Positive Health Benefits of Caffeine

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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: http://www.clinsci.org/cs/109/0055/1090055.pdf

Toxins / Originally posted on the NutritionFacts.org 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


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

13 responses to “Does caffeine impair endothelial function in our arteries?

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  1. 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.

    1. 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.

  2. 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?

  3. 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?

  4. 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.

  5. Hi Dr Greger,

    First off, thank you for all your hard work to help us every day folks! I’ve been on a plant-based diet for about a year and it has dramatically changed my life!!

    Here’s my question, while I get excited every time I go to the doctor and get an update on how much lower my cholesterol has gotten, it seems that about half the time I have my blood pressure checked it is in a spiked state. Sometimes it’s at 110/70, but sometimes its 140/74 or something like that. I follow the daily dozen app and check at least 22-23 boxes on most days and I also don’t eat salt anymore.

    The only thing I can think of is I usually have my blood pressure checked in the morning, after I’ve had a couple cups of coffee, no breakfast, and I’m often stressed about my flooded vmail and email inboxes at the office.

    So, it seems that these are the things that might be causing my blood pressure to spike at times. The question is, what should I consider doing? Is this no big deal? I’m I at long term risk with this pattern? I love coffee and hate to give it up, but I could if it’s really necessary. Or, maybe I just need to find more ways to de-stress (meditation?). Or, maybe I need to be eating more in the morning? Or all of the above? I appreciate your thoughts!

  6. Hello Joe and thank you for your question,
    I am a family physician with a private practice in lifestyle medicine, and also a Health Support Volunteer for this website. Congratulations on eating a healthy, plant-based diet! To answer your questions:

    Having “spikes” in your blood pressure IS something you should be concerned about. Looking just at the upper number (systolic blood pressure), we know that every mm above 120 increases your risk of cardiovascular disease (stroke, heart attack). But, if it never goes much above 140, then your risk is certainly not alarming.

    I suggest that you start by doing several things. If you don’t already own one, I suggest that you buy a home blood pressure cuff. Don’t get a “wrist cuff” because these are not quite as accurate as arm cuffs. You can buy a reliable “upper arm cuff” for $30-$60 from Amazon or WalMart, which inflate and deflate automatically, and have a digital read-out. If your weight is normal, you probably want to get a “regular” sized cuff; if you are on the heavy side, you’ll want to get a “large” size cuff.

    Then, start gathering data about your blood pressure at varying times throughout the day. You might be very sensitive to caffeine. Just check readings before and after your coffee. De-caf coffee is an option, unless you are ultra-sensitive to caffeine. Having coffee on an empty stomach definitely tends to increase the level of caffeine in your bloodstream, so having something to eat before your coffee might be very helpful.

    Also, you say you “don’t eat salt anymore.” You need to quantify your sodium intake, by reading labels carefully. Some people are very sensitive, and should keep their intake as low as 500 mg per day of sodium. If you take lots of BP readings throughout the day, you will be able to see if your BP goes up after meals.

    Finally, you mention stress. This will absolutely and reliably increase your blood pressure. You probably need to develop some strategies to reduce stress. This can be as simple as taking 5 slow, deep breaths every 15 minutes or so. You might also meditate for 5 minutes 2-3 times per day.

    Getting regular exercise can definitely help lower your BP, and reduce your stress. Also, you didn’t mention how much sleep you get. Turns out that getting at least 7-8 hours of sleep has LOTS of health benefits. If you are consistently sleep deprived (e.g. 5 hours or less), this has been linked to high blood pressure.

    Hope this helps some.
    Health Support Volunteer for NutritionFacts.org.

    1. Thank you Dr. Jon for that thorough answer! I will definitely get an upper arm cuff!

      I do get a decent amount of sleep. I’d say I average 7 hours. Could be better, but not bad. My BMI is good. I’m 5’11 and 170 lbs. My LDL is down to around 40 now that I have made the lifestyle change and my HDL is a little more than that (around 44). My resting heart rate is less than 60 BPM. So, I would expect my blood pressure should normally be low – and it usually is! It just seems to be in the mornings with more stress and coffee and less food (I often skip breakfast) that my BP can be on the high side. I’ve been meaning to work in some meditation and deep abdominal breathing so I’ll make a point to start doing that. Thanks again for your insights!!

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