How strong is the evidence for Berries?

Most of the available literature for this topic centers on resveratrol, a polyphenol found in berries (and grapes), covering effects on health, skin, and bone density, including one randomized trial showing improved bone mineral density in postmenopausal women. That evidence is currently rated moderate (48/100), built on 4 published studies, including 1 randomized controlled trial and 3 meta-analyses -- a reasonable base, but not yet enough for full certainty.