MonaVie is a product that contains acai (pronounced a-SAH'ee) berries plus other fruits, but its promoters base their health claims for it on acai berries, which reportedly provide 10 times the antioxidants found in red grapes and 10 to 30 times more than in red wine.
Native people in Brazil have traditionally used acai berries to treat digestive disorders and skin conditions, according to University of Florida researcher Stephen Talcott, who has been investigating the berry. He and colleagues have published findings from laboratory studies showing that acai extracts caused leukemia cells to self-destruct. While Talcott cautioned that the study doesn't show that acai could treat leukemia in humans, he noted that compounds that show good activity against cancer cells in cell cultures are likely to have beneficial effects in the body. I don't agree. It's a long way from test tube results to safe and effective treatments for cancer in humans.
There are no reliable studies on any commercially available products containing acai. (One posted on a Web site promoting MonaVie contains a disclaimer that it involved only a small number of healthy adults and would have to be repeated in a larger group before results could be generalized to the population at large.)
MonaVie is an expensive way to get your antioxidants - it sells for about $40 for a 25.3 ounce bottle. That works out to $4 to $6 per day if you use it as directed. While it is probably safe, I recommend sticking closer to home for your protective phytonutrients. Opt for organically grown blueberries, which are more available, much less expensive, and give you fiber as well as plenty of antioxidant activity. And don't forget black raspberries and pomegranates, both of which have health benefits for which there is good scientific evidence.
As for the glucosamine in some MonaVie products, there are less expensive ways to get that, too. If you have osteoarthritis, I think glucosamine is worth trying, and it may help restore damaged cartilage in joints. But buy a good brand of it and use the recommended dosage for a trial period - two months, say - to see if it helps. If you do not have osteoarthritis, you do not need glucosamine, nor do children need it.
For the record, I also object to MonaVie because it is sold via a mix of multi-level marketing and direct-from-distributor sales. I'm sorry, but I am prejudiced against multi-level marketing of any kind.
Andrew Weil, M.D.