Conventional approach to the therapy of osteoporosis has its drawbacks, hence various alternative substances are tested for their beneficial effects on bone metabolism. As soya isoflavons seem to lose their strong position in prevention of osteoporosis (1), the search for other plant-derived agents continues. Researchers from the Florida State University have been examining the healing potential of prunes for many years. They have just published their latest study (2), which suggests that enriching a diet with dried plums results in the increase of bone mineral density (BMD).

As it was first discovered by Muhlbauer et al., a diet consisting of high amounts of vegetables and fruit has a positive influence on bone density (3). Of all the products, dried plum seems to have the most promising properties (4). Women after menopause are susceptible to rapid bone loss and prunes not only prevent the bone loss, but also reverse the changes that have already taken place. It happens presumably by inhibiting bone resorption. More importantly, the unique characteristics of dried plum enhance the microstructure of bone, supporting the number and architecture of trabeculae. Primary studies confirmed that the consumption of dried plums by postmenopausal women improved the bone turnover markers, but longer-term trial was needed to fully assess the bone-protective effects of prunes.

Scientists from Florida conducted a 1-year prospective randomized trial to examine the effects of daily consumption of prunes on BMD. Women 1-10 years postmenopausal were recruited, as long as they were not on hormone replacement therapy for at least three months or did not take any medication known to change the bone metabolism. Heavy smokers and chronic disease sufferers were excluded. The subjects were advised to maintain their ordinary physical activity and diet. Participants were randomly assigned to one of the two dietary groups – 100g dried plum and 75g died apple as a control. Every woman received 500mg calcium and 400 IU (10mg) vitamin D daily. Bone density was assessed by means of densitometer at the beginning of the trial and at the end.

100 women completed the study, of which 55 were assigned to eating dried plum. It turned out that both diet regimens had bone-protective effects, which was manifested by positive changes of BMD from the baseline. However, as expected, dried plum had more distinctive outcomes. After one year the gain in BMD for ulna and spine was significantly higher in dried plum group than in the dried apple regimen. What is interesting, dried plum was able to lower the serum concentration of C-reactive protein (CRP). It was dropping until the end of the third month of the trial and then remained on the same level.

The mechanisms of how fruit and vegetables enhance bone metabolism remains unclear. A shift in the acid-base balance is a candidate for potential mechanisms. Nonetheless, some studies suggest that high content of vitamin C and K (5) are responsible for bone protection. Dried plums are also exceptionally rich in phenolic compounds such as chlorogenic acid (6), which act as antioxidants and possibly scavenge free radicals responsible for bone loss (7). Apart from that dried plums seem to contain more boron and there have been reports that this element modulates calcium metabolism, hormone balance and in this way can affect BMD (8). The suppression of chronic inflammation, indicated in the prunes lowering of CRP, may also play role in the whole story. Summing up, it seems that plums are particularly beneficial for postmenopausal bone loss because of their unique content of various agents, which all lead to the decrease of the rate of bone turnover.

We shall remember that osteoporosis does not exclusively concern women, but men after 65th year of age also start to lose their bone density. “Don’t wait until you get a fracture or you are diagnosed with osteoporosis”, warns Bahram H. Arjmandi – the co-author of the trial and chairman of the Department of Nutrition, Food and Exercise Sciences in the College of Human Sciences, ”Do something meaningful and practical (…), start eating two to three dried plums per day and increase gradually to perhaps six to ten per day” (9). Results guaranteed.

Written by: Natalia Neumann

Source:
1.“Soy fails to alleviate menopause symptoms.” Natalia Neumann, MedTube Tribune, http://medtube.net/tribune/soy-fails-to-alleviate-menopause-symptoms/
2.Shirin Hooshmand, Sheau C. Chai, Raz L. Saadat, Mark E. Payton2, Kenneth Brummel-Smith and Bahram H. Arjmandi. Comparative effects of dried plum and dried apple on bone in postmenopausal women. Br J Nutr. 2011 May 31:1-8.
3.Muhlbauer RC, Lozano A, Reinli A, et al. (2003) Various selected vegetables, fruits, mushrooms and red wine residue inhibit bone resorption in rats. J Nutr 133, 3592–3597.
4.Hooshmand S, Arjmandi BH.Viewpoint: dried plum, an emerging functional food that may effectively improve bone health. Ageing Res Rev. 2009 Apr;8(2):122-7
5.Iwamoto J, Takeda T & Sato Y (2004) Effects of vitamin K2 on osteoporosis. Curr Pharm Des 10, 2557–2576.
6.Nakatani N, Kayano S, Kikuzaki H, et al. (2000) Identification,quantitative determination, and antioxidative activities of chlorogenic acid isomers in prune (Prunus domestica L.). J Agric Food Chem 48, 5512–5516
7.Basu S, Michaelsson K, Olofsson H, et al. (2001) Association between oxidative stress and bone mineral density. Biochem Biophys Res Commun 288, 275–279.
8.Nielsen FH, Hunt CD, Mullen LM, et al. (1987) Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women. FASEB J 1, 394–397.
9.http://www.sciencedaily.com/releases/2011/08/110818093048.html

Want to know more about bone physiology? Watch on medtube.net: “Cancellous Bone Growth”