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Surprising Finding: Gut Microbes Make Dark Chocolate Healthy

A considerable number of studies are in agreement that dark chocolate has pronounced health benefits1—provided you eat it in moderation (one to two ounces is recommended by some researchers2).

The same cannot be said for milk chocolate, however. There’s a big difference between your average chocolate bar and what could be referred to as “therapeutic” chocolate. To understand this better, here are some definitions:

Cacao is naturally high in antioxidants and other natural compounds that are beneficial for cardiovascular health and weight management. In all, about 40 distinct health benefits3 have been linked to dark chocolate

Knowing the meaning of these terms is important, because if you think you’re improving your health by eating typical milk chocolate candies, you’re fooling yourself.

Cocoa and cacao is typically quite bitter, and rarely fancied by self-proclaimed chocolate lovers, who are really craving the sugar added to most chocolate bars and candy.

That said, certain types of dark chocolate, as well as raw cocoa powder and cacao, are powerful superfoods, ranking among the most anti-inflammatory and antioxidant-rich foods known to mankind.

Interestingly, recent research has shed new light on the mechanism that makes cocoa powder (and dark chocolate) so beneficial for your heart and blood vessels. These benefits, it turns out, are largely dependent on the action of beneficial bacteria in your gut.

Gut Microbes Unlock Dark Chocolate’s Anti-Inflammatory Powers

Research456 presented at the National Meeting & Exposition of the American Chemical Society (ACS) claims to have unraveled the precise reason why dark chocolate is so beneficial.

While it’s known that cocoa powder is rich in potent antioxidants called polyphenols, it was thought that these molecules were poorly digested and absorbed due to their large size.

Researchers have now discovered that certain bacteria in your gut actually break down and ferment the components in dark chocolate, turning them into absorbable anti-inflammatory compounds that benefit your health.

In particular, beneficial microbes including Bifidobacterium and lactic acid bacteria like to “feast” on cocoa, according to the researchers. The microbes also break down the fiber found in cocoa powder, turning it into highly absorbable short fatty acid chains that promote satiety.

The study, which involved three cocoa powders tested in a model digestive tract, may help explain why chocolate has been found to be so good for your heart, as the anti-inflammatory compounds may reduce inflammation of cardiovascular tissue. The study’s lead author explained:

“[W]e found that the fiber is fermented and the large polyphenolic polymers are metabolized to smaller molecules, which are more easily absorbed.

These smaller polymers exhibit anti-inflammatory activity… When these compounds are absorbed by the body, they lessen the inflammation of cardiovascular tissue, reducing the long-term risk of stroke.”

Previous research7 has also shown that eating dark chocolate may help promote gut health by selectively feeding beneficial bacteria, as opposed to harmful ones. It essentially acts as a probiotic, thereby promoting a healthier gut microbiome.

Research Supports Raw Cacao for Cardiovascular Health

As mentioned, a number of previous studies have found that dark unprocessed raw cacao helps reduce your risk for cardiometabolic disorders, including:

Coronary heart disease



 Metabolic syndrome


Elevated fasting glucose and triglycerides

High cholesterol

Abdominal obesity

One meta-analysis8 published in 2011 found that those who ate the highest amounts of dark chocolate had a 37 percent reduced risk for cardiovascular disease and a 29 percent lower risk for stroke, compared to those who consumed the least.

Small amounts of dark chocolate may also reduce your risk of heart attack because, like aspirin, it has a biochemical effect that reduces the clumping of platelets that causes blood to clot. Platelet clumping can be fatal if a clot forms and blocks a blood vessel, causing a heart attack.

Researchers also discovered that a flavonoid compound in dark chocolate called epicatechin may protect your brain after a stroke by increasing cellular signals that shield nerve cells from damage.9

A stroke is similar to a heart attack, but occurs when the blood supply to your brain becomes blocked or reduced, as opposed to blocking the blood supply to your heart.

Another way raw dark chocolate may provide cardiovascular benefit is by assisting with nitric oxide metabolism, as described by Ori Hofmekler.10 Nitric oxide protects your heart by relaxing your blood vessels and thereby lowering your blood pressure.

However, nitric oxide production produces adverse reactions and toxic metabolites, which must be neutralized by your body so they don’t result in oxidative damage to your blood vessel lining (by peroxynitrite oxidation and nitration reactions). Cocoa polyphenols protect your body from these metabolites and help counter the typical age-related decline in nitric oxide production.11

Other Health Benefits of Dark Chocolate

Besides antioxidants, chocolate also contains other potent plant compounds, including anandamide, named after the Sanskrit word for “bliss,” which is a neurotransmitter in the brain that temporarily blocks feelings of pain and anxiety.

Caffeine and theobromine in chocolate have been shown to produce higher levels of physical energy and mental alertness, and there are likely many more healthy chocolate compounds that have yet to be discovered. The following table highlights just some of the benefits conferred by the cocoa bean.12



Anti-thrombotic, including improving endothelial function

Lowers Alzheimer’s risk

Anti-diabetic and anti-obesity

Reduction in C-reactive protein

Cardioprotective, including lowering blood pressure, improving lipid profile, and helping prevent atrial fibrillation

Improved liver function for those with cirrhosis


Improves gastrointestinal flora

Reduces stress hormones

Reduces symptoms of glaucoma and cataracts

Slows progression of periodontitis

Improves exercise endurance

May help extend lifespan

Protects against preeclampsia in pregnant women

Determining Quality Can Be Tricky…

According to Tod Cooperman,13 president of, which performs independent tests on health products, a recent investigation14 revealed there’s a wide range of quality when it comes to chocolate, and rarely can you tell quality by the label alone. Some brands tested did indeed have high levels of antioxidants, but others did not. Some brands had three times the concentration of flavanols compared to others, and one chocolate bar marked 85 percent flavanols actually contained less of the antioxidant than a bar labeled 72 percent.

As reported by Times,15 this kind of discrepancy is due to the fact that “the percentage is a sum of cocoa liquor, cocoa powder and cocoa butter—and cocoa butter does not contain flavanols.” The labels of some brands, however, were very accurate, including Ghirardelli and Endangered Species. Interestingly, Consumer Labs also found that dark chocolate bars may be a safer choice over raw cacao powder, as many of the latter were found to be contaminated with heavy metals.

That said, the closer your cocoa is to its natural raw state, the higher its nutritional value. To avoid contamination issues, I recommend looking for fair traded organic varieties. Ideally, your chocolate or cocoa should also be consumed raw (cacao). When selecting a chocolate bar, you can optimize its nutritional value by looking for higher cacao and lower sugar content.

What to Look for on the Label

In general, the darker the chocolate, the higher the cacao content. However, cacao is fairly bitter, and the higher the percentage cacao, the more bitter it is. The flavanols are what make the chocolate bitter, so manufacturers often remove them. But, it’s the flavanols that are responsible for many of chocolate’s health benefits. To counteract the bitterness, most chocolate is sweetened, so it’s a matter of balancing nutritional benefit with palatability. So, read your labels carefully. In addition to high cacao content, you also want to evaluate each product for the following:

Fructose will reverse some of the positive benefits of chocolate, as it breaks down into a variety of harmful waste products, one of which is uric acid. Uric acid drives up your blood pressure by inhibiting the production of nitric oxide in your blood vessels, which helps your vessels maintain their elasticity. So, excess fructose can lead to elevated blood pressure, as a result of nitric oxide suppression. It also promotes insulin resistance, which is at the heart of virtually all chronic disease.

Using Chocolate as a Therapeutic Tool 

To learn more about the health benefits of high quality chocolate, please listen to the following interview with Dr. Beatrice Golomb, in which she also discusses how to determine your ideal therapeutic dose. In general, it seems preferable to consume smaller amounts of chocolate at more frequent intervals, much like the principle of split dosing for supplements, in order to ensure a steadier stream of nutrients in your bloodstream. According to Dr. Golomb, studies show daily chocolate consumption in divided doses (two to three times per day) is probably beneficial, as long as you aren’t going overboard in quantity, and as long as you’re eating high-quality chocolate.

By Dr. Mercola


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