Currently browsing posts about: Nuts

The walnut industry must be desperate for greater market share.  Walnuts are great and make a terrific snack if you don’t eat too many of them (calories!).  But this is one-food research.  Can one food really make an important difference to health (yes, if you are seriously deficient in essential nutrients but most Americans are not).

One-food research has to be about marketing more than science.

To wit:

A Cross-Sectional Study on the Association of Walnut Consumption with Obesity and Relative Fat Mass among United States Adolescents and Young Adults in NHANES (2003–2020).  2024 Current Developments in Nutrition.  DOI: https://doi.org/10.1016/j.cdnut.2024.104407

Conclusions: For adolescents girls and young women, dietary intake of walnuts combined with other nuts has the strongest inverse association with measures of obesity.

Funding: This study was funded by the California Walnut Commission.

Comment

The study does not find an association between eating walnuts and obesity in adolescents.  I would not expect it to.  People do not eat that many walnuts.  They get most of their calories from fast and ultraprocessed foods.

The California Walnut Commission would like you to think the calories in walnuts do not count.  In a press release, it points out

Nuts, including walnuts, are nutrient dense and considered a key component of many recommended dietary patterns, including the Mediterranean and vegetarian diets. They are also recommended for daily consumption in the latest U.S. Dietary Guidelines.³ Despite the recommendations, nuts remain under-consumed by the U.S. population,³ perhaps due to nuts being calorie dense, leading to potential concerns that including nuts in the diet could promote weight gain. But new research suggests people, especially Gen Z and millennials, should reconsider nuts, like walnuts.

All true, but nuts in general, not specifically walnuts.  This is about increasing the market share for walnuts as opposed to other nuts.

It’s been a couple of years since I’m commented on almond-industry research funding, but it remains hard at work.  Sasha Matera-Vatnick sent me a report of this study from Food Technology.  It essentially reproduced the California Almonds’ press release: New Research: Eating Almonds Can Aid in Post-Exercise Recovery.

The study: Witard, O., Siegel, L., Rooney, J., Marjoram, L., Mason, L., Bowles, E., Valente, T., Keulen, V., Helander, C., Rayo, V., Hong, M. Y., Liu, C., Hooshmand, S., & Kern, M. Chronic almond nut snacking alleviates perceived muscle soreness following downhill running but does not improve indices of cardiometabolic health in mildly overweight, middle-aged, adults. Frontiers in Nutrition. 2024 January 8: doi: https://doi.org/10.3389/fnut.2023.1298868

Method: 25 mildly overweight subject used a treadmill for 30 min after 8-weeks of consuming either 57 g/day of whole almonds (ALMOND) or an isocaloric amount (86 g/day) of unsalted pretzels (CONTROL).

I learned about this one from Bill Marler’s blog: This is Nuts – California and Washington E. coli Outbreak linked to Gibson Farms Walnuts 

This refers to the CDC announcement: E. coli outbreak linked to organic walnuts

The CDC issued a warning: CDC warns of E. coli outbreak linked to organic walnuts sold in bulk

The FDA has its own investigation: Outbreak Investigation of E. coli O157:H7: Bulk Organic Walnuts (April 2024): Do not eat, sell, or serve recalled organic walnuts sold in bulk bins at natural food and co-op retailers in multiple states. FDA’s investigation is ongoing.

The CDC points out:

• Almost all sick people purchased organic walnuts from bulk bins in food co-ops or natural food stores in California and Washington.
• FDA determined that Gibson Farms, Inc supplied these walnuts and Gibson Farms, Inc has recalled these products.: These walnuts have expiration dates between May 21, 2025, and June 7, 2025.
• FDA has a list of stores that may have received these walnuts.

Comment:  All toxic E. coli outbreaks are troubling because the illnesses are so serious and all are preventable if producers were doing what they were supposed to be doing.  But walnuts?  My first question is how could walnuts, firmly encased in shells, get contaminated with animal fecal wastes, the usual source of this strain of E. coli.  This reminds me of the Odwalla juice E. coli problems; the company had harvested apples that had fallen on the ground. Did Gibson harvest walnuts off the ground?  Whatever it did, the company should have been following a food safety plan mandated by the Food Safety Modernization Act, which requires prevention controls and testing to make sure things like this donn’t happen.

Are non-organic walnuts harvested any differently from organic walnuts.   Here’s what one producer says.

The nuts are removed from the tree using a mechanical shaker, a machine that grasps the trunk and shakes the whole tree. The nuts drop to the ground, are then swept into windrows and picked up with harvest machinery. This operation is completed quickly to reduce the time nuts remain on the ground.

Uh oh indeed.  I hope this incident causes some changes in this procedure.

In the meantime, Marler has more to do.

The study: Mixed nut consumption improves brain insulin sensitivity: a randomized, single-blinded, controlled, crossover trial in older adults with overweight or obesity.  American Journal of Clinical Nutrition.  https://doi.org/10.1016/j.ajcnut.2023.12.010

Objective: “This study aimed to investigate longer-term effects of mixed nuts on brain insulin sensitivity in older individuals with overweight/obesity.”

Methods: “In a randomized, single-blinded, controlled, crossover trial, twenty-eight healthy adults (mean±SD; 65±3 years; BMI: 27.9±2.3 kg/m²) received either daily 60 g mixed nuts (15 g of walnuts, pistachio, cashew, and hazelnuts) or no nuts (control) for 16 weeks, separated by an 8-week washout period.”

Results: “Compared with control, mixed nut consumption improved regional brain insulin action in five clusters located in the left…and right occipital lobe.

Conclusions: “Longer-term mixed nut consumption affected insulin action in brain regions involved in the modulation of metabolic and cognitive processes in older adults with overweight/obesity.”

Funding: “This study was supported by a grant obtained from the International Nuts and Dried Fruit Council (INC). The INC had no role in the study design, data collection or analysis, decision to publish, or preparation of the manuscript.”

Comment: Does this study have any clinical significance?  Body weight and composition did not change. I’m all for nut-eating—love them—but for this reason?  Hardly.  Despite what this study implies, nuts have calories and they most definitely count.

I have so many of these waiting to be posted that I might as well do a bunch of them all at once.

Almonds

The study: Prospective Randomized Controlled Trial on the Effects of Almonds on Facial Wrinkles and Pigmentation. Nutrients 2021, 13(3), 785; https://doi.org/10.3390/nu13030785.

Conclusion: “the daily consumption of almonds may contribute to the improvement of facial wrinkles and reduction of skin pigmentation among postmenopausal women with Fitzpatrick skin types I and II.”

Funder: Almond Board of California

Comment: Thanks to Lori Rothman for sending this one.  It’s not the first time I’ve posted an almonds-and-wrinkles study; here’s the other from 2021.   And please note.  It’s not just almonds.  Mangos do this too.  But the Almond Board is working hard on turning almonds into superfoods. Members of the Academy of Nutrition and Dietetics were sent an announcement “Exciting new research investigates the link between almonds and these three key areas: Exercise recovery, prediabetes and skin health. That ad sends you to “Dietitian Tools” on the California Almonds website, where you can find a handy link to the study.

Here’s another one:

The study: Almond intake alters the acute plasma dihydroxy-octadecenoic acid (DiHOME) response to eccentric exercise.Front. Nutr., 09 January 2023  Volume 9 – 2022 | https://doi.org/10.3389/fnut.2022.1042719

Conclusions: “In general, the elevated post-exercise plasma levels of 12,13-DiHOME with almond intake support positive metabolic outcomes for adults engaging in unaccustomed eccentric exercise bouts. Other almond-related benefits for exercisers revealed in this study include reduced feelings of fatigue and tension, better leg-back strength during recovery, and decreased muscle damage during the first day of recovery.”

Funding: This work was supported by Almond Board of California, Modesto, CA. The funder had no role in the study design, data collection, analysis and interpretation, the preparation of the manuscript, or in the decision to submit the article for publication.

Comment: That’s what they all say.

Macadamias

The study: Macadamia nut effects on cardiometabolic risk factors: a randomised trial  J Nutr Sci. 2023.

Conclusion: “Daily consumption of macadamia nuts does not lead [sic]to gains in weight or body fat under free-living conditions in overweight or obese adults; non-significant cholesterol lowering occurred without altering saturated fat intake of similar magnitude to cholesterol lowering seen with other nuts.”

Funding: This study was funded by Hort Innovation, Sydney, Australia (Project code MC17005).  J. J., K. O. and F. M. – None; J. S., S. R. and C. H. have received research funding through their institution from Hort Innovation, Sydney, Australia.  Note: “Hort Innovation is a grower-owned, not-for-profit research and development corporation with the goal of creating value for horticulture growers and those across the horticulture supply chain. It invests more than $120 million in R&D, marketing and trade programs on behalf of industry.”

Peanuts

The study:  Urinary Phenolic Metabolites Associated with Peanut Consumption May Have a Beneficial Impact on Vascular Health Biomarkers. Antioxidants. 2023; 12(3):698. https://doi.org/10.3390/antiox12030698.

Conclusion:  “the present study shows for the first time that regular peanut and peanut butter consumption could have a positive impact on vascular biomarkers in healthy young adults.”

Funding: This research was supported by funding from the Peanut Institute.

Tree Nuts

The study: Tree Nut and Peanut Consumption and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Advances in Nutrition.  May 04, 2023  https://doi.org/10.1016/j.advnut.2023.05.004

Conclusion: “The findings of this review provide evidence of a combined effect of tree nuts and peanuts on a range of biomarkers to create an overall CVD risk reduction.”

Funding: “The findings of this review provide evidence of a combined effect of tree nuts and peanuts on a range of biomarkers to create an overall CVD risk reduction.”

Author disclosures: Two of the authors received previous funding from the International Nut and Dried Fruit Council or the California Walnut Commission.

Comment: If you are interested in doing nut research, trade associations will be happy to fund it.  But maybe only if the results come out the way the funder wants them to?

And another one on tree nuts.

The study: Mixed Tree Nuts, Cognition, and Gut Microbiota: A 4-Week, Placebo-Controlled, Randomized Crossover Trial in Healthy Nonelderly Adults.  J. Nutrition.   VOLUME 152, ISSUE 12, P2778-2788, DECEMBER 2022.  https://doi.org/10.1093/jn/nxac228

Conclusions: “These findings indicate a positive effect of nut on cognition following only 4 wk of consumption in a healthy nonelderly sample, as well as upregulation of a microbial taxa associated with gut health.

Funding: This study was supported by funding from the INC (International Nut and Dried Fruit Council).

Walnuts

The California Walnut Commission and the USDA have put out a request for research proposals on the effects of walnuts on sleep and mental health (I learned about this one from a Tweet (oops, X).  Want to do it?  You can get up to $300,000.

Comment: I guess I don’t have much imagination but I cannot think of a reason why walnuts in particular would have anything to do with sleep or mental health.  But I’ll bet enterprising investigators can figure something out.  Stay tuned on this one.

Overall comment

My point about all of these studies is that you can usually predict who paid for them by their titles and if you know who paid for them, you can pretty well predict what they will find.  Nut trade associations want you to eat more nuts, preferably the kind they represent.  Nuts are just fine for health, but watch the calories.  And do not expect miracles—ever—from eating just one healthy food.

At least five readers recently sent me items about research funding by pecan trade associations and I especially thank Lisa Young and Matthew Rees.

But I will begin with Headline vs. Study from the weekly newsletter (invaluable) Obesity & Energetics Offerings (8-18-23).

• Headline: New Research: Regular Pecan Consumption Could Curb Obesity and Reduce Inflammation.
• University News Article: Adding Pecans to Your Diet Could Help Prevent Obesity and Reduce Inflammation.
• Press-Release: Pecans Give Obesity and Diabetes a Slim Chance: Study Shows the Health Benefits of Pecans, Which May Curb Obesity and Reduce Inflammation.
• Study: Pecans and Its Polyphenols Prevent Obesity, Hepatic Steatosis and Diabetes by Reducing Dysbiosis, Inflammation, and Increasing Energy Expenditure in Mice Fed a High-Fat Diet.

Guess who funded this:

• Funding: We acknowledge funding from the Texas Pecan Board and a grant from the Texas Department of Agriculture.
• Conflicts of Interest: The authors declare no conflict of interest.

Comment: Acknowledged or not, the funding establishes a conflicted interest.  Industry funding influences the outcome of research, whether the researchers recognize it or not.  I will say more about that this week in response to a comment from a reader.

In the meantime, here is another one.

• The study: McKay DL, Eliasziw M, Chen CYO, Blumberg JB. A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial. Nutrients. 2018 Mar 11;10(3):339. doi: 10.3390/nu10030339.
• Acknowledgments: This work was supported by the U.S. Department of Agriculture (USDA) Agricultural Research Service under Cooperative Agreement No. 58-1950-014 and the National Pecan Shellers Association. The National Pecan Shellers Association provided the pecans for the intervention.
• Conflicts of Interest: The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

Comment:  The role of the National Pecan Sheller sAssociation is not clear (to me) from these acknowledgments.  Did the trade association initiate or fund the study, or was its involvement strictly in providing pecans?   Is there a difference?  Perhaps.  It is possible for studies involving vested financial interests to be done objectively, but studies of the “funding effect”—a higher probability of favorable outcomes—to be the norm.  Again, I will speak to this point later this week.

In the meantime, for detailed discussion and references of this issue, see my book, Unsavory Truth: How the Food Industry Skews the Science of What We Eat.

Nuts are demonstrably good for health.  They have high proportions of fat and, therefore, calories, and the calories can add up quickly.  But a small handful makes a great healthy snack.

Why their trade associations feel they need to produce favorable research is beyond me, but as far as I can tell, they are all competing with each other for market share.

Here are a few examples of nut studies funded by trade associations to convince you to eat more nuts.

The point: Whenever you see a study showing amazing health benefits from one single food, there’s a good chance its trade association paid for it.

NUTS IN GENERAL

The study: Mixed Tree Nuts, Cognition, and Gut Microbiota: A 4-Week, Placebo-Controlled, Randomized Crossover Trial in Healthy Nonelderly Adults.  J. Nutrition.   VOLUME 152, ISSUE 12, P2778-2788, DECEMBER 2022.  DOI:https://doi.org/10.1093/jn/nxac228

Conclusions: These findings indicate a positive effect of nut on cognition following only 4 wk of consumption in a healthy nonelderly sample, as well as upregulation of a microbial taxa associated with gut health. The effects appear to be independent of one another, but further exploration is required in those experiencing cognitive decline and/or gut dysbiosis.

Funding: This study was supported by funding from the INC (International Nut and Dried Fruit Council).

ALMONDS

The study: Almond intake alters the acute plasma dihydroxy-octadecenoic acid (DiHOME) response to eccentric exercise.  Front. Nutr., 09 January 2023. Volume 9 – 2022 | https://doi.org/10.3389/fnut.2022.1042719.

Conclusions: In general, the elevated post-exercise plasma levels of 12,13-DiHOME with almond intake support positive metabolic outcomes for adults engaging in unaccustomed eccentric exercise bouts. Other almond-related benefits for exercisers revealed in this study include reduced feelings of fatigue and tension, better leg-back strength during recovery, and decreased muscle damage during the first day of recovery.

Funding: This work was supported by Almond Board of California, Modesto, CA. The funder had no role in the study design, data collection, analysis and interpretation, the preparation of the manuscript, or in the decision to submit the article for publication.

MACADAMIAS

The study: Macadamia nut effects on cardiometabolic risk factors: a randomised trial  J Nutr Sci. 2023.

Conclusion: Daily consumption of macadamia nuts does not lead to gains in weight or body fat under free-living conditions in overweight or obese adults; non-significant cholesterol lowering occurred without altering saturated fat intake of similar magnitude to cholesterol lowering seen with other nuts.

Funding: This study was funded by Hort Innovation, Sydney, Australia (Project code MC17005).  J. J., K. O. and F. M. – None; J. S., S. R. and C. H. have received research funding through their institution from Hort Innovation, Sydney, Australia.  Note: Hort Innovation is a grower-owned, not-for-profit research and development corporation with the goal of creating value for horticulture growers and those across the horticulture supply chain. It invests more than $120 million in R&D, marketing and trade programs on behalf of industry.

PEANUTS

The study:  Urinary Phenolic Metabolites Associated with Peanut Consumption May Have a Beneficial Impact on Vascular Health Biomarkers. Antioxidants. 2023; 12(3):698. https://doi.org/10.3390/antiox12030698.

Conclusion:  the present study shows for the first time that regular peanut and peanut butter consumption could have a positive impact on vascular biomarkers in healthy young adults.

Funding: This research was supported by funding from the Peanut Institute

I’m often saying that industry-funded studies tend to produce results that favor the funder’s commercial interests.  This is true, but there are occasional exceptions.

Here, for example, are two studies based on grants from the American Pistachio Growers to the same group of investigators.  Both are randomized clinical trials with results that must have disappointed the funder.

I. Effects of short-term pistachio consumption before and throughout recovery from an intense exercise bout on cardiometabolic markers

Results: Two weeks of pistachio consumption failed to elicit changes in any biomarker (p < .05).. .Overall, in healthy young men with normal blood lipid and glucose metabolism, little effect of either pistachios or intense exercise on cardiometabolic risk indicators was detected.

II. Influence of pistachios on force production, subjective ratings of pain, and oxidative stress following exercise-induced muscle damage in moderately trained athletes: A randomized, crossover trial.

Results: Creatine kinase, myoglobin, and C-reactive protein increased over time following exercise (p < 0.05); however, there were no advantages following pistachio consumption. No significant changes in vertical jump or superoxide dismutase were elicited during any trial.

Comment:  The second paper put a positive spin on the basically null results: “This study demonstrates that 3.0 oz/d of pistachios can reduce delayed onset of muscle soreness and maintain muscle strength, potentially promoting exercise tolerance and training adaptations.”  My question is why anyone would think that pistachios would make any difference anyway.  They are one food in the diets of people who eat many othere kinds of foods.  I’m all for eating pistachios, if you like them, along with lots of other healthy foods.  There is only one reason to do this kind of one-food research—for marketing purposes.

You don’t believe this?  Check out the nutrition and health section of the Pistachio Growers website.  You can’t make this stuff up.

Hey.  If that’s all it takes, give it a try (I guess).

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