by Marion Nestle

Search results: research bias

May 5 2016

More on corporate funding of nutrition research: exchange of letters

In January this year, JAMA Internal Medicine published my Viewpoint on corporate funding of nutrition research: science or marketing.

Richard Kahn, former chief scientist and medical officer of the American Diabetes Association, wrote a letter in reply (see below for more about him**).  The journal published his letter, along with my response, in its current issue.  Here’s what I said.

In Reply Dr Kahn requests evidence that nutrition research funded by food companies is of lesser quality than studies funded by independent agencies or performed by investigators with nonfinancial conflicts of interest. Concerns about such issues are relatively recent; few published studies address them directly. Instead, concerns about industry sponsorship of nutrition research derive from comparisons with the results of studies of funding by tobacco, chemical, drug, or medical device companies. This research typically finds industry-sponsored studies to report results more favorable to the products of the sponsor than studies not funded by industry. It identifies subtle rather than substantive differences in the quality of this research; industry-funded studies are more likely to underreport unfavorable results and interpret neutral results more positively.1 When results are negative, they are less likely to be published.2

Between March 2015 and March 2016, I identified 166 industry-funded nutrition research studies and posted and discussed them on my blog.3 Of these, 154 reported results favorable to the interest of the sponsor; only 12 reported contrary results. The few studies systematically examining the influence of industry funding on nutrition research tend to confirm results obtained from other industries. For example, a systematic review comparing industry-funded and nonindustry-funded trials of probiotics in infant formula reported no association of funding source with research quality. Industry-funded studies, however, seemed more likely to report favorable conclusions unsupported by the data.4

Dr Kahn states that sponsored studies often specify that the funder had no role in the study. Only recently have some journals required such statements, and I am unaware of research on the extent of this practice or authors’ adherence to it. Among the 166 industry-funded studies that I reviewed, few disclosed involvement of a sponsor.

Dr Kahn asks whether industry funding is any more biasing than career self-interest or intellectual passion. Unlike industry funding, self-interest and passions are intrinsic to every scientist who conducts research, are a matter of public record, cannot be eliminated, and have not been shown to consistently bias research results in the same ways as industry funding.5 Fortunately, nutrition societies and research institutions are developing policies to manage financial relationships with industry.6 Such policies hold promise for preventing financial conflicts of research in nutrition research.

1. Lundh  A, Sismondo  S, Lexchin  J, Busuioc  OA, Bero  L.  Industry sponsorship and research outcome. Cochrane Database Syst Rev. 2012;12:MR000033. PubMed

2. Rising  K, Bacchetti  P, Bero  L.  Reporting bias in drug trials submitted to the Food and Drug Administration: review of publication and presentation. PLoS Med. 2008;5(11):e217. PubMed   |  Link to Article

3. Nestle  M. Food Politics Blog. https://foodpolitics.com/. Accessed March 2, 2016.

4. Mugambi  MN, Musekiwa  A, Lombard  M, Young  T, Blaauw  R.  Association between funding source, methodological quality and research outcomes in randomized controlled trials of synbiotics, probiotics and prebiotics added to infant formula: a systematic review. BMC Med Res Methodol. 2013;13:137. PubMed   |  Link to Article
5. Bero  L.  What is in a name? Nonfinancial influences on the outcomes of systematic reviews and guidelines. J Clin Epidemiol. 2014;67(11):1239-1241. PubMed   |  Link to Article 
6. Charles Perkins Centre. Engagement with Industry Guidelines 2015. University of Sydney, 2015. https://intranet.sydney.edu.au/perkins/research-support/engaging-with-industry.html. Accessed March 2, 2016.
**Richard Kahn is infamous in my circles for supporting the positions of the sugar and soda industries while with the American Diabetes Association and now.  I wrote about what he said in an interview with Corporate Crime Reporter in my book What to Eat (pages 355-356).  Recently, The Russells (of CrossFit) had a lot more to say about Kahn’s ongoing opposition to public health measures.
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Feb 16 2016

Sponsored research Down Under: alcohol and violence

Thanks to my friend Jocelyn Harris of Dunedin, New Zealand for forwarding this editorial from the Otago Daily Times of January 16.

The editorial notes that a recent report finding no linkage between alcohol consumption and violence among Australians and New Zealanders was sponsored by Lion, a leading supplier of alcoholic beverages.

The report is Understanding Behavior in the Australian and New Zealand Night-Time Economies: An Anthropological Study.  Its author, anthropologist Anne Fox, lists these key findings:

  • Alcohol-related violence is just one aspect of a culture of violence.
  • There is no direct relationship between per capita levels of consumption and rates of violence.
  • A drinking culture is both a part of and a reflection of the culture as a whole.
  • Efforts at alcohol control will be ineffective if not related to changes in the macho culture of violence.
  • Scapegoating alcohol as the sole cause of violence merely diverts attention from violent men and the maladaptive cultural norms that allow their behaviour to develop and proliferate.

Her recommendations focus on the behavior of individuals behavior.  They largely dismiss the value of approaches such as limitations on alcohol marketing, the times alcoholic beverages can be sold, or the ways beverage companies create local cultures of drinking.

In a nutshell, the central point of this whitepaper is: it is the wider culture that determines the drinking behaviour, not the drinking. You can’t change a culture by simply changing drinking. It is, of course, justifiable to explore the effectiveness of small measures such as advertising restrictions, increases or decreases in price, relaxation or restriction of hours, but such things tinker at the margins of culture and it is doubtful that they will alter the culture of violence and anti-social behaviour in any meaningful way.

The report explains:

We could become totalitarian and try to stop public festive drinking completely, but it would most likely just move into homes. Or we can live with it and try to determine what the worst outcomes are (police overtime, all night transport cost, lost work hours and productivity, accidents and injuries, street clean-up, etc.,), and work to minimise and deal with them sensibly. We would do better to work cooperatively with all stakeholders to engineer conditions for festive drinking that are the least conducive to violence and anti-social behaviour.

In other words, societies should fix the problem at the level of “festive” drinking, but should not bother to try to prevent it at an earlier stage in the chain of causation of alcohol abuse.

The Otago Daily Times editorial concludes:

It is vital we keep debating the issues, examining the causes and hearing all the voices in the debate.

But that debate must be fair and honest.

It is a real shame, therefore, that Dr Fox has effectively silenced herself by aligning herself with an alcohol industry giant when her findings could have made a valuable contribution had they been genuinely independent.

Presumably, Lion got the report it paid for.  But it left itself—and the author’s work—vulnerable to charges of bias, an inevitable hazard of industry-sponsored research.

A shame indeed.

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Jan 6 2016

Viewpoint: Food-industry Funding of Food and Nutrition Research

My latest Viewpoint, “Corporate funding of food and nutrition research: science or marketing,” was published yesterday in JAMA Internal Medicine 2016;176 (1):13-14.  doi:10.1001/jamainternmed.2015.6667.

The longstanding influence of food industry funding on nutrition research, researchers, and professional societies1 threatens the credibility of nutrition science. So much research is sponsored by industry that health professionals and the public may lose confidence in basic dietary advice. Although most journals now require authors to disclose who pays for their work, disclosure—even done diligently—is not sufficient to alert readers to the extent to which industry funding influences research results and professional opinion. As is well established from experimental and observational research, drug company gifts and grants can have substantial effects. To recipients, however, these effects are almost always unconscious, unintentional, and unrecognized, making them especially difficult to prevent.

Medical schools and medical journals have increased efforts to minimize and manage conflicts of interest with industry. But from my observations, nutrition researchers, journals, and professional societies, like medical researchers, often fail to realize that food-industry funding may affect their work and its credibility.

Two recent investigative articles in the New York Times illustrate the concerns about biases introduced by industry funding. The first3 described the support by Coca-Cola of academic researchers who founded a new organization, the Global Energy Balance Network, to promote physical activity as a more effective method than calorie control (eg, from avoiding sugary sodas) for preventing obesity. The second4 analyzed emails obtained through open-records requests to document how Monsanto, the multinational agricultural biotechnology corporation, on the one hand, and the organic food industry, on the other, recruited professors to lobby, write, and testify to Congress on their behalf.

Both articles3,4 quoted the researchers named in these reports as denying an influence of industry funding and lamenting the paucity of university research funds and the competitiveness of federal grants. Despite leaving their organizations open to accusations that they have sold out to industry,5 officers of nutrition research societies tell me that they cannot function without industry funding of journals and conferences. They have a point. Although the investment by federal agencies in food and nutrition research has increased steadily since the early 1990s, US Department of Agriculture grants are diminishing, and the National Institutes of Health are funding fewer researchers at state agricultural colleges. Investigators have a hard time obtaining grants for projects related to food composition, food technology, nutrients, and nutrient metabolism as federal agencies have understandably shifted priorities toward research on obesity, genetics, and chronic diseases.6

Food companies, such as Quaker Oats, used to support basic research conducted by in-house scientists, but Unilever and Nestlé (no relation) are among the very few companies that continue to do so. Instead, food companies outsource research, much of which can appear as designed for marketing purposes. Recently, in preparation for what I intend to be a more systematic analysis of corporate funding of nutrition research, I began collecting a convenience sample of studies funded by food and beverage companies or trade associations as they appear in journals I happen to be reading. I sort them by whether their results do or do not favor the interests of the sponsor, and post examples online at my blog, https://foodpolitics.com.7

Between March and October 2015, I identified 76 industry-funded studies. Of these, 70 reported results favorable to the sponsor’s interest. Despite ongoing requests to readers of my blog to help me identify funded studies reporting results contrary to a funder’s interest, I have found only 6.  [Note: Since writing this, the score has gone to 90:9.] This discrepancy is consistent with the results of systematic investigations of industry sponsorship, such as one on the role of sugar-sweetened beverages in obesity.8 In general, independently funded studies find correlations between sugary drinks and poor health, whereas those supported by the soda industry do not.9 In the studies I collected, companies or trade associations promoting soft drinks, dairy foods, eggs, breakfast cereals, pork, beef, soy products, dietary supplements, juices, cranberries, nuts, and chocolates supported the study itself, the investigators, or both. These studies all found significant health benefits or lack of harm from consuming the foods investigated, results that can be useful for deflecting criticism of a company or promoting its products.

Mars Inc, for example, the maker of chocolate candies such as M&Ms, funds studies on the effects of cocoa flavanols on arterial function and blood pressure. One such study, published in September 2015,10(p1246)concluded that these compounds “improved accredited cardiovascular surrogates of cardiovascular risk, demonstrating that dietary flavanols have the potential to maintain cardiovascular health even in low-risk subjects.” The study investigators,10 one of whom is employed by Mars, followed well-established scientific protocols in conducting the research. Science is not the issue here. Marketing is the issue. The question is why Mars would fund a study like this and assign one of its employees to help design and write it. In this instance, the answer is obvious. Mars issued a press release “Cocoa flavanols lower blood pressure and increase blood vessel function in healthy people,” and noted these results in a full-page advertisement in the New York Times on September 27, 2015, Neither the press release nor advertisement explained that cocoa flavanols are largely destroyed during all but the most careful processing of chocolate, nor did they mention chocolate at all. They didn’t have to. Uncritical readers are likely to interpret the statements as evidence that chocolate is good for them and that its sugar and calories can be ignored.

The second New York Times article4 raised more insidious concerns about industry involvement with scientists, using Monsanto and organic food companies as cases in point. Although both industries recruit scientists to speak on their behalf, Monsanto has far greater resources. In 1994, I was a member of the Food Advisory Committee to the US Food and Drug Administration (FDA) when that agency approved genetically modified (GM) foods. I observed how Monsanto-funded scientists convinced the FDA that labeling GM foods would be misleading.

Confronted with increasing public support for labeling foods that are produced with GM ingredients, the biotechnology industry supported—and the House of Representatives passed—H.R. 1599 in July 2015. This bill, expected to be considered by the Senate before the end of 2015, has the Orwellian title, “The Safe and Accurate Food Labeling Act,” but some critics call it the “Denying Americans the Right to Know (DARK) Act.” Proposed by Representative Mike Pompeo (Kansas) on the basis that GM foods are safe and, therefore, acceptable, the act would block states from enacting labeling laws (as Vermont has already done) and permit GM foods to be labeled as “natural.” Opponents question the safety of GM foods. But they also raise additional reasons for full transparency in labeling—patents, control of seed stocks, the widespread application of chemical herbicides to GM crops, and the increasingly widespread resistance of weeds to those herbicides. When evaluating conflicting scientific and policy arguments about GM foods, it is useful to know who funds the researchers and their studies.

Should nutrition researchers and professional societies accept funding from food companies? Not without careful thinking. It’s time that food and nutrition researchers and societies recognize the influence of food-industry sponsorship, take steps to control its effects, and ensure that sponsored studies promote public health, not the marketing of food products. Journal editors should ensure that editors and members of editorial boards are free of industry conflicts, require peer reviewers to note food-industry funding in manuscript evaluations, and be wary of accepting industry-funded publications with evident commercial implications. If food companies and trade associations want to fund research, they should consider pooling resources and setting up an independent foundation to administer the grants. Everyone involved in this system should be doing everything possible to advocate for more research funds from federal granting agencies. Nothing less than the credibility of nutrition research and advice is at stake.

REFERENCES

1 Nestle  M. Food Politics: How the Food Industry Influences Nutrition and Health.3rd ed. Berkeley: University of California Press; 2013.
2 Lo  B, Field  MJ, eds. Conflict of Interest in Medical Research, Education, and Practice. Washington, DC: National Academies Press; 2009.
3 O’Connor  A. Coca-Cola funds scientists who shift blame for obesity away from bad diets. New York Times. August 9, 2015. http://well.blogs.nytimes.com/2015/08/09/coca-cola-funds-scientists-who-shift-blame-for-obesity-away-from-bad-diets/?_r=0. Accessed October 22, 2015.
4 Lipton  E. Food industry enlisted academics in G.M.O. lobbying war, emails show. New York Times. September 5, 2015. http://www.nytimes.com/2015/09/06/us/food-industry-enlisted-academics-in-gmo-lobbying-war-emails-show.html. Accessed October 22, 2015.
5 Simon  M. Nutrition scientists on the take from Big Food: has the American Society for Nutrition lost all credibility? June 2015. http://www.eatdrinkpolitics.com/wp-content/uploads/ASNReportFinal.pdf. Accessed October 22, 2015.
6 Toole  AA, Kuchler  F. Improving health through nutrition research: an overview of the U.S. nutrition research system. Econ Res Rep No. 182. January 2015.http://www.ers.usda.gov/media/1760111/err-182.pdf. Accessed October 27, 2015.
7 Nestle  M. Food Politics blog. https://foodpolitics.com. Accessed October 27, 2015.
8 Lesser  LI, Ebbeling  CB, Goozner  M, Wypij  D, Ludwig  DS.  Relationship between funding source and conclusion among nutrition-related scientific articles. PLoS Med. 2007;4(1):e5. PubMed   |  Link to Article
9 Massougbodji  J, Le Bodo  Y, Fratu  R, De Wals  P.  Reviews examining sugar-sweetened beverages and body weight: correlates of their quality and conclusions. Am J Clin Nutr. 2014;99(5):1096-1104. PubMed   |  Link to Article
10 Sansone  R, Rodriguez-Mateos  A, Heuel  J,  et al; Flaviola Consortium, European Union 7th Framework Program.  Cocoa flavanol intake improves endothelial function and Framingham Risk Score in healthy men and women: a randomised, controlled, double-masked trial: the Flaviola Health Study. Br J Nutr. 2015;114(8):1246-1255. doi:10.1017/S0007114515002822. PubMed   |  Link to Article

ARTICLE INFORMATION

Corresponding Author: Marion Nestle, PhD, MPH, Department of Nutrition, Food Studies, and Public Health, New York University, 411 Lafayette, Fifth Floor, New York, NY 10003-7035 (marion.nestle@nyu.edu).

Published Online: November 23, 2015. doi:10.1001/jamainternmed.2015.6667.

Conflict of Interest Disclosures: Dr Nestle’s salary from New York University supports her research, manuscript preparation, website, and blog at https://foodpolitics.com. She also earns royalties from books and honoraria from lectures to university and health professional groups about matters relevant to this Viewpoint.

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Aug 19 2015

Coca-Cola’s sponsorship of favorable research: the saga continues

When the New York Times published an article describing Coca-Cola’s financial sponsorship of university researchers who de-emphasize the role of sugary drinks in raising the risk of obesity and type 2 diabetes, it kicked up a storm.

USA Today’s editorial board said:

It isn’t that companies pay scientists to put out false research. It’s that companies fund the work of scientists who happen to be doing research that spurs consumers to look away from science that hurts corporate interests.

Soft drinks are far less dangerous than cigarettes, but GEBN’s website, tweets and videos come right out of Big Tobacco’s playbook, brought into the digital era. Its leaders have done research in the past under about $3 million in grants given to their universities.

USA Today also printed a response by a Coca-Cola spokesman:

A recent New York Times article created confusion about our support of research and non-profit organizations, stating we want people to think that only exercise matters and not diet — but nothing could be further from the truth. We have always operated under the fact that a healthy, balanced diet and regular exercise are key ingredients for a healthy lifestyle.

That said, we need to do a better job of being even more transparent about the research we fund, the non-profit organizations we support and the way we publicly share this information. And we will.

Yesterday, Senator Richard Blumenthal sent letters to the University of Colorado, West Virginia University, and the University of South Carolina urging them to  clarify the nature of the University’s relationship with projects funded by Coca-Cola and to review the academic integrity of such grant agreements.

I believe your university must determine whether this research is in effect promoting a predisposed and biased agenda, rather than reflecting the impartiality and objectively (sic) expected from a public academic institution.

Years of litigation with tobacco companies were necessary to fully expose the tragic public health consequences when companies lie about the hazards of the products they sell.  I am deeply concerned that we may force future generations to relive this history if corporate-sponsored studies devoid of scientific integrity are permitted once again to deceptively downplay and conceal the dangers of a product consumed on a mass scale.

Do not underestimate Senator Blumenthal’s ability to deal with food companies.  He, you may recall, was responsible for withdrawal in 2009 of the ill-conceived Smart Choices program during his stint as Connecticut’s attorney general.

I’m still waiting for the Global Calorie Balance Network to issue its promised statement.  Stay tuned.

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May 21 2015

This week’s post on industry-sponsored research

As promised, I am posting examples of industry-sponsored research every time I collect five.  These, like the others, produce results favorable to the sponsor’s interests.

I am happy to post examples of sponsored studies that do not favor the sponsor’s interests, and this first one comes closest.  This Unilever-sponsored study found that consuming the product had no effect on blood flow in people with high blood cholesterol levels, although it did lower their levels of LDL (the “bad” cholesterol).

The effect of a low-fat spread with added plant sterols on vascular function markers: results of the Investigating Vascular Function Effects of Plant Sterols (INVEST) study. By Rouyanne T Ras, Dagmar Fuchs, Wieneke P Koppenol, Ursula Garczarek, Arno Greyling, Christian Keicher, Carole Verhoeven, Hakim Bouzamondo, Frank Wagner, and Elke A Trautwein.  Am J Clin Nutr 2015; 101:733-741 doi:10.3945/ajcn.114.102053.

  • Conclusion: The intake of a low-fat spread with added PSs [plant sterols] neither improved nor worsened FMD [flow-mediated dilation]or other vascular function markers in hypercholesterolemic men and women. As expected, serum LDL cholesterol decreased, whereas plasma PSs increased after PS intake.
  • Sponsor: Unilever Research and Development

The next four are more typical:

Dairy proteins, dairy lipids, and postprandial lipemia in persons with abdominal obesity (DairyHealth): a 12-wk, randomized, parallel-controlled, double-blinded, diet intervention study. By Mette Bohl, Ann Bjørnshave, Kia V Rasmussen, Anne Grethe Schioldan, Bashar Amer, Mette K Larsen, Trine K Dalsgaard, Jens J Holst, Annkatrin Herrmann, Sadhbh O’Neill, Lorraine O’Driscoll, Lydia Afman, Erik Jensen, Merete M Christensen, Søren Gregersen, and Kjeld Hermansen.  Am J Clin Nutr 2015; 101:870-878 doi:10.3945/ajcn.114.097923

  • Conclusion:  We found that a whey protein supplement decreased the postprandial chylomicron response compared with casein in persons with abdominal obesity, thereby indicating a beneficial impact on CVD risk.
  • Sponsor: Arla Foods Ingredients Group P/S, and the Danish Dairy Research Foundation, among some independent sources.

Policy Statement: Snacks, Sweetened Beverages, Added Sugars, and Schools. Council on School Health, Committee on Nutrition, American Academy of Pediatrics.  Pediatrics Volume 135, number 3, March 2015.

  • Conclusion: A positive emphasis on nutritional value, variety, appropriate portion, and encouragement for a steady improvement in quality will be a more effective approach for improving nutrition and health than simply advocating for the elimination of added sugars.
  • Conflicts reported: One of the members of the committee writing this statement is supported by the National Dairy Council and the American Dairy Association.  Another receives support from the Nestle Nutrition Institute.

Maternal long chain polyunsaturated fatty acid [omega-3] supplementation in infancy increases length- and weight-for-age but not BMI to 6 years when controlling for effects of maternal smoking. L.M. Currie, E.A. Tolley, J.M. Thodosoff, E.H. Kerling, D.K. Sullivan, J. Colombo, and S.E. Carlson . Prostaglandins, Leukotrienes and Essential Fatty Acids, 2015.  http://dx.doi.org/10.1016/j. plefa.2015.04.001

  • Conclusion: Our results… suggest that LCPUFA [omega-3s] could have positive effects on stature without negative effects on weight status; and that LCPUFA could mitigate lower stature and higher BMI associated with maternal smoking, particularly in boys.
  • Sponsor: Mead Johnson Nutrition, the maker of the LCPUFA omega-3 supplement

Mediterranean Diet and Age-Related Cognitive Decline:  A randomized Clinical Trial. Cinta Valls-Pedret, MSc; Aleix Sala-Vila, DPharm, PhD; Mercè Serra-Mir, RD; et al.  JAMA Intern Med. Published online May 11, 2015. doi:10.1001/jamainternmed.2015.1668.

  • Conclusion: In an older population, a Mediterranean diet supplemented with olive oil or nuts is associated with improved cognitive function.
  • Conflicts reported: Dr Salas-Salvado reports receiving research funding and is a nonpaid member of the scientific advisory committee of the International Nut Council. Dr Ros also reports receiving research funding and is a nonpaid member of the scientific advisory committee of the California Walnut Commission.

Let me comment on this last one, which may seem like pushing things, given that the study itself was funded by the agency for biomedical research of the Spanish government.  I would have left it off this list had I not read an article about it in the Wall Street Journal.

The Journal interviewed Dr. Ros, the lead author:

The diminished decline in cognitive function likely stems from the abundance of antioxidants and anti-inflammatory agents found in the supplemental foods…He recommends that, to decrease age-related cognitive delay, people should add 5 tablespoons of olive oil as a well as a handful of nuts a day into their diet.

But the Journal also interviewed a clinical neuropsychologist who was not involved in the study:

The changes observed in cognition were very small and didn’t actually show that those diets improved cognition, they just showed less decline. Based on the research…people shouldn’t rush out to buy lots of olive oil and nuts.

My point here is that the sole purpose of this study was to prove the health benefits of olive oil and nuts.  Yes, these are healthy foods, but so are many others.  Like virtually all such studies, this one seems designed to produce the desired answer.

On his Weighty Matters blog, Dr. Yoni Freedhoff explains how biases play out in supposedly unbiased research journals, in this case, the British Journal of Sports Medicine.  Dr. Freedhoff talks about the journal’s temporary withdrawal of a paper arguing that diet is more important than physical activity in weight loss on the grounds that the authors did not disclose conflicts of interest.  In contrast, an editorial arguing the opposite, by authors who also did not disclose conflicts, went unchallenged and was not withdrawn.

Dr. Freedhoff asks: “Are these sorts of conflicts important to disclose?”

On the basis of today’s and many other examples, my answer is an unqualified yes.

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Mar 6 2011

The perils of food and nutrition research

I write a monthly (first Sunday) Food Matters column for the San Francisco Chronicle.  Today’s is about the difficulties of doing nutrition research.  The Chronicle headline writer titled it, “Be skeptical of food studies.”  Oops.

I’m not skeptical about Food Studies—the capitalized field of study—at all.  My NYU department started undergraduate, master’s, and doctoral programs in Food Studies in 1996 and they have flourished ever since.

The column is about small-letter food studies, meaning nutrition and food research studies:

Q: You were quoted saying that you didn’t believe newspaper reports linking diet sodas to an increased risk of stroke and heart disease. How do you decide whether research is good or bad?

A: This one was easy. I didn’t think it made sense. Mind you, I’m no fan of diet sodas. They violate my rule never to eat anything artificial. And I don’t like the taste of artificial sweeteners.

Whenever a study comes out claiming harm – or benefits – from eating a single food or ingredient, I get skeptical. That’s why I also questioned these recent study results: high-fructose corn syrup (HFCS) makes rats gain weight faster than sucrose (table sugar); zinc supplements prevent symptoms of the common cold; and pomegranate juice has greater health benefits than any other kind of fruit.

When I read about single-factor studies, I want to know three things: Is the result biologically plausible? Did the study control for other dietary, behavioral or lifestyle factors that could have influenced the result? And who sponsored it?

Plausibility: The diet soda study used a self-reported questionnaire to find out how often people reported drinking diet sodas. Nine years later, people who reported habitually drinking diet sodas had a 60 percent higher rate of stroke and heart attacks. The rate was somewhat lower when controlled for age, sex, race, smoking, exercise, alcohol, daily calories and metabolic syndrome.

Leaving aside the unreliability of self-reported dietary intake, the study raises a more important question. Was it designed to investigate the link between diet sodas and stroke or was this just an accidental finding? The questionnaire undoubtedly asked hundreds of questions about diet and other matters. Just by chance, some of them could be giving results that look meaningful. And the increase in stroke risk seems surprisingly high for something not previously known to be a stroke risk factor.

Mostly, I can’t think of a biological reason why diet sodas might lead to cardiovascular disease unless they are an indicator for some other stroke risk factor such as obesity, high blood pressure or binge drinking. It would take a study designed to test this idea specifically – and a good biological explanation – to convince me that diet sodas cause strokes.

The plausibility issue also rises in the HFCS study. Again, I’m not a fan of HFCS – we would all be healthier if we ate less sugar – but from a biochemical standpoint, HFCS and table sugar are pretty much the same. They have similar amounts of glucose and fructose, are digested as quickly and are metabolized the same way. Even the average amounts consumed are about the same. That soda companies are replacing HFCS with sucrose is strictly about marketing, not health.

Controls: The zinc-and-colds study was a comprehensive review (a “meta-analysis”) of previous studies done since the first one in 1984. Eleven studies have showed some benefit; seven have not. All of them were placebo controlled, double-blind. This meant that half the participants were given a dummy pill, and neither participants nor investigators were supposed to know who was taking what.

But in some studies, the zinc takers complained about the taste of the pills, hinting that they knew what they were.

I’ve heard this before. In the early 1970s, National Institutes of Health investigators did a study of vitamin C and the common cold. They got about 300 NIH employees to take either vitamin C or a placebo, double-blind. The tantalizing result: People taking vitamin C reported fewer colds and milder symptoms than people taking placebos.

Alas, many participants withdrew from the study before it ended. When asked why, they admitted tasting the pills. The investigators reanalyzed the results. Bingo! No matter what pill the participants actually took, those who thought they were taking vitamin C reported fewer colds and milder symptoms.

If the studies were not really blinded, the zinc results are questionable. I have no doubt that many people feel better when they take zinc supplements, but I’m not sure whether that’s because of something zinc really does or just its placebo effect.

Sponsorship: Vested interests influence the design and interpretation of studies. The best-designed studies control for factors that might influence results. Even so, their results require interpretation. Interpretation requires interpreters. Interpreters bring their own biases into the interpretation.

I mention pomegranate juice because one of its major producers sponsors studies to hype its benefits. Yes, pomegranates are delicious, but antioxidant powerhouses? So are most fruits. Pomegranates may have high antioxidant activity, but compared with what? Its maker does not say. Sponsored research is also about marketing, not health.

Nutrition research is hard to do, which makes study design and interpretation particularly challenging. Nutrition is a thinking person’s field, requiring careful analysis at every step. When you hear a result that sounds too good to be true, it usually is.

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Apr 25 2022

Conflict-of-interest disclosure of the week

A reader, Effie Schultz, sent this one, with a comment that it comes with the longest conflict of interest statement she had ever seen (I’ve noted one that was two pages long in the first item in a post in 2015).

Association of Low- and No-Calorie Sweetened Beverages as a Replacement for Sugar-Sweetened Beverages With Body Weight and Cardiometabolic Risk: A Systematic Review and Meta-analysis.  McGlynn ND, and 20 other authors.  JAMA Network Open, March 14, 2022. 2022;5(3):e222092.  doi:10.1001/jamanetworkopen.2022.2092

The research question: Are low- and no-calorie sweetened beverages (LNCSBs) as the intended substitute for sugar-sweetened beverages (SSBs) associated with improved body weight and cardiometabolic risk factors similar to water replacement?

The conclusion: This systematic review and meta-analysis found that using LNCSBs as an intended substitute for SSBs was associated with small improvements in body weight and cardiometabolic risk factors without evidence of harm and had a similar direction of benefit as water substitution. The evidence supports the use of LNCSBs as an alternative replacement strategy for SSBs over the moderate term in adults with overweight or obesity who are at risk for or have diabetes.

Comment: Research on artificial sweeteners remains controversial.  I think we will be arguing forever about their safety and efficacy in helping people lose weight.  Studies with conflict of interest disclosures like the excessively extensive one here do not help resolve the research questions.

I strongly support revealing conflicted interests that might influence any aspect of research design, conduct, and interpretation.  For this study, I would be interested in financial ties or arrangements with companies that might either gain or lose sales or marketing advantages from results showing artificial sweeteners or diet drinks to be harmless or beneficial, as these do.  At issue here is whether financial ties to companies with corporate interests in the outcome of such research bias results or interpretation, consciously or unconsciously.

You have to search through this mess of unnecessary and distracting disclosures to find the ones that matter.  They are there.  You have to search for them.

Much of what is disclosed is irrelevant and, therefore, not helpful.

You may well disagree with that assessment.  Judge for yourself.

Conflict of Interest Disclosures: Ms McGlynn reported receiving a Canadian Institutes of Health Research (CIHR)-Masters Award during the conduct of the study and being a former employee of Loblaws Companies Limited outside the submitted work. Dr Khan reported receiving grants from CIHR, International Life Science Institute, and National Honey Board outside the submitted work. Dr Chiavaroli reported being a Mitacs Elevate postdoctoral fellow and receiving joint funding from the Government of Canada and the Canadian Sugar Institute. Mr Au-Yeung reported receiving personal fees from Inquis Clinical Research outside the submitted work. Ms Lee reported receiving graduate scholarship from CIHR and the Banting & Best Diabetes Centre at the University of Toronto outside the submitted work. Dr Comelli reported being the Lawson Family Chair in Microbiome Nutrition Research at the Joannah and Brian Lawson Centre for Child Nutrition, University of Toronto, during the conduct of the study and receiving nonfinancial support from Lallemand Health Solutions, donation to research program from Lallemand Health Solutions, personal fees from Danone, sponsored research and collaboration agreement from Ocean Spray, and nonfinancial support from Ocean Spray outside the submitted work. Ms Ahmed reported receiving scholarship from the Toronto Diet, Digestive tract, and Disease Centre (3D) outside the submitted work. Dr Malik reported receiving personal fees from the City and County of San Francisco, Kaplan Fox & Kilsheimer LLP, and World Health Organization outside the submitted work and support from the Canada Research Chairs Program. Dr Hill reported receiving personal fees from General Mills and McCormick Science Institute. Dr Rahelić reported receiving personal fees from the International Sweeteners Association, Abbott, AstraZeneca, Boehringer Ingelheim, Eli Lilly, Novo Nordisk, Merck, MSD, Salvus, and Sanofi outside the submitted work. Dr Salas-Salvadó reported receiving personal fees from Instituto Danone Spain, nonfinancial support from Danone Institute International, personal fees as director of the World Forum for Nutrition Research and Dissemination from the International Nut and Dried Fruit Council Foundation, financial support to the institution from Fundación Eroski, and financial support to the institution from Danone outside the submitted work. Dr Kendall reported receiving grants and/or in-kind support from Advanced Food Materials Network, Agriculture and Agri-Food Canada, CIHR, Almond Board of California, Barilla, Canola Council of Canada, International Nut and Dried Fruit Council, Peanut Institute, Pulse Canada, Tate and Lyle Nutritional Research Fund at the University of Toronto, and Unilever; receiving nonfinancial support from General Mills, Kellogg, Loblaw Brands Limited, Oldways Preservation Trust, Quaker Oats (Pepsi-Co), Sun-Maid, White Wave Foods/Danone, International Pasta Organization, California Walnut Commission, Primo, Unico, International Carbohydrate Quality Consortium (ICQC), and Toronto Diet, Digestive tract, and Disease Centre (3D) outside the submitted work; receiving personal fees from McCormick Science Institute and Lantmannen; and being a member of the Diabetes and Nutrition Study Group (DNSG) Executive Board and Dietary Guidelines, a member of the expert committee of the DNSG Clinical Practice Guidelines for Nutrition Therapy, a member of the scientific advisory board of the McCormick Science Institute, a scientific advisor for the International Pasta Organization and Oldways Preservation Trust, a member of the ICQC, an executive board member of the DNSG, and being the director of the Toronto Diet, Digestive tract, and Disease Centre (3D) Knowledge Synthesis and Clinical Trials Foundation. Dr Sievenpiper reported receiving nonfinancial support from DNSG of the European Association for the Study of Diabetes (EASD), grants from CIHR through the Canada-wide Human Nutrition Trialists’ Network (NTN), PSI Graham Farquharson Knowledge Translation Fellowship, Diabetes Canada Clinician Scientist Award, CIHR Institute of Nutrition, Metabolism and Diabetes and the Canadian Nutrition Society (INMD/CNS) New Investigator Partnership Prize, and Banting & Best Diabetes Centre Sun Life Financial New Investigator Award during the conduct of the study; receiving grants from American Society for Nutrition, International Nut and Dried Fruit Council Foundation, National Honey Board (the US Department of Agriculture [USDA] honey checkoff program), Institute for the Advancement of Food and Nutrition Sciences (IAFNS; formerly ILSI North America), Pulse Canada, Quaker Oats Center of Excellence, United Soybean Board (the USDA soy checkoff program), Tate and Lyle Nutritional Research Fund at the University of Toronto, Glycemic Control and Cardiovascular Disease in Type 2 Diabetes Fund at the University of Toronto (a fund established by the Alberta Pulse Growers), and Nutrition Trialists Fund at the University of Toronto (a fund established by an inaugural donation from the Calorie Control Council); receiving personal fees from Dairy Farmers of Canada, FoodMinds LLC, International Sweeteners Association, Nestlé, Abbott, General Mills, American Society for Nutrition, INC Nutrition Research and Education Foundation, European Food Safety Authority, Nutrition Communications, International Food Information Council, Calorie Control Council, Comité Européen des Fabricants de Sucre, International Glutamate Technical Committee, Perkins Coie LLP, Tate and Lyle Nutritional Research Fund at the University of Toronto, Danone, Inquis Clinical Research, Soy Nutrition Institute, and European Fruit Juice Association outside the submitted work; serving on the clinical practice guidelines expert committees of Diabetes Canada, EASD, Canadian Cardiovascular Society, and Obesity Canada/Canadian Association of Bariatric Physicians and Surgeons; being an unpaid scientific advisor for the Food, Nutrition, and Safety Program and the Technical Committee on Carbohydrates of IAFNS; being a member of the ICQC, executive board member of the DNSG of the EASD, and director of the Toronto Diet, Digestive tract, and Disease Centre (3D) Knowledge Synthesis and Clinical Trials Foundation; his spouse is an employee of AB InBev. No other disclosures were reported.

Reference: For a summary of research on the “funding effect”—the observations that research sponsored by food companies almost invariably produces results favorable to the sponsor’s interests and that recipients of industry funding typically did not intend to be influenced and do not recognize the influence—see my book, Unsavory Truth: How Food Companies Skew the Science of What We Eat.

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Apr 29 2024

More on snakes: from culinary marvels to conflicted science

Last week I posted a debate about the health and environmental consequences of eating snakes, mainly because it never occurred to me that anyone would take it seriously.  I thought it was funny.

Shows you what I know.  Busted.

The eating-snakes-is-sustainable position was based on a study that I obviously had not read.

But a reader, Michael Tlusty, did.  He says the paper raises two issues.

His first has to do with the newsletter that posted the story, FoodManufacture.com.  He says:

Nowhere in the story does the reporter link to the actual research paper (Natusch, D., Aust, P.W., Caraguel, C. et al. Python farming as a flexible and efficient form of agricultural food security. Sci Rep 14, 5419 (2024). https://doi.org/10.1038/s41598-024-54874-4) – I see this a lot – why can’t journalists properly acknowledge scientific efforts?

His second is a critique of the study methods.

they compare ectotherm farming of snakes to that of salmon – however, the data for salmon farming comes from 2011 and 1998. There have been significant improvements since then, so they are biasing their analysis to favor the current snake data. Furthermore, I doubt that salmon would be the substitute for snake. Species more like tilapia and carp would be, and these fish can be fed with completely vegetarian diets. So yes while the invasiveness of pythons is a primary con as you point out, the authors inflate the benefit of snake eating relative to other more substitutable foods.

And then comes the kicker—the reason why I am posting this on Monday when I usually post items about conflicted science.

 And in the spirit of your newsletter, in the ethics declaration on the paper, it states “This work was partly funded by an initiative working to better understand snakes used in the leather trade, which is itself partially funded by companies that use snake skins. ” – so this is an attempt to make luxury snake skin items more “palatable” by turning snake farming into a food security argument.

I am always grateful to hear from sharp-eyed readers, even when they catch me violating a firm principle that dates back to my time in molecular biology graduate school: Always read the original paper.  No exceptions.

As I said, busted.

On a lighter note, it turns out eating snakes is a thing (maybe you knew this already?).  According to this week’s New Yorker, it’s a sign of masculinity in Oklahoma.  I commend this article to your attention: How to Eat a Rattlesnake.

Thanks to Jennifer Wilkins for sending it.  She, by the way, has a new Substack: Eat Right Here.

Addition: Can we really eat invasive species into submission? (thanks to Stephen Zwick for sending)

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