A few studies from Pennsylvania State University indicate that while inflammation has a negative effect on bone health, dietary intervention with prunes may ultimately help prevent bone loss and maintain bone strength. Conducted among 235 postmenopausal women, the findings of the collective study were shared through a poster session at the North American Menopause Society’s annual meeting in Atlanta, Georgia.
Establishing a Baseline: Inflammation and Bone Health
In the United States, approximately 10 million adults over the age of 50 have osteoporosis, and women are four times more likely than men to experience the condition1.This is due in part to a drop in estrogen levels with the onset of menopause, resulting in loss of trabecular and cortical bone density.2.3. Trabecular bone is the spongy, honeycomb-like inner core while cortical bone is the strong exterior of the bone.Along with aging, estrogen deficiency contributes to an increase in inflammatory mediators that further enhance bone resorption and suppress bone formation4.
A new cross-sectional study from Penn State titled – Inflammatory Cytokines are Associated with Lower Trabecular Bone Score at the Lumbal Spine in Postmenopauzal Women5 – explored the relationship between circulating inflammatory mediators and various measures of bone health, including bone density, geometry and strength. The study was conducted to establish the relationship between inflammatory mediators and bone outcome at baseline in women enrolled in the randomized controlled parent study (described below) prior to the pruning intervention.
“Evidence from several observational studies suggests a link between chronic inflammation and osteoporosis and fracture risk. Looking at postmenopausal women, we began our research by examining the relationship between biomarkers of inflammation and bone. This helped us establish a baseline prior to a prune dietary intervention,” said co-investigator, Dr. Connie Rogers, PhD, MPH, professor and head, Department of Nutritional Sciences, University of Georgia.
The findings indicate that higher levels of inflammation markers were associated with lower trabecular bone scores at the lumbar spine in the study participants — essentially, the more inflammation, the worse the bone health.
“Our findings demonstrate that inflammatory markers are negatively associated with bone health in postmenopausal women, suggesting that inflammation may be an important mediator of postmenopausal bone loss and a potential target for nutritional therapies,” Rogers said.
Intervening with nutrition: the “pruning effect” on bones
Also conducted at Penn State, the Parent Clinical Study – Prunes Preserve Cortical Bone Density and Estimated Strength in a 12-Month Randomized Controlled Study in Postmenopausal Women: The Prune Study6 – evaluated the influence of 50 g (5-6 prunes)/day and 100 g (10-12 prunes)/day on volumetric bone mineral density (vBMD), bone geometry and estimated bone strength during a 12-month dietary intervention. The study participants were the same as those evaluated in the Penn State inflammation study discussed above.
Treatment groups among the study participants were evaluated as follows: control (no prunes), 50 g (5-6 prunes)/day, 100 g (10-12 prunes)/day and a pooled group, representing the combined group of women who ate five to six or 10-12 prunes a day.
“We previously showed that consuming 5-6 prunes per day for 12 months resulted in preservation of bone at the total hip level, a finding that was observable at six months and persisted through month 12. In this second part of the randomized controlled trial, 3D bone imaging provided additional information on bone’s response to prune consumption on a daily basis,” said lead researcher, Dr. Mary Jane De Souza, PhD, FACSM, Distinguished Professor and Director of The Women’s Health and Exercise Lab, Pennsylvania State University.
De Souza’s latest findings indicate that consumption of plums preserves vBMD and strength at weight-bearing tibial sites that are primarily cortical sites.
“We found that the pooled group of women experienced some bone benefits. Specifically, estimated bone strength at the tibia was maintained in the pooled group and cortical volumetric bone density was maintained in the groups of 5-6 plums per day and 10-12 plums per day. As such, it appears that prunes may help prevent bone loss, especially in the hip and shin,” said De Souza.
Specific additional results include:
- The estimated strength-elongation index (SSI) was evaluated in the 14% diaphyseal tibia for control versus pooled groups and the estimated strength was reported to decrease in the control group from baseline to 12 months, but not in the combined plum group.
- Cortical vBMD was evaluated in control group versus 100g plum groups, and it was reported that in the 14% diaphyseal tibia, cortical vBMD decreased in the control group from baseline to 12 months, but did not change in the 100g group.
- In the 38% diaphyseal tibia, total vBMD was evaluated and total vBMD was reported to decrease in the control group from baseline to 12 months, but not in the 100g group.
The abstract results are being prepared for expected publication in Menopause: The Journal of The North American Menopause Society, December 2022. Full papers are pending.