Coffee (2024)

Coffee may affect how cancer develops, ranging from the initiation of a cancer cell to its death. For example, coffee may stimulate the production of bile acids and speed digestion through the colon, which can lower the amount of carcinogens to which colon tissue is exposed. Various polyphenols in coffee have been shown to prevent cancer cell growth in animal studies. Coffee has also been associated with decreased estrogen levels, a hormone linked to several types of cancer. [5] Caffeine itself may interfere with the growth and spread of cancer cells. [6] Coffee also appears to lower inflammation, a risk factor for many cancers.

The 2018 uproar in California due to warning labels placed on coffee products stemmed from a chemical in the beverage called acrylamide, which is formed when the beans are roasted. Acrylamide is also found in some starchy foods that are processed with high heat like French fries, cookies, crackers, and potato chips. It was classified in the National Toxicology Program’s2014 Report on Carcinogens, as “reasonably anticipated to be a human carcinogen”based on studies in lab animals. However, there is not yet evidence of a health effect in humans from eating acrylamide in food. Regardless, in March 2018 a California judge ruled that all California coffee sellers must warn consumers about the “potential cancer risk” from drinking coffee, because coffee-selling companies failed to show that acrylamide did not pose a significant health risk. California’slaw Proposition 65, or The Safe Drinking Water and Toxic Enforcement Act of 1986, fueled the ruling, which requires a warning label to be placed on any ingredient from a list of 900 confirmed or suspected carcinogens.

However, many cancer experts disputed the ruling, stating that the metabolism of acrylamide differs considerably in animals and humans, and the high amount of acrylamide used in animal research is not comparable to the amount present in food. They cited the beneficial health effects of coffee, with improved antioxidant responses and reduced inflammation, both factors important in cancer prevention. Evidence from the American Institute for Cancer Research concludes that drinking coffee mayreduce risk for endometrial and liver cancer, and based on a systematic review of a large body of research, it is not a riskfor the cancers that were studied.

In June 2018, the California Office of Environmental Health Hazard Assessment (OEHHA) proposed a new regulation exempting coffee from displaying cancer warnings under Proposition 65. This proposal was based on a review of more than 1,000 studies published by the World Health Organization’s International Agency for Research on Cancer that found inadequate evidence that drinking coffee causes cancer. In January 2019, OEHHA completed its review and response to comments and submitted the regulation to the Office of Administrative Law (OAL) for final review.

Although ingestion of caffeine can increase blood sugar in the short-term, long-term studies have shown that habitual coffee drinkers have a lower risk of developing type 2 diabetes compared with non-drinkers. The polyphenols and minerals such as magnesium in coffee may improve the effectiveness of insulin and glucose metabolism in the body.

• In a meta-analysis of 45,335 people with type 2 diabetes followed for up to 20 years, an association was found with increasing cups of coffee and a lower risk of developing diabetes. Compared with no coffee, the decreased risk ranged from 8% with 1 cup a day to 33% for 6 cups a day. Caffeinated coffee showed a slightly greater benefit than decaffeinated coffee. [7]
• Another meta-analysis of prospective cohort studies showed similar associations. When comparing the highest intake of coffee (up to 10 cups a day) with the lowest (<1 cup), there was a 30% decreased risk of type 2 diabetes in those drinking the highest amounts of coffee and caffeine and a 20% decreased risk when drinking decaffeinated coffee. Further analysis showed that the incidence of diabetes decreased by 12% for every 2 extra cups of coffee a day, and 14% for every 200 mg a day increase in caffeine intake (up to 700 mg a day). [8]

Caffeine is a stimulant affecting the central nervous system that can cause different reactions in people. In sensitive individuals, it can irritate the stomach, increase anxiety or a jittery feeling, and disrupt sleep. Although many people appreciate the temporary energy boost after drinking an extra cup of coffee, high amounts of caffeine can cause unwanted heart palpitations in some.

Unfiltered coffee, such as French press and Turkish coffees, contains diterpenes, substances that can raise bad LDL cholesterol and triglycerides. Espresso coffee contains moderate amounts of diterpenes. Filtered coffee (drip-brewed coffee) and instant coffee contain almost no diterpenes as the filtering and processing of these coffee types removes the diterpenes.

Despite these factors, evidence suggests that drinking coffee regularly may lower the risk of heart disease and stroke:

• Among 83,076 women in the Nurses’ Health Study, drinking 4 or more cups of coffee each day was associated with a 20% lower risk of stroke compared with non-drinkers. Decaffeinated coffee also showed an association, with 2 or more cups daily and a 11% lower stroke risk. The authors found no such association with other caffeinated drinks such as tea and soda. These coffee-specific results suggest that components in coffee other than caffeine may be protective. [9]
• A large cohort of 37,514 women concluded that moderate coffee drinking of 2-3 cups a day was associated with a 21% reduced risk of heart disease. [10]
• In addition, a meta-analysis of 21 prospective studies of men and women looking at coffee consumption and death from chronic diseases found a link between moderate coffee consumption (3 cups per day) and a 21% lower risk of cardiovascular disease deaths compared with non-drinkers. [11]
• Another meta-analysis of 36 studies including men and women reviewed coffee consumption and risk of cardiovascular diseases (including heart disease, stroke, heart failure, and deaths from these conditions). It found that when compared with the lowest intakes of coffee (average 0 cups), a moderate coffee intake of 3-5 cups a day was linked with a 15% lower risk of cardiovascular disease. Heavier coffee intake of 6 or more cups daily was neither associated with a higher nor a lower risk of cardiovascular disease. [12]

Naturally occurring polyphenols in both caffeinated and decaffeinated coffee can act as antioxidants to reduce damaging oxidative stress and inflammation of cells. It may have neurological benefits in some people and act as an antidepressant. [13] Caffeine may affect mental states such as increasing alertness and attention, reducing anxiety, and improving mood. [14] A moderate caffeine intake of less than 6 cups of coffee per day has been associated with a lower risk of depression and suicide. However in a few cases of sensitive individuals, higher amounts of caffeine may increase anxiety, restlessness, and insomnia. Suddenly stopping caffeine intake can cause headache, fatigue, anxiety, and low mood for a few days and may persist for up to a week. [15]

• A prospective cohort study following 263,923 participants from the National Institutes of Health and American Association of Retired Persons found that those who drank 4 or more cups of coffee a day were almost 10% less likely to become depressed than those who drank none. [15]
• In a meta-analysis of observational studies including 330,677 participants, the authors found a 24% reduced risk of depression when comparing the highest (4.5 cups/day) to lowest (<1 cup) intakes of coffee. They found an 8% decreased risk of depression with each additional cup of coffee consumed. There was also a 28% reduced risk of depression comparing the highest to lowest intakes of caffeine, with the greatest benefit occurring with caffeine intakes between 68 and 509 mg a day (about 6 oz. to 2 cups of coffee). [16]
• A review looking at three large prospective cohorts of men and women in the U.S. found a decreasing risk of suicide with increasing coffee consumption. When compared with no-coffee drinkers, the pooled risk of suicide was 45% lower among those who drank 2-3 cups daily and 53% lower among those who drank 4 or more cups daily. There was no association between decaffeinated coffee and suicide risk, suggesting that caffeine was the key factor, rather than plant compounds in coffee. [17]

• Parkinson’s disease (PD) is mainly caused by low dopamine levels. There is consistent evidence from epidemiologic studies that higher consumption of caffeine is associated with lower risk of developing PD. The caffeine in coffee has been found in animal and cell studies to protect cells in the brain that produce dopamine.
  • A systematic review of 26 studies including cohort and case-control studies found a 25% lower risk of developing PD with higher intakes of caffeinated coffee. It also found a 24% decreased risk with every 300 mg increase in caffeine intake. [18]
  • A Finnish cohort study tracked coffee consumption and PD development in 6,710 men and women over 22 years. In that time, after adjusting for known risks of PD, those who drank at least 10 cups of coffee a day had a significantly lower risk of developing the disease than non-drinkers. [19]
  • A large cohort of men and women were followed for 10 and 16 years, respectively, to study caffeine and coffee intake on PD. The results showed an association in men drinking the most caffeine (6 or more cups of coffee daily) and a 58% lower risk of PD compared with men drinking no coffee. Women showed the lowest risk when drinking moderate intakes of 1-3 cups coffee daily. [20]
• Alzheimer’s disease: In the CAIDE (Cardiovascular Risk Factors, Aging and Dementia) study, drinking 3-5 cups of coffee a day at midlife (mean age 50 years) was associated with a significantly decreased risk of Alzheimer’s disease later in life compared with low coffee drinkers after 21 years of follow-up. [2]
  • However, three systematic reviews were inconclusive about coffee’s effect on Alzheimer’s disease due to a limited number of studies and a high variation in study types that produced mixed findings. Overall the results suggested a trend towards a protective effect of caffeine against late-life dementia and Alzheimer’s disease, but no definitive statements could be made. The authors stated the need for larger studies with longer follow-up periods. Randomized controlled trials studying a protective effect of coffee or caffeine on the progression of Alzheimer’s disease and dementia are not yet available. [21-23]

There are various proposed actions of caffeine or components in coffee that may prevent the formation of gallstones. The most common type of gallstone is made of cholesterol. Coffee may prevent cholesterol from forming into crystals in the gallbladder. It may stimulate contractions in the gallbladder and increase the flow of bile so that cholesterol does not collect. [24]

A study of 46,008 men tracked the development of gallstones and their coffee consumption for 10 years. After adjusting for other factors known to cause gallstones, the study concluded that men who consistently drank coffee were significantly less likely to develop gallstones compared to men who did not. [24] A similar large study found the same result in women. [25]

• In a large cohort of more than 200,000 participants followed for up to 30 years, an association was found between drinking moderate amounts of coffee and lower risk of early death. Compared with non-drinkers, those who drank 3-5 cups of coffee daily were 15% less likely to die early from all causes, including cardiovascular disease, suicide, and Parkinson’s disease. Both caffeinated and decaffeinated coffee provided benefits. The authors suggested that bioactive compounds in coffee may be responsible for interfering with disease development by reducing inflammation and insulin resistance. [26]
• In a large prospective cohort of more than 500,000 people followed for 10 years, an association was found between drinking higher amounts of coffee and lower rates of death from all causes. Compared with non-drinkers, those drinking 6-7 cups daily had a 16% lower risk of early death. [26] A protective association was also found in those who drank 8 or more cups daily. The protective effect was present regardless of a genetic predisposition to either faster or slower caffeine metabolism. Instant and decaffeinated coffee showed a similar health benefit.

A plain “black” cup of coffee is a very low calorie drink—8 ounces only contains 2 calories! However, adding sugar, cream, and milk can quickly bump up the calorie counts. A tablespoon of cream contains 52 calories, and a tablespoon of whole milk contains 9 calories. While 9 calories isn’t a lot, milk is often poured into coffee without measuring, so you may be getting several servings of milk or cream in your coffee. A tablespoon of sugar contains 48 calories, so if you take your coffee with cream and sugar, you’re adding over 100 extra calories to your daily cup.

However, the real caloric danger occurs in specialty mochas, lattes, or blended ice coffee drinks. These drinks are often super-sized and can contain anywhere from 200-500 calories, as well as an extremely large amount of sugar. With these drinks, it’s best to enjoy them as a treat or dessert, and stick with plain, minimally sweetened coffee on a regular basis

1. Je Y, Liu W, and Giovannucci E. Coffee consumption and risk of colorectal cancer: a systematic review and meta-analysis of prospective cohort studies. International Journal of Cancer, 2009. 124(7): p. 1662-8.
2. Eskelinen MH, Kivipelto M. Caffeine as a protective factor in dementia and Alzheimer’s disease. J Alzheimers Dis. 2010;20 Suppl 1:S167-74.
3. Grosso G, Godos J, Galvano F, Giovannucci EL. Coffee, Caffeine, and Health Outcomes: An Umbrella Review. Annu Rev Nutr. 2017 Aug 21;37:131-156.
4. van Dam RM, Hu FB, Willett WC. Coffee, Caffeine, and Health.NEJM.2020 Jul 23; 383:369-378
5. Je Y, Giovannucci E. Coffee consumption and risk of endometrial cancer: findings from a large up-to-date meta-analysis. International Journal of Cancer. 2011 Dec 20.
6. Arab L. Epidemiologic evidence on coffee and cancer. Nutrition and Cancer, 2010. 62(3): p. 271-83.
7. Ding M, Bhupathiraju SN, Chen M, van Dam RM, Hu FB. Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: a systematic review and a dose-response meta-analysis. Diabetes Care. 2014 Feb;37(2):569-86.
8. 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.
9. Lopez-Garcia E, Rodriguez-Artalejo F, Rexrode KM, Logroscino G, Hu FB, van Dam RM. Coffee consumption and risk of stroke in women. Circulation. 2009;119:1116-23.
10. de Koning Gans JM, Uiterwaal CS, van der Schouw YT, et al. Tea and coffee consumption and cardiovascular morbidity and mortality. Arterioscler Thromb Vasc Biol. 2010;30:1665-71.
11. Crippa A, Discacciati A, Larsson SC, Wolk A, Orsini N. Coffee consumption and mortality from all causes, cardiovascular disease, and cancer: a dose-response meta-analysis. Am J Epidemiol. 2014;180:763-75.
12. Ding M, Bhupathiraju SN, Satija A, van Dam RM, Hu FB. Long-term coffee consumption and risk of cardiovascular disease: a systematic review and a dose-response meta-analysis of prospective cohort studies. Circulation. 2014 Feb 11;129(6):643-59.
13. Ding M, Satija A, Bhupathiraju SN, Hu Y, Sun Q, Han J, Lopez-Garcia E, Willett W, van Dam RM, Hu FB. Association of Coffee Consumption With Total and Cause-Specific Mortality in 3 Large Prospective Cohorts. Circulation. 2015 Dec 15;132(24):2305-15.
14. Lara DR. Caffeine, mental health, and psychiatric disorders. J Alzheimers Dis. 2010;20 Suppl 1:S239-48.
15. Guo X, Park Y, Freedman ND, Sinha R, Hollenbeck AR, Blair A, Chen H. Sweetened beverages, coffee, and tea and depression risk among older US adults. PLoS One. 2014 Apr 17;9(4):e94715.
16. Wang L, Shen X, Wu Y, Zhang D. Coffee and caffeine consumption and depression: A meta-analysis of observational studies. Aust N Z J Psychiatry. 2016 Mar;50(3):228-42.
17. Lucas M, O’Reilly EJ, Pan A, Mirzaei F, Willett WC, Okereke OI, Ascherio A. Coffee, caffeine, and risk of completed suicide: results from three prospective cohorts of American adults. World J Biol Psychiatry. 2014 Jul;15(5):377-86.
18. Costa J, Lunet N, Santos C, Santos J, Vaz-Carneiro A. Caffeine exposure and the risk of Parkinson’s disease: a systematic review and meta-analysis of observational studies. J Alzheimers Dis. 2010;20 Suppl 1:S221-38.
19. Sääksjärvi K, Knekt P, Rissanen H, Laaksonen MA, Reunanen A, Männistö S. Prospective study of coffee consumption and risk of parkinson’s disease. Eur J Clin Nutr. 2008;62:908–915.
20. Ascherio A, Zhang SM, Hernan MA, Kawachi I, Colditz GA, Speizer FE, Willett WC. Prospective study of caffeine consumption and risk of parkinson’s disease in men and women. Ann Neurol. 2001;50:56–63.
21. Panza F, Solfrizzi V, Barulli MR, Bonfiglio C, Guerra V, Osella A, Seripa D, Sabbà C, Pilotto A, Logroscino G. Coffee, tea, and caffeine consumption and prevention of late-life cognitive decline and dementia: a systematic review. J Nutr Health Aging. 2015 Mar;19(3):313-28.
22. Santos C, Costa J, Santos J, Vaz-Carneiro A, Lunet N. Caffeine intake and dementia: systematic review and meta-analysis. J Alzheimers Dis. 2010;20 Suppl 1:S187-204.
23. Carman AJ, Dacks PA, Lane RF, Shineman DW, Fillit HM. Current evidence for the use of coffee and caffeine to prevent age-related cognitive decline and Alzheimer’s disease. J Nutr Health Aging. 2014 Apr;18(4):383-92.
24. Leitzmann MF, Willett WC, Rimm EB, et al. A prospective study of coffee consumption and the risk of symptomatic gallstone disease in men. JAMA. 1999;281:2106-12.
25. Leitzmann MF, Stampfer MJ, Willett WC, Spiegelman D, Colditz GA, Giovannucci EL. Coffee intake is associated with lower risk of symptomatic gallstone disease in women. Gastroenterology. 2002;123:1823-30.
26. Loftfield E, Cornelis MC, Caporaso N, Yu K, Sinha R, Freedman N. Association of Coffee Drinking With Mortality by Genetic Variation in Caffeine Metabolism: Findings From the UK Biobank. JAMA Intern Med. 2018 Jul 2.
27. Moderate caffeine consumption during pregnancy. Committee Opinion No. 462. American College of Obstetricians and Gynecologists. Obstet Gynecol 2010;116:467–8.