“Over my career, I have tested numerous fruits, including figs, dates, strawberries and raisins, and none of them come anywhere close to having the effect on bone density that dried plums, or prunes, have. All fruits and vegetables have a positive effect on nutrition, but in terms of bone health, this particular food is exceptional.
Dried plum(s) significantly increased bone mineral density of the ulna & spine in comparison with dried apples.
In comparison with corresponding baseline values, only dried plum(s) significantly decreased serum levels of bone turnover markers, including bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase-5b.
The findings of this present study confirm the ability of dried plums(s) in improving bone mineral density in postmenopausal women in part due to suppressing the rate of of bone turnover and bone resorption."
-Bahram H. Arjmandi, Florida State’s Margaret A. Sitton Professor and chairman of the Department of Nutrition, Food and Exercise Sciences in the College of Human Sciences.
Hooshmand, S et al "Comparative effects of dried plum and dried apple on bone in postmenopausal women," British Journal of Nutrition 106(6):923-30, September, 2011. Epub 2011 May 31.
First it was calcium. Then it was weight-bearing exercise. Then it was vitamin D. And yes, it's still all of these (though less calcium lately)--but now there's a new kid on the bone mineral density block.
Now, consider the dried plum (formerly known as "the prune") for a boost in your bone health!
Yes, there's always that "back-up plan" of drug options--the bisphosphonates & raloxifene, if all else fails.
But, now there's a serious suggestion by the FDA of a five-year limit on drug therapy--or at least taking a recommended "drug holiday". Stay tuned for revised drug labeling in November 2011. Read more here.
According to the FDA, between 5.1 million and 5.7 million patients in the United States have received prescriptions for the drugs for each of the years 2005 through 2009.
Earlier this month (September 2011) an FDA staff report said there was no advantage of taking the popular bone drugs of Boniva, Actonel, and Fosamax for more than five years.
“These results suggest no significant advantage of continuing drug therapy beyond 5 years,” according to agency’s 45-page review of scientific evidence.
As for side effects, the report said, there is no solid evidence the drugs, called bisphosphonates, cause unusual breaks of the femur bone, a jaw injury called osteonecrosis, or esophageal cancer. At the same time, the agency said, those rare but dangerous outcomes cannot be ruled out because it has been so difficult to study them for various reasons.
“The safety of long-term bisphosphonate therapy continues to be unclear as study results are conflicting,” according to the F.D.A. report. Duff Wilson, "FDA Staff: 5 Years May Be Enough for Bone Drugs," New York Times, September 7, 2011.
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Meet the Dried Plum!
Looks like perfect timing to consider adding prunes to your diet and take a careful look at Hooshmand's & Arjmandi's new research.
I couldn't wait to look at this study--and I admit that I'm a rank amateur--but, I'm impressed with the results of their well-designed study. These researchers have been analyzing the effects of dried plums on bone strength for years in their lab--first in animals, and then in humans.
In 2002 they even ran a short-term 3 month prune study on women, which had positive outcomes. (click here) And they've also pored over years of published research by other scientists on the effects of nutrients & prunes on bones.
Best of all--they provide detailed explanations of how it is possible for the lowly prune to physiologically make bones stronger. Now even I get it!
The Florida State & Oklahoma State University Postmenopausal Bone Study Explained - Dried Plums Face-off Against Dried Apples
Who was in this study?
100 postmenopausal women completed the study over a period of 12 months. No one was on bone medications, anabolic agents, steroids, or any drugs that can alter bone or calcium metabolism. Women with metabolic bone disease, other chronic diseases, or heavy smokers were excluded. Anyone who regularly ate prunes or prune juice could not participate. No one had a BMD t-score at any site below 2.5 sd of the mean.
What did the participants have to eat?
Fifty-five women were in a treatment group (and completed the study) that was assigned to consume 100 grams of prunes a day--that's about 10 prunes--for 12 months. "Because of the known laxative properties of dried plums, the participants were asked to gradually incorporate the plums into their diet."
Note: One HHLL reader took an early test-drive of the prune regimen, but made the mistake of eating 10 prunes all at once--and suffered the consequences. Her physician recently told her to go off of Fosamax--since she'd been on it for over 5 years. She was highly motivated to keep her bones strong, and eating prunes seemed like a good plan, so, after her initial "faux pas" she figured out an easy way to consume the 10 prunes--just space them out--eating about one an hour works well for her, and she loves the taste!
Forty-five women were in a second treatment group (and completed the study) that was assigned to consume 75 grams of dried apples--which have an equivalent amount of calories, carbohydrates, fat, and fiber--as the dried plums.
Both groups also took 500 mg of calcium, plus 400 IUs of vitamin D.
Compliance was high--at 82%--the same for the apple & dried plum groups. The women liked the prunes.
How was the study designed? What did the researchers measure?
Physical measurements: At the study's start everyone had medical, nutritional, & physical activity histories taken. Height & weight was measued at the start, and at 3, 6, and 12 months.
BMD measurements: Bone density was measured at the start--and at the end of the treatment with dual-energy x-ray absorptiometry--and the whole-body, lumbar spine, hip & forearm BMD's were all measured.
Bone marker measurements: Blood samples to measure biomarkers of bone turnover were taken from everyone at the start, and at 3, 6, and 12 months. Here's what the researchers looked at:
- The markers of bone turnover: bone-specific alkaline phosphatase (BALP), osteocalcin (OC)
- The markers of bone resorption: tartarate-resistant acid phosphatase-5b (TRAP5b)
- The marker of inflammation: C-reactive protein (CRP) was taken to determine the potential anti-inflammatory role of dried plums in modulating bone metabolism
Who won? The Apples or the Plums? And, the envelope, please!!
- Both fruits were palatable, and the "dosage" was easy to adhere to.
- Both groups were still eating the same amount of food at the start of the study, as they were throughout the study, yet, remarkably, no one gained weight, in spite of the additional calories.
- Both dried fruit groups experienced bone-protective effects based on the positive changes from baseline in the ulna, spine, femoral neck, total hip, and whole-body BMD.
- The dried prune group had more significant increases in the BMD of the ulna & spine--compared to the dried apple group.
- The dried plum group had a significant reduction in the markers of bone turnover (a good thing!), compared to the dried apple group. The reduction in these markers helps to explain how dried plums improve the BMD of post-menopausal women, in part, due to slowing down the rate of bone turnover.
- The dried plum group had a significant decrease in the marker of bone resorption (a good thing!) at 3 months and it remained the same through the end of the study. The dried apple group didn't change much over the course of the study--but it increased at the 12 month mark (not a good thing!)
- The inflammation marker (CRP) decreased (a good thing!) in the plum group after 3 months--and remained the same until the end of the study. In the apple group, the CRP was the same after 3 months, and decreased thereafter--ending up insignificantly higher than the plum group.
What Ten Prunes a Day Can Do for Your Bones and the Reasons Why It Works
- Bone density increased. Ten dried plums a day (100 grams) eaten daily for 12 months showed increases over baseline in the bone mineral density of the ulna, spine, femoral neck, total hip, and whole-body. Both the prune & dried apple groups showed similar bone density improvements in the neck of the femur and the total hip.
- Ulna & spine. The dried plum group showed significant increases of the ulna (long bone of the forearm) & spine compared to the dried apple group. According to the authors, "These findings suggest that dried plum is particularly effective in reducing the risk of fracture in the ulna & spine as indicated by the higher BMD in these sites."
- No bone loss. None of the women in the study lost any bone--whether they were eating dried apples or prunes.
- The earlier animal studies. Earlier animal studies strongly suggest that dried plums have a potent effect on preventing & reversing bone loss as "evident by the higher bone densities, [higher] mineral contents, [increased] percentage of the trabecular bone area (this is the all-important lattice-like network of struts that supports our bones & women can lose up to 50% of this type of bone-read more here), and the tendency to reduce marrow space in the long bones in rats."
- Bone biomarker improvements. Bone mineral density biomarkers found in the blood also showed improvement after 12 months. According to Arjmandi, this is due in part to the ability of dried plums to suppress the rate of bone resorption, or the breakdown of bone, which tends to exceed the rate of new bone growth as people age.
- No weight gain. Although the women consumed about 200 calories worth of prunes a day, neither their weight nor BMI increased--perhaps due to the increased fiber content of the prunes--about 6-7.1 grams of fiber.
- The vitamin C, K, boron, & phytochemical connection to bone health. Prunes are high in the antioxidant compounds of neochlorogenic and chlorogenic acids (click here) that scavenge potentially damaging free radicals. Previous studies have shown this action helps to prevent bone loss. Click here & here. Prunes have higher amounts of boron than most fruits--and "boron modulates bone and calcium metabolism, and plays an important role in preserving BMD." Click here. And prunes have high amounts of vitamin K which influences bone health by improving calcium balance & promoting normal bone mineralization.
- Dried plums may improve bone mass by slowing down the rate of bone turnover. The authors speculate that dried plums may improve bone health by suppressing the rate of bone resorption more so than the rate of bone formation. However, this can only be shown through bone biopsies.
- Dried plums reduce inflammation--perhaps another reason why they improve bone. The dried plums in this study significantly reduced the C-Reactive Protein (CRP) levels (a measure of inflammation) after 3 months--and this improved level was maintained, thereafter. A high CRP is linked to a number of chronic diseases, including osteoporosis. Click here.
Full Disclosure & Author Acknowledgements: This study was supported by the National Research Initiative of the USDA Cooperative State Research, Education & Extension Services, grant #2005-35200-17053. The California Dried Plum Board provided the dried plums, & Bayer Healthcare supplied the calcium & vitamin D supplements. There are no conflicts of interest.
Nutritional Data for a Ten-Prune Serving
Serving Size: 10 prunes
|Amount Per Serving|
Potassium: 732 mg
Boron: 3 mg
Magnesium: 41 mg
Vitamin K: 59.5 mdg
Dr. Bahram H. Arjmandi and a Study Participant Discuss the Study (1:46 minutes)
Please click here if you don't see the video.
Want Even More Evidence of the Benefits of Dried Plums?
First off--just take a look at Dr. Arjmandi's extensive bibliography!
These highlights come for Pamela Durkin, a registered nutritional consultant and freelance journalist living in Victoria, Australia. Source: Alive Magazine #342, April 2011 A HHLL sent it to me.
- Prunes are a natural laxative because they're high in insoluble fiber, which helps them to absorb water. They also contain "a compound called dihydroxyphenyl isatin, which stimulates the intestine, causing it to contract." Good reason NOT TO EAT 10 prunes at one time!!!
- Prunes also contain soluble fiber which helps to lower cholesterol.
- It's loaded with potassium which helps to lower blood pressure.
- It contain phenolic compounds (neochlorogenic and chlorogenic acids) that help to inhibit the oxidation of LDL cholesterol.
- It's high in boron which helps to regulate mineral metabolism, optimize estrogen levels, & increase calcium absorption.
- Boron helps to convert vitamin D to its active form, which helps the osteoblasts utilize calcium for bone formation.
- Prunes are loaded with disease-fighting carotenoids like beta-carotene, lutein, & zeaxanthin, as well as anthocyanins, proanthocyanins, and phenols. No surprise that they have a higher ORAC (measure of antioxidant activity) than blueberries---clocking in at 8,059 for a 100 gram serving--which is exactly the 10 prunes that Dr. Arjmandi is recommending. The blueberry measures in at 4,669.
Learn more from Pamela Durkin by following the link to her article.
It's not often we see such a provocative study about a functional food. I've never considered eating prunes before reading this study--but I'm definitely going to give them a try! Full disclosure: I haven't started yet.
HHLL reader "Teacher Fan" gives them a big thumbs up. Just take her advice--space them out over the day. She now keeps a bag in her purse to munch on throughout the school day.
For more on the ongoing controversies about bone health, osteopenia, and prescription bone meds, see below:
What's the Best Way to Treat Osteopenia? Diet, Vitamin D, Calcium, Drugs Like Bisphosphonates, or Weight Training? Check Your Fracture Risk with the W.H.O. FRAX Tool to Help You Decide
NPR's Award-winning broadcast: How A Bone Disease Grew To Fit The Prescription, (a must read!) by Alix Spiegel
Reconsidering Calcium Supplements - What the Experts Say about Bone Health, Calcium Requirements, Dairy, and Strength Training
And, HOT OFF THE PRESS, from HHLL reader, Tom. Wall Street Journal, September 20, 2011, "Yes, You Are Getting Shorter," by Melinda Beck One more good reason to add dried plums to the menu!
OK, HHLL readers, please weigh in with your opinions! Does this sound too good to be true---or worth a try?