Coffee Found to Adversely Affect Blood Vessel Health

by | May 12, 2010 | 2010, Caffeine, Cardiovascular Health, Circulatory Health

Written by Greg Arnold, DC, CSCS. A study in 20 healthy males showed that one cup of coffee could decrease flexibility of blood vessels by 22% and increase diastolic blood pressure by 6%.

As the most consumed beverage on earth, coffee is second only to oil as the most valuable legally traded commodity, garnering $70 billion each year in global retail sales (1). Coffee consumption in the U.S. reached an all-time high in the 1960’s, with each American drinking nearly three cups of coffee per day. Americans currently drink an average of 1.5 cups per day (2).

There exists in coffee what is known as the ‘coffee paradox’ because although it is high in antioxidants thanks to a class of antioxidants called chlorogenic acids (3), coffee is also high in caffeine (4). This has resulted in conflicting research on the health effects of coffee that include short-term consumption decreasing cardiovascular and metabolism health detrimental cardiovascular and metabolic influences (5) yet regular consumption lowering the risk of cardiovascular disease and type 2 diabetes (6). It is suggested that the caffeine in coffee produces the detrimental short-term effects and the antioxidant intake producing the long-term benefits.

Now a new study (7) has again found short-term detrimental health effects of coffee, this time on blood vessel health. In the study, 20 healthy, non-obese patients (10 males and 10 females) ingested either one cup of caffeinated coffee (contained 130 mg caffeine) or one cup of decaffeinated coffee (containing 5 mg caffeine) in random order at 5- to 7-day intervals. After each cup of coffee, researchers assessed blood vessel health via the flow mediated dilatation (8) which measures how flexible a blood vessel is and how easily it relaxes. They also measured blood pressure 1 hour after coffee ingestion.

Following consumption of caffeinated coffee, flow-mediated dilatation decreased by 22% after 1 hour (p = 0.04) (7.7 to 6.0%), indicating decreased artery flexibility). While there was a 19% increase in flow-mediated dilatation after decaffeinated coffee consumption (6.9 to 8.5%), there was a significant source of error (p = 0.12) so those results have less credibility.

When looking at blood pressure, diastolic blood pressure (the bottom number) increased by 6% after caffeinated coffee consumption (68 to 72 mm Hg, p = 0.001) with a 2% increase in the decaffeinated coffee group (66 to 67 mm Hg, p = 0.07).  For Systolic blood pressure (the top number), caffeinated coffee produced a 3% increase (113 to 116 mm Hg, p = 0.003) with a 1% decrease after decaffeinated coffee consumption (112 to 111 mm Hg, though this had too much error (p = 0.22) and cannot be counted as credible).

For the researchers, “caffeinated coffee acutely induced unfavorable cardiovascular effects, especially on [blood vessel] function”.

Source: Buscemi, Silvio, et al. “Acute effects of coffee on endothelial function in healthy subjects.” European journal of clinical nutrition 64.5 (2010): 483.

© 2010 Macmillan Publishers Limited

Posted May 12, 2010.

References:

  1. “Coffee – The Market – The Economics of Coffee” posted on First Science, August 15, 2003.
  2. “U.S. Coffee Consumption” posted on the U.S. Food and Drug Administration website.
  3. Fujioka K, Shibamoto T (2008). Chlorogenic acid and caffeine contents in various commercial brewed coffees. Food Chem 106, 217–221.
  4. “Caffeine” – posted on Medicine Net website.
  5. oisey LL, Kacker S, Bickerton AC, Robinson LE, Graham TE (2008). Caffeinated coffee consumption impairs blood glucose homeostasis in response to high and low glycemic index meals in healthy men. Am J Clin Nutr 87, 1254–1261.
  6. van Woundenbergh GJ, Vliegenthart R, van Rooij FJ, Hofman A, Oudkerk M, Witteman JC et al. (2008). Coffee consumption and coronary calcification: the Rotterdam Coronary Calcification Study. Arterioscler Thromb Vasc Biol 28, 1018–1023.
  7. Buscemi S.   Acute effects of coffee on endothelial function in healthy subjects Eur J Clin Nutr 64: 483-489; advance online publication, February 3, 2010; doi:10.1038/ejcn.2010.9.
  8. “Flow-Mediated Dilatation” – posted on Hitachi Medical Systems Europe website.