Prunes – these sweet, dried plums are more than just delicious snacks. They pack a phytochemical and antioxidant punch, and offer up a variety of health benefits that go far beyond what they are best known for – supporting better bowel habits.
The familiar laxative effect of prunes is partly due to their fiber content, but since prune juice—a water extract devoid of fiber—is also known to exert a stool softening effect, there’s more to it than just the fiber alone. Prunes and prune juice contain natural sorbitol, a sugar alcohol known to have a laxative effect, and chlorogenic acid, which also has laxative properties. Chlorogenic acid is a promising antioxidant compound which has been shown to be anxiolytic in a mouse model of anxiety. This potential reduction in anxiety may be why prune extracts have also demonstrated positive effects on learning and memory in mice, which may make them beneficial for people of all ages.
Beyond their tried-and-true use for improving bowel function, research has also shown prunes to have positive effects on cardiovascular health. In one study, subjects consuming prunes or prune juice had significant reductions in blood pressure, compared to those who only consumed water. This is potentially due to the high potassium content of prunes. In another study, phytochemicals isolated from prunes were shown to protect human endothelial cells from hydrogen peroxide-induced oxidative damage in vitro. In this study the specific compounds extracted for testing were melanoidins, formed by sugars reacting with proteins during food processing and preservation, which suggests these protective factors might be present in prunes but not in fresh plums. Further research showed that post-menopausal women given 75g/day of prunes had significantly lower levels of C-reactive protein at 3 months than a comparative group given the same amount of dried apples. At 12 months, compared to baseline, the prune group had small reductions of 3.5% in total cholesterol and 8% in LDL-cholesterol.
A growing body of research also shows the impressive effects of prunes on bone health, particularly in post-menopausal women, for whom bone preservation is an especially critical issue. Prunes are a good source of boron, which is a critical mineral for bone strength. Post-menopausal women given 100g/day of dried plums showed increased serum levels of bone-specific alkaline phosphatase, a marker for bone formation. Compared to an intervention group given dried apples, the dried plum group showed significant increases in bone mineral density in the spine and ulna. Animal models of osteoporosis suggest prunes may upregulate bone-building osteoblasts and may help to preserve bone mass in the spine and tibia.
Of course, large amounts of prunes—especially in the form of juice—are not necessarily appropriate for everybody. Despite their beneficial effects on health, people struggling to manage their blood sugar should be aware that all dried fruits are concentrated sources of sugar, since the water has been removed from them. However, prunes are a sensible choice, as a 60 gram serving (about 2 ounces) has a glycemic index of 29, and a glycemic load of just 10. The sweet taste of prunes is slightly misleading; prunes generally do not cause large post-prandial spikes in blood glucose. This is likely due to their high fiber, fructose, and sorbitol content.
The relatively benign effects of prunes on blood glucose might be why a recent study found prunes to be helpful for weight loss. If they can satisfy a craving for something sweet without triggering a desire for more and more, in addition to inducing a feeling of satiety because of their fiber, it makes sense that consuming prunes in moderation could be a stealthy and surprising ace-in-the-hole for dieters, while also being an all-around great choice for individuals wanting to support cardiovascular heath, and brain and bowel function.