Grapes reduce diabetes risk? Hold off on grape- binging until you read this

Don’t Go Green

If you’re concerned about protecting yourself from developing type 2 diabetes, please think twice before making grapes 3 percent of your diet.

I just read a new University of Michigan study that found some impressive health benefits linked to eating grapes:

• Lower blood pressure
• Improved heart function
• Reduced inflammation in the heart and blood
• Lower triglycerides
• Reduced oxidative damage
• Improved glucose tolerance

That list might turn just about any health-conscious person into a dedicated grape eater. Especially because that cluster of benefits would reduce the risk of metabolic syndrome and type 2 diabetes.

But before you clear out the grape bin in your grocer’s produce section, let’s take a closer look.

I smell a rat

For three months, researchers fed rats a diet that included a mix of powdered green, red and black grapes (not actual grapes, mind you), which made up 3 percent of the diet. The UM team also used a control group of rats that didn’t eat any grape powder.

And here’s what the headline on the press release said: “Grapes Reduce Risks for Heart Disease and Diabetes, UM Animal Study Shows.”

But here’s what the headline didn’t say…the control group didn’t get the grape powder, but it DID receive added calories and sugars to balance the extra calories and sugars found in the grapes.

Riiiiight. “Balance.” Why…it’s almost as if the researchers purposely designed their study to MASK the effects of increased calorie and sugar intake.

So how much sugar is in a grape?

To borrow a quote from William Campbell Douglass, M.D.: “For the most part, green grapes might as well be Hershey’s kisses.”

That’s right. A green grape has THAT much sugar — which makes them a particularly bad choice for diabetics, despite the headline from the UM press release.

Give me some skin

But keep in mind that the researchers used a combination of grapes for the study. A red or purple grape is a different story–especially when you remove the meat of the grape and focus on the antioxidant-rich skin.

And it’s the skin from those dark grapes that is likely responsible for all the good news from the UM study–and the over-reaching headline.

The skins of dark red, blue, and purple vegetables are rich in resveratrol–a type of antioxidant polyphenol, which happens to be most abundant in the skins of red and purple grapes.

Remember a few years ago when every headline was screaming “Good news: Red wine is good for your heart!”? Well, there’s a good reason for that. While red wine is fermenting, winemakers leave in what they call the “must”– the skins, seeds, and even the stems of red grapes. Meanwhile, yeasts used in winemaking actually feed on and eliminate the sugars in grape meat.

Result: Red wine delivers a concentration of the best part of the grape (resveratrol and other powerful antioxidant polyphenols), without the inferior part of the grape (the sugar).

So if you’re looking for a list of healthy benefits, skip the grapes–especially the green ones–and take some resveratrol or a glass of wine instead. Even a University of Michigan lab rat would probably prefer a nice glass of burgundy to a boring green grape.

To Your Good Health,

Jenny Thompson

Source:
“Grapes Reduce Risks for Heart Disease and Diabetes, UM Animal Study Shows” University of Michigan press release, 4/26/10, med.umich.edu