How much coffee is too much?

The question

I love my coffee - I could drink it all day. How much coffee is too much? What are the dangers to my health?

The answer

Believe it or not, there are more potential health benefits associated with drinking coffee than health hazards. Research suggests that if you drink enough of it, you'll lower the risk of developing type 2 diabetes, heart disease, asthma, gallstones, Parkinson's disease, liver cancer and possibly breast and colon cancers.

The most promising evidence for coffee's health benefits come from studies on diabetes. According to one large report, people who drank 4 to 6 cups of coffee per day were 28 per cent less likely to develop type 2 diabetes compared to those who drank two cups or fewer. Consuming more than six cups each day reduced the risk by 35 per cent.

Many of coffee's health benefits are attributed to antioxidants, some of which become more potent during roasting. Antioxidants in coffee - in both caffeinated and decaffeinated - are thought to reduce inflammation in the body and improve how the body uses insulin, the hormone that lowers blood sugar. Coffee also contains magnesium and chromium, minerals linked to blood sugar regulation.

But coffee isn't for everyone. If you have heartburn or reflux disease (GERD) you should limit or avoid it. Coffee - both regular and decaffeinated - relaxes the muscle that keeps stomach acid from rising into the esophagus and throat. Coffee also stimulates acid secretion in the stomach.

Drinking too much coffee each day may also increase the risk of miscarriage. That's why Health Canada advises women of childbearing age consume no more than 300 milligrams of caffeine per day - roughly two 8 ounce cups of coffee per day. Keep in mind that most cups at coffee shops are much larger than 8 ounces! All other healthy adults should consume at most 400 milligrams of caffeine daily.

Here's how different types of coffee compare when it comes to caffeine (in milligrams):

Coffee, roasted, ground, filter drip, 8 ounces: 179

Coffee, instant, 8 ounces: 76 - 106

Coffee, decaffeinated, 8 ounces: 3

Espresso, 1 ounce: 64

Starbuck's Coffee, Grande, 16 ounces: 330

Starbuck's Coffee, Venti, 20 ounces: 415

Starbuck's Latte, Grande, 16 ounces: 150

Tim Horton's coffee, small, 8 ounces: 80

Tim Horton's coffee, extra large, 20 ounces: 200

Send dietitian Leslie Beck your questions at dietitian@globeandmail.com. She will answer select questions, which could appear in The Globe and Mail and/or on The Globe and Mail web site. Your name will not be published if your question is chosen.

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