The benefits are likely to be due to the anti-inflammatory agents and antioxidants that occur naturally in coffee: polyphenols (such as chlorogenic and quinic acids) and diterpenes (such as cafetol and cahveol). Much of the health of coffee probably extends to no coffee as only caffeine, not these other compounds, is eliminated with decaffeinated coffee.
Studies have found that coffee has a positive effect on the risk of various conditions and diseases, i. including several forms of cancer. But not all benefits have the same strength of evidence behind them. Of course, adding lots of cream and sugar to your coffee can offset some of the benefits you get from it.
In general, people can safely consume up to 400 mg of caffeine a day, the amount in two to four eight-ounce cups of coffee.
For some, too much coffee irritates the stomach, causes anxiety or jitter, disturbs sleep, and increases heart rate. Three or more glasses a day appear to cause migraines in people predisposed to them. And pregnant women, people at risk for osteoporosis, and those taking certain medicines (including some antibiotics, antidepressants and antipsychotics) should limit their caffeine intake.
How Hard Are Health Claims?
Giovannucci weighs where current research is sound and where more research is needed.
The strongest evidence: Coffee lowers the risk of endometrial cancer, gallstones, non-alcoholic fatty liver disease, liver fibrosis, cirrhosis and liver cancer, oral cancer2 and 1
9659 and diabetes9 ●
Coffee reduces the risk of colon cancer, coronary heart disease, heart failure, stroke, melanoma and non-melanoma skin cancers, Parkinson's disease and respiratory diseases; and improves alertness, concentration, focus, energy levels and mood.
Some evidence: Coffee lowers the risk of age-related cognitive decline, Alzheimer's disease, breast cancer, depression, pancreatic cancer, prostate cancer; and increases the variety of healthy bacteria in the gut.
Limited evidence: Coffee reduces the risk of weight gain and decline by the elderly, probably because caffeine increases alertness or response time.
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