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 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?
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