, toxicity, and mood. In addition, the extent to which chocolate can promote or harm one’s health can vary considerably depending on a number of factors which makes it even more difficult to determine if the benefits justify the risks. Part three of this article discusses how chocolate can fit into a healthy diet as well as some of the considerations that can make it more of a health food and less of an indulgence.
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