Prunes have had a bad image as an unpalatable, medicinal food for the elderly and at best are seen as a natural laxative. But prunes—increasingly referred to as dried plums to boost their appeal—can provide a number of benefits to our health, according to recent studies, potentially reducing the likelihood of colon cancer and osteoporosis and helping with weight loss.
Studies from Florida State University, published in the British Journal of Nutrition, showed that prunes helped reverse bone loss in rats subjected to treatments that produced osteoporosis. In a human study, post-menopausal women were each given 100 grams of prunes per day (about 10 prunes) and a comparison group was told to consume 100 grams of dried apples. After 12 months, the group eating the prunes had significantly higher bone mineral density in the ulna (an arm bone) and spine. Authors of the study said that prunes can suppress bone breakdown, which tends to exceed new bone growth as people age. This effect may be due to high levels of the mineral boron in prunes. Other foods high in boron are plums, grapes, avocados, almonds and peanuts.
Research from Texas A&M University and the University of North Carolina has shown that prunes can positively affect gut bacteria (the microbiome) and help to reduce the risk of colon cancer. There are trillions of bacteria in the intestinal tract—more than 400 individual species have been identified—and disruptions to this microbiome can cause intestinal inflammation, which can promote the development of colon cancer. Prunes contain antioxidant compounds that can neutralize free radicals that damage DNA. In a rat study on precursors to colon cancer, rats fed with prunes (and their regular chow!) showed significantly reduced numbers of precancerous changes in the intestinal walls compared to a control group.
Research by the University of Liverpool found that eating prunes as part of a weight loss diet helped in weight control. One hundred overweight or obese men and women were tested for 12 weeks. Half the subjects were given about 14 prunes per day along with their diet, and the other half got advice on healthy snacks. (Both diets contained an equal number of calories.). The group that ate prunes lost 4.4 pounds and an inch from their waist. The control group lost 3.5 pounds and 0.7 inches from the waist. The group eating prunes also experienced greater feelings of fullness during the diet.
And prunes, of course, are well known for their ability to help with constipation. This is due to their fiber and high sorbitol content, which retains fluid in the intestines. Sorbitol is a natural sugar found in many fruits. It is metabolized relatively slowly, so that prunes do not cause a rapid rise in blood sugar. Many people with diabetes can eat them in moderation, and they are a safe laxative for most people (but check with your health care provider).
Despite this dried fruit’s reputation, the benefits listed in this column will hopefully encourage more people to start eating prunes, even if some might decide to disguise their taste in shakes or stir-fries. If you have a family history of colon cancer or osteoporosis, have low bone density yourself, or are eating a diet high in red or processed meat, you may want to give prunes a chance.
Bolinas resident Sadja Greenwood is a former assistant clinical professor at the University of California, San Francisco.