Chocolate Eases Stress You Didn’t Know You Were Under

Antioxidant-rich dark chocolate reduces free radical damage, oxidative stress

Dark Chocolate BarNow, I don’t know about you, but chocolate is a cure-all for me. It’s the perfect treat for celebrating small victories, warming up on a cold winter night, or nursing your wounds after a bad day.

And now researchers have found that dark chocolate can do more than elevate your mood or soothe your soul. It can also protect against free radical damage.

Undoing Free Radical Damage

Researchers from the UK, Switzerland, and Australia looked at the impact dark chocolate could have on free radical damage.[1] Free radical damage has long been believed to be a risk factor of many of the chronic diseases that accompany aging, including heart disease, eye degeneration, memory loss, damage from UV light and cancer. And thanks to the wide and varying situations that can cause or contribute to free radical damage, we are sorely in need of some help.

See, every time you eat, breathe or move, your body uses fuel created from the food you eat to produce energy. But just as a car using gasoline to produce energy releases harmful by-products of this process as exhaust, so, too, does your own body’s energy-producing efforts produce a dangerous by-product — free radicals.

Free radicals are highly reactive forms of oxygen that are missing an electron. When they come into contact with normal molecules, they try to steal an electron, damaging the healthy cell and its DNA. In fact, some estimates show that every cell in your body takes 10,000 oxidative hits to its DNA daily!

Antioxidants, however, gobble up as many free radicals as they can and deactivate them, preventing them from doing damage.

So researchers decided to see if dark chocolate could be an effective source of antioxidants. And lest you think they were simply being hopeful, consider this: Chocolate has an ORAC of 13,120 per 100 grams. (ORAC is a commonly accepted measure of the antioxidant potential of a food.) That’s four times more than green tea and twice as much as red wine.[2]

And while the flavonoids (particularly flavanols) are the main antioxidant claim to fame of chocolate, this little taste delight is also rich in other known antioxidants, including quercetin and epicatechin,[3] as well as amino acids like phenylethylamine and tryptophan, which help to elevate mood. 

And speaking of perking up your mood …

Ease Your (Oxidative) Burdens With Chocolate

Researchers worked with 14 healthy male participants, age 21 to 23, having them cycle for 2.5 hours at about 60 percent maximum capacity. This type of prolonged exercise is often used in research to mimic oxidative stress, which is the result of free radical damage, as well as other environmental toxins, i.e., smoking, radiation, etc.

After a couple of preliminary runs, researchers had all 14 participants do three different trials. In the first, they fasted for two hours before cycling. In the second, they ate an energy bar two hours before cycling. In the third, they ate a dark chocolate bar (70 percent cocoa) two hours before exercising. The energy bar and chocolate bar were virtually identical in terms of calories, fat and carbohydrates. Also, there was a week-long break between tests.

Blood samples were taken four times per test: before eating, immediately before exercising (which was two hours after the bars were consumed), immediately after exercising, and again one hour post-exercise.

Researchers found that the dark chocolate significantly increased antioxidant capacity, as compared to the fasting and energy bar trials. They also found that free F2-isoprostane concentration was greater in the fasting and energy bar groups post-exercise, but there was no significant change after the dark chocolate test. Say what?

OK, free F2-isoprostanes are free radicals that are present in your body when fat and cholesterol have oxidized. This is a bad thing, so for these compounds to be stable after eating dark chocolate is a very good thing.

Additionally, insulin levels decreased post-exercise in all three trials, as did glucose levels. However, there was a significant spike in insulin levels pre-exercise in the dark chocolate trial, as compared to the energy bar and fasting tests. Researchers acknowledged that previous research has shown that adding cocoa to different foods can in fact stimulate increased insulin responses.[4]

They concluded that dark chocolate consumption “may affect insulin, glucose, antioxidant status, and oxidative stress responses.”

But Wait, There’s More

A second, unrelated study supports these findings. Another group of researchers from the UK tested the effects of regular dark chocolate consumption on male cyclists.[5] They had 20 active, young men cycle at 60 percent maximum capacity and eat either 40 grams of dark chocolate or a cocoa-free “chocolate” twice a day for two weeks, then two hours before the exercise test. Researchers found that the dark chocolate significantly lowered free F2-isoprostanes (remember those?), and also reduced oxidized LDL (“bad”) cholesterol. The only downside was that the chocolate had no impact on exercise performance.

Researchers concluded, “Regular [dark chocolate] consumption is associated with reduced oxidative-stress markers.”


Clearly, these studies show that dark chocolate can be a delicious health boon. But the danger of telling you that chocolate is good for you presents the same danger as saying the sun or red wine are good for you. Get too much and you’ll undo all the benefits. Chocolate products themselves can start to cause more harm than good when you add in the sugar, fat, etc. 

So, when it comes to chocolate, choose one with 70 percent cocoa content or higher. These bars tend to be a bit more bitter than sweet, which speaks to the higher cocoa concentration. Also, aim for less than 10 grams of sugar per serving.

Finally, when it comes to quantity, think choc-a-little not a lot. Limit yourself to 2 to 3 ounces a day at most. And, as always, try to go organic.

[1] Davison, G et al. The effect of acute pre-exercise dark chocolate consumption on plasma antioxidant status, oxidative stress and immunoendocrine responses to prolonged exercise. Eur J Nutr. 2011 Apr 5. [Epub ahead of print].

[2] Lee, KW et al. Cocoa has more phenolic phytochemcials and a higher antioxidant capacity than teas and red wine. J Agric Food Chem. 2003 Dec 3;51(25):7292-5.

[3] Sanchez-Rabaneda, F et al. Liquid chromatographic/electrospray ionization tandum mass spectrometric study of the phenolic composition of cocoa (Theobroma cacao). J Mass Spectrom. 2003 Jan;38(1):35-42.

[4] Brand-Miller, J et al. Cocoa powder increases postprandial insulinemia in lean young adults. J Nutr. 2003;133:3149-52.

[5] Allgrove, J et al. Regular dark chocolate consumption’s reduction of oxidative stress and increase of free-fatty-acid mobilization in response to prolonged cycling. Int J Sport Nutr Exerc Metab. 2001 Apr;21(2):113-23.

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