Your brain on chocolate

Robert H. Shmerling, MD

Senior Faculty Editor, Harvard Health Publishing

Follow me on Twitter @RobShmerling

Did you know that places where chocolate consumption is highest have the most Nobel Prize recipients? It’s true, at least according to a 2012 study published in the New England Journal of Medicine. Of course, that could be a coincidence. But is it possible that intelligence or other measures of high brain function are actually improved by the consumption of chocolate? A new review summarizes the evidence and concludes with a resounding “maybe.”

Keeping your brain healthy

When it comes to preserving and improving brain function, let’s face it: we need all the help we can get. With age, diseases that cause dementia, such as stroke, Alzheimer’s disease, and Parkinson’s disease, become more common. And since we have an aging population, predictions are that dementia will become much more common in the near future. Yet despite decades of research, there are no highly effective treatments for dementia.

As for preventive measures, the best recommendations are those your doctor would make anyway, such as regular exercise, choosing a healthy diet, maintaining a normal blood pressure, not smoking, and drinking only in moderation. “Brain exercise” (such as challenging math problems or word games) and a variety of supplements are unproven for long-term preservation of brain function or prevention of cognitive decline. While some studies suggest that antioxidants, fish oil, stimulants such as caffeine, or other specific foods may help improve brain function or prevent dementia, these benefits are hard to prove and studies have been inconclusive at best.

What’s the scoop on chocolate and the brain?

A review published in the May 2017 edition of Frontiers in Nutrition analyzed the evidence to date that flavanols (found in dark chocolate and cocoa, among other foods) may benefit human brain function. Flavanols are a form of flavonoids, plant-based substances that have anti-inflammatory and antioxidant effects. Here’s a sample of the findings:

  • Short-term consumption may be helpful. For example, a 2011 study of young adults found that two hours after consuming dark chocolate (with high flavanol content), memory and reaction time were better than among those consuming white chocolate (with low flavanol content). However, other similar studies showed no benefit.
  • Long-term consumption may be helpful. One 2014 study found that among adults ages 50 to 69, those taking a cocoa supplement with high flavanol content for three months had better performance on tests of memory than those assigned to take a low-flavanol cocoa supplement.
  • Several studies demonstrated evidence of improved brain blood flow, oxygen levels, or nerve function as measured by imaging tests or tests of electrical activity in the brain after the consumption of cocoa drinks. But because these changes were not routinely associated with improved performance on cognitive tasks, it’s hard to connect the results directly to better brain function.

Ultimately, the authors suggest that while these findings are encouraging and intriguing, more research is needed, especially since most studies so far have been small and many were unable to eliminate the possibility of a placebo effect. In addition, these studies cannot account for many other variables that can affect brain function (such as medical problems, cognitive function at baseline, or medication use).

Where else can you find flavanols?

Dark chocolate and cocoa are not the only foods that contain flavanols. Many fruits and vegetables are rich in flavanols, including apples, red grapes, broccoli, cherry tomatoes, beans, kale, and onions. Perhaps it’s no coincidence that a healthy diet is typically one that is high in fruits and vegetables and, as a result, high in flavanol content as well. However, studies examining the relationship between specific fruits and vegetables, dietary flavanol consumption, and brain function have not yet been performed.

The bottom line

As noted in this research, not all chocolate is the same. Dark chocolate and cocoa have high flavanol levels, while milk chocolate and white chocolate have much lower levels. In addition, many types of chocolate are high in sugar, fats, and calories. So, even if dark chocolate turns out to be good for the brain, it’s unlikely that doctors will recommend a Godiva bar a day.

I know many people who are more than willing to accept any suggestion that chocolate is healthy (if only to justify their high consumption of chocolate). But, it’ll take more than the evidence we have now to convince me that chocolate or flavanols can truly preserve or improve brain function. And it’s possible that too much could cause more harm than good. And about that connection between Nobel Prize winners and countries with the highest chocolate consumption? I can’t prove it, but I doubt you’ll increase your chances of winning a Nobel Prize by upping your chocolate intake.

Related Information: A Guide to Cognitive Fitness


  1. lakshmi dey

    Happiness Quotient high. Tastes great but in moderation

    Paediatrician now 83 hence geriatrician in a retirement facility

  2. V

    This article mentioned cocoa-which is the processed cacao which has a different nutritional value as raw cacoa. I thought the benefits often cited relate to cacoa and not cocoa, which because it’s been roasted at high temperature, lowers the entire nutritional value and enzyme content. I make my own chocolate using cacoa butter, raw cacao powder and fruits and nuts without sugar. Tastes amazing!

  3. Sugandha Biswas

    Haha! Rob, this article is worth reading(ofcourse a chocolate lover).
    But apart from a healthy and sharp brain, there are other mind-boggling benefits of eating chocolates like killing obesity, increasing the life expectancy etc.

  4. miriam cohen

    I knew it all along! Chocolate (dark, 70 % and up ) is food for the Gods! I’m sure it helped scientists and writers win the Nobel prize. Indeterminate studies to the contrary, I will continue to savour this delectable treat!
    Miriam Cohen

  5. Bob Lang

    Don’t forget, cocoa powder has very little sat fat; while dark chocolate has a high content of that artery clogging fat. Better suggestion, drink skim milk and cocoa powder. There are many commercial mixes off the grocery shelf that make “instant” hot chocolate and are low cal too.

  6. Beckett

    So. This article says essentially nothing. Maybe…More study needed…there are no details re: the number of people, how much chocolate they ate, or the percentage of cocoa. Oh! And you could probably get the same benefits, assuming there are any, from fruits and vegetables.
    A few minutes of research brought me to a quote by the author of the initial paper Schmerling cited: “Messerli said the whole idea is absurd…”
    I totally agree. Not even a resounding maybe.
    “Yet despite decades of research, there are no highly effective treatments for dementia.” Maybe because there are too many ‘researchers’ wasting time studying chocolate.

    • Pamela

      I admit, I came to the same conclusion and at the end of your paragraph I laughed so hard. Thank you for saying what I thought. I wasted my time, yet I had a feeling I would. I just love chocolate.

      • Beckett

        Two of us wasted time and now wasting more time still talking about it. LOL
        I also find it interesting that so many of the comments are from folks who found anything in the article to imply there are any actual benefits to eating chocolate. Perhaps they just read the headline? No need to waste time reading the actual article.
        Well. Chocolate makes me happy. The real kind – with fat and sugar. Happiness will make my life longer and my mind sound.

  7. Robert Benson

    About 30 years ago I read an article about the benfits of flavonoids in dark chocolate. I have taken 1/2 oz everyday since. I have not been able to state if there has been a change in me but I have noticed a change in the block sizes and packaging but at only 80 I figure in another 20 years I should be able to give a full report on the benefit it has provided me.

  8. Ivan Stanley MUJABI

    This article was really an eye opening one especially on some of the benefits of dark chocolate and other flavanols present in other foods.. My QN is; has the daily maximum dose /amount been established, so that we avoid the overconsumption as its associated with health issues?And what are those health problems ass/w overconsumption..?

  9. Violet Ewing

    Interesting theory on brain power relative to Chocolate.
    Since chocolate has been consumed for thousands of years in Mexico , and the rest of the Americas, with the drink , and mole sauces , more geniuses should be borne from these areas .
    Also, the health factor could be studied regarding the Parkinson’s ailment, not common in People with origins from the Americas, even though many may have Iberian roots.

  10. David Hanson

    We eat cacao nibs every day – these have no added sugar or fat.

  11. andrew goldstein

    For many of us, it’s not particularly critical to have to “prove” another positive effect of dark chocolate consumption. We already have the experience of eating it. Nevertheless, an ounce or two of putative health benefit will do very nicely thank you.

  12. Bob

    What about the carcinogenic cadmium content in some commercially available cocoa?

  13. donn cavnar

    i have been making my own chocolate out of pure 100% cocoa powder using water and splenda and a little vanilla that’s it for about ten years, not much calorie and no fat that i know of, i don’t know why all these modern day super nutritionists haven’t figured that out, tastes great by the way. DONN CAVNAR GARDNERVILLE ,NV

    • kris

      Splenda no good– use pure stevia, make sure not adulterated with sugars

      • Mary Parsons

        I use one teaspoon of cocoa powder in my plant-based smoothie, with one large tablespoon of Triple Zero Vanilla Yogurt, half banana, and 6 oz. of 30 cal. almond milk, and ice. Every once in awhile, if I have fresh strawberries, i’ll throw in 2-3 of those. Very refreshing drink, relatively low in sugar, high in protein and healthy fresh fruit. This is one way to get the cocoa powder and keep the sugar and fat low. I wonder about the alkali in processing cocoa powder and if it’s bad healthwise.

  14. Eduardo Tuesta

    Thanks, Dr. Shmerling. Very interesting your article. I have a question, Does chocolate have any antidepressant properties? Thank you!

  15. Ruth White

    Why is the Harvard Women’s Health Watch newsletter more expensive than the Harvard Men’s Health Watch?

    • PJ

      Very good question. Might someone answer this please?

      This is coming from a young woman with traumatic arthritis undergoing double knee replacements that worsened my health and reading that most orthopedic surgeries are done to younger woman with way less success…..hmmmmm…is this still a mans world? Sad

  16. Sarvika Bommakanti

    Dr. Shmerling, thank you for the article, it was very interesting to read! I had a question regarding flavanols, are there different kinds of flavanols? For example, are the flavanols present in cocoa different from the flavanols present in vegetables? Thank you!

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