by Marion Nestle

Currently browsing posts about: Fruit

Apr 22 2024

Industry-funded study of the week: Prunes

I learned about this one from this article:  Prune consumption may prevent bone loss for postmenopausal women.  Dietary supplementation with prunes can have a broad range of effects on immune, inflammatory and oxidative stress markers in postmenopausal women, according to a recent study…. Read more

When I see a headline like this, my first question is , as always, who would pay for something like this?

I went right to the study:  De Souza MJ, Strock NCA, Williams NI, Lee H, Koltun KJ, Rogers C, Ferruzzi MG, Nakatsu CH, Weaver C. Prunes preserve hip bone mineral density in a 12-month randomized controlled trial in postmenopausal women: the Prune Study. Am J Clin Nutr. 2022 Oct 6;116(4):897-910. doi: 10.1093/ajcn/nqac189.

Conclusion: “The results of this investigation provide compelling evidence of the long-term efficacy of daily prune consumption.”

Funding: We thank the California Prune Board (Award Number: 180215) for the funding and prunes and the participants in this study.

Author disclosures: CW and CR are members of the Nutritional Advisory Panel for the California Prune Board. All other authors report no conflict of interest.

Comment: Bingo on this one.  Wouldn’t it be wonderful if all you had to do to prevent bone loss was to eat 5 prunes a day?   Go for it!

Mar 25 2024

A rare gem: an industry-funded study with a negative result, and for blueberries yet!

I’ve posted several studies sponsored by the blueberry industry , most recently on their effects on menopausal symptoms.  Blueberry trade associations, as I discuss in my book Unsavory Truth: How the Food Industry Skews the Science of What We Eat, led the way in promoting research suggesting this fruit is a “superfood.”

If only.

They are still at it, apparently, but sponsorship does not always guarantee the desired outcome.  Here is a rare exception to the rule that industry-sponsored studies almost invariably give results favorable to the sponsor’s marketing interest.  Let’s give credit where it is due.

  • The study:  Chronic and postprandial effect of blueberries on cognitive function, alertness, and mood in participants with metabolic syndrome – results from a six-month, double-blind, randomized controlled trial.  The American Journal of Clinical Nutrition.  Available online 6 February 2024, https://doi.org/10.1016/j.ajcnut.2023.12.006
  • Methods: “A double-blind, randomized controlled trial was conducted, assessing the primary effect of consuming freeze-dried blueberry powder, compared against an isocaloric placebo, on cardiometabolic health >6 mo and a 24 h postprandial period (at baseline).”
  • Results: “Postprandial self-rated calmness significantly improved after 1 cup of blueberries (P = 0.01; q = 0.04; with an 11.6% improvement compared with baseline between 0 and 24 h for the 1 cup group), but all other mood, sleep, and cognitive function parameters were unaffected after postprandial and 6-mo blueberries.”
  • Conclusion: “Although self-rated calmness improved postprandially, and significant cognition-metabolite associations were identified, our data did not support strong cognitive, mood, alertness, or sleep quality improvements in MetS participants after blueberry intervention.”
  • Conflict of interest: “AC reports financial support provided by the US Highbush Blueberry Council (USHBC) and Biotechnology and Biological Sciences Research Council (BBSRC, UK). AC and EBR both act as advisors and consultants to the United States Highbush Blueberry Council grant committee. All other authors report no conflicts of interest.”
  • Funding: “This work was supported by the United States Highbush Blueberry Council with oversight from the USDA and the Biotechnology and Biological Sciences Research Council (United Kingdom). The funders of this research had no involvement in this publication and have placed no restrictions on the publication of these data.”

Comment: In this instance, the last statement could well be correct (it isn’t always, alas).  I like blueberries but they are not a superfood.  There is no such thing as a superfood.  If you want to eat healthfully, by all means eat fruit—and enjoy the ones you like best.

Dec 6 2023

Yet another Salmonella outbreak from cantaloupe

I’m having a hard time with this one.

Once again, the FDA is warning all of us : “Do not eat, sell, or serve recalled cantaloupes or recalled products containing pre-cut cantaloupe.”

The warning lists the products implicated and all the ones that have been recalled.

The CDC says much the same:

CDC is concerned about this outbreak because the illnesses are severe and people in long-term care facilities and childcare centers have gotten sick. Do not eat pre-cut cantaloupes if you don’t know whether Malichita or Rudy brand cantaloupes were used.

As of November 30, the toll is:

Total Illnesses: 117
Hospitalizations: 61
Deaths: 2

But that’s only in the U.S.  Canada reports illnesses too: 63 sick, 17 hospitalized and 1 death.

This, mind you, is from eating cantaloupe.

It’s not that nobody knew cantaloupe poses special safety problems.  It’s grown on the ground and is hard to wash.  If it is grown anywhere near animal wastes, it has a high risk of getting Salmonella on its rind.  Cutting through the rind can move harmful bacteria on the rind into the interior.

Food safety lawyer Bill Marler, who tracks such things, reminds us of previous lawsuits over cantaloupe food poisonings.

He also has some useful things to say about Salmonella during a Cantaloupe Outbreak – Symptoms and Treatment

Cantaloupes, he points out, might still be in season, but Salmonella should not be.

He quotes Perdue (sic Purdue) Extension on how to make cantaloupe safer: scrub and wash in very hot water.

But Marler has been quoted as saying he does not eat cut fruit (implying you should not either).

What’s infuriating about all this is that Congress passed the Food Safety Modernization Act to give the FDA the power to require safety plans from producers of every food under its jurisdiction.  This means cantaloupe growers are supposed to take steps—and test—to make sure the fruit is not contaminated with pathogenic bacteria.

Clearly, the system isn’t working.

The FDA needs to find out why not.

The FDA is chronically and infamously underfunded for what it is supposed to do.

Congress needs to pay attention to this issue.

Nobody should get this sick from eating cut fruit.

And if you haven’t seen the film featuring Marler (I’m in it too, briefly), take a look at Poisoned on Netflix.  It talks about cantaloupe, among other things worth knowing.

Oct 19 2023

A feast for the eyes: USDA’s Pomological Collection

I ran across a notice about this video: The USDA’s wondrous fruit watercolors.  It’s only 5 minutes and a revelation.

It’s just what we need this week—something lovely at a dark time.

I had never heard of the USDA’s collection of 7500 hand -illustrated fruits and vegetables, most of them contributed by women.

I’m happy to know about them.  The illustrations are available online at the National Agricultural Library.

You can search for images here.

They are in the public domain.

Overwhelmed as I am with an overabundance of Concord grapes this year, I searched for them.

They look good enough to eat, no?

This collection is a national treasure and I am thrilled to know about it.

Sep 18 2023

Fruit-industry studies of the week: Blueberries

I missed posting these last week (oops).

Blueberries set the standard for industry-funded studies (I discussed the origins of blueberry-industry funding in my book, Unsavory Truth).  Blueberry producers are still at it.  Here are two examples.

I.  This one started with a press release sent to my email:

From: Blueberries <updates@blueberrycouncil.org>
Date: August 29, 2023 at 11:59:59 AM EDT
Subject: Study Alert: New Research Links Blueberries to Gut Health Benefits

A new study published in Nutrients suggests blueberries may hold benefits for those suffering from functional gastrointestinal disorders (FGID). In this study, FGID patients saw greater abdominal symptom relief and improved markers of well-being, quality of life, and life functioning after consuming freeze-dried blueberry powder for 6 weeks as compared to a placebo treatment.

The study: Wilder-Smith CH, Materna A, Olesen SS. Blueberries Improve Abdominal Symptoms, Well-Being and Functioning in Patients with Functional Gastrointestinal Disorders. Nutrients. 2023; 15(10):2396. https://doi.org/10.3390/nu15102396.

Conclusion: Blueberries relieved abdominal symptoms and improved general markers of well-being, quality of life, and life functioning more than placebo in patients with FGID. Consequently, the polyphenol and fiber components of blueberries exert broad beneficial effects separate from the sugars present in both treatments.

Funding: This research was funded by a grant from the US Highbush Blueberry Council.

Comment: Of course it was.

II.  I read about this one in ConscienHealth.

Burning Fat with Wild Blueberries in 11 Athletes

This is nearly perfect clickbait that is just about meaningless for an average person in real life. Researchers did a study of fat oxidation after consuming freeze-dried powder from wild blueberries. They found an increased oxidation rate associated with consuming that powder in the 11 aerobically trained males they studied. So the press office at Cal Poly Humboldt, where the researchers work, issued a release saying wild blueberries help with burning fat.  From there, twitter and health reporters take the next leap, writing headlines like “eating wild blueberries can help you lose weight.”

The study: Pilolla KD, Armendariz J, Burrus BM, Baston DS, McCarthy KA, Bloedon TK. Effects of Wild Blueberries on Fat Oxidation Rates in Aerobically Trained Males. Nutrients. 2023; 15(6):1339. https://doi.org/10.3390/nu15061339.

Conclusion: “Results indicate that WBs may increase the rate of FAT-ox during moderate-intensity activity in healthy, active males.”

Funding: “This research was funded by Cal Poly Humboldt’s Dean of Research.* Freeze-dried Wild blueberry powder was donated by the Wild Blueberry Association of North America (WBANA).

Comment: I agree that simply providing product to be tested is not an earth-shaking conflict of interest, but because the powder came from the WBANA the ties seem closer.  In any case, the idea that blueberry powder—not nearly as delicious as the real thing—can have these kinds of effects should raise eyebrows from the get go.  Studies of the health effects of one sincle food always require critical thinking and more than a modicum of skepticism.

As for the asterisk*:  My son went to Humboldt State College (long before it was taken over by Cal Poly) so I was especially interested in this.

Sep 15 2023

Fruit-industry study of the day: IV. Avocados

I want to end the week with this unusual example.

Yes, avocados are fruits (hint: fruits have seeds).

This story begins with an emailed ad from an avocado trade association to subscribers to Today’s Dietitian.

In the largest study of its kind, published in the Journal of the American Heart Association, researchers across multiple institutions looked at the impact of consuming one avocado per day on weight-related measures, markers of cardiometabolic risk and diet quality—insights you won’t want to miss.

If you click around to further discussion, you get this:

Daily avocado consumption led to reductions in total and LDL cholesterol and improved diet quality compared to the control group. The Avocado Nutrition Center supported this study, and although the findings from one study cannot be generalized to larger populations, this study supports a growing body of evidence that suggests consuming heart-healthy avocados is associated with better diet quality.

Let’s take a look:

Comment: I don’t usually include the names of authors of industry-funded studies because I don’t see the “funding effect” (a higher probability of positive results) as personal to individual investigators; I see it as systematic.  But I listed these authors because they produced something quite rare: an industry-funded study that did not find positive results.  And they said so explicitly, without hedging or trying to spin the results so they looked  more favorable.

The avocado marketers did the spinning.  This, alas, is yet another hazard of  doing studies funded by food trade associations with vested interests in research outcome.  Investigators have no control over how the sponsor will use or spin their research results, as we see in this example.

Addition, September 16

I often hear criticisms that I don’t deal with the science when I post industry-funded studies.  I don’t because how the science is conducted is rarely the problem.  Instead, industry influence turns up most frequently in the study design or in the interpretation of the results.  That’s what’s happening here, as a reader, mrpicasso2, writes:

Wow! This is astounding how the Avocado marketers try to spin the results in their favor. “Changes in most secondary and additional outcome measures (cardiometabolic risk factors), except for modest decreases in total cholesterol and LDL‐C concentrations, were not statistically significant” became “Daily avocado consumption led to reductions in total and LDL cholesterol and improved diet quality compared to the control group.”

And even the “improved diet quality” is a big stretch because the Healthy Eating Index (HEI) values (even when split into below and above the median subgroups) were not significantly different. It’s true the avocado arm values were numerically higher (0.064 vs 0.044, and 0.083 vs 0.069) but without reaching statistical significance they are indistinguishable.

Of course the Avocado marketers don’t mention that there were 9 adverse events in the Avocado diet arm compared with none in the habitual diet group.

This reminds me of the story of the boy who was so excited to get a pile of horse manure for his birthday because he reasoned that with so much manure there had to be a pony near by.

Sep 13 2023

Fruit-industry funded study of the day: III. Mango leaf extract

The study:  Martinez-Canton M, Galvan-Alvarez V, Garcia-Gonzalez E, Gallego-Selles A, Gelabert-Rebato M, Garcia-Perez G, Santana A, Lopez-Rios L, Vega-Morales T, Martin-Rincon M, et al. A Mango Leaf Extract (Zynamite®) Combined with Quercetin Has Exercise-Mimetic Properties in Human Skeletal Muscle. Nutrients. 2023; 15(13):2848. https://doi.org/10.3390/nu15132848

Hypothesis:  Zynamite PX®, a mango leaf extract combined with quercetin, enhances exercise performance by unknown molecular mechanisms.

Conclusion: Zynamite PX® elicits muscle signaling changes in resting skeletal muscle resembling those described for exercise training and partly abrogates the stress kinases responses to exercise as observed in trained muscles.

Funding: This investigation was co-financed in part by Nektium Pharma S.L., Ministerio de Economía y Competitividad…Consejo Superior de Deportes de España (EXP_75097), FEDER and Cabildo de Gran Canaria…and FDCAN (Fondo de Desarrollo de Canarias).

Conflicts of Interest: The present investigation was partially financed by Nektium Pharma S.L, who provided the polyphenolic compounds and participated in the experimental design, although they were fully excluded from participation in experimental data collection, data analysis and interpretation of results. The remaining funding agencies had no role in study design, data collection, management, data analysis, interpretation of data, writing of the report, and the decision to submit the report for publication.

Comment: This is a classic example of an industry-funded supplement study with favorable interpreted favorably.  The manufacturer paid for the study as part of a private-public partnership to aid businesses in the Canary Islands.

 

Sep 12 2023

Fruit-industry study of the day. II. Figs.

For this one I thank Jerry Hagstrom, who writes The Hagstrom Report (Ag news as it happens) to which I subscribe.

This too begins with a press release: “REDISCOVER FIGS: THE ANCIENT FRUIT WITH MODERN APPEAL: Newly Published Literature Review Suggests the Intake of Figs Regularly in the Diet, Alone or with Other Dried Fruits, Increases Select Micronutrient Intake and is Associated with Higher Diet Quality.”

The study: Sandhu AK, Islam M, Edirisinghe I, Burton-Freeman B. Phytochemical Composition and Health Benefits of Figs (Fresh and Dried): A Review of Literature from 2000 to 2022. Nutrients. 2023 Jun 3;15(11):2623. doi: 10.3390/nu15112623.
Conclusion: Data suggest that the intake of figs regularly in the diet, alone or with other dried fruits, increases select micronutrient intake and is associated with higher diet quality, respectively. Research in animal and human models of health and disease risk provide preliminary health benefits data on figs and their extracts from fig parts; however, additional well-controlled human studies, particularly using fig fruit, will be required to uncover and verify the potential impact of dietary intake of figs on modern day health issues.
Funding: This research was funded by California Fig Advisory Board.
Comment: The title of this study triggered my usual question: “who paid for this?” In this case, the authors get high marks for cautious interpretation of their findings and explicit statement about what is and is not known.
Despite the promising preliminary research of figs and extracts from fig parts, additional well-controlled human studies, particularly using fig fruit, will be required to uncover and verify the potential impact of dietary intake of figs or nutraceutical applications on critical health issues such as managing cardiovascular disease, diabetes, and supporting gut health. Other areas such as satiety and cognitive function may also be worthy of exploration as evidence develops.