Is Grape Juice Good for Adult Hearts?

Q. My dad doesn't drink wine, so he drinks grape juice for his heart. After seeing the Dr. Oz show about arsenic in juice, I'm wondering: Is that smart?
-- Armstrong, via e-mail

A. While Dr. Oz broke the story about arsenic in apple juice on TV last fall, Consumer Reports added grape juice to the worry list in its January 2012 issue. (Dr. Oz did a second show with the CR team). One frustrating thing for CR's investigators, who found arsenic and lead in certain juices, was a lack of any pattern. Their words: "Our findings . . . can't be used to draw general conclusions about arsenic or lead in any particular brand." There's not an official limit for either toxin in juice, though the FDA's working on this.

Meanwhile, tell your dad to drink no more than 12 ounces of grape juice a day, and to spread out consumption frequency so he gets no more than 4 grams of sugar an hour (to avoid blood sugar spikes). That's tricky since grape juice averages 4 grams of sugar per ounce, but diluting it with sparkling water helps.

Here's the kicker: Grape juice isn't doing his heart much good. It's primarily the alcohol in wine that's heart-protective. Yes, there's a substance called resveratrol in wine and red grape juice that in theory helps, but unless you drink 180 bottles a day or so, you won't get enough to make a difference. We don't think resveratrol's ready for prime time anyway. Here's why.

For wine drinkers, one 5-ounce glass a day is best. For your dad, we'd say eat grapes. Cup for cup, the fruit has a third fewer calories and sugar and lots more vitamins than the juice. There's also some resveratrol in grape skins.

If you're a wine drinker, you'll like this: Wine helps keep your heart and mind young.