To joe, or not to joe? The science surrounding coffee.

As I finish what will be my last sip of coffee for the day I feel nearly superhuman. I’m happier, my productivity is at a Ryan Seacrest like levels (apparently the man is quite productive) and heck, if the New York City marathon were held today I’m pretty confident that I would win, easily. Yes, coffee truly is the nectar of the Gods. But – very big but(t) – is it actually good for me? Or is my three a day routine a recipe for an early death? Science, take it away:

The Good:

Exercise and fat burning:

Drinking coffee one hour before endurance exercise improves times by approximately 5% and this leads to the preferential burning of fat as an exercise fuel (1).  It’s uncertain though whether coffee actually aids in fat-loss. Looking good so far, coffee.

Blood pressure, cholesterol and cardiovascular health:

Anti-coffee people, AKA tea drinkers, will often criticise coffee because it raises blood pressure.  Guess what? They’re wrong. A review of studies to date on coffee and blood pressure found that there was no evidence that coffee drinking in moderation (three cups or less) had any negative effect on blood pressure. In fact, coffee reduced blood pressure in non-smokers (2).

Another criticism of those retched tea drinkers is that coffee raises cholesterol. Sadly, they could be right on this front.  Drinking moderate amounts of coffee (2-3 cups plus daily) can increase cholesterol levels (3). However, this doesn’t appear to increase the risk of cardiovascular disease. In fact, cardiovascular disease risk is reduced in those that consume coffee (4). This indicates that unless you have high cholesterol, drinking coffee in moderation should have no detrimental cardiovascular effects and may in fact be beneficial.

Other diseases: 

A high quality review study, reported that the risk of type-2 diabetes decreased 12% for every two cups of coffee consumed. Another study found that consuming three cups of coffee a day maximally decreased the risk of Parkinson’s disease (5).  Coffee, you’re the best.

The great

It gets even better, coffee drinkers.

Life expectancy: 

If you thought coffee was good already, you’re about to think it’s great! A review paper analysing the results of studies on over one million people, found that those that consumed coffee regularly were less likely to die of any cause than those who did not regularly consume coffee. Specifically, those that consumed between 3-5 cups daily had the lowest risk of dying (6).  Not convinced yet? Another study found coffee consumption to decrease the risk of death from any cause (7). Oh, and what’s this? Yes, a further study found coffee to decrease the risk of death, although this time four cups daily was the sweetest at reducing death risk (8). So this leads me to ask, is there anything coffee can’t do?

The bad:

Unfortunately, yes there is.

Pregnancy:

Consuming moderate to high levels of coffee during pregnancy is associated with an increased risk of delivering a low birth weight baby. Although, consuming low levels of coffee appears to be safe (9).

The undecided:

While excess coffee is definitely bad news in pregnancy, whether it increases stress, anxiety and headaches is unclear.

Stress, anxiety, headaches:

Believe it or not, there is actually not a great number of studies on this topic. The most relevant for stress is a study from 1984 (too old to be accurate) which found no link between coffee and anxiety (10). For headaches, there was found to be only a very small risk of headaches at extremely high consumption levels (11).  All in all, the science isn’t clear on this one, but if you’re consuming six cups a day you might be a bit stressed and have a sore head, so drink (coffee) in moderation.

Is it healthful:

Most people: Coffee may improve exercise performance, enhance cardiovascular health, decrease type-2 diabetes and Parkinson’s disease, and it may even let you live a longer life.  Java up!

Our verdict: Very healthful. 

If you’re pregnant: If you’re pregnant limit your coffee intake to very low levels, it could cause premature birth!

Our verdict: Unhealthful.

If you have high cholesterol, anxiety, or get headaches: If you have high cholesterol, get headaches, suffer from anxiety or are highly stressed maybe limit your coffee intake to low-moderate levels, although the scientific evidence isn’t entirely clear on this just yet.

Our verdict: Moderately healthful in moderation, unhealthful in excess.

I hope this has been healthful.