by Marion Nestle

Currently browsing posts about: Nuts

Oct 16 2023

Industry funded studies of the week: Nuts and more nuts

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.

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Aug 21 2023

Industry-funded study of the week: Pecans again

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).

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.

 

 

Jul 26 2023

Industry-funded research #3: nuts

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 BiomarkersAntioxidants. 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

Mar 20 2023

Industry-funded studies: null results!

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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Mar 13 2023

Industry-funded study of the week: Walnuts

I always enjoy the Headline vs Study section of the newsletter, Obesity and Energetics Offerings.

I particularly like this one because the headline says one thing but the study says another, and the authors put a positive spin on the results (interpretation bias).

The study: The Effects of Walnuts and Academic Stress on Mental Health, General Well-Being and the Gut Microbiota in a Sample of University Students: A Randomised Clinical Trial.  Nutrients 202214(22), 4776; https://doi.org/10.3390/nu14224776

Rationale: Poorer mental health is common in undergraduate students due to academic stress. An interplay between stress and diet exists, with stress influencing food choices.

Results: Academic stress was associated with lower gut microbial diversity in females, which was improved by walnut consumption.  The effects of academic stress or walnut consumption in male participants could not be established due to small numbers of participants. Thus, walnut consumption may have a protective effect against some of the negative impacts of academic stress, however sex-dependent mechanisms require further study.

Overall conclusion: While daily consumption of walnuts could not alleviate disturbances in mood, it had a protective effect against the negative impacts of academic stress on mental health…daily walnut consumption over 16 weeks was able to alleviate the negative effects of academic stress on the diversity of the gut microbiota in females, however the relevance of these changes to the biochemistry of chronic stressors such as academic stress requires further study.

Funding: This research was co-funded by the University of South Australia (UniSA) and the California Walnuts Board & Commission…Walnuts for the study participants were provided by the California Walnuts Board & Commission. ..We thank Walnuts Australia for providing walnuts to the control group (upon completion of the study)….

Conflicts of interest: The sponsors had no role in the design, execution, interpretation, or writing of the study. The authors declare no conflict of interest.

Comment: The study didn’t show much, despite the enormous amount of work that went into it.  This looks like an excellent example of interpretation bias—putting a positive spin on barely significant results.  Industry-funded research usuall gets interpreted positively and recipients of industry funding believe that it does not influence them or cause conflicted interests.  But much research says it does.  And then, of course, this is a study of the effects of one food, usually not eaten in large amounts (nuts are expensive!) in diets containing large numbers of other foods.  Attributing big health effects to any one food hardly ever makes sense.

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Jan 23 2023

Industry-funded studies of the week: Nuts, again and again

So many people send me these things that I can hardly keep up.  Let’s take a look at two this time.  Thanks to Hugh Joseph and Matthew Kirby for these:

I.  The impact of almonds and almond processing on gastrointestinal physiology, luminal microbiology, and gastrointestinal symptoms: a randomized controlled trial and mastication study   Alice C Creedon, Eirini Dimidi, Estella S Hung, Megan Rossi, Christopher Probert, Terri Grassby, Jesus Miguens-Blanco, Julian R Marchesi, S Mark Scott, Sarah E Berry, Kevin Whelan.  The American Journal of Clinical Nutrition, Volume 116, Issue 6, December 2022, Pages 1790–1804, https://doi.org/10.1093/ajcn/nqac265

  • Conclusions: “Almond consumption has limited impact on microbiota composition but increases butyrate in adults, suggesting positive alterations to microbiota functionality. Almonds can be incorporated into the diet to increase fiber consumption without gut symptoms.”
  • Funding: Supported by an Almond Board of California grant (to KW). The funders provided financial support, and the whole and ground almonds consumed by participants in the trial, but had no role in study design, conduct, analysis, interpretation, or decision to publish.
  • Author disclosures: ACC was funded by a PhD studentship funded by Almond Board of California. ED has received an education grant from Alpro, research funding from the British Dietetic Association, Almond Board of California, the International Nut and Dried Fruit Council, and Nestec Ltd, and has served as a consultant for Puratos. MR and KW have received research funding from Almond Board of California, Danone, and International Dried Fruit and Nut Council, and are co-inventors of volatile organic compounds in the diagnosis and dietary management of irritable bowel syndrome. MR is also cofounder of Bio&Me, a gut health food brand. TG supervises PhD students partially funded by Mondelez and McCain Foods Ltd, and has previously received research funding from Almond Board of California. SEB has received grant funding from Almond Board of California, Malaysian Palm Oil Board, and ZOE Ltd, and receives consultancy and options from ZOE Ltd. All other authors report no conflicts of interest.
  • Comment: The Almond Board is doing its job, apparently.

II. Almond intake alters the acute plasma dihydroxy-octadecenoic acid (DiHOME) response to eccentric exercise.   David C. Nieman1* Ashraf M. Omar2 Colin D. Kay3,  Deepak M. Kasote3,  Camila A. Sakaguchi1,  Ankhbayar Lkhagva2,  Mehari Muuz Weldemariam2 and  Qibin Zhang. Front. Nutr., 09 January 2023. https://doi.org/10.3389/fnut.2022.1042719

  • Conclusions:These data support some positive effects of almond intake in improving mood state, retaining strength, decreasing muscle damage, increasing the generation of gut-derived phenolic metabolites, and altering the plasma oxylipin DiHOME response to unaccustomed eccentric exercise in untrained adults. 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.”
  • 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.”
  • Conflict of Interest: “The 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.”
  • Comment:  I disagree.  The fact that the Almond Board funded the study if nothing else gives the appearance of conflicted interests, especially because studies so clearly document the influence of funding whether recognized by recipients or not.

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Dec 12 2022

Industry-funded study of the week: Headline vs. Study

As regular readers know, I subscribe to the weekly newsletter, Obesity and Energetics Offerings, and particularly enjoy its section on Headline vs Study.

Here’s a particularly amusing example, which right away triggers my question: Who paid for this?

Headline vs Study

Let’s take a look.

Headline: Snacking on Almonds Can Help People Reduce Calorie Intake: Study.

A handful of almonds may be the latest weight loss hack, new research suggests.

new study from the University of South Australia found that eating 30 to 50 grams of almonds could regulate appetite, leading to less calories consumed each day.

The research, which examined both the hormones that regulate appetite and how almonds could aid in controlling hunger, discovered that the consumption of the nut ultimately led to about 300 fewer calories [sic*]consumed at the following meal.

Press Release: Believe It or ‘Nut’, Almonds Can Help You Cut Calories, Study Finds.

Examining how almonds can affect appetite, researchers found that a snack of 30-50 grams of almonds could help people cut back on the number of kilojoules they consume each day.

Published in the European Journal of Nutrition, the study found that people who consumed almonds — as opposed to an energy-equivalent carbohydrate snack — lowered their energy intake by 300 kilojoules (most of which came from junk food) at the subsequent meal.

Study:  Acute feeding with almonds compared to a carbohydrate-based snack improves appetite-regulating hormones with no effect on self-reported appetite sensations: a randomised controlled trial. Carter, S., Hill, A.M., Buckley, J.D. et al.Eur J Nutr (2022). https://doi.org/10.1007/s00394-022-03027-2

Results: “…Cholecystokinin, ghrelin, glucagon-like peptide-1, leptin and polypeptide YY AUCs were not different between groups. Self-reported appetite ratings and energy intake following the buffet did not differ between groups.”

Conclusion: “More favourable appetite-regulating hormone responses to AL did not translate into better self-reported appetite or reduced short-term energy consumption. Future studies should investigate implications for longer term appetite regulation.”

Funding: “This work was funded by the Almond Board of California. This funding source had no role in the design of this study or the analysis and interpretation of the data.”

Conflict of interest: “AMC has consulted for Nuts for Life (an initiative of the Australian Tree Nut Industry). S-YT has previously been involved in studies funded by the Californian Walnut Commission. AMC, JDB and S-YT have previously been involved in studies funded by International Nut and Dried Fruit Council.”

*Comment: How could the headline get it so wrong?  The authors write: “Although not significant, the AL group consumed 300 kJ less energy in the meal challenge than the SB group, 270 kJ of which came from discretionary foods, which may be a clinically important benefit in weight management.”  The sic partly explains the problem.  The 300 refers to kilojoules (kj), not calories.  300 kj = 72 calories, not 300.  No wonder the result wasn’t statistically significant.

But the press release and resulting headline explain why the nut industry funds studies like this.  Even when the result shows no difference, the PR people can spin the data to produce the expected favorable result.

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Oct 24 2022

Industry-funded study of the week: Pistachios

I haven’t posted anything about pistachio industry conflicts of interest since 2019 so it’s time for another one.

Here’s a press release sent to me by a reader, Matthew Kadey:

NEW STUDY REVEALS PISTACHIOS ARE AN ANTIOXIDANT POWERHOUSE…Antioxidant-rich foods are regularly encouraged as part of a healthy lifestyle, and research suggests that a diet high in antioxidants may even help to reduce the risk of death.1 While certain fruits and vegetables are often thought of as high-antioxidant foods, a new study conducted by Cornell University and published in the journal, Nutrients, produced surprising results2. Pistachios have a very high antioxidant capacity, among the highest when compared to values reported in research of many foods commonly known for their antioxidant capacity, such as blueberries, pomegranates, cherries, and beets.3,4,5  (I’ve posted the references at the end).

My first question, as always when I see a press release like this: Who paid for it?

The study: uan, Wang, Bisheng Zheng, Tong Li, and Rui Hai Liu. 2022. Quantification of Phytochemicals, Cellular Antioxidant Activities and Antiproliferative Activities of Raw and Roasted American Pistachios (Pistacia vera L). Nutrients 14, no. 15: 3002. https://doi.org/10.3390/nu14153002

Conclusion:  It is shown that the roasting of pistachios could produce a series of beneficial phytochemical changes, leading to enhanced biological activity. Pistachios are a nutrient-dense food containing a unique profile of good-quality protein, fats, minerals, vitamins, and antioxidants, such as carotenoids and polyphenols, with cellular antioxidant activity. Dietary Guidelines for Americans 2020–2025 suggested including nuts as a health dietary pattern. Further research on antiproliferative activity and mechanisms of action of free-form extracts of roasted pistachios, and more biological activities related cellular antioxidant activity and oxidative stress, are worthy of further investigation.

 

Funding: This study was partially supported by Innovative Leading Talents Project of Guangzhou Development Zone and 111 Project: B17018, Cornell China Center, and American Pistachio Growers: 2021-09.

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

Comment: Roasted pistachios are healthy?  No surprise here.  Further research needed?  Also no surprise.  This is another example of an industry-funded study with unimpressive results but plenty of interpretation bias, along with the usual contention that industry funding does not induce conflicts of interest.  Alas, it does.

References to the press release paragraph

1 Jayedi A, Rashidy-Pour A, Parohan M, Zargar MS, Shab-Bidar S. Dietary Antioxidants, Circulating Antioxidant Concentrations, Total Antioxidant Capacity, and Risk of All-Cause Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Observational Studies. Adv Nutr. 2018 Nov 1;9(6):701-716. doi: 10.1093/advances/nmy040. PMID: 30239557; PMCID: PMC6247336.
2 Yuan W, Zheng B, Li T, Liu RH. Quantification of Phytochemicals, Cellular Antioxidant Activities and Antiproliferative Activities of Raw and Roasted American Pistachios (Pistacia vera L.). Nutrients. 2022; 14(15):3002. https://doi.org/10.3390/nu14153002
3 Wolfe KL, et al. Cellular Antioxidant Activity (CAA) Assay for Assessing Antioxidants, Foods, and Dietary Supplements. J Agric. Food Chem. 2007, 55, 8896–8907.
4 Song W, et al. Cellular Antioxidant Activity of Common Vegetables. J. Agric. Food Chem. 2010, 58, 6621–6629. DOI:10.1021/jf9035832
5 Wolfe, K., Kang, X., He, X., Dong, M., Zhang, Q., and Liu, R.H. Cellular antioxidant activity of common fruits. J. Agric. Food Chem. 56 (18): 8418-8426, 2008.

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