New research suggests the ‘prune effect’ appears to target a specific bone area most prone to fracture 

A newly published study among 18- to 25-year-old women shows that eating about a serving of prunes daily for a year may be a safe and inexpensive solution to reduce the risk of bone loss associated with oral contraception use. The study was published in the September issue of Current Developments in Nutrition, an American Society of Nutrition publication.

Specifically, findings show that bone mineral density at the ultradistal radius increased significantly among women taking oral contraceptives (OC) plus 50 grams of prunes daily over 12 months. The ultradistal radius is an area especially rich in trabecular bone, which is not solid but is full of holes connected by thin rods and plates of bone tissue.  

“Trabecular bone is particularly important for bone health, since skeletal sites with more trabecular bone are those that are most prone to fracture due to osteoporosis,” said Dr. Shirin Hooshmand, PhD, RD, Primary Investigator, San Diego State University.  

While the reasons for the “prune effect” aren’t completely understood, research suggests that the effects of prunes occur primarily through inhibition of bone resorption by reducing the activity of osteoclasts, a type of bone cell that breaks down bone tissue.  

“As a nutrient-rich fruit, prunes have a combination of minerals, vitamin K, phenolic compounds and fiber that is unique among foods and is important for bone integrity,” Hooshmand said.  

According to 2024 figures from the National Institutes of Health, approximately 25% of U.S. women aged 15 to 44 who currently use contraception reported using the pill as their method of choice. Research has shown that the use of OC can be detrimental to bone health density particularly in younger women.  

The new study’s findings expand upon a growing body of research investigating prunes’ effects on bone health. For example, the Prune Study, a 12-month randomized controlled trial conducted with 183 postmenopausal women aged 55 to 75, showed similar bone benefits with daily prune consumption of 50 grams, which is about one serving. 

“Now, in addition to findings among postmenopausal women, our study helps begin to round out the prune-bone health effect story to include younger women with increased risk for bone loss,” Hooshmand said. 

Easy Ways to Enjoy More Prunes 

The latest study is a reminder that California Prunes are delicious, versatile and nutritious. With a deep, sweet flavor and luxurious texture that’s “juicier” than that of most dried fruit, prunes are more than an easy snack and they pair beautifully in sweet or savory applications.  

“Chefs and dietitians alike appreciate the flavor, versatility and many health benefits of prunes,” said Kiaran Locy, Director of Brand & Industry Communications for the California Prune Board. “California has a long history of growing the highest-quality prunes in the world, and this craftsmanship really shows when they’re used in recipes.” 

The California Prune Board offers these recipes for late-summer inspiration: 

• Whipped Feta Dip with Prune Puree, Roasted Bell Peppers & Crushed Pistachios – This fresh, no-cook feta dip from registered dietitian Liz Shaw is bright, herby – and a bit naturally sweet with the addition of pureed prunes. It’s perfect for an easygoing outdoor gathering, whether with crunchy bell peppers and buttery pistachios or with other dippers like seedy crackers and cucumber sticks. 

• Roasted Cauliflower with Prunes, Olives, Sun-Dried Tomatoes and Chili – An easy, one-pan side dish from James Beard Foundation Award Winning chef Gregory Gourdet, this brings together an unexpected combination of roasty, earthy, sweet and briny flavors, along with some heat and a generally sun-kissed Mediterranean vibe. Serve it with grilled meat or as part of a summer vegetarian spread. 

• Farro Salad with Prunes and Zesty Herb Vinaigrette – Staying in the Mediterranean mood, this salad recipe developed by Kristy Del Coro, MS, RDN, LDN packs a ton of flavor with crunchy fennel and nuts, sweet prunes, fresh herbs and orange zest. It’s also a wilt-proof pick for a summer potluck and especially good with grilled poultry. 

For more ideas about using prunes in recipes, cooks can visit www.californiaprunes.org.  

More About the Study 

This parallel-arm, 12-month randomized, controlled trial initially included 90 healthy young females aged 18-25 years. Participants were first divided into two groups: those not taking OC (n=30) and those taking OC (n=60). Those taking OC (for at least 1 year but no more than 5 years) were then randomly assigned to the prune group (n=30) and instructed to eat 50 grams of prunes daily, or the non-prune group (n=30) and instructed to avoid eating prunes. Due to attrition, the 28 participants completed the 1-year trial in both OC groups. Participant anthropometrics and blood bone biomarker measurements were taken at the start of the study, half-way through and at the 12-month mark; bone mineral density scores, via dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, were taken at the start of the study and at the 12-month mark.  

The OC + prune group had a total compliance rate for prune consumption of 87%. Unlike both OC groups, more non-OC participants identified as Asian and Hispanic, and none as Black or Other. The majority of study participants were White females. Findings show no statistically significant differences between or within groups for blood bone biomarkers; bone mineral density at the lumbar spine, right femur, left femur, non-dominant radius and ulna, or total body; and for any site of the tibia. However, bone mineral density at the non-dominant ultradistal radius increased significantly from baseline to 12 months in non-OC and OC+ prune groups.  

Study limitations include varying doses and types of OCs used and a less-than-optimal compliance rate. 

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ABOUT THE CALIFORNIA PRUNE BOARD 
The California Prune Board was established in 1952 to represent growers and handlers under the authority of the California Secretary of Food and Agriculture. California is the world’s largest producer of prunes with orchards across 14 counties in the Sacramento and San Joaquin valleys. Promoting a lifetime of wellness through the enjoyment of California Prunes, the organization leads the premium prune category with generations of craftsmanship supported by California’s leading food safety and sustainability standards. California Prunes. Prunes. For life. 

For more information, contact: 
Kiaran Locy, Director of Brand & Industry Communication 
California Prune Board 
klocy@californiaprunes.org   
916-749-3442