5 replies to this topic

[nameless]

I was looking up some grapeseed extract info on cholesterol, and ran across this study done on Meganatural gold. It was done a couple of years ago and although the maker's of the supplement use this study as a way to promote their grape extract as a way to lower cholesterol, if you delve into the numbers a bit, it seems as if the extract may have done more harm than good.

Article link: http://www.naturalpr..._231study1.html

Synopsis: Following the in vitro study, researchers supplemented nine healthy subjects with 200 mg/d or 300 mg/d of MegaNatural Gold one week apart. The antioxidant activity was found to be most potent in the higher dose.

Then, researchers conducted a three-week study with 17 subjects--nine with normal blood pressure and eight with high blood pressure--taking 600 mg/d of the supplement (two 300 mg doses). The high cholesterol group had a 12 percent decrease in total cholesterol, 19 percent decrease in high-density lipoprotein (HDL), 16 percent decrease of low-density lipoprotein (LDL), and a rise in triglycerides, although the triglycerides remained in normal range. Plasma antioxidant capacity was also significantly increased in the high cholesterol group.

Looking at the numbers we get: 12% drop in total cholesterol, which is sort of a meaningless number, as the drop in HDL lowers the total cholesterol level too.

LDL drop of 16%: Good.
HDL drop of 19%: Very bad.
And triglycerides went up, although they didn't say by what percentage. Depending on what type of lipid testing they used, the drop in LDL levels could have been because LDL particle sizes became smaller (higher triglycerides tend to do that). And small LDL is a very bad thing to have.

So... to me, doesn't this show that high doses of grape seed extract has a negative effect on cholesterol levels? A 19% drop in HDL is worse for you than whatever benefit a 16% drop in LDL would have, and that's assuming the LDL drop was an actual particle number drop and not due to particle sizes becoming smaller.

Any thoughts on this study or why grape seed would lower HDL levels? Although I don't take MegaNatural Gold, it's a popular type of extract. Vitamin Shoppe, Nature's Way, Swanson's, GNC, etc. all use it.

[wydell]

Do you have a cholesterol problem? If not, why worry about one study? Grapeseed seems to have so many beneficial studies associated with it. I have rarely seen any negative reports on grapeseed.

[nameless]

Yes, I have a low HDL problem, so it is a concern.

I found the study interesting (as it was in fact a negative study) and was mostly curious as to why the results occurred. Dosage? Type of grape seed used? Error in study? And yeah, it's rare to see grape seed studies with negative reports -- the only other one I've seen was related to a rise in blood pressure, if a high dose was used along with vitamin C.

How many HDL studies have been done (on humans) using high dose grape seed extract? The one's I've found have been on heavy smokers (resulting in reduced oxidized LDL) and rodents.

[ortcloud]

Yes, I have a low HDL problem, so it is a concern.

I found the study interesting (as it was in fact a negative study) and was mostly curious as to why the results occurred. Dosage? Type of grape seed used? Error in study? And yeah, it's rare to see grape seed studies with negative reports -- the only other one I've seen was related to a rise in blood pressure, if a high dose was used along with vitamin C.

How many HDL studies have been done (on humans) using high dose grape seed extract? The one's I've found have been on heavy smokers (resulting in reduced oxidized LDL) and rodents.

These studies were done with high amounts of grape seed extract, so I wouldnt make a decision on whether to take it or not based on what happens with larger doses. Just stick with more reasonable amounts and monitor your hdl to see what happens and you should be ok.

[mikeinnaples]

Not that its really relevant.... Last week of December I was at LDL 189 HDL 26. This is a genetic cause and not dietary or exercise related.

From end of December to end of Feb, I have been taking 300mg grapeseed twice a day during the this time period. I also have been taking 25mg of simvastatin, 2g fish oil, and 1g niacin (500mg tr and 500mg pure nicotinic acid). In the 2 month period, even with the grapeseed I raised my HDL to 42 and lowered my LDL to 134.

Take that as you will.

[nameless]

Not that its really relevant.... Last week of December I was at LDL 189 HDL 26. This is a genetic cause and not dietary or exercise related.

From end of December to end of Feb, I have been taking 300mg grapeseed twice a day during the this time period. I also have been taking 25mg of simvastatin, 2g fish oil, and 1g niacin (500mg tr and 500mg pure nicotinic acid). In the 2 month period, even with the grapeseed I raised my HDL to 42 and lowered my LDL to 134.

Take that as you will.

I'd say the niacin is what raised your HDL. The statin + fish oil may have helped a little bit too. But the question remains, would it have gone up higher without such a high dose of grapeseed?

I haven't found any other studies using high dose grapeseed in regard to HDL. I am guessing the above study's results were due to dosage, fluke or something odd about the participants, but without other studies, who knows?

And a normal dosage of grapeseed (50-200mg) daily probably will be beneficial and have no negative effect on lipids. I didn't mean to put this post up to scare anyone away from grapeseed (I take a grape/red wine extract myself). I am mostly interested if the study is valid, if there were any other studies with similar results, and if there is a scientific reason for the results.