Antioxidants protect NO synthase, the enzyme that produces the artery-relaxing signal, nitric oxide. This may explain why those who eat especially antioxidant-rich plant foods have improved flow-mediated dilation of the brachial arteries.
The Power of NO,
Our understanding of nitric oxide has come a long way since it was named "molecule of the year" in 1992 and won some folks a Nobel Prize in '98. But it's a key biological messenger within the body and its message is: "open sesame". It's released by the lining of our arteries to tell the muscle fibers within the walls of our arteries to relax, so our arteries open up and let the blood flow.
That's why when people are having a heart attack, they're giving nitroglycerine, which your body converts to nitric oxide to open up our arteries. In fact that's how Viagra works: it boosts nitric oxide signaling, which leads to dilation of the penile arteries.
The ED we really need to be concerned about, though, is endothelial dysfunction: dysfunction of the lining of all our arteries, considered a first step toward atherosclerosis, our leading cause of death.
Here's what happens: NO, nitric oxide, is produced by an enzyme called NO synthase. If you have a lot of free radicals in your body, though, they come in and not only gobble up the NO -- they hijack this enzyme -- they hijack NO synthase, take it over, and have it instead start making more free radicals.
So our arteries become dysfunctional. They don't relax when they should. And that can contribute to the hardening of our arteries.
If, however, we flood our body with antioxidants by eating healthy foods, it should quench those free radicals and let NO get back to its job.
So recently, for the first time ever, researchers studied the effects of eating high antioxidant foods on NO activity. We saw what choosing higher antioxidant plant foods did to inflammation. What effect does it have on our arterial function?
You can hook people up to a device that measures the dilation of their arteries and blood flow through ultrasound. In the study, people started eating their normal miserable diet, then switched to an even more miserable diet, and their arterial dilation capacity dropped, though not significantly.
They started out eating a pretty crappy diet to begin with, but which they then let people get back to, so then their NO activity came back to baseline. Then they had these people eat the higher antioxidant foods, like berries, and within a period of just two weeks, a significant jump in their arteries' ability to relax and dilate normally.
This is where they should have been in the first place, or even higher. This study suggests that choosing antioxidant-rich plant foods can improve blood flow to all parts of our bodies.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is transcript contributed by Bruce A. Hamilton.
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For more context, check out my associated blog post, Antioxidants in a Pinch: Dried Herbs and Spices.