Is There Anything to Green Drinks?

Q: My sister says powdered "green drinks" make her feel healthier and more energetic. Do you think there is anything to this?

A: I can't speak for your sister, but no well-designed clinical studies support claims that these drinks—a mix of water and powdered green plants or vegetables—boost energy, enhance immunity, lower blood pressure, or fight cancer. However, I do think they're generally safe—with a few exceptions.

Many green drinks contain powdered spinach, kale, and broccoli that, manufacturers say, provide as much nutrition in a scoop or two as in several servings of veggies. This is a stretch. I prefer to get my nutrients from whole foods, which contain a blend of vitamins, minerals, antioxidants, and fiber that is more beneficial when consumed in the diet than from drink mixes.

Most of these mixes also include substances that contain chlorophyll—the compound that makes plants green. However, the only nutrient in chlorophyll that's useful to humans is magnesium.

If green drinks energize your sister, she should continue consuming them, but know that a well-balanced diet could provide the same, if not better, results. A couple of caveats: Read labels carefully to avoid extra calories or additional supplements (especially if you're taking a multivitamin). And steer clear of formulas made with blue-green algae and spirulina; some brands have been found to contain toxins.

Andrew Weil, M.D., is a pioneer in the field of holistic health and founder and director of the Program in Integrative Medicine at the College of Medicine, University of Arizona. He received his medical training at Harvard University.