We are told coffee has health benefits, but it turns out that you shouldn’t overdo: American researchers examined tens of thousands of people and found out that drinking over 4 cups of coffee per day increases the chance of early mortality by 50%. The hypothesis: caffeine becomes toxic in high doses.

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Researchers in the United States found out that the risk of early mortality (death) significantly escalates when consuming over 4 cups of coffee per day. The study was published in the latest issue of the “Mayo Clinic Proceedings” journal.

During a major long-term national study1, data from nearly 44,000 participants were examined between the years 1979-1998. During the study period, 2,512 deaths were recorded among the participants, 32% of which were due to cardiovascular disease.


The researchers found that those who drank more than 28 cups of coffee each week had up to a 56% greater risk of early mortality – with the greater risk being in men and women younger than 55 years of age. The results stayed the same even when the researchers eliminated confounding variables such as fitness level and traditional cardiovascular risk factors such as diabetes, smoking, alcohol consumption, and obesity.

The researchers are still unclear about the mechanism through which coffee becomes toxic. The speculations include that the contributors to the increased risk of early mortality are the caffeine naturally in in coffee and sugar added to the coffee before drinking. Based on the findings at hand, the researchers recommended limiting coffee consumption to no more than 3 cups per day.

Last May, a large-scale study was published revealing that regular consumers of coffee lived longer2. The research, conducted by the National Institutes of Health (NIH), followed over 400,000 men and women aged 50-71 years – slightly older than the aforementioned study – and found that men who drank 6 cups of coffee or more per day – regardless of caffeine content – had a 10% lower chance of dying compared to those who didn’t drink coffee, while women’s risk was reduced 15% for the same amount of coffee.

It was also found that a moderate coffee consumption was associated with a greater survival rate. The researchers found that drinking one cup of coffee per day decreased the chance of mortality by 6% in men, and 5% in women. When the researchers eliminated confounding variables – such as heart and lung disease, infections, accidents and injuries, socio-economic status, weight, alcohol consumption, smoking, and physical activity – the findings remained the same. The researchers noted that it is still unclear at what degree of coffee consumption the mortality risk declines.

It was speculated that among the more than 1,000 compounds in coffee that affect health, the possible contributors to the protective effect are antioxidant polyphenols, which decrease destructive processes in the body and are believed to extend the lifespan.

But coffee does a lot more. Many other studies show that it may reduce Parkinson’s disease tremor symptoms, depression, and risks of diabetes, liver and breast cancers, and even high blood pressure.

It should be noted that the exact amount of coffee and caffeine consumed in both studies is unknown, as there was no cited measurement for ‘cup,’ as the intake was reported by drinkers. Further, the composition and exact caffeine content of the various cups of coffee was unknown – and coffee beverages do indeed vary widely. This means there is a notable degree of inconsistency between active factors that could impact the significance of the results.

The Bottom Line
A recent systematic review of many studies investigating the affect of coffee and caffeine on mortality risks (including cardiovascular)3 came to the conclusion that coffee drinking may not pose a significant risk for most people, and in fact may present some benefit – and the cut-off point of intake remains uncertain. According to the studies reviewed here, it is likely most prudent to limit daily coffee intake to 4 cups (8 fluid ounces or 240 ml each) in people below 55 years of age, and 6 cups for those above. In the meantime, research into the matter will likely continue…

For more foods not to eat, see our presentation.

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Sources:

  1. Sui X, Lavie CJ, Hebert JR, Earnest CP, Zhang J, Blair SN. Association of Coffee Consumption With All-Cause and Cardiovascular Disease Mortality. Mayo Clinic Proceedings. Published online 19 August 2013 at http://www.mayoclinicproceedings.org/article/S0025-6196(13)00578-8/abstract
  2. Freedman ND, Park Y, Abnet CC, Hollenbeck AR, Sinha R. Association of coffee drinking with total and cause-specific mortality. N Engl J Med. 2012 May 17;366(20):1891-904.
  3. Malerba S, Turati F, Galeone C, Pelucchi C, Verga F, La Vecchia C, Tavani A. A meta-analysis of prospective studies of coffee consumption and mortality for all causes, cancers and cardiovascular diseases. Eur J Epidemiol. 2013 Jul;28(7):527-39.


Comments 29

  1. superheavy61

    I don’t drink much coffee at all. One cup a day, and very rarely two cups. My problem is sodas, especially coke. I can easily drink one coke a day, and on weekends two. I had triple bypass surgery nine years ago, and have steadily gained weight over the years after my surgery, I am hoping the “Trim Down Club” will be the solution for both my wife, and me. I think with coffee, or anything else, moderation is the key.

    • shim1956

      I use to be a little over 300lbs. in my first marriage. I was not happy. And I drank a lot of soda. Well after 20 years of drinking soda and not being happy after my divorce I started drinking about 5 cu ps of green tea, which is good for you, and then the rest of the day nothing but water. I lost 50 lbs. just by doing that. Then I kept that up and ate nothing after 4 p.m. and got down to 150 lbs. Smaller than I was when I graduated in high school. I am back up to 184 because my last lumbar spinal surgery, I had 3 spinal surgeries, I could not do anything and gained 50 lbs back. Up to 200 again. I am down to 184 and still trying to get down to 150 I don’t want to go lower than that because I was never small to begin with. I know I will make it.

  3. jarasool

    Wow; this is really confusing. Aren’t these two studies contradictory to one another? Can someone please help me sort this out? I LOVE coffee. In the past I was up to 3 (strong) cups per day, but because I developed kidney stones began eschewing coffee altogether about a year ago. I missed it so much that I have recently added it back to my regime. I switched to organic (from Sprouts) and add regular with decaf so it’s what I call half-caf. Am drinking about 1 cup of this a day. I am a 47 year old female. Thanks! Oh, I should mention that I have also been trying to drink one tea-bag’s worth of green tea per day as well.

  5. LadyEdana

    Remember that coffee dehydrates the body, so you should be drinking extra water if you drink large quantities of coffee. I love coffee, but I recognize that a nice cup of tea is a great respite to having a lot of coffee.

    • shim1956

      I got off coffee a lot of years ago and went to green tea. It is good for you and it replaces any need for the bitter taste of coffee when you drink way to much coffee. Coffee is not good for you at all. Try green tea. It is really great for you.

  6. halmehr

    “…The research, conducted by the National Institutes of Health (NIH), followed over 400,000 men and women aged 50-71 years – slightly older than the aforementioned study – and found that men who drank 6 cups of coffee or more per day – regardless of caffeine content – had a 10% lower chance of dying compared to those who didn’t drink coffee, while women’s risk was reduced 15% for the same amount of coffee…”
    “…among the more than 1,000 compounds in coffee that affect health, the possible contributors to the protective effect are antioxidant polyphenols, which decrease destructive processes in the body and are believed to extend the lifespan.
    But coffee does a lot more. Many other studies show that it may reduce Parkinson’s disease tremor symptoms, depression, and risks of diabetes, liver and breast cancers, and even high blood pressure…”

    Not sure why everyone is worried, the NIH report seems to indicate more benefits than harm with up to six cups a day – am I missing something here?

  11. Mike1219

    TMI: the contradiction in these articles tells us nothing . Black coffee is significantly different than coffee with cream and sugar/artificial sweetener It’s different than instant coffee. People who drink more than 4 cups of coffee a day are probably white collar workers and get their coffee for free in the office they work in . The longer the work day the more coffee they drink and probably little movement or exercise.. More stress comes with this lifestyle as well which can contribute to a negative survival rate. are just too many variables to make this study valid. The coffee drinker study needs to be more specific to be relevant. We waste more money on
    unreliable research studying insignificant bs and need to spend it on education of reliable facts.

  16. Rodinka47

    I just read an article on this website this morning telling me that Coffee is the best and that it has lots of antioxidants and such… Now this guy said it’s gonna kill us! Just keep drinking! I have some days 4 or more some day only one cup. There’s lots out there that could kill us! Smoking, crossing the street, fast foods and just that our number is up! And who did they test: a group of seniors! 55-71…. People are likely to die in their old age! Or haven’t they noticed… Don’t smoke and you’ll be fine. Keep an edge on your knife, Boy, Keep an edge on your knife.

  20. stewartmay

    given that we are all going to die at some stage then I think coffee is like everything else to be used in moderation but a few cups a day should be ok as far as I can see
    these 2 articles are both contradictory and confusing to most people so we all have to make our own choices.

  24. Ossie-Sharon

    A bit more perspective was added to the article. The issue is indeed confusing, so as with most other issues, moderation is key. Personally, I think a lot has to do with the cleanliness of the coffee – so many coffee products are treated with dangerous pesticides, and this could make a difference. Perhaps going organic may help.

  26. Mariaheller

    Very confusing article. It’s good , it’s bad? Drink more drink less. What are you trying to say. One contradicts the other. This is what turns me off to anything. Just when I think I’m eating healthy, I read that it’s not good for you. It really confuses me. All my life I’ve read this is good for you. The following year the same thing is not good for you. It’s confusing and depressing and that’s when I want to give up. It’s not just the coffee.

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