Flavanols in cacao - what are they and what do they do?

In previous articles we've seen that cacao could have a number of health benefits. It has a fantastic content of essential minerals such as magnesium, and contains unique compounds such as theobromine, which can have an energising effect, and phenylethylamine or PEA, which is associated with good mood.

But perhaps the most important benefits of cacao are its apparent protective effects, including for our heart, brain, skin, and immune system. This protective activity is thought to be thanks to cacao’s super content of flavanols.

What are flavanols?

Flavanols are a type of polyphenol, a broad group of natural compounds found in plants. Many polyphenols, including flavanols, play a protective role for plants. And when we consume them, they’re thought to have a protective or antioxidant effect for us too (see more on this below).

Now, there are many different types of flavanols. The flavanols found in cacao include catechins and tannins. Both of these are also found in tea. Catechins in particular are thought to be responsible for the amazing health benefits of green tea.

Flavanols have a bitter taste and are responsible for the bitterness of pure cacao and dark chocolate. So yes, the bitterness is good for you!

Are flavanols really antioxidants?

It’s long been believed that plant compounds such as flavanols have a direct antioxidant activity in the body. A substance acts as a direct antioxidant by donating electrons to free radicals to stop them having a damaging effect in the body. Vitamins C and E, for example, are known to act in this way.

However, it’s now thought that rather than acting as antioxidants, flavanols and similar compounds actually have a mild toxic effect in the body. However, this doesn’t mean they are bad for us! What this is actually thought to do is stimulate production of our body’s own antioxidants, including glutathione – perhaps our cells’ most important and most powerful antioxidant1. So flavanols may not be antioxidants after all – they could just help us to make more of our own. In either case, this is a good thing!

Flavanols and heart health

The flavanols in cacao or dark chocolate are particularly associated with benefits for heart health. Studies suggest they can lower blood pressure2,3,4,5, reduce blood ‘stickiness’3,4, improve responsiveness of the blood vessels3,4, reduce inflammation4 and even reduce cholesterol5. All of these effects support normal, healthy blood flow and reduce our risk of heart problems.

Flavanols and blood sugar control

As well as directly supporting heart health, cacao flavanols may also improve blood sugar control. For example, research has suggested flavanols could improve our cells’ sensitivity to insulin and their ability to take up glucose from the blood6. Improving blood sugar control could not only help protect against diabetes, but also help manage appetite and cravings, and support better energy and mood.

Flavanols and the skin

Cacao flavanols could also help protect our skin in the sun. A small study on 30 people found that those consuming a high-flavanol chocolate for 12 weeks were able to stay under UV light (mimicking sunlight) for twice as long before their skin started to redden7. However, eating cacao or dark chocolate doesn’t reduce your need for topical sun protection – stay safe!

Flavanols may also improve skin condition and reduce signs of ageing. In a study on 24 women, those who drank a high-flavanol cocoa drink for 12 weeks were found to have improved blood flow to their skin, increased skin thickness (thinning of the skin occurs with ageing) and improved skin hydration8.

Flavanols and the brain

Flavanols in cacao could help protect or even improve our cognitive abilities as we get older. For example, a study on 90 elderly people found that those taking a high-flavanol cocoa drink for eight weeks showed greater improvements in tests of attention and verbal skills compared to those taking a low-flavanol drink9.

Cacao flavanols may help our brain in various ways: by improving blood flow to the brain10; by improving insulin sensitivity in the brain9 (impaired insulin sensitivity is potential factor in dementia) and even by encouraging the growth of new brain cells11.

Flavanols and immunity

Cacao flavanols may also help to balance our immune system. They can promote anti-inflammatory activity, and so may help to prevent diseases related to inflammation12 – such as arthritis, heart disease and inflammatory bowel disease. They may also help stop the immune system going into overdrive, a factor that can be at the root of allergies and autoimmune conditions13,14.. And their anti-inflammatory and antioxidant effects (or ability to increase our body’s own antioxidants) may help to protect against cancer, too15.



  1. Guyenet, S. (2011). Polyphenols, Hormesis and Disease: Part II. [Blog] Whole Health Source. Available at: http://wholehealthsource.blogspot.co.uk/2011/02/polyphenols-hormesis-and-disease-part.html [Accessed 4 Jan. 2017].
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  2. Sudano I et al. Cocoa, blood pressure, and vascular function. Curr Hypertens Rep. 2012 Aug;14(4):279-84.
  3. Monahan KD. Effect of cocoa/chocolate ingestion on brachial artery flow-mediated dilation and its relevance to cardiovascular health and disease in humans. Arch Biochem Biophys. 2012 Nov 15;527(2):90-4.
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  7. Heinrich U et al. Long-term ingestion of high flavanol cocoa provides photoprotection against UV-induced erythema and improves skin condition in women. J Nutr. 2006 Jun;136(6):1565-9.
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