Does caffeine impair endothelial function in our arteries?

Hello Dr. Greger. Latest in nutrition Volume 8 was a fantastic DVD. It was very informative and applicable to my lifestyle. I especially liked the healthy ice cream idea, I’m going to try that! I don’t want to pester you with an email, so I thought I’d post it here. In regards to creatine, you mentioned that most creatine supplements are contaminated with heavy metals, yet consuming a creatine supplement as a vegetarian increased cognitive function. Now my question to you is this: Is there any safe creatine supplement and if there was one, would you recommend consuming it?  Also in reference to caffeine, you mentioned it has positive health benefits. This study shows that the caffeine in coffee caused impaired endothelial function:

Toxins / Originally posted on the Facebook page


I’m so glad you liked volume 8! For creatine see my video Creatine Brain Fuel Supplementation.

I’m so glad you asked the caffeine question, as I’ve been such an outspoken advocate of green tea consumption (see, for example, The Healthiest Beverage and Dietary Brain Wave Alteration). As I detailed in my video The Power of NO, endothelial dysfunction is the first step towards atherosclerosis–our #1 killer–and so we need to keep the inner lining of our arteries healthy by any means necessary.

Last year, a study entitled “Impact of Acute Caffeine Ingestion on Endothelial Function in Subjects With and Without Coronary Artery Disease” was published in the American Journal of Cardiology. They performed the most rigorous investigation to date, a randomized, double-blind, placebo-controlled cross-over study that found that caffeine significantly improved endothelial function. They concluded “In conclusion, acute caffeine ingestion significantly improved endothelial function assessed by brachial artery FMD in subjects with and without CAD and was associated with lower plasma markers of inflammation.” That was for the amount of caffeine found in about 2 cups of coffee, 4 cups of black tea, or 8 cups of green. Similar benefits were found previously at a higher dose (3, 6, and 12 cups respectively).

So why do studies on brewed coffee, espresso, and energy drinks show negative effects? Well, there are a lot of other substances in these beverages besides caffeine, some of which may also be removed in the decaffeination process. Since there appear to be compounds in coffee that both impair and improve endothelial function (whereas in tea, both green and black, it appears to be all improvement), one might turn to epidemiological studies to look at overall risk and benefit of coffee consumption (see, for example, my Update on Coffee and Coffee and Cancer).

Though filtered coffee may be good, the evidence supporting the benefits of green tea are much stronger and more consistent. So I continue to recommend people drink tea instead of coffee, not because coffee is bad for you, but because green tea appears to be much better. More on caffeine can be found in my video What About the Caffeine?

Image Credit: Phil Monger / Flickr

  • KMC

    How about the acrylamide in coffee? Is there enough to be concerned about?

  • Lawrence

    I had a heart attack in May 2013. Since then I have been focused on my diet and doing more exercise. I am a Vegan Plus, meaning I eat a wide variety of whole, preferably organic plants while avoiding added salt, sugar, unfermented soy, alcohol and caffeine. If you could put together a summary foods to consume and foods to avoid I am sure many people would be grateful. Thank you in advance.

    • Thea

      Lawrence: I think you might be interested in Dr. Greger’s post on his nutrition recommendations:

      Other than that, you kind of have to go through the videos to pick out which foods he particularly recommends and particularly doesn’t recommend. At least, I’m not aware of any other compilation. You may want to search for those videos on NutritionFacts which specifically deal with heart health. He has a series on nuts that might interest you. Also I think the series on amla relates to the heart, though I may not be remembering that correctly.

      Also, someone recently pointed me to a video lecture by Dr. Greger that is on YouTube. In that video, Dr. Greger specifically recommended 1-2 tablespoons flax ground seeds every day and being sure to get enough B12 in your diet for optimum heart health. He recommended staying away from oils like corn and ___? (can’t remember the list). It’s best to stay away from all oils, but if you are going to have some, he recommended picking olive or canola. All of what I’m talking about in this paragraph is from a speech that is a decade old. So, I’m not sure how much still applies. But I would guess that these parts would still apply today, especially for heart health.

      Your diet already sounds pretty healthy. Good for you! I hope your efforts help you avoid another heart attack.

  • David Garcia

    A question about endothelial health and beta cells. This study shows that improved blood vessel/endothelial health can allow beta cells to grow and distribute insulin.
    Can someone comment about this, and the other potential ways the pancreas’ beta cells can regenerate/heal/reset? If this study proves out, then could coffee help with beta cell healing?

  • Lissen Up

    I liked that the results of the study showed no negative differences among the tested items. Good effects from all.

  • Casper

    If a person is on Lipitor and has dramatically improved his TBC to where the numbers look great on paper, but this person has eaten an animal-based diet (and continues to) his whole life (70 yrs), will the damage to his Endothelium still put the person at risk for heart attack?

  • ChPo

    Although I’m a “mostly vegan vegetarian,” and eat a lot of whole plant foods, I am very active and find that green tea lowers my blood sugar and causes stomach pain and nausea. I sometimes feel I’ll pass out. I can only drink it with a large meal. Coffee with soy milk doesn’t, so that’s what I drink. (I have to put soy milk or nut milk in it, or it too hurts my stomach). Do you have comments about that? Thank you for your wonderful website and the selfless work you do.