Questions patients ask

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Cancer is one of the biggest health risks in Europe. Patients are understandably worried about how their diet and lifestyle could increase – or decrease – their risk of developing cancer. It can be difficult to remain up-to-date with the latest health advice, and media reports of new medical studies can sometimes be confusing rather than helpful.

Healthcare professionals play a vital role in informing and reassuring patients about cancer and one of Europe’s favourite drinks – coffee. Below are some common questions asked by patients, with answers based on peer-reviewed scientific evidence.

ISICS cancer topic graphics V5

Q: Does coffee or caffeine cause cancer?

A: No. Many studies have looked at the potential association between drinking coffee and the risk of developing cancer. Overall, the scientific evidence suggests there is no association between moderate coffee consumption of around 3-5 cups per day and an increased risk of developing cancer1-4.

Q: Is coffee associated with any type of cancer?

A: No. In 2016 the International Agency for Research on Cancer (IARC) concluded that a review of the extensive scientific literature did not show an association between coffee consumption and cancer1.

The European Food Safety Authority also concluded in their Scientific Opinion on the Safety of Caffeine that ‘caffeine intakes from all sources up to 400 mg per day (about 5.7 mg/kg bw per day for a 70-kg adult) consumed throughout the day do not give rise to safety concerns for healthy adults in the general population’2. They reported that there was no evidence for health concerns between caffeine intake at this level and cancer risk.

Q: Is it true that drinking coffee is associated with bladder cancer?

A: Although some earlier studies suggested there may have been a potential link, a 2016 international review of the most up-to-date scientific research concluded that there is inadequate evidence to suggest that coffee consumption is associated with bladder cancer, stating that other lifestyle factors such as smoking played a major role1.

Q: Does coffee or caffeine cause prostate cancer?

A: No, there is no evidence to suggest that drinking coffee is associated with an increased chance of developing prostate cancer1,5,6.

Q: Is it true that drinking coffee is associated with lung cancer?

No. Current research does not suggest an association7. A review by the International Agency for Research on Cancer, published in 2016, concluded that there is inadequate evidence to suggest a link between coffee consumption and lung cancer1. Other factors such as smoking are important risk factors and may confound studies if not properly considered.

Q: Does coffee or caffeine cause breast cancer?

A: No. Research has found that drinking coffee is not associated with an increase in the risk of developing breast cancer1, particularly in postmenopausal women8-10.  In premenopausal women, much of the research suggests that drinking coffee may help to reduce the risk of developing breast cancer11,12 although other results differ, and more work is required before firm conclusions can be drawn.

Q: Does coffee or caffeine cause bowel cancer?

A: No, there is no evidence of such a link. In fact some of the research shows that drinking coffee may help to reduce the risk of developing bowel cancer1,13-16.

Q: Does coffee or caffeine cause stomach cancer?

A: No, the majority of research has found no association between drinking coffee and developing stomach cancer1,17 particularly in women and in Europeans18,19.

Q: Does coffee or caffeine cause liver cancer?

A: No. In fact, research suggests that coffee consumption is associated with a significant reduction in the risk of developing liver cancer1,20.

Q: Why has some research suggested that coffee drinking is associated with an increased risk for certain cancers?

A: Such studies tend to be in the minority and are often inconclusive. There are also other factors that need to be considered, for example, smoking is well known to be associated with increased cancer risk, and smokers are also more likely to be coffee drinkers, which may lead to an unfounded association between coffee and cancer.

A 2016 review of all the evidence concluded that coffee drinking is not associated with an increased risk of cancer, and in fact is associated with a reduced risk of cancers of the liver and endometrium1.

Q: Does the type of coffee I drink affect my risk of cancer?

A: Some research has shown a difference between decaffeinated and caffeinated coffee and the development of cancer. However, the results have been very variable and no reliable patterns have been established. Only one study to date has looked at the influence of coffee preparation (boiled vs. filtered)21 and further research is needed to draw any conclusions.

Q: Does drinking very hot coffee cause cancer?

A: in 2016, IARC concluded that consuming very hot beverages at temperatures greater than 65oC was associated with an increased risk of oesophageal cancer1. However, as any hot drink consumed at temperatures above 65oC is hot enough to scald the mouth and tongue22,23,it is very unlikely that anyone would drink coffee at such temperatures. Coffee is typically drunk at temperatures lower than 60°C, which is below IARC’s definition of a ‘very hot beverage’.

References

1Loomis D. et al. (2016) Carcinogenicity of drinking coffee, mate, and very hot beverages. The Lancet Oncology, 17(7)877-878.
2EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA) (2015) Scientific Opinion on the safety of caffeine. EFSA Journal, 13(5):4102.
3Arab L. (2010) Epidemiologic evidence on coffee and cancer. Nutr Cancer, 62:271-83.
4WCRF, ‘Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective, 2007’. Available at: http://www.dietandcancerreport.org/
5Park C. H. et al. (2010) Coffee consumption and risk of prostate cancer: a meta-analysis of epidemiological studies. BJU Int, 106:762-9.
6Liu H. et al. (2015) Coffee Consumption and Prostate Cancer Risk: A Meta-analysis of Cohort Studies. Nutr Canc, 67(3):392-400.
7Xie Y. et al. (2015) Coffee consumption and the risk of lung cancer: an updated meta-analysis of epidemiological studies. Eur J  Clin Nutr, published online ahead of print.
8Bhoo Pathy N. et al. (2010) Coffee and tea intake and risk of breast cancer. Breast Cancer Res Treat, 121:461-7.
9Jiang W. et al. (2013) Coffee and caffeine intake and breast cancer risk: an updated dose-response meta-analysis of 37 published studies. Gyne Oncol, 129(3):620-9.
10Li X.J. et al. (2013) Coffee consumption and risk of breast cancer: An up to date meta-analysis. PLoS One, 8(1):e52681.
11Nkondjock A. et al. (2006) Coffee consumption and breast cancer risk among BRCA1 and BRCA2 mutation carriers. Int J Cancer, 118:103–7.
12Kotsopoulos J. et al. (2007) The CYP1A2 genotype modifies the association between coffee consumption and breast cancer risk among BRCA1 mutation carriers. Cancer Epidemiol Biomarkers Prev, 16:912–6.
13Tavani A. et al. (2004) Coffee, decaffeinated coffee, tea, and cancer of the colon and rectum: a review of epidemiological studies 1990–2003. Cancer Causes Control, 15:743–57.
14Giovannucci E. (1998) Meta-analysis of coffee consumption and risk of colorectal cancer. Am J Epidemiol, 147:1043–52.
15Galeone C. et al (2010) Coffee consumption and risk of colorectal cancer: a meta-analysis of case–control studies. Cancer Causes Control, 21:1949-59.
16Li G. et al. (2012) Coffee consumption and risk of colorectal cancer: a meta-analysis of observational studies. Pub Health Nutr, 16(2):346-57.
17Botelho F. et al. (2006) Coffee and gastric cancer: systematic review and meta-analysis. Cad Saude Publica, 22:889–900.
18Li L. et al. (2015) Coffee consumption and the risk of gastric cancer: a meta-analysis of prospective cohort studies. BMC Cancer, 15:733.
19Liu H. et al. (2015) Effect of Coffee Consumption on the Risk of Gastric Cancer: A Systematic Review and Meta-Analysis of Prospective Cohort Studies. PLoS One, 10(5):e0128501.
20Sang L. X. (2013) Consumption of coffee associated with reduced risk of liver cancer: a meta-analysis. BMC Gastroenterol, 13:34.
21Nilsson L.M. et al (2010) Consumption of filtered and boiled coffee and the risk of incident cancer: a prospective cohort study. Cancer Causes Control, 21:1533-44.
22Lee H.S. and O’Mahony M. (2002) At What Temperatures Do Consumers Like to Drink Coffee?: Mixing Methods. J Fd Sci, 67(&):2774-2777.
23Brown F. and Diller K.R. (2008) Calculating the optimum temperature for serving hot beverages. Burns, 34(5):648-54.

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