It may not be the most prepossessing of fruits, but the prune, a.k.a. dried plum, has an inner beauty that you won’t want to miss. Most significantly, it contains nutritional factors that can improve gut health and help lower your risk of colon cancer.
A new study by Texas A & M has highlighted regular consumption of prunes, in particular, as contributing to lower colon cancer risk. Colorectal cancer, which includes cancers of the colon and rectum, is the third most common cancer diagnosed in the U.S. today (excluding the range of skin cancers). As with most cancers, it is widely accepted that diet plays a role in your risk of this cancer. For instance, it has been shown that a diet high in processed foods like hots dogs and other luncheon meats increases risk, while a diet of whole foods, high in vegetables and fruits, lowers it.
By the way, in the U.S. now you’ll often hear “dried plums” in place of “prunes.” The reason is that the California Dried Plum Board (the state where 99% of the U.S. prune supply is grown), conducted a focus group for their target consumer cohort (women aged 25-54). Participants responded more favorably to the name “dried plums” than “prunes,” so the former term is now the official marketing name, though most everywhere else in the world no one seems to have a problem calling the wrinkled fruit just good ol’ “prunes.”
How do prunes do it?
Prunes are a treasure chest of vital nutrients that help reduce the risk of chronic disease: potassium, fiber, phytochemicals, including antioxidants. But the key influence of this dried fruit is its effect on the bacteria in the colon — the gut microbiome, which is just beginning to be understood as a prime factor in the health of the whole body, hence, the increasing emphasis on probiotics, fermented foods, avoiding routine use of antibiotics, etc.
In one animal study, scientists compared rats fed either a diet containing prunes or a control diet (same diet without prunes). Those fed the prunes had significant increases in the auspicious gut bacteria known as Bacteroidetes and Firmicutes. These same rats also exhibited fewer signs of precancerous lesions, usually indicators of future cancer development. The conclusion from study author Dr. Nancy Turner:
“From this study we were able to conclude that dried plums did, in fact, appear to promote retention of beneficial microbiota and microbial metabolism throughout the colon, which was associated with a reduced incidence of precancerous lesions.”
Other good reasons to eat prunes in moderation
Prunes (stewed or soaked) have long been celebrated as a digestive aid, especially for their gentle laxative effect. This is true because they contain both soluble and insoluble fiber, as well as high sorbitol levels. Sorbitol is an unfermentable sugar, sometimes called a prebiotic, which has been shown to serve as a good medium for the production of desirable intestinal microorganisms and also the reason for the laxative effect.
Interestingly, despite the high sugar content, prunes to do not contribute to a rapid rise in blood sugar concentration, perhaps due to the moderating influence of their high fiber and sorbitol content. In a review published in Critical Reviews in Food Science and Nutrition in 2001, prunes were acclaimed as “the epitome of functional foods.” A sampling of its admirable traits:
Dried prunes contain approximately 6.1 g of dietary fiber per 100 g, while prune juice is devoid of fiber due to filtration before bottling.
Prunes contain large amounts of phenolic compounds (184 mg/100 g), mainly as neochlorogenic and chlorogenic acids, which may aid in the laxative action and delay glucose absorption.
Phenolic compounds in prunes had been found to inhibit human LDL oxidation in vitro, and thus might serve as preventive agents against chronic diseases, such as heart disease and cancer.
Additionally, high potassium content of prunes (745 mg/100 g) might be beneficial for cardiovascular health.
Dried prunes are an important source of boron, which is postulated to play a role in prevention of osteoporosis. A serving of prunes (100 g) fulfills the daily requirement for boron (2 to 3 mg).”
In 2013, studies published in Critical Reviews in Food Science and Nutrition touted the prune’s role not only in colon cancer reduction, but also other major chronic diseases, like obesity, diabetes, heart disease and more:
“Dried plums contain significant amounts of sorbitol, quinic acid, chlorogenic acids, vitamin K1, boron, copper, and potassium. Synergistic action of these and other compounds, which are also present in dried plums in less conspicuous amounts, may have beneficial health effects when dried plums are regularly consumed.
Snacking on dried plums may increase satiety and reduce the subsequent intake of food, helping to control obesity, diabetes, and related cardiovascular diseases. Despite their sweet taste, dried plums do not cause large postprandial rise in blood glucose and insulin.
Direct effects in the gastrointestinal tract include prevention of constipation and possibly colon cancer. The characteristic phenolic compounds and their metabolites may also act as antibacterial agents in both gastrointestinal and urinary tracts.
The indirect salutary effects on bone turnover are supported by numerous laboratory studies with animals and cell cultures.”
Caveats of eating prunes
Because of their high fructose content, it is important to consume prunes in moderation. One medium prune has about 1.2 grams of fructose. If you’re insulin- or leptin resistant (overweight, diabetic, hypertensive, or very high cholesterol), it would be wise to limit fructose intake to a maximum 15 grams per day from ALL sources, including whole fruit.
If you are not insulin/leptin resistant (normal weight without diabetes, hypertension or abnormally high cholesterol), the general rule would be to limit fructose intake to 25 grams/day (or less) from ALL sources.
It would be best to buy organic dried fruits without preservatives or sulfating agents. Also, it’s a good idea to place prunes in water, bring to a quick boil and let “sit” for at least 15 minutes to restore water balance. This also makes them much softer and easier to eat (gentler on the teeth), just take care if you use unpitted prunes! Soaked prunes can be stored in the refrig for 4 or 5 days.
Enjoy your dried plums/prunes many whichways
- Add a few soaked prunes to whole plain yogurt for a great afternoon or evening snack. Dash of ground clove or nutmeg is nice.
- Add to vegetable or meat stews for an interesting sweet note.
- Toss a couple into a smoothie for good fiber and sweetener (just make sure pits removed!)