CARDIA Study Results on the Health Effects of Coffee and Tea

Many of us enjoy a hot cup of coffee in the morning.  In fact, more than half of all Americans consume coffee.  On average, they consume 2 cups er day.  Caffeine itself can have both potentially beneficial as well as adverse effects on your cardiovascular system.  On the one hand, caffeine can cause short-term but not long-term elevations in blood pressure.  As well, coffee contains the diterpene, cafestol, which can increase your LDL cholesterol levels.  On the other hand, higher intakes of coffee have been associated with a lower risk of type 2 diabetes.  However, results from studies of habitual coffee intake over long periods of time have been equivocal.

Previous research on tea consumption has demonstrated beneficial effects on the cardiovascular system including both a decreased risk of heart attack and stroke.  These beneficial effects are believed to be a result of the polyphenols found in teaspecifically the flavonoids.

Results from CARDIA Study:

The Coronary Artery Risk Development in Young Adults (CARDIA) study was recently published in the medical journal, Arteriosclerosis, Thrombosis, and Vascular biology (Reis et al, 2010). Specifically, the CARDIA Study looked at the long-term effects of coffee, tea, and caffeine consumption on coronary and carotid atherosclerosis.

The CARDIA study followed a cohort of 5115 white and black adults who were between the ages of 18 to 30 years at the onset of the study.  The researchers conducted subsequent exams over the next 20 years on this cohort.  Over this 20 year period, the researchers looked to find an association between coffee, decaffeinated coffee, tea, and caffeine consumption and  “the presence and progression of coronary artery calcified (CAC) plaques and carotid intima-media thickness later in life.”

The study authors concluded:

“In conclusion, the present long-term population-based study showed no substantial association between habitual coffee, decaffeinated coffee, or caffeine consumption assessed during young adulthood and well-documented markers of coronary and carotid atherosclerosis measured 15 to 20 years later.”

Tea consumption:

“However, tea consumption displayed evidence for a protective association with coronary calcification. Our findings suggest that tea consumption may prevent the development and progression of coronary calcification, whereas coffee and caffeine intake at the levels reported in the current study do not appear to be beneficial or harmful.”

In short, the CARDIA study did not find that coffee or caffeine consumption had any adverse effects on coronary or carotid atherosclerosis.  They did find that tea consumption was associated with beneficial effects on the coronary (heart) arteries, but not carotid (neck).

[box type=”note”]* The study authors referred to simply recording ‘hot’ and ‘cold’ tea consumption which I would presume would be largely composed of black tea. They did not specify or break down this consumption between green tea or black tea.[/box]

Find out more about the health benefits of drinking green tea


  1. Reis JP, Loria CM, Steffen LM, Zhou X, van Horn L, Siscovick DS, Jacobs DR Jr, Carr JJ.Coffee, Decaffeinated Coffee, Caffeine, and Tea Consumption in Young Adulthood and Atherosclerosis Later in Life. The CARDIA Study.  Arterioscler Thromb Vasc Biol. 2010 Jul 8.

5 thoughts on “CARDIA Study Results on the Health Effects of Coffee and Tea

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  • October 20, 2010 at 10:20 pm

    I only drink tea and I know with recent studies it has been said they have good antioxidants. I’m really glad as I love my cuppa…regularly lol
    Patricia Perth Australia

  • July 28, 2010 at 7:47 pm

    This is more good news for people like me. I like to drink both coffee and tea. I know that this particular study didn’t prove that there were real benefits for coffee drinkers, but other studies have suggested substantial benefits in other areas of our health.

    I am convinced that the more earthy a food is, the more healthy that food is. That is not a good reason for all you guys to stock up on Guinness.

  • July 20, 2010 at 5:31 pm

    I have been cutting back on my coffee intake and increasing my tea intake.

    I was at a point where I “needed” an afternoon cup of coffee and I hated the fact that I “needed” it.

    Recently, I have been drinking a green tea with ginger, yerba mate, ashwagandha, and a bunch of other energizing herbs & adaptogens.

    Of course, I still get my morning mug o’ Starbucks bold roast…I’m not crazy


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