For years, calcium was lauded as the cure for aging bone loss. Move over calcium, dried plums are here to stay.
Dried plums – also referred to as prunes – are tasty and healthy. Plums are delicious fruits when eaten fresh and they are also good dried.
Prunes or dried plums have many benefits, including providing a laxative effect – something they are quite famous for.
New research continues to confirm that dried plums have an exciting and unexpected effect upon mature women: It reverses bone loss.
In a 2016 study published in the Osteoporosis International journal, researchers from Florida State University and San Diego State University tested 48 women who had osteopenia – severe bone loss, – indicated with bone mineral density testing.. The women were between 65 and 79 years old.
The women were randomly divided into three groups. For six months, one group ate 50 grams of dried plums per day. Another group ate 100 grams of plums a day. The third group was a control group.
After the six months, the researchers found that the two plum groups stopped losing bone density. Meanwhile, their TRAP-5b levels (a marker for bone resorption) was significantly decreased. The researchers stated:
“These results confirm the ability of dried plum to prevent the loss of total body BMD in older osteopenic postmenopausal women and suggest that a lower dose of dried plum (i.e., 50 g) may be as effective as 100 g of dried plum in preventing bone loss in older, osteopenic postmenopausal women. This may be due, in part, to the ability of dried plums to inhibit bone resorption.”
Bone mineral density increased by dried plums
In 2014, researchers from San Diego State University and Florida State University studied 160 postmenopausal women for a year. They were all osteopenic.
The women were split into two groups. They were all measured for bone mineral density. One group ate 100 grams of dried plum each day for a year. The other group ate 75 grams of dried apples for a year. Both groups also supplemented with 500 milligrams of calcium with 400 IU of vitamin D per day.
After the year was up they were tested again. The researchers found that the group that ate the dried plums each day had significantly increased bone mineral density compared with the control group: Who also took the calcium/D plus dried apples.
Changes in bone loss chemicals
The researchers also tested the mechanisms of bone loss among the subjects. They found that the biochemical called osteoprotegerin was significantly increased. Osteoprotegerin is known to halt the process of bone loss. The women who ate the dried plum had double the levels of osteoprotegerin compared to the apple group.
The researchers also found that levels of RANKL – or NF-kB a receptor stimulator – were increased. And sclerostin levels in the blood – which are linked with hastened bone loss – were dramatically reduced in the dried plum group. The apple group had triple the levels of this bone loss trigger compared to the dried plum group.
Other research confirms dried plums’ bone loss suppression
The researchers divided 236 post-menopausal women into two groups. For twelve months, one group ate 100 grams of dried plums per day and the other group ate 100 grams of dried apples per day. This was in addition to their normal diets plus a standardized supplementation plan for both groups – 500 milligrams calcium and 400 IU of vitamin D per day.
Before the trial, every three months and after the twelve-month period, the women were tested for bone strength, physical activity, blood levels of bone density and bone turnover markers along with other signs of bone health.
The researchers found that all the biomarkers and tests indicated that the dried plums significantly suppressed bone loss. The research found that alkaline phosphatase and tartrate-resistant acid phosphatase-5b levels were significantly lower, for example. These indicate a slower turnover of bone minerals and reduced bone loss.
The research was led by Dr. Bahram Arjmandi, Professor and Chair of Florida State’s Nutrition, Food and Exercise Sciences Department.
“Dried plums are the most bone-friendly fruit that I have seen in decades. They are nature’s solution to maintaining good bone health,” said Dr. Arjmandi. “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 have.”
Plums contain a variety of nutrients, including bone health-promoting vitamin K, potassium, copper and boron. According to Dr. Arjmandi, these work synergistically to prevent bone mineral loss, which can lead to osteoporosis.
Dr. Arjmandi has also found that California plums seem to provide some of the best nutrient levels. “Incorporating California dried plums (prunes) into holiday recipes is a step in the right direction. After people start cooking with and snacking on them they love the taste. The good news is they are good for you.”
Other research shows bone loss reversed with prunes
Another study confirming dried plum’s ability to reverse bone loss comes from Oklahoma State University. While certainly mice have different metabolism from humans, mice also have bones and as they age they will also have bone loss. The researchers studied mice who were post-menopausal. The mice were given either a control diet or a diet supplemented with either plumes or other dried fruits.
For eight weeks, those mice given dried fruit were given prunes, dried mango, dried apple or dried grape.
Only the prune diet prevented bone loss among the mice.
The researchers also found that the prune diet also reversed bone loss among the aging female mice. The researchers found:
“[Plum’s] ability to down-regulate osteoclast differentiation coincident with up-regulating osteoblast and glutathione (GPx) activity. These alterations in bone metabolism and antioxidant status compared to other dried fruits provide insight into dried plum’s unique effects on bone.”
Another study found that fructooligosaccharides (FOS) – a prebiotic nutrient found in bananas, chicory root, garlic, wheat, barley, leeks, onions and other foods – along with the dried plums and a soy-based diet was successful in reversing bone loss in animal research.
What’s the difference between prunes and dried plums?
California produces 99% of the dried plums consumed in the United States and 48% of the world’s supply of dried plums.
What is the difference between dried plums and prunes? Only the name. In 2000, the U.S. Food and Drug Administration accepted a new identity standard – changing prunes to dried plums – a more accurate description.
Vitamin D from the Sun
The other critical element for bone health is suggested by the supplement plan of some of the Florida State research: Vitamin D.
Vitamin D is critical to bone health and this has been proven in numerous studies. Areas where there is an insufficiency in UVB exposure suffer higher levels of bone loss and fractures.
Studies have found that more people break bones in the wintertime. While some figure this caused by more snow and ice activity, it also appears to have a lot to do with the fact that wintertime avails less UVB exposure and thus less vitamin D.
Vitamin D supports hormone metabolism and bone mineralization processes. Serum 1,25-dihydroxyvitamin D in itself does not reduce fractures, but it stimulates the maturation of osteoblasts and osteoclasts while inhibiting proliferation of osteoblasts. This produces higher levels of bone mineralization, inclusive of calcium and phosphorus.
Learn more about healthy sun and the best form of vitamin D.
Other strategies for reducing bone loss
In addition to dried plums, researchers are increasingly finding that diets rich in plant nutrients (phytonutrients) have the effect of reducing and even reversing bone loss. A review of research from Switzerland found that consuming polyphenols helps prevent bone loss, including those from tea, grape seed, citrus fruits and olives in addition to dried plum. They also found that the Mediterranean diet – a diet that maintains a significant amount of plant foods along with olive oil and tomatoes – apparently helps prevent bone loss as well.
Researchers from Texas Tech University also found in their research that phytonutrients provide the best strategy to prevent bone loss among post-menopausal women. The researchers found that phytonutrients such as pectin, lycopene, flavonoids, resveratrol, phenolics and phloridzin – nutrients that are contained in many fruits as well as tomatoes, contribute to preventing bone loss among aging women.
Vitamin D and calcium certainly should not be left out of the equation. But the San Diego State study did illustrate that the effectiveness of at least supplemented vitamin D with calcium had nowhere near the effects of dried plums. Plus, recent research brings into question the safety of consuming too much supplemental calcium. Calcium supplementation has been linked to increased risk of cardiovascular conditions.
Consistent with these points, a 2016 study from Australia’s University of Wollongong conducted a meta-analysis of 73 studies on plums. The researchers concluded:
“Plums have been shown to possess antioxidant and antiallergic properties, and consumption is associated with improved cognitive function, bone health parameters and cardiovascular risk factors.”
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Adams C. Healthy Sun: Healing with Sunshine and the Myths About Skin Cancer. Logical Books, 2009.
Case Adams is a California Naturopath and a Board Certified Alternative Medicine Practitioner with a PhD in Natural Health Sciences, and diplomas in Homeopathy, Aromatherapy, Bach Flower Remedies, Blood Chemistry, Clinical Nutritional Counseling and Colon Hydrotherapy. He has authored 26 books on natural healing strategies.