Story at-a-glance

• Dark chocolate has a bitter taste from the high number of cocoa flavanols, which can increase the measured speed and capacity of brain oxygenation, also raising performance 11% faster than baseline
• When dark chocolate was used as a delivery mechanism for ursolic and oleanolic acids, participants lost weight and had reduced waistline circumference measurements
• In moderation, dark chocolate helps reduce oxidative stress, contains healthy fat and antioxidants, can combat diabetes and heart disease, and may improve your mood
• "Raw" chocolate refers to products made from unroasted cacao beans, which is rich in flavanols responsible for many health benefits, compared with milk chocolate, which is high in sugar with minute amounts of flavanols

Although they sound the same, and some people use the terms interchangeably, flavonoids and flavanols are different. Flavonoids are a family of plant compounds, of which flavanols are one subclass. You can find flavonoids in fruits, vegetables, tea, chocolate and wine. Evidence shows it’s flavanol-rich dark chocolate that improves cognitive performance and mood.

The chemical properties of flavanols impact the bioavailability of the compounds and help determine their biological activity. As a family, flavonoids have antidiabetic, anti-inflammatory, anticancer and neuroprotective properties.

Oregon State University reports there is evidence that some flavonoids can improve cognitive function, but it is not known if they can help lower risk for those who are at risk for cognitive decline and dementia.1

For at least 4,000 years, chocolate has been a symbol of luxury, wealth and power.2 Of all the treats available, chocolate remains one of the most popular in the world. However, while dark chocolate has known health benefits, the same cannot be said for milk chocolate.

Flavanols Raise Brain Oxygenation and Cognitive Performance

In 2017, a meta-analysis was published in Frontiers in Nutrition evaluating the association between cocoa flavonoids and cognitive performance.3 Cocoa and cocoa products are a substantial source of flavanols. Scientists suggest cocoa can help counteract cognitive decline, especially in people at risk.

They speculated that the administration of cocoa flavanols may improve cognitive function and protect performance that occurs during sleep loss in healthy people. A study published in Scientific Reports delved further into this hypothesis.4

Using a randomized double-blind study design with young healthy adults, the researchers showed that cocoa flavanols increased the speed and capacity of brain oxygenation in response to the administration of carbon dioxide.

The participants also exhibited 11% faster performance than baseline when the demand was high.5 ZME Science spoke with Catarina Rendeiro from the University of Birmingham, who led the study. She described what the researchers were looking for, saying:6

“I have been for the last 10-12 years interested in the health benefits of plant-derived flavonoids, particularly their effects on brain and cognitive function. We have known for many years that flavanols from cocoa (in particular) can improve vascular function in humans by improving vessel/arterial function.

These benefits are apparent even after one single dose. However, the extent to which some of these benefits could translate into the brain vasculature was less clear.”

The researchers engaged 18 healthy people whom they tested in two trials. During the first, the participants consumed cocoa rich in flavanols and in the second processed cocoa with low levels of flavanols. Neither the participants nor the researchers were aware of which type had been consumed during the trials.

Two hours later the participants breathed 5% carbon dioxide (CO2) to increase blood flow to the brain. Normally, the air you breathe is composed of 0.04% CO2.7 CO2 causes vasodilation and vascular changes in the brain, including raising blood flow.8 The air delivered to the participants was just over 100 times greater than the normal concentration of CO2 in the air.

The researchers then measured the increased blood flow and oxygenation to the brain using customized helmets. They found the participants who ate high flavanol cocoa showed three times more oxygenated hemoglobin than those who ate the low flavanol cocoa.

Interestingly, the researchers also found a few participants did not show any benefits from flavanols and had the healthiest oxygenation responses. While speaking to ZME Science, Rendeiro said:9

“It is currently unclear why these subjects had higher responses but it might be related to higher levels of fitness, but we did not measure this in the study.

Consuming foods rich in flavanols, such as grapes, green tea, apples, berries can provide levels of flavanols that are beneficial for brain function. The fact that we can see benefits even in a perfectly healthy brain it is good news for all of us. There shouldn’t be any downsides from consuming flavanols from fresh fruits and vegetables …”

Chocolate Improves Taste of Natural Triterpenes

In a second study of cocoa, researchers used 70% cocoa chocolate as a delivery mechanism for ursolic acid and oleanolic acid.10 These are triterpenoid compounds with known pharmacological effects, including liver protection after chemically-induced injury in laboratory animals11 and antimicrobial activity in the fight against human pathogens.12

Oleanolic acid is sold in China for liver disorders and both are recognized as having anti-inflammatory and antihyperlipidemic properties when tested in lab animals.13 Researchers have found the health benefits of ursolic acid may include "anti-inflammatory, antioxidant, antiapoptotic, and anticarcinogenic effects."14

An animal study found ursolic acid increased calorie burn, skeletal muscle and brown fat development associated with weight loss, and increased strength. It also improved glucose tolerance.15

The objective of the study was to evaluate the effect of consuming 70% chocolate infused with ursolic and oleanolic acids that had been isolated from the Mansoa hirsuta DC plant.16 Initially, the researchers sought a combination with microbiological and sensory properties that were well accepted. There were 100 volunteers who participated in the “acceptance analysis.”

To evaluate the health effect, the researchers engaged 45 volunteers who were divided into a test group, a control group and a placebo group. The test group received a chocolate formulation containing the triterpenes; the placebo group received chocolate without the triterpenes; and the control group was instructed not to eat any chocolate of any kind during the course of the study.

The test group received 25 grams (g) of 70% cocoa chocolate with the added triterpenes over a four-week period. All were asked to maintain their regular activities and diet. Before and after the intervention the participants had their weight, height and waist circumference measured. Lipid profile and fasting blood sugar tests were also done.

In the control group in which no one consumed chocolate, there were no significant changes in the anthropometric measurements or lab tests. In the test group, after eating the chocolate with the ursolic and oleanolic acids, 50% lost approximately 2 kilograms (kg) (4.4 pounds) and 73.3% had reduced waist circumference. In the placebo group, which ate the regular chocolate, 86.6% gained weight.

In Moderation, Dark Chocolate Has Health Benefits

As demonstrated by the research discussed above, dark chocolate in moderation may have health benefits, but too much can raise your risk of weight gain and subsequent insulin resistance. Cocoa beans are rich in fat (54%), fiber (16%), protein (11%) and carbohydrates (31%).17

The largest source of bioactive compounds comes from flavonoids, which can improve central and peripheral vascular function. When consumed in moderation, flavanol-rich dark chocolate may improve insulin sensitivity by reducing your body's oxidative stress and improving endothelial function. This indicates that dark chocolate rich in flavanols may be a beneficial addition to your diet.

However, while dark chocolate has health benefits, milk chocolate does not. Unfortunately, the vast majority of chocolate sold and eaten is in the form of milk chocolate candy, which is loaded with sugar and has minute amounts of healthy cocoa. Additionally, one study found that the added milk proteins can reduce the bioavailability of epicatechin, a flavonoid important to antioxidant activity, in chocolate candies.18

In addition to the flavonoids, researchers have also found theobromine and other methylxanthines in dark chocolate that may affect health.19 For instance, theobromine improved memory in an animal study. But, as with most foods found in nature, the likelihood is the health effects come from the combination of polyphenols found in the food and not from a single ingredient.

There is some evidence that hearing loss may be inversely associated with chocolate consumption, yet it has no effect on tinnitus.20 Another review of the literature analyzed 13 clinical trials and found athletes experienced a reduction in oxidative stress linked to cocoa ingestion, but no clear conclusion could be drawn on the impact it had on exercise performance or recovery.21

A 2013 paper in The Netherlands Journal of Medicine also reviewed the health benefits of cacao, noting that some consider it a "complete food," as it contains:22

• Healthy fats
• Antioxidants
• Nitrogenous compounds, including proteins, methylxanthines theobromine and caffeine
• Minerals, including potassium, phosphorus, copper, iron, zinc and magnesium
• Valeric acid, which acts as a stress reducer despite the presence of stimulants

Bitter Chocolate May Help Improve Your Mood

Human trial data from Loma Linda University, presented at the Experimental Biology 2018 annual meeting in San Diego, revealed chocolate helps improve stress levels, inflammation, mood, memory and immune function. The caveat? It must contain at least 70% cacao and be sweetened with organic cane sugar. According to the scientists:23

"While it is well-known that cacao is a major source of flavonoids, this is the first time the effect has been studied in human subjects to determine how it can support cognitive, endocrine and cardiovascular health … These studies show us that the higher the concentration of cacao, the more positive the impact on cognition, memory, mood, immunity and other beneficial effects."

A number of other studies have confirmed cacao can benefit your heart, blood vessels, brain and nervous system, and helps combat diabetes and other conditions rooted in inflammation.

As noted in a paper published in the journal Oxidative Medicine and Cellular Longevity,24 "Cocoa contains about 380 known chemicals, 10 of which are psychoactive compounds” and it “has more phenolics and higher antioxidant capacity than green tea, black tea, or red wine …”

“The antioxidant properties of cocoa or cocoa-derived products enriched in flavonoids may help protect against diseases in which oxidative stress is implicated as a causal or contributing factor.

The phenolics from cocoa may thus protect against diseases in which oxidative stress is implicated as a causal or contributing factor, such as cancer. They also have antiproliferative, antimutagenic, and chemoprotective effects, in addition to their anticariogenic effects.”

Another compound found in cacao is phenylethylamine, which has been shown to boost mood in a way similar to that of tryptophan, which your body converts to serotonin. Cocoa also contains chemical compounds shown to boost mood. One study found the polyphenols in a dark chocolate drink mix helped reduce anxiety and induce a sense of calm when consumed daily for one month.25

There were 72 participants who completed the trial, in which they drank a chocolate drink standardized to 500 milligrams (mg), 250 mg or zero mg of polyphenols. The researchers found those taking the high-dose polyphenol chocolate drink increased their self-assessed calmness and contentedness in relation to those drinking the placebo chocolate drink.

When colorectal cell lines were incubated with cocoa extract for 24 hours in the lab, the researchers found the chocolate had an impact on genetic up and down regulation.26 They believe the results suggest "valuable clues for future clinical studies of cocoa health benefits are highlighted as [an] anticancer agent in this study once validation studies are carried out."

Cacao to Chocolate — Raw Dark Chocolate Is What You Want

The results of these studies demonstrate the importance of consuming dark chocolate rich in flavanols to experience the health benefits. As I show in this short video above, you can create your own delectable and healthy chocolate treat at home that satisfies your sweet tooth.

Although some people use the terms interchangeably, there is a difference between cocoa and cacao. Many of the studies discussed used a cocoa-based product, but it’s helpful to understand the differences. Cacao is the term used for the evergreen plant and the dried seeds, which ultimately become chocolate. Raw cacao nibs have the highest levels of polyphenols.

Ideally, you’ll want to buy them whole and grind them at home. You can use a coffee grinder for this. You can also nibble on them like you would chocolate chips. A healthy amount would be around one-half to 1 ounce per day. I personally grind 1 tablespoon of raw cacao nibs twice a day and put them into my smoothies.

Cacao becomes cocoa when the beans are roasted and ground into a powder from which most of the fat is removed. Cocoa butter, which you can purchase from health food stores and some grocers, is the yellow fat that’s extracted from the beans.

The cacao beans go through 14 steps in processing before resulting in the chocolate that is ready for distribution to your local store. If the chocolate is processed from cacao seeds that are not roasted, then you’re buying “raw chocolate.”

When you are selecting your chocolate, the evidence shows health benefits are greatest in products with a higher percentage of cacao and lower percentage of sugar. Since cacao has a bitter taste, you’ll also find the higher percentage chocolates are more bitter.

It’s the polyphenols that make the chocolate bitter, so some manufacturers remove them, but it’s also the polyphenols that are responsible for many of the health benefits. That’s why, for health benefits, it’s best to choose 70% or higher cacao chocolate.

On the other hand, “white chocolate” contains only the butter extracted from the beans and none of the cocoa, which is the ingredient chocolate gets its name from. Instead, white chocolate is a health-zapping mix of pasteurized milk, vanilla flavoring and processed sugar.