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‘The most important thing we’ve learned about coffee over the past 20 years is that there’s very little indication that it’s bad for you,” says Edward Giovannucci, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health. “If anything, there’s more evidence that it may be healthy to drink.”
The benefits are probably because of anti-inflammatories and antioxidants found naturally in coffee: polyphenols (such as chlorogenic and quinic acids) and diterpenes (such as cafestol and kahweol). Many of coffee’s health perks probably extend to decaf, too, because with decaf only the caffeine, not these other compounds, is removed.
Studies have found that coffee has a positive effect on the risk of a variety of conditions and diseases, including several forms of cancer. But not all of the benefits have the same strength of evidence behind them. Of course, adding loads of cream and sugar to your coffee may offset some of the benefits you get from it.
In general, people can safely consume up to 400 mg of caffeine per day, the amount in two to four eight-ounce cups of coffee.
For some, too much coffee irritates the stomach, causes anxiety or the jitters, disrupts sleep and increases the frequency of heart palpitations. Three or more cups per day appears to trigger migraines in people prone to them. And pregnant women, people who are at risk of osteoporosis and those taking certain drugs (including some antibiotics, antidepressants and antipsychotics) should limit their intake of caffeinated coffee.
How solid are health claims?
Giovannucci weighs in on where the current research is solid and where more investigation is needed.
● Strongest evidence: Coffee lowers the risk of endometrial cancer, gallstones, nonalcoholic fatty liver disease, liver fibrosis, cirrhosis, and liver cancer, oral cancers and Type 2 diabetes.
● Moderate evidence: Coffee lowers the risk of colorectal cancer, coronary heart disease, heart failure, stroke, melanoma and nonmelanoma skin cancers, Parkinson’s disease and respiratory disease; and it 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 it increases the variety of healthy bacteria in the gut.
● Limited evidence: Coffee lowers the risk of weight gain and falls by the elderly, possibly because caffeine increases alertness or reaction time.
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