Curious article. No need to shoot the messenger, it's something worth discussing. The concerns may be valid, or they may be a false alarm, but we won't find out by shooting anyone.
Am looking for the paper, haven't found it yet. Of all the 600 articles on that research that I found on the net, most seem to be regurgitation of the same information - some shorter and less detailed, none that I found with more information. Nowhere does any reporter bother to report what 'symptoms' become worse after drinking Red Bull, or to what degree (other than 'sticky blood').
Willoughby seems to have done several papers on blood cell and blood vessel response to nitric oxide - his findings in other studies were that reduced response to nitric oxide is characteristic of heart disease.
Here's a study that found that taurine made blood less sticky, not more - it lowered blood clotting (platelet aggregation) by 10% - which goes against the idea that taurine increases the risk of stroke (which is a blood clot that travels to the brain).
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Taurine does reduce nitric oxide - which may actually be good during a cluster attack. When people are in cycle, nitroglycerin is usually a pretty good trigger, suggesting that we are too sensitive to nitric oxide, or have too much.
But like nitric oxide, taurine also relaxes blood vessels - this is the opposite of the idea that Red Bull causes blood vessels to clench up and may contribute to stroke.
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Here's a study that found that taurine actually improves the vascular reactivity of diabetic mice - they were less likely to have the abnormal over-reaction to adrenaline and close the blood vessels too much, less likely to have over-expansion of blood vessels in response to acetylcholine.
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The general conclusion about taurine is that it reduces blood pressure ... lower blood pressure is generally linked to a lower risk of stroke.
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Here's a study that found that taurine reduced brain damage when stroke was induced in lab animals; it suggested that taurine has potential in treating strokes.
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There may be some other risk factor that taurine increases - too soon to tell. Or it may be something other than taurine in the Red Bull that affects whatever it is that Willoughby was measuring (for example, WTF is glucuronolactone?) Or it may be that Willoughby is basing his predictions on something that doesn't translate to real risk. Don't know, will be watching this one.
I do think that mixing Red Bull with calcium channel blockers is a potentially bad idea.