There are a lot of myths about the hazardous effects of drinking coffee.
Many of us use it as a healthy energizing beverage, while others find it addictive and harmful.
Habitual coffee intake is very common in modern societies (one of the most popular drink’s in the world), so it is important to understand the impact coffee has.
Evidence provided in this article will cover coffee made from roasted coffee beans, so all conclusions can only be made from this source without the combination of using sugar and milk (which are the most common used additions to this beverage).
Most of the health benefits come from the antioxidants coffee contain, as coffee is one of the best source of it among all food group!
Several different compounds contribute to coffee's antioxidant content, e.g., caffeine, polyphenols, volatile aroma compounds and heterocyclic compounds.
Many of these are efficiently absorbed, and plasma antioxidants increase after coffee intake.
As inflammation and oxidative stress have been linked with aging, cardiovascular disease and cancer, we will have a look at the scientific data of coffee consumption and the impact it has on the mentioned risk factors [1,2].
Coffee consumption and its evidence as a risk factor for cardiovascular disease has been controversial,however, the findings may suprise you.
According to the meta-analysis conducted by Ding et al, which included 36 trials of 1.29 million of participants, moderate coffee consumption was inversely associated with cardiovascular disease (CVD).
The lowest risk was noted in the group where consumption was 3-5 cups per day, heavier coffee consumption was not linked with elevated CVD risk .
Coffee consumption has been incosistently associated with risk of stroke. Meta-analysis performed by Larrson and Orsin has shown that comparing with no coffee consumption, moderate coffee consumption (2 cups per day) may be weakly inversely associated with risk of stroke .
Previous statements on heart failure prevention from the American Heart Association have stated consumption of cofee with increased risk of heart failure, but the newest data are suggesting the opposite.
The result of meta-analysis suggest a J-shaped relationship between coffee consumption and heart failure incidence which translates to a statement that moderate coffee consumption (4 cups/day) may have protective impact, however higher consumption linked to higher risk of heart failure comparing to no consumption .
Liver function, Cirrhosis
People who suffer from chronic liver diseases might be particulary interested in findings which reveal the benefits of drinking coffee, because there is a lot of good data.
Several past studies have linked coffee with a protective role on serum liver function tests, specifically ALT, AST, and gamma-glutamyltransferase levels [6,7].
Large Systematic review, included 432 133 participants, proved that and an increase in daily consumption of two cups of coffee is associated with a near 50% lower risk of cirrhosis.
Furthermore, unlike many medications, coffee is generally well tolerated and has an excellent safety profile .
The newest meta-analysis (2016) has assessed coffee consumption and the impact it has on non-alcoholic fatty liver and metabolic syndrome.
Findings suggest that coffee consumption can have protective role on fibrosis, also coffee intake was associated with less likelihood of metabolic syndrom, however more studies are needed to confirm these findings .
Type 2 diabetes
Meta-analysis from China has shown that coffee consumption is inversely related to the prevalence of type 2 diabetes and fasting glucose level. It has showed increased cofee intake reduced risk of type 2 diabetes and fasting glucose level .
Another meta-analysis has shown that association between coffee consumption and type 2 diabetes was stronger in women that for men.
A stronger association of coffee intake with type 2 diabetes was found for non-smokers and subjects with body mass index <25kg/m2.
Dose-response analysis suggested that incidence of type 2 diabetes by 12% for every 2 cups/day increment in coffee intake, 11% for every 2 cups/day increment in decaffeinated coffee intake and 14% for every 200mg/day increment in caffeine intake .
Alzheimer's disease, Dementia and Mild Cognitive Impairment
The study performed by Solfrizzi et al has proven that normal cognitive functioning older individuals who habitually consumed 1-2 cups of coffee/day had a lower rate of the incidence of Mild Cognitive Impairment (MCI) than those who never or rarely consumed coffee .
The results from Cardovascular Risk Factors, Aging and Dementia (CAIDE) study has suggested that 3-5 cups per day at midlife were associated with a decreased risk of dementia/Alzheimer's disease by about 65% at late-life .
On the other hand, the systematic review performed by Panza et al has suggested that coffee drinking impact on dementia and AD prevention were to limited to draw any conclusions .
Meta-analysis undertaken by Jee et al has linked coffee consumption with increased serum cholesterol levels in some, but not all, studies.
Increased serum lipids were greater in studies of patients with hyperlipidemia and in trials of caffeinated or boiled coffee.
However pooled results of the studies that used filtered coffee (those which removed cholesterol raising agent by filtration) have demonstrated only minimal effects of coffee on serum cholesterol levels.
In conclusion, findings confirm that coffee should be filtered prior to drinking .
On the other hand Steffen et have failed to proved that coffee consumption is correlated with increased risk of hypertension.
According to assessed studied results, no recommendation can be made for or against coffee consumption as it relates to blood pressure and hypertension .
Meta-analysis undertaken by Larrson and Wolk, included four cohort and 5 case-control studies showing coffee consumption of 2 cups per day was associated with a 43% reduced risk of liver cancer.
Li et al has assessed 11 case-control and 4 cohorts studies and suggested that coffee consumption appears to have a protective benefit in oral cancer .
Sugiyama et al have performed meta-analysis that assessed the impact of coffee intake on bladder cancer. The results has suggested, that individuals who drank coffee occasionally, 1-2 cups/day, had lower risk of bladder cancer than non-drinkers .
Gan et all have shown that coffee consumption is significantly linked with a decreased risk of collorectal cancer at ≥ 5 cups per day. The funding support the recommendations of including coffee as a healthy beverage for the prevention of colorectal cancer .
There seems to be no link between the overall risk of breast and prostate cancer and coffee intake. However, for subgroups of postmenopausal breast cancers, advanced prostate cancers, and breast and prostate cancer survivors an inverse association with coffee intake is indicated .
Total and Cause-Specific Mortality
Freedman et al examined the association of coffee drinking with subsequent total and cause-specific mortality.
Results suggested that coffee intake was inversely associated with total and cause specific mortality, however wheter was a causal or associational finding remained unclear .
Similar meta-analysis of twenty prospective cohort studies has indicated that coffee consumption is inversely associated with a reduced risk of total mortality .
Coffee is not recommended for pregnant and nursing woman (caffein intake), children (sleeping disturbances), people with gastroesophageal reflux disease (GERD), individuals with electrolytes imbalances or deficiencies (i.e. iron, calcium etc.), people persistently stressed (coffee increases catcholoamines level), also people who take medications should speak with the qualified pharmacist, hence coffee interacts with many drugs (i.e. Levothyroxin or tricyclic antidepressants are poorly absorbed).
Having read this, your probably scratching your head and wondering why you haven't been drinking this ambrosia-like beverage more frequently before. You should always remember the quote: „Everything is poisonous, nothing is poisonous, it is all a matter of does”.
The last advice is: filter your coffee prior to drink!
- Illy E. The complexity of coffee. Sci Am. 2002; 286:86–91
- Olthof MR, Hollman PC, Katan MB. Chlorogenic acid and caffeic acid are absorbed in humans.J Nutr.2001;131:66–71
- Ding M., Bhupathiraju S.N., Satija A., Van Dam R.M., Hu F.B., Long-term coffee consumption and risk of cardiovascular disease: a systematic review and dose-response meta-analysis of prospective cohort studies. Cirrculation, 2014 Feb 11; 129(6): 643-59
- Larsson S.C., Orsini N., Coffee consumption and risk of stroke. A dose-response Meta-analysis of prospective studies. Am J Epidemiol. 2011; 174(9): 993-1001
- Mostofsky E., Rice M.S., Leviatan E.B., Mittleman M.A., Habitual Coffee Consumption and Risk of Heart Failury: A Dose-Response Meta-Analysis. Circ Hearh Fail 2012 Jul 1; 5(4); 401-405
- Casiglia E., Spolaore P., Ginocchio G., Ambrosio G.B., Unexpected effects of coffee consumption on liver enzymes. European Journal of Epidemiology. 1993; 9(3)L 293-297
- Klatsky AL, Morton C, Udaltsova N, Friedman GD. Coffee, cirrhosis, and transaminase enzymes.Archives of Internal Medicine.2006;166(11):1190–1195
- Kennedy O.J., Roderick P., Buchanan R., Fallowfield J.A., Hayes P.C., Parkes J., Systematic review with meta-analysis: coffee consumption and the risk of cirrhosis. Alimentary Pharmacology & Therapeutics, Vol 43, Issue 5, pages 562-574, March 2016
- Larrson S.C., Wolk A., Coffee consumption and risk of liver cancer: a meta-analysis. Gastroenterology 2007 May; 132(5): 1740-5
- Lin W-Y., Pi-Sunyer F.X., Chen Ch-Ch., Davidson L.E., Liu Ch-S., Li T-Ch., Wu M-F., Li Ch-I., Chen W., Lin Ch-Ch., Coffee consumption is inversely associated with type 2 diabetes is Chinese. Eur J. Clin Invest 2011 Junl 41(6): 659-666
- Jiang X., Zhang D., Jiang W., Coffee and caffeine intake and incidence of type 2 diabetes mellitus: a meta-analysis of prospective studies. Eur J. Nutr. 2014 Feb; 53(1) 25-38
- Solfrizzi V., Panza F., Imbimbo B.P., D'Introno A., Galluzzo L., Gandin C., Misciagna G., Guerra V., Osella A., Baldreschi M., Di Carlo A., Iznitari D., Seripa D., Pilotto A., Sabba C., Logroscino G., Scafato E., Coffee Consumption Habits and the Risk of Mild Cognitive Impairment: The Italian Longitudal Study on Aging. Journal of Alzheimer's Disease 2015, vol. 47., no. 4, pp. 889-899
- Panza F., Solfrizzo V., Barulli M.R., Bonfiglio C., Guerra V., Osella A., Seripa D., Sabba C., Pilotto A., Logroscino G., Coffee, tea and caffeine consumption and prevention of late-life congnitive decline and dementia: a systematic review. J Nutr Health Aging 2015 Mar; 19(3): 313-28
- Jee S.H., He J., Appel L.J., Whelton P.K., Suh I.I., Klaq M.J., Coffee Consumption and Serum Lipids: A Meta-Analysis of Randomized Controlled Clinical Trials. Am. J. Epidemiol. 2001; 153(4): 353-362
- Steffen M., Kuhle C., Hensrud D., Erwin P.J., Murad M.H., The effect of coffee consumption on blood pressure and the development of hypertension: a systematic review and meta-analysis. J. Hypertens. 2012 Dec; 30(12): 2243
- Marventano S., Salomone F., Godos J., Pluchinotta F., Rio D., Mistretta A., Grosso G., Coffee and tea consumption in realtion with non-alcoholic fatty liver and metabolic syndrome: A systematic review and meta-analysis of observational studies. Clin Nutr 2016 Mar 30
- Li Y.M., Peng J. Li L.Z., Coffee consumption associated with reduced risk of oral cancer: a meta-analysis. Oral Surg 2016 Apr 121(4):381-389
- Sugiyama K., Sugawara Y., Tomata Y., Nishino Y., Fukao A., Tsuji I., The association between coffee consumption and bladder cancer incidence in a pooled analysis of Miyagi Cohort Study and Ohsaki Cohort Study. Eur J. Cancer Prev. 2016 Feb 12
- Gan Y., Wu J., Zhang S., Li L., Cao S., Mkandawire N., Ji K., Herath C., Gao C., Xu H., Zhou Y., Song X., Chen S., Chen Y., Yang T., Li J., Quao Y., Hu S., Yin X., Lu Z., Association of coffee consumption with risk of colorectal cancer: a meta-analysis of prospective cohort studies. Oncotarget. 2016 Apr 7
- Bohn S.K., Blomhoff R., Paur I., Coffee and cancer risk,epidemiological evidence, and molecular mechanisms. Mol Nutr Food Res. 2014 May; 58(5): 915-30
- Freedman N.D., Park Y., Abnet C.C. Hollenbeck A.R., Sinha R., Association of coffee drinking with total and cause-specific mortality. N Engl J. Med. 2012 May 17; 366(20) 1891-904
- Je Y., Giovannucci E., Coffee consumption and total mortality: a meta-analysis of twenty prospective cohort studies. Br. J Nutr. 2014 Apr 14; 111(7) 1162-73