We’ve all heard claims chocolate is healthy. But if you’re anything like me, you’ve wondered if that’s a vicious rumour started by a chocolate multinational. I’m delighted to tell you in fact scientists have found plenty of evidence for the health benefits of chocolate eaten in moderation. But there are a few things you need to know.

Just in time for Christmas… chocolate can actually be good for you. Image credit: Austin Kirk via Flickr

A long but not so sweet history

The Latin name for cocoa, Theobroma, means “food of the gods”.

The word “chocolate” comes from the Aztecs and means “bitter water”.

It’s thought cocoa was first grown as a domestic crop by the Olmec Indians, and we have evidence cocoa was already being drunk in 1900 B.C.

Both the Mayans and Aztecs believed the cocoa bean, which is actually a seed, had magical (and aphrodisiac) properties. We know Aztecs even used cocoa beans as currency – one hundred cocoa beans bought a slave.

Cocoa was initially consumed as a bitter, unsweetened drink and it wasn’t until the 16^th century that the Spanish began to add sugar.

The first chocolate bar as we know it was made in 1847, by adding melted cocoa butter back to the cocoa. Cocoa butter is a pale yellow fat extracted from the cocoa bean.

The extremely sweet milk chocolate we are all familiar with now bears little resemblance to the original bitter, frothy drink consumed by the Mayan and Aztec elite.

And therein lies a problem.

The darker the better

The milk chocolate that may appear in your Christmas stocking is more sugar than cocoa. The lower the percentage cocoa on the label, the more sugar has been added.

So when scientists say chocolate is good for you, they mean 70% cocoa (or higher) dark chocolate. If you’re a milk chocolate fan, sadly you’re getting lots of the bad stuff (sugar) and not as much of the good stuff (cocoa).

You should also know that in cheaper chocolates, the healthy cocoa butter is replaced by less healthy vegetable (often palm) oil. There are many reasons we should avoid eating palm oil.

Chocolate really is good for you

Aside from the fact dark chocolate is loaded with minerals, it also contains a number of different compounds with proven health benefits.

In particular, dark chocolate is one of the highest food sources of polyphenols, which are nutrients known to play a role in the prevention of cancer and cardiovascular disease.

Daily consumption of small amounts of dark chocolate reduces blood pressure and reduces the risk of heart disease.

Research out this year suggests that particular bacteria in our stomach digest dark chocolate and ferment it into anti-inflammatory compounds that are really good for our hearts.

Eating chocolate also decreases our risk of stroke. One study of 44,000 people found people who ate chocolate every week had a 22 percent reduced risk of suffering a stroke compared to people who didn’t eat chocolate.

Dark chocolate also increases levels of the HDL (good) cholesterol and reduces the level of LDL (bad) cholesterol.

Eating dark chocolate rich in polyphenols may prevent or at least delay the onset of diabetes because it improves our sensitivity to the hormone insulin.

And if all of that isn’t enough, the cocoa polyphenols reduce anxiety and promote feelings of calmness and contentedness.

Flavonoids are a type of polyphenol that act as antioxidants, protecting our cells against damage and are found in the high amounts in unsweetened cocoa powder and dark chocolate. Flavonoids are responsible for dark chocolate’s bitter taste.

Flavonoids have been shown to enhance memory in rodents and also in people (but only in very high amounts).

Another study found memory, impulse control and reaction times all improved after eating chocolate.

I also can’t resist sharing with you the fact that the more chocolate people in a given country eat, the more Nobel prizes that country has won, with Switzerland topping the list for both. Hmmm, correlation versus causation anyone?

There’s even some truth to the idea that chocolate is an aphrodisiac. Women who consume chocolate daily have significantly higher libidos than those who don’t eat chocolate.

Want more good news? There’s evidence dark chocolate may prevent skin cancer and that theobromine, another bitter-tasting component of cocoa can prevent dental cavities.

The key to all of these health benefits is to eat dark chocolate that has been minimally processed given that processing can take out some of the healthy components.

And don’t eat too much of it – studies recommend anywhere from six to forty grams per day. You’ll be pleased to know dark chocolate is more filling than milk chocolate, so eating dark chocolate reduces our cravings for other sweet foods.

Ok, what’s the bad news?

The bad news is that the ongoing sustainability of the world’s cocoa crop is at risk.

Some think chocolate will become a luxury item within ten years which would be a return to where it all began with the Aztecs – a food only available to the wealthy. Chocolatier Drew Maddison, The Ministry of Chocolate

The cocoa tree is native to the tropical rainforests of Central and South America, only growing in a band 20 degrees north or south of the equator. Seventy percent of the world crop grows in West Africa and ninety percent is grown by small-scale family farmers.

A cacao pod like this one might contain 20 to 50 cocoa beans; enough for about 30 grams of chocolate. Image credit Bobby Neptune / USAID via Flickr

Cultivation of cocoa is an extremely delicate process – the trees are susceptible to temperature changes, drought, excessive rain, wind, insects and diseases such as Witches’ Broom and Frosty Pod Rot. All of these factors reduce the yield from a cocoa plantation.

As a result, climate change looms as a major threat to chocolate production.

Another issue is that cocoa farmers make the same amount of money by farming rubber instead of cocoa and rubber is a much easier crop to grow and manage.

Today, 3.5 million tonnes of cocoa are produced every year, but those in the industry predict the demand will be 4.5 million tonnes as soon as 2020.

We’re running out of chocolate? Hit the panic button now!

Links and stuff

• Smithsonian: a brief history of chocolate
• Infographic: What science says about chocolate
• World Cocoa Foundation – lots about the sustainability of chocolate
• Cocoa is now being farmed in Australia!

May your Festive Season be filled with a suitably healthy amount of chocolate and I hope you have many relaxing days ahead with family and friends.

Thanks so much for your support of Espresso Science over the last six months. I’ve had a blast and will be back with more Shots of Science in 2015.