by Marion Nestle
Aug 30 2021

Industry-funded study of the week: prunes, this time

My NYU colleague Mitchell Moss sent me this notice of new research: Eating just 5 prunes a day reduces risk of heart disease, inflammation.

That was worth tracking down and I soon found a press release from the California Prune Board: New study: Eating prunes daily improves risk factors for heart disease and inflammation

In a statement, the senior author says:

In this randomized, controlled study, researchers found that eating 50 grams of prunes (about 5-6 prunes) each day for just 6 months resulted in improved CVD risk biomarkers – including raising the body’s “good” cholesterol, known as HDL, and lowering the ratio of total cholesterol to HDL. Eating prunes daily also promoted higher antioxidant capacity and lowered levels of the inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha associated with CVD risk. Notably, body mass index and weight of the study participants were maintained during the trial despite adding prunes to the usual diet.

The study:  Dried Plum Consumption Improves Total Cholesterol and Antioxidant Capacity and Reduces Inflammation in Healthy Postmenopausal Women

Dietary intervention: “48 postmenopausal women were randomly assigned to consume 0, 50, or 100 g of dried plum each day.”

Results: “After 6 months of intervention, total cholesterol (TC) in the 100 g/day treatment group (P = .002) and high-density lipoprotein cholesterol in the 50 g/day treatment group (P = .005) improved significantly compared to baseline.”

Conclusion: “…consumption of 50–100 g dried plums may improve CVD risk factors in healthy postmenopausal women by increasing total antioxidant capacity and antioxidant enzyme activity, lowering lipid peroxidation, and lowering IL-6.”

Authors’ statement: “The authors declare that there is no conflict of interest.”

Funding: “This study was funded by the San Diego State University Grant Program, the California Dried Plum Board (No. 57114A;, No. NCT02325895), and the Kasch-Boyer Endowed Scholarship in Exercise and Nutritional Sciences in San Diego State University.”

Comment:  Add prunes to the long list of fruit-and-vegetable trade associations trying to convince you that their particular product has unique health benefits.  Prune sellers have a particular difficulty with sales: prunes have long been equated with laxatives.  Hence: the Dried Plum Board.  Also hence: health benefits beyond the digestive tract.

Do prunes have more general health benefits?  Why not?  All fruits and vegetables have health benefits.  Is one better than another?  Maybe in some ways, but the best approach is to eat as wide a variety as possible.

Eat the fruits you like!

Reference: For a summary of research on the “funding effect”—the observation that research sponsored by food companies almost invariably produces results favorable to the sponsor’s interests but that recipients of industry funding typically do not recognize its influence—see my book, Unsavory Truth: How Food Companies Skew the Science of What We Eat.