by Marion Nestle

Currently browsing posts about: Fruit

Apr 24 2023

Industry-funded study of the week: blueberries and menopause

NutraIngredients, a newsletter I read daily, caught my eye with this headline:

Blueberries benefit postmenopausal women with high blood pressure: Study:  Daily blueberry consumption improves endothelial function in postmenopausal women with high blood pressure, according to a recent study…. Read more

I looked it up, of course.

  • The study: Daily blueberry consumption for 12 weeks improves endothelial function in postmenopausal women with above-normal blood pressure through reductions in oxidative stress: a randomized controlled trial. Food Funct., 2023,14, 2621-2641
  • Objective: “to examine the efficacy of blueberries to improve endothelial function and blood pressure in postmenopausal women with above-normal blood pressure, and to identify potential mechanisms for improvements in endothelial function.”
  • Method: Postmenopausal women with elevated blood pressure or hypertension were given 22 g/day of freeze-dried highbush blueberry powder or placebo powder for 12 weeks.
  • Findings: The sum of plasma (poly)phenol metabolites increased in the blueberry group compared to baseline, and were higher than the placebo group.  Increases in several plasma flavonoid and microbial metabolites were also noted. No major differences were found for blood pressure, arterial stiffness, blood biomarkers, or endothelial cell protein expression following blueberry consumption (my emphasis).
  • Conclusion: “These findings suggest daily consumption of freeze-dried blueberry powder for 12 weeks improves endothelial function through reduced oxidative stress in postmenopausal women with above-normal blood pressure”
  • Conflicts of interest: There are no conflicts to declare.
  • Acknowledgements: This research was funded by the US Highbush Blueberry Council, the USDA National Institute of Food and Agriculture [Grant No. 2020-67017-30833/Project Accession No. 1021875], and the College of Health and Human Sciences at Colorado State University.

Comment: Yes there is a conflict of interest, but the authors don’t seem to recognize it.  This is a classic case of interpretation bias; the study didn’t show much of anything but the authors conclude that blueberry powder does some good.

High marks to NutraIngredients for disclosing the funding source right at the top of the article:

Published in the journal Food and Function, the study was supported by the US Highbush Blueberry Council and the USDA National Institute of Food and Agriculture.

 

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Mar 27 2023

Industry-funded study of the week: Strawberries

It feels like spring (at last!) in New York so I’m thinking about strawberries.

Last September, Lisa Young sent me a copy of an email she had received from a public relations agency.

Good Morning –

Today is World Alzheimer’s Day and a new study has found that eating Strawberries may reduce the risk of Alzheimer’s Disease and related dementias.

In fact, the compounds that give strawberries their beautiful red color may have several health benefits, such as lowering the risk of heart disease and some cancers and improving blood sugar control. And now researchers have found that one of those compounds, known as pelargonidin, may slow or prevent the development of Alzheimer’s Disease by lowering the number of twisted fibers inside the brain that contain a protein called tau. These twisted fibers are a hallmark of Alzheimer’s Disease.

The new study, which was supported by the National Institute of Aging and the California Strawberry Commission, was conducted postmortem on the brains of participants of the Rush Memory and Aging Project (MAP). Participants with the highest level of pelargonidin intake prior to their death also had less buildup in the brain of protein fragments called amyloid beta plaques – another hallmark of Alzheimers Disease. Pelargonidin is primarily found in berries. In this study, strawberries were the principal source of pelargonidin….

The study: Agarwal P, Holland TM, James BD, Cherian LJ, Aggarwal NT, Leurgans SE, Bennett DA, Schneider JA. Pelargonidin and Berry Intake Association with Alzheimer’s Disease Neuropathology: A Community-Based Study. J Alzheimers Dis. 2022;88(2):653-661. doi: 10.3233/JAD-215600. PMID: 35694918.

Results: “participants in the highest quartile of pelargonidin intake when compared to those in the lowest quartile, had less amyloid-β load (β (SE) = -0.293 (0.14), p = 0.038), and fewer phosphorylated tau tangles…”

Conclusion: “Higher intake of pelargonidin, a bioactive present in strawberries, is associated with less AD neuropathology, primarily phosphorylated tau tangles.”

Comment: I love strawberries and grow them in pots on my terrace.  But this study?  It looks at one chemical among many in strawberries and associates it with improved symptoms.  Association, alas, does not indicate causation.  If you give this a moment’s thought, could you believe that eating a few strawberries every day would help you prevent Alzheimer’s?  I’m all for plant-based diets.  And I’m all for eating strawberries.  But to imply that strawberries alone can control hunger, be good for your heart, especially if they come from California (as the Commission says on its website), seems a bit much.

Are strawberries demonstrably better for Alzheimer’s than any other berry or fruit?  The California Strawberry Commission is not interested in asking comparative questions.  It just wants you to buy more strawberries.

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Feb 27 2023

Industry funded study of the week: watermelon, of all things

The study: The Effect of Watermelon Juice Supplementation on Heart Rate Variability and Metabolic Response during an Oral Glucose Challenge: A Randomized, Double-Blind, Placebo-Controlled Crossover Trial.

Methods:  This was a two-week controlled clinical trial to measure the effects of watermelon juice on responses to oral glucose challenge tests in healthy young adults.  These usually decrease heart rate variability (not good).

Results: Watermelon juice countered the reduction in heart rate variability.

Funding: “This research was funded by the National Watermelon Promotional Board.”

Comment: I learned about this study from an article in NutraIngredients-USA: “Watermelon juice may decrease dysfunctsion linked to hyperglycemic episodes.” That headline made me ask my usual question: Who paid for this?  Bingo.

I give NutraIngredients much credit for the funding reveal right after the first paragraph, and for its clear explanation of a complicated study rationale and design.

The authors say they have no conflicts of interest to declare.  I continue to believe that the funding source establishes an automatic conflict of interest.

Once again, as I discuss in detail in my book, Unsavory Truth, the key point about industry-funded studies is that funding recipients do not recognize the influence or the conflict.

But what a coincidence that industry-funded studies so often come out with results favorable to the sponsor’s commercial interest, which in this case is this: The National Watermelon Promotional Board “operates with a single objective: to increase consumer demand for watermelon through promotion, research, and educational programs.”

Dec 19 2022

Industry-funded study of the week: Grapes!

Thanks to Larissa Zimberoff (“Technically Food”) for forwarding this gem of a press release.

Grape Consumption Helps Counter UV Damage to Skin

Recent study reinforces promising role of grapes in photoprotection

A recent human study published in the scientific journal Antioxidants found that consuming grapes protected against ultraviolet (UV) damage to the skin.[1]  Study subjects showed increased resistance to sunburn after consuming 2 ¼ cups of grapes [sic] every day for two weeks. Additionally, subjects displaying UV resistance also demonstrated unique microbiomic and metabolomic profiles suggesting a correlation between the gut and skin. Natural components found in grapes known as polyphenols are thought to be responsible for these beneficial effects.

The title alone makes me ask: Who paid for this?

Here’s the study: [1] Pezzuto, J.M.; Dave, A.; Park, E.-J.; Beyoğlu, D.; Idle, J.R. Short-Term Grape Consumption Diminishes UV-Induced Skin Erythema. Antioxidants 202211, 2372. https://doi.org/10.3390/antiox11122372

Funding: “This work was supported in part by the California Table Grape Commission (J.M.P and J.R.I./D.B.).”  The funding statement continues:

The sponsor was not involved in the preparation of the article; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit this article for publication.

Comment: That’s what they all say, despite much overall evidence to the contrary.

Why the sic?  The study was not, in fact, done wtih grapes.,  It was done with “whole grape powder – equivalent to 2.25 cups of grapes per day – for 14 days.”

Are powdered grapes the same as whole grapes?  Would anyone be willing to eat 2.25 cups of whole grapes every day for 14 days?

I like grapes, and grow two kinds on a fence in Ithaca, some for eating, the Concord ones for jam.  Grapes are fruit.  Fruit is good for health.  Eat them if you like them.  They are useful parts of healthy diets.

Are grapes the only fruit that helps counter UV damage to skin?  I doubt it.  But I’m guessing sunscreens work better.

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Sep 8 2022

USDA’s new collection of miscellaneous charts

The USDA’s Economic Research Service was damaged serriously when the Trump Administration moved its offices out of Washington DC to Kansas, and it is taking some time to recover.

It’s still publishing what it calls Charts of Note.

These are on all kinds of topics dealing with farm production and food consumption.  Here are a couple of examples I found particularly interesting.

Here’s the first:

This one shows that small and medium size farms make money selling direct to consumers at farmers’ markets and via Community Supported Agriculture, but the largest farms benefit most from these opportunities.  Restaurants and grocery stores don’t source much from smaller farms and neither do regional distributors.

The challenge for small and medium size farms is to find more and better distribution channels.\

And here’s the second:

I picked this one because I like the design and because this watermelon has seeds.  You can hardly buy a watermelon with seeds anymore.

I’ve been convinced that seedless watermelons don’t taste as good as the ones with seeds.  This year, I bought some seeds from old-fashioned watermelon and planted them in my place in Ithaca, New York.   They are now ripe, and edible.  But alas: I don’t think they taste any better than the ones without seeds.

Next year, we plant seedless.

One big question: how do you get create seeds for seedless watermelons?   This, I had to look up.

Seedless melons are referred to as triploid melons while ordinary seeded watermelons are called diploid melons, meaning, that a typical watermelon has 22 chromosomes (diploid) while a seedless watermelon has 33 chromosomes (triploid). To produce a seedless watermelon, a chemical process is used to double the number of chromosomes. So, 22 chromosomes are doubled to 44, called a tetraploid. Then, the pollen from a diploid is placed on the female flower of the plant with 44 chromosomes. The resulting seed has 33 chromosomes, a triploid or seedless watermelon. The seedless watermelon is sterile. The plant will bear fruit with translucent, nonviable seeds or “eggs.”

Aren’t you glad I asked?

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Coming soon!  My memoir coming out in October.

For 30% off, go to www.ucpress.edu/9780520384156.  Use code 21W2240 at checkout.

 

Sep 6 2022

Food industry funded studies of the week: grapes!

I very much appreciate the weekly newsletter, ObesityandEnergetics.org (If you want to subscribe, do so here).

I particularly enjoy its section, Headline vs Study.  Here’s the most recent, with my additions.

Headline: “Astonishing” Effects of Grape Consumption and “Remarkable” Impacts on Health and Lifespans.

Study: Grape Powder (Not Grapes) Modulates Gene Expression, Reduces Non-Alcoholic Fatty Liver Disease, and Extends Longevity… In Female Mice.

I took a look at the study.

  • Conclusion: “These results suggest the potential of dietary grapes to modulate hepatic gene expression, prevent oxidative damage, induce fatty acid metabolism, ameliorate NAFLD (non-alcohol fatty liver disease), and increase longevity when co-administered with a high-fat diet.”
  • Funding: This work was supported in part by the California Table Grape Commission. The sponsor was not involved: in the preparation of the article; in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.

Here is another study:

Study: Behavioral and Genetic Changes of Grape Powder (Not Grapes)… In Female Mice.

Its funding?  “This research was supported in part by the California Table Grape Commission.”

And one more:

Study: Grape Powder (Not Grapes) Modifies Hepatic and Urinary Metabolite Profiles… In Female Mice.

This study is also enlightening.

  • Conflicts of interest: [onE of the authors] “serves on the scientific advisory board of the California Table Grape Commission. There are no other conflicts to declare.”
  • Acknowledgements:  [two of the authors] “acknowledge grant support from the California Table Grape Commission and seed grant funding from Long Island University. The California Table Grape Commission was not involved: in the preparation of the article; in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.”

Comment:  As usual, these authors deny the problems inherent in industry funded studies that have marketing of health benefits as their primary purpose.  Grapes are fruits.  Fruits are healthy.  Do grapes perform health miracles?  Only if you believe in miracles.  Should you eat grapes?  Sure, if you like them.

You don’t believe this is about marketing?  Here’s one more headline (thanks to Karen Zornow Leiding for sending).  And you know who funded this.

Eating grapes can counteract harmful effects from processed foods, while boosting metabolism too

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Coming soon!  My memoir coming out in October.

For 30% off, go to www.ucpress.edu/9780520384156.  Use code 21W2240 at checkout.

 

Jul 25 2022

Industry-funded study of the week: more prunes

Several people sent me this one:

Prunes preserve hip bone mineral density in a 12-month randomized controlled trial in postmenopausal women: the Prune Study.  The American Journal of Clinical Nutrition,  nqac189, https://doi.org/10.1093/ajcn/nqac189

Conclusions: A 50g daily dose of prunes can prevent loss of total hip BMD [bone mineral density] in postmenopausal females after six months, which persisted for 12-months…we propose that the 50g dose represents a valuable non-pharmacological treatment strategy that can be used to preserve hip BMD in postmenopausal females and possibly reduce hip fracture risk

Sources of Support: California Prune Board (Award Number: 180215)

Acknowledgments: We thank the California Prune Board for the funding and prunes…The California Prune Board had no role in the data collection and analysis, decision to publish, or preparation of manuscript.in this study.

Comment: The California Prune Board did not have to have that kind of role to get the outcome it wanted.  Research on funding effects shows that industry influence is exerted primarily in the ways the research question is framed and the results interpreted.  It also shows that investigators hardly ever recognize how industry funding exerts influence.

Reference:  Unsavory Truth: How Food Companies Skew the Science of What We Eat.

May 30 2022

Industry-funded study of the week: cranberries—again!

Cranberry marketing gets wilder and wilder.  Last week I posted a study of endothelial function paid for by the cranberry industry.

But here’s a study that tops it.  I learned about it from a headline in NutraIngredients.com: Cranberry consumption may boost memory and ward off dementia in elderly, study finds.

Oh come on.  Really?

I went right to it.

The study: Chronic Consumption of Cranberries (Vaccinium macrocarpon) for 12 Weeks Improves Episodic Memory and Regional Brain Perfusion in Healthy Older Adults: A Randomised, Placebo-Controlled, Parallel-Groups Feasibility Study.  Emma Flanagan, Donnie Cameron, Rashed Sobhan, Chloe Wong, Matthew G. PontifexNicole TosiPedro MenaDaniele Del Rio3, Saber Sami, Arjan Narbad, Michael Müller, Michael Hornberger and David Vauzour.  Front. Nutr., 19 May 2022 | https://doi.org/10.3389/fnut.2022.849902

Design: This was a 12-week randomised placebo-controlled trial of freeze-dried cranberry powder in 60 older adults aged between 50 and 80 years. Investigators measured memory and executive function, did neuroimaging, and took blood samples before and after .

Results: “Cranberry supplementation for 12 weeks was associated with improvements in visual episodic memory in aged participants when compared to placebo.”

Conclusions: “The results of this study indicate that daily cranberry supplementation (equivalent to 1 small cup of cranberries) over a 12-week period improves episodic memory performance and neural functioning.”

Funding: “This research was supported by a Cranberry Institute grant…The Cranberry Institute was not involved in the design, implementation, analysis, and interpretation of the data.”

Conflict of Interest: “DV, MH, MM, and AN received funding from the Cranberry Institute.  The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.”

Publisher’s Note:  “All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.”

Comment: This is the first time I have ever seen a Publisher’s Note like this.  Even the publisher is troubled by the fact that this study is funded by a cranberry industry trade group and the four most senior authors report funding from the group.  Without even getting into whether cranberry powder is equivalent to cranberries, whether anyone can eat cranberries without adding their weight in sugar, or whether any other fruit might have similar effects, we should ask whether it makes any sense at all to think that any one single food could boost memory and prevent dementia in the elderly.

For detailed discussion of how industry funding influences research, and the consequences of such practices, see my book Unsavory Truth: How Food Companies Skew the Science of What We Eat.