Currently browsing posts about: Fruit

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:

• The study: Effect of Incorporating 1 Avocado Per Day Versus Habitual Diet on Visceral Adiposity: A Randomized Trial. J Am Heart Assoc. . 2022 Jul 19;11(14):e025657.  doi: 10.1161/JAHA.122.025657. Epub 2022 Jul 5.  Authors: Alice H Lichtenstein ¹, Penny M Kris-Etherton ², Kristina S Petersen ³, Nirupa R Matthan ¹, Samuel Barnes ⁴, Mara Z Vitolins ⁵, Zhaoping Li ⁶, Joan Sabaté ⁷, Sujatha Rajaram ⁷, Shilpy Chowdhury ⁴, Kristin M Davis ⁸, Jean Galluccio ¹, Cheryl H Gilhooly ¹, Richard S Legro ⁹, Jason Li ⁶, Laura Lovato ¹⁰, Letitia H Perdue ¹⁰, Gayle Petty ¹, Anna M Rasmussen ⁶, Gina Segovia-Siapco ⁷, Rawiwan Sirirat ⁷, April Sun ⁶, David M Reboussin ¹⁰
• Conclusions: “In conclusion, in this randomized controlled multicenter parallel trial, the addition of 1 avocado per day to the habitual diet for 6 months in individuals with visceral adiposity did not reduce VAT and had minimal effect on risk factors associated with cardiometabolic disorders.”
• Funding: This work was supported by the Avocado Nutrition Center.

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.

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.

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.”

I am way behind on posting all the industry-funded studies sent to me and collected, so will share a week’s worth of fruit studies .  This is to emphasize the obvious point that fruit is good for you, but one is not necessarily better than another–except to its marketers.  Enjoy!

Here’s the first: strawberries.

I heard about this from two news releases, and because it was sent to me by Charles Platkin, Executive Director, Center for Food as Medicine  and Distinguished Lecturer at Hunter College, City University of New York.

• From CBS News, Boston:  “Strawberries could improve heart and brain health, researchers say.“
• From Neuroscience News: “Berry Good News: Daily Strawberries Boost Cognitive & Cardio Health.”

Wow.  This is exciting.  I had strawberries with my cereal for breakfast this morning.

I could not wait to read the study.

Uh oh.  Not yet published.  But given in a poster session at the American Society for Nutrition meetings in Boston last month.

• Title: The Impact of Strawberries on Cognition and Cardiovascular Health of Older Healthy Adults: A Randomized, Crossover, Double-Blind, Placebo-Controlled Clinical Trial .
• Objectives: The polyphenolic compounds in strawberries may improve cognitive function and cardiovascular health due to their antioxidant capacities. This study aimed to examine the effects of strawberries on cognitive function and cardiometabolic health in healthy aging adults.
• Methods:  This was a randomized, crossover, double-blind, placebo-controlled clinical trial with 35 healthy older adults  given 26 grams of freeze-dried strawberry powder (not strawberries) and a control powder daily for 8 weeks each.
• Results:  The strawberry powder group increased processing speed.  The control group increased episodic memory.  : The powder also had other effects: “Strawberry consumption reduced systolic blood pressure…Total antioxidant capacity significantly decreased during the control trial …and significantly increased with strawberry consumption.”
• Conclusions: This study demonstrates that daily consumption of 26 grams of freeze-dried strawberry powder moderately improves cognitive processing speed, lowers systolic blood pressure, and increases total-antioxidant capacity, potentially promoting cognitive function and improving cardiovascular risk factors.
• Funding Sources: This study was funded by California Strawberry Commission.

Comment: Of course it was.  Who else would care about the effects of strawberry powder.  Not that no other fruit powders were tested; I would expect all of them to produce similar effects, whatever those effects might be.  Given that the control group performed better on memory tests, you could interpret the results as not particularly meaningful.  But one characteristic of industry funded studies is to put a positive spin on whatever results occur.  We can argue about the methods when the study is actually published.  In the meantime, we have press releases.

Oh.  And my morning strawberries were somewhat local, red all the way through, and tasted like strawberries.  Do I feel smarter as a result?  Sure, why not.

Every now and then the USDA recruits a talented designer and produces terrific charts like this one.

I thought this was perfect for a hot summer day.  Enjoy!

My distant (but dearly loved) cousin, the food package designer Michael Kravit, thought I would enjoy seeing this example of first-rate food marketing—and of a healthy product yet.

First, open the box.

Cut. Scoop. Enjoy!

You aren’t sure how?  The company even supplies a video.

I’d like to see more like this.

Thanks to Bradley Flansbaum for sending this one from a journal not on my usual reading list: “In persons with constipation or IBS-C, kiwifruit vs. psyllium increased spontaneous bowel movements.”

I like the way this press release gets right to the point.

An industry-funded randomized trial assessed the effect of daily consumption of kiwifruit versus psyllium on GI function and comfort in 184 adults who were healthy, had functional constipation (FC), or met Rome III diagnostic criteria for constipation-predominant irritable bowel syndrome (IBS-C).

The study: Consumption of 2 Green Kiwifruits Daily Improves Constipation and Abdominal Comfort—Results of an International Multicenter Randomized Controlled Trial.  The American Journal of Gastroenterology ():10.14309/ajg.0000000000002124, January 9, 2023. | DOI: 10.14309/ajg.0000000000002124.

Authors: Gearry, Richard MD, PhD; Fukudo, Shin MD, PhD; Barbara, Giovanni MD; Kuhn-Sherlock, Barbara PhD; Ansell, Juliet PhD; Blatchford, Paul PhD; Eady, Sarah MSc; Wallace, Alison PhD; Butts, Christine PhD; Cremon, Cesare MD; Barbaro, Maria Raffaella PhD; Pagano, Isabella MD; Okawa, Yohei PhD; Muratubaki, Tomohiko PhD; Okamoto, Tomoko PhD; Fuda, Mikiko MS; Endo, Yuka MD; Kano, Michiko MD, PhD; Kanazawa, Motoyori MD, PhD; Nakaya, Naoki PhD; Nakaya, Kumi PhD; Drummond, Lynley BTech (Hons)

Summary of the study

Methods: Participants included healthy controls (n = 63), patients with functional constipation (FC, n = 60), and patients with constipation-predominant irritable bowel syndrome (IBS-C, n = 61) randomly assigned to consume 2 green kiwifruits or psyllium (7.5 g) per day for 4 weeks, followed by a 4-week washout, and then the other treatment for 4 weeks. The primary outcome was the number of complete spontaneous bowel movements (CSBM) per week.

Results: Consumption of green kiwifruit was associated with a clinically relevant increase of ≥ 1.5 CSBM per week (FC; 1.53, P < 0.0001, IBS-C; 1.73, P = 0.0003) and significantly improved measures of GI comfort (GI symptom rating scale total score) in constipated participants (FC, P < 0.0001; IBS-C, P < 0.0001).

Conclusion: This study provides original evidence that the consumption of a fresh whole fruit has demonstrated clinically relevant increases in CSBM and improved measures of GI comfort in constipated populations. Green kiwifruits are a suitable dietary treatment for relief of constipation and associated GI comfort.

Financial support: Zespri International Ltd. was the principal sponsor and reviewed, approved, and funded the study design. The New Zealand study center trial was jointly funded by a grant from the New Zealand government (Contract C11X1312) and the sponsor company, Zespri International Ltd. In Italy and Japan, Zespri International Ltd. was the sole funder for each study center trial. The funder did not contribute to the study design or data analysis.

Potential competing interests: J.A. and P.B. are employed by Zespri International who part-funded the study. R.G. and L.D. sit on the Science Advisory Board, have received travel and research grants from Zespri International. SF and GB have received research travel grants from Zespri International.

Comment:  Can you guess what Zespri International sells?  Go on.  Take a wild guess.  I’ll admit it.  I’d go for kiwi over psyllium every time.  But we are talking here about an average improvement of 1.5 bowel movements a week, which may or may not be clinically meaningful..  I do give the authors credit for claiming a benefit for “fresh whole fruit,” not specifically kiwifruit.  The study didn’t compare kiwi to other fruits (and why would it, given the kiwi fruit sponsor).  But overall, this is yet another study done for marketing far more than scientific purposes.

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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