Florida State University's Professor Bahram Arjmandi is leading a randomised clinical trial to examine the effects of prunes or dried apples on the bone mineral density of post-menopausal women, an age-group at highest risk of osteoporosis.
The work follows Arjmandi's 2004 female rat study from his time at Oklahoma State University, that reported a diet supplemented with dried plums produced significant restoration of bone mass.
"I've never seen results that were more consistent," said Prof. Arjmandi. "If the findings from FSU's human study are similarly positive and reproducible, they could help researchers isolate the compounds responsible."
And this could mean opportunities for supplements, suggested Arjmandi, despite noting that eating the fruit itself is the best way to benefit from the potent, concentrated plant-based chemicals such as polyphenols.
"Many women prefer to modify their lifestyle and dietary practices in order to prevent fracture due to osteoporosis," he said.
Osteoporosis is estimated to affect about 75m people in Europe, the USA and Japan. According to the International Osteoporosis Foundation, the total direct cost of osteoporotic fractures is €31.7bn in Europe, and 17.5bn in the US (2002 figure). The total annual cost of osteoporosis in the UK alone is over £1.7bn (€2.5bn), equivalent to £5m (€7.3m) each day.
The FSU researchers have randomly assigned their post-menopausal recruits to receive either a daily supplement of 100 grams of prunes (approximately nine or ten fruit) or an equal amount of dried apples. The trial does not include a placebo group.
"Our FSU research is unique in that all participants, women between two and 10 years postmenopausal, can hope to potentially benefit in some manner," said Arjmandi in a release.
"During this 12-month investigation, half the women will supplement their daily diets with nine to ten dried plums, totaling 100 grams. The other half will consume a comparable portion of dried apples, which also have known health benefits. For instance, several studies indicate that a daily helping of pectin-rich apples can help lower triglycerides and cholesterol levels," he said.
Women in both intervention groups will also receive daily supplements of calcium (500 milligrams) and vitamin D (200 international units, IU) and will undergo blood and urine tests every three months. Bone mineral density measurements were taken at baseline and will be taken again at the end using dual-energy X-ray absorptiometry, or iDXA, said to be the latest in whole-body scanning technology.
iDXA (or intelligent DXA) is the newest in the bone densitometry technology, capable of measuring both bone and body composition (fat and lean tissue) with higher precision, accuracy and speed than any of the previous DXA models.
It is said to be able to accommodate heavier patients (up to 400 lbs) and measure their bone and body composition accurately, which was not the case with the previous models.
"Given its rapidly growing and aging population, the state of Florida has been an ideal location for this research," said Arjmandi.
Plans for further studies have already begun, he confirmed. "Currently, my colleagues and I are preparing a major proposal for the National Institutes of Health that exceeds $1.5 million, which would enable a longer, more extensive dried plum investigation in both male and female animal models of osteoporosis."