Coffee is an almost essential part of our daily routine. About two-thirds of the American population consumes coffee every day. Although there is a notable amount of scientific research on the topic, the answer to whether coffee causes cancer is still very much blurred. For decades it was believed that caffeine, the active ingredient in coffee, was dangerous to health. But recently, in the last decade, there have been a lot of studies showing the beneficial effect of coffee not only in increasing longevity but also survival in case of certain cancers.
The most concern regarding the carcinogenicity of coffee is due to a substance called Acrylamide. It is a chemical produced from natural carbohydrates and asparagine, an amino acid, when cooked at higher temperatures, especially frying, roasting, or baking. Acrylamide is found in coffee as it is formed during the process of roasting the coffee beans, making coffee a significant source of acrylamide. It is also foundin certain foods like potato chips, French fries, toasts, and cookies. It is also foundin cigarette smoke. The International Agency for Research on Cancer (IARC) earlier classified acrylamide as group 2B probable carcinogen based on evidence that it is capable of causing cancer in animals, but further research is required to determine if it increases the risk of cancer in humans. Now the World Health Organization (WHO) has declared coffee as not classifiable as to its carcinogenicity to humans.
Does it increase the risk of cancer?
Carcinogenicity of coffee in case of esophageal and gastric cancer is implicateddue to the hightemperature of the drink rather than the type of drink. Reviewed data from various studies showthat there is no conclusive link between coffee and cancer. Though coffee is typically consumedat much lower temperatures, it is important to note that drinking coffee at 70 degrees centigrade or more can increase the risk of esophageal cancer.
A few studies had shown a positive association between coffee drinking and lung cancer, but later it was found to be a confounding factor as coffee drinking and smoking are also independently related, and after adjustment for tobacco consumption, an association of coffee with lung cancer was found to be decreased and inconclusive.
Does it decrease the risk of cancer?
Studies show that coffee contains many biologically active substances like caffeine, lignans, several polyphenols, and flavonoids. These compounds cause an increase in the basal metabolic rate, increases DNA repair, decreases inflammation, cell damage, and other disease processes. It also decreases the risk of cardiovascular diseases and Parkinson's disease.
There is evidence that coffee lowers the risk of adult-on set diabetes and insulin resistance, thereby indirectly decreasing the risk of liver cancer, colorectal cancer, endometrial cancer, and breast cancer.
Drinking coffee has also been shown to decrease the riskof oral cancers, head and neck cancers, prostate cancer, colon and rectal cancer, breast cancer, melanoma or skin cancer, liver cancer, and endometrial cancer.
For more than 20 other cancers, the results were inconclusive.
Overall, there are several health benefits to drinking coffee but the risks are unclear, and further research is needed to fully understand the mechanisms underlying its association with cancer in animals. It is also advisable to limit other foods that contain acrylamide like French fries, chips, and cookies.