Coffee is probably the most popular beverage in the world. This is despite its history of negative research. So was that all a storm in a coffee cup? Should we or shouldn’t we drink our cup of coffee?

The research controversy on drinking coffee

Much of the research on coffee around the 1990s was negative, associating coffee consumption with increased risk of certain diseases such as cardiovascular disease and cancer. But these studies have been re-examined more recently, with newer findings added to the data pool, shedding light on some issues in that research. 

One of the key findings was that adjustments were not made for the many confounders in the earlier studies. What this means is that the results might not have been due to the effects of the coffee, but rather something else associated with the coffee. This is an example where the finding of a study shows a correlation with an effect, but it turns out not to be the causation. With coffee, one of the key confounders was smoking. At the time of many of these studies, having a cup of coffee was highly associated with having a cigarette alongside it. The two were inextricably linked. Coffee break at work meant time for a smoke. 

Other confounders in addition to smoking might also be:

  • High levels of sugar – both in the coffee as sugar, syrup, or artificial sweetener – and in the biscuit/cookie/cake served with it. This can lead to blood glucose spikes every time coffee is consumed.
  • Sedentary behavior.
  • Trans-fat ridden creamers added to the coffee.

The early studies didn’t tease out these associations – particularly the tobacco – and thus coffee got a bad rap. Better-designed research nowadays is telling a different story.  

The bottom line is that the current evidence suggests that coffee is fine, but the poor health behaviors and unhealthy products associated with its use make coffee an easy target to malign. 

Potential health benefits seen from well-designed studies

The following are findings from more recent studies on coffee consumption. Moderate consumption is associated with:

  • anti-oxidant activity
  • boosting energy
  • improving mood
  • increasing memory and concentration
  • helping to maintain blood sugar control
  • improving blood flow
  • better long-term cognitive function and memory
  • improves constipation
  • reduced risk of:
    • cardiovascular disease
    • some cancers – especially colorectal, biliary, pharyngeal, lung, liver, breast, and prostate
    • liver disease – including cirrhosis, non-alcoholic fatty liver disease, fibrosis, hepatitis C
  • lower rate of all-cause mortality

Recently the USDA reviewed all the data surrounding coffee and, for the first time in history, gave the recommendation to continue enjoying coffee in moderation.

Additionally, we have to consider the social aspect of coffee. Coffee is often used as an excuse for meeting a friend or colleague. These social connections can also be beneficial for our health.

So how much coffee?

The “dose” of coffee that is seen to have these beneficial effects in studies is generally 4-5 cups of coffee. BUT – in these research studies, a cup of coffee is a 6oz cup. When we drink coffee in ‘real life’ it is typically in a mug or in a to-go cup, which is more likely to be 12 oz than 6oz.  

So the equivalent of the research 4-5 cups is actually more like 1-2 mugs.

Does the dose matter?

The dose does indeed matter. It seems that if you go higher than the 4-5 x 6oz cups a day, then the beneficial effects are lost, and there might indeed be detrimental effects. So do watch how much you drink. Too much of a ‘good’ thing can become a challenge for the body.

But I get jittery with coffee. Should I be drinking it too? 

There is a proportion of the population who do not do well on coffee. This is estimated to be about 15% of the population. These people know who they are! They have one cup of coffee and get the jitters and shakes and even if it’s still morning, they will often not be able to sleep that night.  

This population is highly sensitive to caffeine and metabolize it slowly. This relates to their detoxification genes – specifically individual polymorphisms.  

If you are one of these people – don’t start drinking coffee to try and get some of the benefits listed above!   

If you drink coffee in the afternoon and your sleep maybe isn’t as good as if you don’t drink it – this doesn’t put you in this ultra-sensitive category… just take it slow and enjoy it in the morning instead. Maybe if you’re one of these people, you are better off with just the one mug of coffee a day instead of two. 

(As an aside – the slow-metabolizers of caffeine might also be another group that confounds the results of coffee studies. The effects in this population maybe very different from the general population.)

I can drink coffee before I go to bed and still sleep well.  So can I drink more than two mugs?

On the flip side to the caffeine slow-metabolizers, are the fast-metabolizers of coffee.  These people can drink coffee and it doesn’t bother them at all. Their polymorphisms increase the metabolism of the caffeine. They can have a cup before bed and still sleep well.

The danger with this population is that they often are looking for a ‘buzz’ from their coffee – but never get it. This can lead to them being over-consumers. So if you feel you are one of these people – don’t keep drinking more and more just because it doesn’t affect your sleep. The ‘dose’ level for benefits is still two mugs a day. 

So is coffee a health food?

While studies are now showing some health benefits to drinking moderate amounts of coffee – it still shouldn’t be considered a health food.  

Many of the benefits may be due to its anti-oxidants. But in the US, the top two sources of anti-oxidants in the diet of the general population come from ketchup and coffee!! It doesn’t mean that these are our best sources – just that, sadly, they are the most common sources! So would I suggest drinking coffee over eating fruits and vegetables to get your anti-oxidants? No. But if you enjoy coffee – keep enjoying it in moderation and without the bad habits associated with it.  

And choose organic coffee. Remember that a hot water extraction of the beans is what makes our coffee. During that extraction process, pesticides can also be extracted – so choose beans that are organically grown, thus without pesticides. 

Any other caveats?

In addition to the slow caffeine metabolizers who do best avoiding coffee, the following should also be considered: 

  • In the elderly population with hypertension, coffee might further increase blood pressure. This population might be wise to reduce the quantity consumed.
  • There is a possibility for some interactions with certain psychiatric medications, as coffee does affect mood and is a neuro-stimulant.  
  • High-stress levels. Often coffee might be used as a crutch when we are stressed – but this might not be the best thing. The people in this population are not the best candidates for coffee consumption and generally do better without coffee and caffeine.

Take home message

Moderate (1-2 mugs) consumption of coffee does not seem to be detrimental to health and might have some health benefits for the majority of the population.

When we are looking at ways to improve our health, we should focus our efforts on those changes that have the most impact. For example, proper hydration, good consumption of fruit and vegetables, stress reduction, and sleep. While consuming coffee might not be detrimental to our health, there are other priorities we should focus on to improve our health over getting anti-oxidants from our cup of coffee everyday!

So enjoy your couple of mugs of organic coffee – skipping the sides of sugar, creamers, and tobacco. It no longer has a bad reputation and can be enjoyed, guilt-free.

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