by Marion Nestle

Currently browsing posts about: Fruit

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; ClinicalTrials.gov, 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.

Jan 11 2021

Sponsored research study of the week: mangos and skin wrinkles (I’m not kidding)

I learned about this one from a press release: “Can eating mangoes reduce women’s facial wrinkles?”

new study from researchers at the University of California, Davis, finds eating Ataulfo mangoes, also known as honey or Champagne mangoes, may have another benefit — reducing facial wrinkles in older women with fairer skin. The study was published in the journal Nutrients.

Postmenopausal women who ate a half cup of Ataulfo mangoes four times a week saw a 23 percent decrease in deep wrinkles after two months and a 20 percent decrease after four months.

Surely, this can’t be serious?  Who paid for this?

The study: Prospective Evaluation of Mango Fruit Intake on Facial Wrinkles and Erythema in Postmenopausal Women: A Randomized Clinical Pilot Study.  Vivien W. Fam, Roberta R. Holt Carl L. Keen, Raja K. Sivamani .  and Robert M. Hackman.  Nutrients 202012(11), 3381; https://doi.org/10.3390/nu12113381

Method: Women were given either 85 g or 250 g of mangos to eat every day for 16 weeks.  Their wrinkles were photographed and measured before and after.

Conclusion: “The intake of 85 g of mangos reduced wrinkles in fair-skinned postmenopausal women, while an intake of 250 g showed the opposite effect.”

Funding: “This study was supported in part by a grant from the National Mango Board (NMB)…which also supplied the fresh mangos for the study. The NMB had no role in the study design, data collection, data analysis, manuscript preparation, or publication decision.”

Conflicts of Interest: The authors declare no conflict of interest.

Comment:  I love mangos (despite being somewhat allergic to them), but come on.  According to the press release, the researchers “said it’s unclear why consuming more mango would increase the severity of wrinkles but speculate that it may be related to a robust amount of sugar in the larger portion of mangoes.”  Another interpretation is that mangos have no effect (which makes more sense).  In any case, this study did not compare mangos to any other fruit.  This is a classic case of an industry-sponsored study coming out with results favorable to the sponsor’s interests and allowing those interests to be announced in a press release.  The authors may think industry sponsorship does not create a conflict of interest, but much evidence strongly suggests that it does (I reviewed that evidence in my book, Unsavory Truth).

Nov 16 2020

Industry-funded studies of the week: blueberries—again!

Thanks to Lisa Young for sending this announcement: New Research Examines Blueberries’ Positive Impact in Men with Type 2 Diabetes. 

I am already on record as saying that I love blueberries, but I wish they weren’t marketed as superfoods.  All fruits, vegetables, nuts, and grains provide nutrients and fiber.  That makes all of them worth eating for their nutrition-and-health value as well as their taste.  Singling out one or another makes no sense to me, but I’m not in the business of selling one rather than another.  Because similar results would be expected from studies of many other fruits, I put this one in the category of marketing research.

Effect of Blueberry Consumption on Cardiometabolic Health Parameters in Men with Type 2 Diabetes: An 8-Week, Double-Blind, Randomized, Placebo-Controlled Trial.  Kim S Stote, Margaret M Wilson, Deborah Hallenbeck, Krista Thomas, Joanne M Rourke, Marva I Sweeney, Katherine T Gottschall-Pass, Aidar R Gosmanov.  Current Developments in Nutrition, Volume 4, Issue 4, April 2020, nzaa030. 

Conclusion: “Consumption of 22 g freeze-dried blueberries for 8 wk may beneficially affect cardiometabolic health parameters in men with type 2 diabetes.”

Funding:  “Supported by the US Highbush Blueberry Council (to KSS, MMW, and ARG) and by resources and the use of facilities at the Stratton VA Medical Center, Albany, NY, USA.  Author disclosures: KSS, MMW, and ARG received intervention products from the US Highbush Blueberry Council. All other authors report no conflicts of interest.  The US Highbush Blueberry Council supplied the funds to conduct the study but was not involved in the design, implementation, analysis, or interpretation of data.

Comment:  The funder does not have to be involved.  Everyone knows funders are not interested in funding research that might produce results unfavorable to their product.  Freeze-dried blueberries sound like medicine.  I’d rather eat the real things.

Aug 27 2020

Odd items I’ve been saving up

For no particular reason other than curiosity, I’ve been hanging on to these items.  This feels like a good time to share them.

Mar 9 2020

Industry-funded study of the week: fruit extracts and cognitive function

I learned about this one from Nutra-Ingredients-latam.com, one of those industry newsletters I avidly follow: “Grapes plus blueberries may boost cognitive function in college students.”

The study: Acute Intake of a Grape and Blueberry Polyphenol-Rich Extract Ameliorates Cognitive Performance in Healthy Young Adults During a Sustained Cognitive Effort.  Philip P, et al.  Antioxidants 2019, 8, 650; doi:10.3390/antiox8120650.

Purpose: “This study investigated the acute and sustained action of a polyphenols-rich extract from grape and
blueberry (PEGB), on working memory and attention in healthy students during a prolonged and intensive cognitive effort.”

The comparison: “Participants were asked to either consume 600 mg of polyphenol-rich active extract made from
grape (Vitis vinifera L.) and wild blueberry (Vaccinium angustifolium) (Memophenol, Activ’Inside, Beychac et Caillau, France), or a placebo containing pure maltodextrin (Maltrin® M100, Roquette, Lestrem, France) and providing no polyphenol.”

Conclusion: “Our findings suggest that consumption of PEGB coupled with a healthy lifestyle may be a safe alternative to acutely improve working memory and attention during a sustained cognitive effort.”

Funding: This study was funded by Activ’Inside (Bordeaux area, France).

Comment: All I had to do was see the title of this study to guess that it was funded by a company with a vested interest in the study’s outcome.  Activ’Inside makes antioxidant extracts for purposes like this.  I’m all for college students eating grapes and blueberries rather than taking drugs to keep them up all night, but flavanol extracts?  Not the same.  Chalk this one up to marketing, not science.

Jan 13 2020

Sponsored research study of the week: Apples

Every now and then a study comes out that I just love.

Two apples a day lower serum cholesterol and improve cardiometabolic biomarkers in mildly hypercholesterolemic adults: a randomized, controlled, crossover trial.

At last, scientific proof of what we’ve always been taught.

Well, two apples, but OK.

Also OK, who paid for this?

Supported in part by AGER (Agribusiness and research) grant no. 2010-2119 funding the project “Apple fruit quality in the post-genomic era, from breeding new genotypes to post-harvest: nutrition and health.”

AGER is an Italian foundation devoted to promoting Italian agribusiness, supported, it says, by banking foundations.

I’ll take that at face value and enjoy the research.

Nov 18 2019

Industry-funded study of the week: Pomegranates

The study: Matthews LG, Smyser CD, Cherkerzian S, Alexopoulos D, Kenley J, Tuuli MG, et al. (2019) Maternal pomegranate juice intake and brain structure and function in infants with intrauterine growth restriction: A randomized controlled pilot study. PLoS ONE 14(8): e0219596.

The findings (my emphasis): “There were no group differences in brain injury, metrics or volumes. However, treatment subjects displayed reduced diffusivity within the anterior and posterior limbs of the internal capsule compared with placebo. Resting state functional connectivity demonstrated increased correlation and covariance within several networks in treatment subjects, with alterations most apparent in the visual network in per-protocol analyses. Direct effects on health were not found.

Conclusion: In conclusion, maternal pomegranate juice intake in pregnancies with known IUGR was associated with altered white matter organization and functional connectivity in the infant brain, suggesting differences in brain structure and function following in utero pomegranate juice exposure, warranting continued investigation.

Funding: This work was supported by National Institute of Health Grants R01 HD29190 (D. M. Nelson), K02 NS089852 (C.D. Smyser), U54 HD087011 and P30 HD062171 (T.E. Inder), The Foundation for Barnes-Jewish Hospital (D. M. Nelson) and an unrestricted gift to Washington University School of Medicine from POM Wonderful, Los Angeles, CA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Comment: This is a classic example of interpretation bias.  Studies of bias associated with industry funding find that it shows up mostly in the framing of the research question or in the interpretation, as this one demonstrates.  The study did not find anything significant but concluded that drinking pomegranate juice during pregnancy is good for the growing fetus.

Bottom line: Fruit juices (of any kind) are good for health as long as volumes are small.  Eating the fruit itself is better–less sugar, more fiber.

Nov 4 2019

How industry funding of research introduces biases from the get-go

I get letters like this from food trade associations all the time.  Here is the latest:.

The U.S. Highbush Blueberry Council has issued a request for research proposals (RFP) for which it offers grants ranging from $75,000 to $300,000 (or larger).

Here’s the get-go bias point (my emphasis):

The goal of our research funding is to provide initial funds, or additional funds, to explore blueberry health benefits.

The Council wants research to demonstrate benefits.  Of course it does.  These will be useful for marketing.

A priority for funding will be given to human clinical studies however the committee is also interested in further investigation of possible health benefits for pet or performance animals including dogs, cats and horses.

If the proposal is unlikely to demonstrate benefit, it won’t be funded.

That’s why I consider industry-funded research to be about marketing, not science.