'Everything is potentially toxic - even coffee and chocolate'*

*But it’s really really hard to overdose on either.

WE’RE CONSTANTLY HEARING that coffee and chocolate are bad for us, but before you swear off them forever, take heart: it’s almost impossible to overdose on either.

That’s the good news – but in slightly less good news, both contain psychoactive components which can affect the brain.

So just how bad for you are they?

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We spoke to pharmacologist (the study of the positive interaction of drugs with the body) and toxicologist (the study of the negative effects of drugs on the body – or how much of something it takes to poison you) Dr Craig Slattery about coffee and chocolate and just how poisonous they actually are.

Here comes the science…

Let’s start with coffee. It is believed that 90% of all adults consume caffeine in some form or other during the day – from coffee to tea to caffeinated fizzy drinks.

So, it’s important to almost all of us – although some of us more than others, clearly.

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“Caffeine is the most widely consumed psychoactive drug in the world,” explains Dr Slattery.

A psychoactive drug is anything that has an effect on the brain. In this case, caffeine stimulates the brain, makes you mentally sharper and better able to handle heavy cognitive tasks, as well as being a mood enhancer.

Caffeine works by blocking adenosine (a neurotransmitter in the brain that makes you feel drowsy naturally) and while not eliminating tiredness, delays its onset.

Caffeine is an antagonist – it sticks to the same receptor as adenosine and competes with it.

By the way, technically  you can’t be addicted to coffee – no matter what you say. But you can be physically dependent on it, as Dr Slattery explains:

Addiction is a psychological thing where you become attached to the mood enhancement effect – so you get a high from taking something and you get addicted to that feeling. A physical dependence is where your body has adapted to the caffeine and you can suffer withdrawals if you stop ingesting caffeine.

Caffeine withdrawal can result in headaches, drowsiness and irritability.

But in terms of poisoning yourself with coffee – you’d have to try really hard. The daily recommended limit for caffeine is no more than 500mg per day – which is about 5 mugs of brewed (not instant) coffee.

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To overdose on caffeine to a poisonous level, you’d need to drink approximately one mug of coffee per kilo in body weight in about a ten minute period.

However, there are effects from caffeine at lower doses – such as insomnia and palpitations from more than 1 gram per day, or agitation, paranoia or psychosis if you ingest 500mg in 30 seconds.

So maybe don’t do that.

Chocolate heaven…

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And now for the chocolate. Long story short you’d need 5kg of good quality dark chocolate to send yourself shuffling off this mortal coil.

Common misconceptions

Chocolate doesn’t contain caffeine and it’s not physically addictive – so it doesn’t perk you up and those cravings are literally all in your mind.

Doesn’t stop you having them though, does it?

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It is a mood enhancer though…

Chocolate contains theobromine which comes from the same family as the stimulant in coffee but it’s not as strong. So if you’re watching your caffeine intake, it’s ok – you can still have chocolate. Unless caffeine is added to the chocolate, there’s no caffeine in there.

Chocolate also contains small levels of serotonin which along with the theobromine will enhance your mood.

Not only that, but it also contains phenylethylamine – otherwise known as ‘the love drug’. As Dr Slattery explains it’s responsible for a lot of nice feelings.

When you take it (phenylethylamine) the neurochemical response is very similar to what you see when someone falls in love. You get a surge in dopamine and serotonin that gives you that kind of elation and ‘high’ feeling.

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Most of the negative effects of chocolate are actually a side effect of the amount of sugar in the chocolate bar and not the cocoa component itself. So, if you really want to indulge the higher the cocoa levels in your chosen treat the better.

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You’re welcome, world.

Science Week takes place from 8-15th November 2015. This is Science Week’s 20th birthday, and the theme for this year is Science Week 2.0 – Design Your Future. Over the course of the week, there will be 800 events held nationwide, with an participating audience of 250,000. For events in your area, check out www.science.ie. Craig will be speaking about the science of chocolate during the week. Find out when and where here.

Craig Slattery is an employee of the Health Products Regulatory Authority (HPRA). Any views or opinions expressed are solely his own, and are not representative of his employer.

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