Prunes are the latest in a long line of foods linked to health benefits, in this case maintaining healthy bones after the menopause. At Florida State University, Professor Bahram Arjmandi and his team have been looking at the effects of prunes in ovariectomised rats, a well-established model of post-menopausal bone loss. They found that even at low levels of dietary intake, the dried prunes not only gave substantial protection against bone loss, but also led to improved bone structure (Deyhim et al ’05).

This is an exciting finding, and in a follow-up study (Franklin et al ‘06), the scientists discovered that the prunes were probably doing this via a dual mechanism; simultaneously slowing the erosion of bone and stimulating its growth, thereby shifting bone into so-called anabolic dominance. (See Slowing the Ageing Process on this site)

Having previously shown that prunes improved bone biomarkers in humans, the team is now going all out to discover whether 10 prunes a day can prevent post-menopausal bone loss, and a major clinical trial is already under way. They expect great things. Referring to the animal study, Professor Arjmandi said, "I've never seen results that were more consistent. If the findings from our human trial are similarly positive and reproducible, many women will want to modify their lifestyle and dietary practices in order to prevent fracture due to osteoporosis.”

There is, however, a slight problem with the trial design. Women in Arjmandi’s control group will receive an equivalent amount of dried apple, a heart-healthy fruit known to help reduce plasma levels of cholesterol and triglycerides. This group, however, will probably find that their bones are improved too, as apple extracts have also been shown to protect against bone loss (Puel et al ’06). This is not really surprising, as apples – like prunes – contain flavonoids, considered to be the active compounds. So in the Florida trial, it seems very likely that both the prune and the apple eaters will end up with better bones!