As we stagger, groaning, into 2018, many of us are resolved to get into better shape. To help, I’m kicking off a new Radio Times health column that, over the coming weeks will, dear readers, keep you up to date with the latest health research.
As we all know, one of the most depressing things about new year’s resolutions is that they involve giving things up. So let’s start on a positive note by celebrating some really good news about one of our favourite vices.
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A white, crystalline powder, it’s produced by plants to protect themselves against insect attack. It’s also the world’s most widely consumed psychoactive drug. I use it several times a day to keep myself awake and alert. It is, of course, caffeine.
You can get your caffeine in energy drinks, but I prefer to get mine in the form of tea or coffee.
Not only does coffee perk me up in the morning, but there is strong evidence that coffee drinkers enjoy a range of other health benefits. A recent study, published in the British Medical Journal, which looked at more than 220 studies, found that drinking coffee was associated with a significantly lower risk of heart disease and cancer, possibly because it’s rich in antioxidants and other anti-inflammatory compounds. Coffee drinking was also associated with a lower rate of Alzheimer’s and Parkinson’s disease.
Based on this and other studies, the most effective “dose” is between two and five cups a day. (In terms of health benefits, the studies don’t distinguish between instant coffee and brewed, but when it comes to caffeine content, a cup of instant coffee contains 60–80mg of caffeine, while freshly brewed contains slightly more caffeine, from 60 to 120mg.) But don’t overdo it. If you drink more than two to five cups a day any benefits drop off. It’s also unwise for pregnant women to drink lots, as it’s linked to a slightly higher risk of prematurity and miscarriage.
Another downside to coffee, at least when it’s drunk at night, is that it keeps some people awake. The amount you can drink without inducing insomnia is partly dependent on a liver enzyme called CYP1A2, which controls the speed at which caffeine is cleared from your body. I have quite high levels and can drink coffee in the evening with no problems, while one cup in the afternoon has my wife twitching.
A final bit of good news I recently came across is that drinking coffee may help you do more exercise. Studies show that coffee drinking makes exercise feel easier and reduces symptoms of fatigue, and it seems to be just as beneficial for regular coffee drinkers as for novices. The optimum amount is around 3mg of caffeine per kilogram of bodyweight, so for someone who weighs 70kgs that would mean two cups of coffee taken an hour before exercise. But do skip the muffin. Cheers.
Dr Michael Mosley presents Trust Me I’m a Doctor on Wednesdays at 8.30pm on BBC2. Mosley's book, The Clever Guts Diet: How to revolutionise your body from the inside out, is out now