|Image 1: Bought in bulk, grape-seed extract is actually reasonably cheap... and it does not even taste as awful as some other herb / seed extracts ;-)|
[b]ased on the currently available literature, grape seed extract appears to significantly lower systolic blood pressure and heart rate, with no effect on lipid or CRP levels.These results suggest that we (at least some of) the beneficial health effects that have been observed in rodent studies actually translate to human beings - something we cannot (yet?) say for some of the next generation "panacea" ;-) This is also important in view of the significance of the results GSE-administration had on exercise-induced oxidative stress in a more recent study by scientists from the universities of Konya and Dicle in Turkey (Belviranli. 2011), which was published in the latest issue of the British Journal of Nutrition.
The experiments were carried out with 64 adult male Sprague Dawley rats who were randomly assigned to one of the following six groups:
- sedentary control (C, n=10),
- chronic exercise control (CEC, n=11),
- acute exercise control (AEC, n=11),
- GSE-supplemented control (GC, n=10),
- GSE-supplemented chronic exercise (GCE, n=11), and
- GSE-supplemented acute exercise (GAE, n=11)
The dosage, according to the scientists, was chosen because it had elicited beneficial anti-oxidant effects in previous studies on alloxan induced diabetes (El-Alfy. 2005) and age-related oxidative damage (Balu. 2006). And, as Belviranli et al. had suspected, it exhibited similar protective effects against the oxidative stress triggered by both chronic, 5x a week treadmill exercise at 25m/min for 45 minutes, as well as, acute running on the treadmill at 30m/min until exhaustion.
Rat to human equivalent dosage calculation: If you have already read my dissertation on how to calculate the so-called human-equivalent-dose (HED), you will probably already have whipped out your calculator and are just about to type "100mg times the K-value for rats, which is 6; divided by the K-value for humans, which is 37" ... and what does your calculator tell you? Correct! The HED of 100mg/kg GSE in rats is 16.33mg/kg - in other words, if you weigh 80kg you will have to take roughly 1,300mg of grape-seed extract per day to mimic the dosage that was used in the study.
|Image 2: Click here to learn how to calculate human equivalent doses (HED)|
|Figure 1: Effects of acute or chronic exercise and grape seed extract (GSE) supplementation on plasma malondialdehyde (MDA) levels (data calculated based on Belviranli. 2011).|
|Figure 2: Effects of acute or chronic exercise and grape seed extract (GSE) supplementation on plasma nitric oxide (NO) levels (data calculated based on Belviranli. 2011).|
So, even if your favorite anti-aging and health (onilne-)magazine or vendor appears to have forgotten about grape-seed extract. For a physical culturist like you and me, it may yet well be worth to (re-)include the extract from the seeds of the fruits of Vitis vinifera, which are a particularly rich source of vitamin E, linoleic acid and, most importantly, oligomeric proanthocyanidins, into our supplement regimen. And if the current study does not convince you, it may help, if I remind you of the 2006 study by Kijima et al. who were able to show that GSE due to its anti-aromatase activity can suppress tumor growth in a breast cancer model (Kijima. 2006) ... ah, and before I forget: don't be stupid and buy over-priced caps. Use google and find yourself a source of bulk grape-seed extract - don't worry the taste is not all too bad ;-)