Niki Bezzant: Get smart with a caffeine fix

We think caffeine gives us the jitters and keeps us awake. Photo / Getty Images

When it comes to food and health, we like to think in absolutes. Is food X good or bad for me? Nutritionists hate being asked this question because most of the time the answer is: that depends.

Healthy eating is all about context.

Of course doughnuts are not as healthy as walnuts. If you eat doughnuts every day then, yes, it's fair to say they're bad for you. But a doughnut once in a while - if the rest of your diet is great - won't kill you.

Coffee is often characterised as bad. But that's probably not entirely true or fair. There is evidence on both sides of the fence about coffee's benefits and harms and, again, it probably comes down to context.

The caffeine - also the reason we like it so much - gets most attention. We think it gives us the jitters and keeps us awake.

But there are also some benefits. The European Food Safety Authority (EFSA) states 75mg of caffeine increases attention and alertness for about four hours (a 30ml shot of espresso has 116mg caffeine).

It can also boost your workouts: the EFSA states taking as little as 3-4mg of caffeine per kg of body weight, an hour before exercise, increases endurance.

For a 70kg person that's around 210mg of caffeine - about what's in a double-shot flat white.

Coffee may have some benefits.

There is evidence associating coffee drinking with reduced risk of disease, including type 2 diabetes, Alzheimer's and liver cancer. Last month, a study found coffee-drinking was linked to a reduced risk of death from heart disease, stroke, diabetes, neurological diseases and suicide.

It is important to note, though, that these are observational studies. They're not saying drinking coffee causes you to live longer.

So what are the downsides? Experts say too much caffeine can induce anxiety and panic attacks. And it can interfere with sleep: it takes about five to seven hours, on average, to eliminate half the caffeine you consume from your body.

For most people, drinking coffee in the morning won't interfere with sleep at night but drinking coffee later in the day might.

Whether caffeine is addictive seems to be the subject of scientific debate. However, caffeine withdrawal is recognised by the American Psychiatric Association.

Suddenly giving up coffee can cause some people mild headaches, anxiety or flu-like illness. Experts advise that if you want to cut down, do it gradually.

So how much is too much coffee? Our individual tolerances vary but for most people (pregnant women and children are advised to limit intake), it's thought 300-400mg of caffeine a day is harmless. That's about 3 shots of espresso.

Beware the multiple double-shot coffees and don't forget, those milky coffees add energy, so think of them as food, not just drinks.

Niki Bezzant is editor in chief of Healthy Food Guide.