The Bone Density Trial Nobody Expected From a Laxative Food
A food best known for one specific digestive reputation just held up in a 12-month bone-density trial.
Prunes are unusually rich in polyphenols and boron, compounds that appear to suppress the bone-breakdown side of bone turnover — without needing extra calcium or vitamin D added alongside them.
Key Findings
- Zero bone loss in the prune group over 12 months, versus a 1.1% drop in hip bone density for the control group
- A companion trial found prunes also preserved bone strength at the tibia (shin bone)
- A 2025 review of 11 studies, 747 people found a similar benefit at the lower spine
- The effective dose was specific: 50g daily — about 5-6 prunes, not a large serving
The 12-month trial
A randomized controlled trial — "The Prune Study" — had postmenopausal women eat 50 grams of prunes daily, about 5 to 6 prunes, and tracked their bone density over a full year. The control group lost 1.1% of total hip bone mineral density; the prune group showed no change at all.1 A companion analysis found prunes also preserved cortical density and estimated bone strength specifically at the tibia (shin bone).
What a 2025 review added
A 2025 systematic review and meta-analysis pooling 11 studies and 747 participants found a borderline-significant bone density benefit at the lumbar spine as well.2 Larger trials backed by the USDA and the California Prune Board are now running through 2029-2030 to confirm dose and duration more precisely.
The practical takeaway
- The tested dose is specific and modest — about 5-6 prunes (50g) daily, not a large "more is better" serving
- The trials used prunes alone, not stewed or juiced substitutes
- This isn't a substitute for calcium, vitamin D, or weight-bearing exercise — it's an additive dietary habit with real trial support
Sources
- "Prunes preserve hip bone mineral density in a 12-month randomized controlled trial in postmenopausal women: the Prune Study." American Journal of Clinical Nutrition. ajcn.nutrition.org
- "Effects of Prunes on Bone Density in Humans: A Systematic Review and Meta-Analysis of Randomized Controlled Trials." Nutrients, 2025. mdpi.com
