The Peculiar Bone-Healthy Fruit
“Eat your prunes!” has been the refrain of caring grandmas through the ages. Grandma was probably thinking of your digestive health, but recently prunes have been in the news for a different reason. A Florida State University study led by Shirin Hooshmand and Bahram H. Arjmandi claims that prunes are “the most effective fruit in both preventing and reversing bone loss.”1
What’s so Peculiar About Bone-Healthy Prunes?
While it’s true that studies have shown prunes to be more effective at increasing bone density when tested against figs, dates, strawberries and raisins, it’s important to look at why this is so, and whether there something in prunes that can’t be found in other fruits. And the answer is: NO.
Ironically, plums – and by extension prunes – are one of the few fruits that contain small amounts of oxalates, a substance that can bind to calcium, thus making it less bioavailable. Blackberries, blueberries, raspberries, strawberries, currants, kiwifruit, concord (purple) grapes, figs, and tangerines also contain oxalates in small quantities – small enough to ignore as it relates to calcium absorption.
As I wrote in Vivian Answers Day #5, prunes were found to decrease bone loss in animals due to their high concentration of polyphenols (a class of antioxidants). In the Save Our Bones Program, I discuss the importance of polyphenols to bone health and the fact that these plant pigments have been shown to increase the production of osteoblasts.
The Story Behind the Story
Are prunes a miracle food for bone health? When we look a little closer, it’s actually rather amusing that the one fruit used to study the effect of polyphenols on bone health happens to be acidifying. Especially when there are so many alkalizing fruits and vegetables that are rich in polyphenol content.
Unfortunately, mainstream science all too often takes a reductionist view and seems unable to see the forest for the trees (or the fruit salad for the pitted prunes). They focus on objects in isolation without looking at the larger picture.
In this instance, well-meaning scientists took components of one fruit and studied its effect on bone density, ignoring that prunes are not unique in their micronutrient composition, but are unique in that there are only a handful of fruits that are acidifying. So it’s important to dig a little deeper, find the ‘active’ substance in prunes, and then search for that very same beneficial ingredient in a broad range of foods.
What’s the ‘Take-Away’?
The bottom line is that polyphenols are definitely an important component of bone health, and the studies on prunes served to highlight this.
But you would be much better served by choosing one of the many alkalizing fruits or vegetables that contain the same beneficial polyphenols found in prunes. Of course, if you really love prunes, you can continue to have some – as long as you pay attention to the acid-alkaline balance, nothing is off limits on the Save Our Bones Program.
Best Sources of Polyphenols
The highest levels of polyphenols are found in green tea. Unfortunately, green tea (and all leaf teas, especially decaffeinated) is high in fluoride, and thus can end up doing more harm than good. If you’d like to get the health benefits of green tea without the fluoride, check out Vivian Answers Day #12, where I talk about an organic green tea extract that’s free of toxic pesticides and fluoride.
Fortunately, polyphenols are also present in a wide variety of fruits and vegetables.
- Although alcohol and chocolate are acidifying, I’m sure you’ll be happy to know that red wine (thanks to its high concentration in the skin of red grapes) and chocolate contain polyphenols.
- Alkalizing pomegranate juice, typically available in most supermarkets, is a refreshing drink that’s rich in polyphenols and other antioxidants.
- Among fruits, apples, blackberries, cantaloupe, cherries, grapes, pears, pomegranates, raspberries, and strawberries are polyphenol superstars.
- In the vegetable category, broccoli, cabbage, celery, onions, and parsley take the lead.
Organic is always preferable. By eating organic produce as much as possible you will of course minimize your exposure to toxic, acidifying pesticides. But in addition to that, as a general rule, organically grown crops have significantly higher levels of polyphenols, as well as magnesium, iron, and vitamin C.
Variety is Not Only the Spice of Life…
It’s also critical to your bone health! Another element that tends to get lost when one food is proclaimed as “the answer” is the importance of variety. If you think you must eat prunes every day, for example, you miss out on the wide variety of nutrients you get be eating a more varied diet.
Hundreds of polyphenols have been found in fruits and vegetables. The best way to cover your bases and get a full range of polyphenols and other nutrients is to eat a varied diet.
So instead of telling kids and grandkids to eat their prunes, let’s start saying, “Eat your apples, and broccoli, and cantaloupe, and pomegranates, and …” It’s a bit of more of a mouthful, but a very tasty one!
1 Shirin Hooshmand, Bahram H. Arjmandi. “Viewpoint: Dried plum, an emerging functional food that may effectively improve bone health”. Ageing Research Reviews 8(2009) 122-127