Search results: american journal of clinical nutrition

Stanford University issued a press release to announce the results of a study comparing physiological effects of eating plant-based meat alternatives (Beyond Meat) to eating foods of animal origin.

A diet that includes an average of two servings of plant-based meat alternatives lowers some cardiovascular risk factors compared with a diet that instead includes the same amount of animal meat, Stanford Medicine scientists found.

The study:  A randomized crossover trial on the effect of plant-based compared with animal-based meat on trimethylamine-N-oxide and cardiovascular disease risk factors in generally healthy adults: Study With Appetizing Plantfood—Meat Eating Alternative Trial (SWAP-MEAT).  Crimarco A, et al.  American Journal of Clinical Nutrition, August 11, 2020.  https://doi.org/10.1093/ajcn/nqaa203

Overall conclusion: “This study found several beneficial effects and no adverse effects from the consumption of plant-based meats.”

The sponsor: “Supported by a research gift from Beyond Meat Inc. (to CDG)…Funding for this study was provided by Beyond Meat. In an effort to reduce any influences on the outcomes of this study, a statistical analysis plan was submitted to ct.gov. The main analysis was conducted by a third-party individual who had no involvement with the study design or collection of data, and was blinded to all study participants.

Comment

Ordinarily, I would simply present this study as a classic example of how industry-funded studies predictably produce results that favor the commercial interests of their sponsors, a topic to which I devoted my book, Unsavory Truth: How Food Companies Skew the Science of What We Eat.

But CDG is Christopher Gardner, the study’s lead scientist, whose impressive track record of managing complicated clinical trials of diet and health I greatly admire.

Gardner describes himself as a vegan (meaning that he eats no animal products).

Knowing of my concerns about industry-funded research, he wrote me some months ago to say that this study was in the works and to point out that he has done at least six industry-funded studies with null findings (he sent me a PowerPoint slide deck to prove it).  In his correspondence, he said:

• “I believe this is the FIRST industry funded study I’ve run that had a significant positive health finding.”
• “Beyond Meat was not involved in design or analysis, and to this day still doesn’t know the study outcome.”
• “I’m preparing myself for being called out as a vegan industry shill….hoping I’ve established a reputation for objectivity to withstand this ?”
• “PS – Hope you enjoy the study acronym (Study With Alternative Plantfood – Meat Eating Alternative Trial: SWAP-MEAT)” [Indeed I do].

OK.  So let’s take this study on its merits.

Gardner asked healthy non-vegetarian adults (36) to consume 2 servings a day of either Beyond Meat or regular meat (what the study calls Animal Meat).  The Beyond Meat and Animal Meat were provided to participants.  The rest of their diets was on their own.

For 8 weeks, they ate Beyond Meat or Animal Meat.  For the next 8 weeks, they switched over to the other kind.

Results: Participants consuming Beyond Meat displayed lower levels of

• LDL-cholesterol (the bad kind)
• Body weight (by 1 or 2 pounds)
• TMAO (Trimethylamine N-oxide)—but only for those who consumed Animal Meat first and Beyond Meat second (not the other way around)

Beyond Meat may be plant-based, but it is ultraprocessed.  FoodNavigator produced a nice comparison.

Beyond Meat would dearly love to demonstrate that its ultraprocessed composition is immaterial to its health benefits.  Hence: this study.

Beyond Meat is already using it for marketing purposes: “New study finds health benefits of plant-based meats.”

As I see it, there are two issues here: (a) what else the participants were eating and (b) the significance of the TMAO measurements.

(a) The diet: This was not a controlled dietary intake trial conducted in a closed metabolic ward.  Participants were free to eat whatever they liked and how much they liked.  They lost a little weight during the Beyond Meat phase, which means they must have been eating fewer calories during that phase, as they reported (this graph is in the Supplementary material).

Reported daily calories were under 2000, which means that lots of calories must not have been reported.  So it’s hard to know what the weight loss is actually due to.

(b)  TMAO: You make TMAO after you eat foods containing choline, a compound common in animal-based foods: meat, poultry, fish, and eggs.  A 2019 editorial review in JAMA discusses the association of TMAO with heart disease risk.

Now, researchers are homing in on another possible culprit: a dietary metabolite linked to red meat called trimethylamine N-oxide, or TMAO. Three recent meta-analyses confirmed that high blood levels of TMAO are associated with increased risks of cardiovascular disease and all-cause mortality. One of the studies, published in the Journal of the American Heart Association in 2017, found a more than 60% heightened risk of both major adverse cardiovascular events and death from all causes in people with elevated TMAO. Other research has associated higher TMAO levels with heart failure and chronic kidney disease.

On the other hand, an analysis by Dr. Bret Scher raises questions about whether TMAO has any real meaning for health (and I thank Stephen Zwick for sending this to me).

In my opinion, this is an example of a well-run study that, in the end, lends very little to our knowledge of human health….The main outcome from this intervention had to do with TMAO. Why is this problematic? Well, it has to do with the fact that small, short-term trials are unable to measure meaningful endpoints, such as who lives, dies, or who gets heart disease.  So, instead, the authors have to choose the surrogate outcome markers that they believe relate to human health.

Dr. Scher believes that “There is no convincing evidence that these results impact someone’s health.”  As Scher has discussed previously, he sees no cause-and-effect relationship between TMAO levels and health.  You can read his arguments here:

• Eating red meat increases TMAO levels. Should we care?
• TMAO — Smoking gun or passive observer?

The bottom line?  This study suggests that two servings a day of Beyond Meat is unlikely to be harmful.  Whether substituting Beyond Meat for real meat is truly useful for health in the absence of other dietary changes remains to be confirmed, hopefully by independently funded research.

The American Journal of Clinical Nutrition has a new study with a startling conclusion: “frequent consumption of fried potatoes appears to be associated with an increased mortality risk” (here’s a news report about it).

For lovers of French fries, this is unhappy news.  Or is it?

The study looked at potato intake (fried and unfried) reported by 4440 participants aged 45–79 y at baseline for 8 years, as part of a study on osteoarthritis.  Participants with the highest consumption of potatoes had the same mortality as those consuming the lowest amount.

But when they looked at the subgroup consuming fried potatoes 2–3 times per week, the risk of mortality doubled.

It’s not potatoes that might be a problem; it’s just those that are fried.  Even so,

• The study is based on intake reported in food frequency questionnaires
• The results are not cleanly dose-related; mortality rates were higher among people reporting fried potatoes twice a week than those reporting more
• People who eat lots of fried potatoes are likely to indulge in other unhealthful dietary or lifestyle practices.

But this is not the first study to report health problems among frequent eaters of fried potatoes.  See:

• Potato consumption and risk of cardiovascular disease: 2 prospective cohort studies
• Fried-food consumption and risk of type 2 diabetes and coronary artery disease: a prospective study in 2 cohorts of US women and men
• Maternal intake of fried foods and risk of gestational diabetes mellitus.
• Potato Consumption and Risk of Type 2 Diabetes
• Adolescent Energy Drink Use Related to Intake of Fried and High-sugar Foods

This is a lot to blame on one food.  I vote for lifestyle confounding.

Put French fries in your once-in-awhile category.  I’m saving my allotment for the Belgian ones.

I’m having a hard time keeping up with these, but here are five more industry-funded studies with results favorable to the sponsor, bringing the total of industry-positives to 124 since last March, versus just 12 with unfavorable results.  This percentage is lower than that found in more systematic studies.  If you know of such studies, please send.

In the meantime, here’s the next set.

A randomized controlled trial to determine the efficacy of a high carbohydrate and high protein ready-to-eat food product for weight loss.  N. R. Fuller, M. Fong, J. Gerofi, L. Leung, C. Leung, G. Denyer andI. D. Caterson.  Clinical Obesity. Article first published online: 19 JAN 2016. DOI: 10.1111/cob.12137

• Conclusion: There was no significant difference in percentage weight loss from screening to 6 weeks between the two groups…Both diets were nutritionally matched and well-accepted over the 6-week period. This study shows that the inclusion of a ready-to-eat food product can be included as part of a dietary programme to achieve a clinically significant weight loss over a short period.
• Funding: This study was supported by a research grant from Arnotts Biscuits Ltd. The funder had no role in the protocol design, the conduct of the study, the analysis of the data, nor the writing of the manuscript.
• Comment: The idea of this study was to get participants to include Vita-Weat biscuits in their diets.  The control group was simply advised about healthy eating.  Both groups lost weight.  Arnotts Biscuits makes Vita-Weat.

Obesity, Fitness, Hypertension, and Prognosis: Is Physical Activity the Common Denominator?  Carl J. Lavie, MD, Parham Parto, MD; Edward Archer, PhD. JAMA Intern Med. 2016;176(2):217-218. doi:10.1001/jamainternmed.2015.7571.

• Conclusions: Although excess caloric load has been suggested as a major contributor to obesity, we believe that marked declines during the past 5 decades in leisure time and occupational physical activity explain the notable increase in BMI over time… Therefore, substantial efforts are needed, beginning in children and adolescents and extending into adulthood, to increase levels of physical activity across all ages and in both sexes, which would have substantial effects on preventing obesity and improving levels of CRF [cardiorespiriatory fitness].
• Conflict of Interest Disclosures: Dr Lavie reported being the author of the book The Obesity Paradox and serving as a lecturer for the Coca Cola Company (on physical activity, exercise, fitness, and the obesity paradox and not on their products). Dr Archer reported received speaking fees from industry and nonprofit organizations.
• Comment: Coca-Cola has been especially active in funding investigators who promote the idea that physical activity is more important that diet in determining health status.  This paper is a commentary on a study demonstrating that “high BMI and low aerobic capacity in late adolescence were associated with higher risk of hypertension in adulthood…interventions to prevent hypertension should begin early in life and include not only weight control but aerobic fitness, even among persons with normal BMI.”

Dietary anthocyanin intake and age-related decline in lung function: longitudinal findings from the VA Normative Aging Study.  Amar J Mehta,, Aedín Cassidy, Augusto A Litonjua, David Sparrow, Pantel Vokonas, and Joel Schwartz.  Am J Clin Nutr February 2016 vol. 103 no. 2 542-550

• Conclusions: An attenuation of age-related lung function decline was associated with higher dietary anthocyanin intake in this longitudinal sample of predominantly elderly men. Further prospective studies are needed to confirm these novel associations.
• Conflicts: AC has a grant, unrelated to this project, to conduct observational and experimental studies of blueberries and cardiovascular health outcomes from the US Highbush Blueberry Council. None of the other authors had competing interests to declare.
• Comment:  This paper is about blueberry anthocyanins.  The authors report “Blueberry intake was associated with the slowest rate of annual decline in lung function; compared with no or very low intake.”

The effects of lutein on cardiometabolic health across the life course: a systematic review and meta-analysis.  Elisabeth TM Leermakers, Sirwan KL Darweesh, Cristina P Baena, Eduardo M Moreira, Debora Melo van Lent, Myrte J Tielemans, Taulant Muka, Anna Vitezova, Rajiv Chowdhury, Wichor M Bramer, Jessica C Kiefte-de Jong, Janine F Felix, and Oscar H Franco.  Am J Clin Nutr February 2016 vol. 103 no. 2 481-494

• Conclusions: Our findings suggest that higher dietary intake and higher blood concentrations of lutein are generally associated with better cardiometabolic health. However, evidence mainly comes from observational studies in adults, whereas large-scale intervention studies and studies of lutein during pregnancy and childhood are scarce.
• Funding: ETML, DMvL, MJT, JCK-dJ, and OHF are employees at ErasmusAGE, a center for aging research across the life course funded by Nestlé Nutrition (Nestec Ltd.), Metagenics Inc., and AXA. Nestlé Nutrition (Nestec Ltd.), Metagenics Inc., and AXA had no role in the design or conduct of the study; the collection, management, analysis, or interpretation of the data; or the preparation, review, or approval of the manuscript. None of the authors reported a conflict of interest related to the study.

Dietary protein intake is associated with body mass index and weight up to 5 y of age in a prospective cohort of twins.  Laura Pimpin, Susan Jebb, Laura Johnson, Jane Wardle, and Gina L Ambrosini.  First published December 30, 2015, doi: 10.3945/​ajcn.115.118612.  Am J Clin Nutr February 2016 vol. 103 no. 2 389-397

• Conclusion: A higher proportion of energy from protein during the complementary feeding stage is associated with greater increases in weight and BMI in early childhood in this large cohort of United Kingdom children.
• Conflicts: JW: was principal investigator of the Gemini study with responsibility for data collection; and all authors: advised on the analyses or interpretation of data and contributed to manuscript preparation. JW received grants from Cancer Research UK and from Danone Baby Nutrition during the conduct of the study. LJ received institutional consultancy fees from Danone Baby Nutrition during the conduct of the study. All other authors declared no conflicts of interest.

I’ve collected five more studies funded directly or indirectly by food companies or trade associations, with results useful for marketing purposes.  This brings the total to 105 that I’ve noticed since last March versus only 9 with results that must have disappointed the sponsors.

Canned Vegetable and Fruit Consumption Is Associated with Changes in Nutrient Intake and Higher Diet Quality in Children and Adults: National Health and Nutrition Examination Survey 2001-2010.  Marjorie R. Freedman, PhD; Victor L. Fulgoni III, PhD.  J Acad Nutr Diet. 2015  http://dx.doi.org/10.1016/j.jand.2015.10.013.

• Conclusions: Results suggest CVþCF consumption was associated with higher intake of select nutrients, a higher-quality diet, and comparable adiposity measures and blood pressure.
• Funding for this project was received from the Canned Food Alliance.  As senior vice president at Nutrition Impact, LLC, V. L. Fulgoni III provides food and nutrition consulting and database analyses for various members of the food and beverage industry.  No potential conflict of interest was reported by M. R. Freedman.

Regular Fat and Reduced Fat Dairy Products Show Similar Associations with Markers of Adolescent Cardiometabolic Health.   O’Sullivan, T.A.; Bremner, A.P.; Mori, T.A., Beilin, L.J., Wilson, C., Hafekost, K., Ambrosini, G.L., Huang, R.C., Oddy, W.H..Nutrients 2016, 8, 22.

• Conclusion: Although regular fat dairy was associated with a slightly better cholesterol profile in boys, overall, intakes of both regular fat and reduced fat dairy products were associated with similar cardiometabolic associations in adolescents.
• Conflicts of Interest: Therese A. O’Sullivan received a grant from The Dairy Health and Nutrition Consortium Australia…which provided funding for the analysis and write up of this study. No other authors declare a conflict of interest.

Suboptimal Plasma Long Chain n-3 Concentrations are Common among Adults in the United States, NHANES 2003–2004. Rachel A. Murphy, Elaine A. Yu, Eric D. Ciappio, Saurabh Mehta and Michael I. McBurney   Nutrients 2015, 7, 10282–10289; doi:10.3390/nu7125534.

• Conclusion: Suboptimal LCn-3 [omega-3] concentrations are common among U.S. adults. These findings highlight the need to increase LCn-3 intake among Americans.
• Conflicts of Interest: M.I.M., E.D.C. and R.A.M. are employees of D.S.M. Nutritional Products, L.L.C., manufacturers and suppliers of omega-3 nutritional lipids. E.Y. and S.M. have no conflicts of interest to disclose.

Red Raspberries and Their Bioactive Polyphenols: Cardiometabolic and Neuronal Health Links.  Britt M Burton-Freeman, Amandeep K Sandhu, and  Indika Edirisinghe.  Adv Nutr January 2016 Adv Nutr vol. 7: 44-65, 2016. doi: 10.3945/​an.115.009639

• Conclusion: The body of research is growing and supports a potential role for red raspberries in reducing the risk of metabolically based chronic diseases.
• Funding: Supported in part by various donors and the National Processed Raspberry Council.

Dietary flavonoid intake and incidence of erectile dysfunction. Aedín Cassidy, Mary Franz, and Eric B Rimm.  American Journal of Clinical Nutrition. First published ahead of print January 13, 2016 as doi: 10.3945/ajcn.115.122010.

• Conclusions: These data suggest that a higher habitual intake of specific flavonoid-rich foods is associated with reduced ED incidence. Intervention trials are needed to further examine the impact of increasing intakes of commonly consumed flavonoid-rich foods on men’s health.
• Authors’ disclosure: AC and EBR received funding from the US Blueberry Highbush Council for a separate project unrelated to this publication.
• Comment: The University of East Anglia, where the lead author works, sent out a press release “Blueberries associated with reduced risk of erectile dysfunction.”

As regular readers know, I’ve been posting studies funded by food companies with results favorable to the companies’ interests whenever I run across five of them.   Since mid-March, I’ve posted 7 such collections for a total of 37 studies (two of the posts listed 6 studies).  These are all papers published since March.

With each set, I asked readers to send examples of studies that do not favor the sponsor’s interest.

They are rare, but do exist.  I’ve been sent two so far.  I’m guessing it will be a long time before I collect five, so have a look:

Butter increased total and LDL cholesterol compared with olive oil however resulted in higher HDL cholesterol than habitual diet. Sara Engel and Tine Tholstrup.  American Journal of Clinical Nutrition, July 1, 2015, doi: 10.3945/​ajcn.115.112227.

• Conclusions: Moderate intake of butter resulted in increases in total cholesterol and LDL cholesterol compared with the effects of olive oil intake and a habitual diet (run-in period). Furthermore, moderate butter intake was also followed by an increase in HDL cholesterol compared with the habitual diet. We conclude that hypercholesterolemic people should keep their consumption of butter to a minimum, whereas moderate butter intake may be considered part of the diet in the normocholesterolemic population.
• Sponsor: Danish Dairy Research Foundation
• Comment: The data clearly show that butter raises blood cholesterol levels.  The authors spin it as positively as possible—higher HDL and it’s OK for people with normal cholesterol to eat moderate amounts of butter—but they make the downside quite clear.  In this study, “moderate” butter means 4.5% of calories or just 2/3 of a tablespoon for someone eating 2000 calories.  That’s not much, alas.

Influence of Pistachios on Performance and Exercise-Induced Inflammation, Oxidative Stress, Immune Dysfunction, and Metabolite Shifts in Cyclists: A Randomized, Crossover Trial.  David C. Nieman, Johannes Scherr, Beibei Luo, Mary Pat Meaney, Didier Dréau, Wei Sha, Dustin A. Dew, Dru A. Henson, Kirk L. Pappan.  PLoS One, November 19, 2014. DOI: 10.1371/journal.pone.0113725

• Conclusion: In summary, 2-weeks pistachio nut ingestion was associated with reduced 75-km cycling time trial performance and increased post-exercise plasma levels of raffinose, sucrose, and metabolites related to leukotoxic effects and oxidative stress.
• Funder: This work was supported by American Pistachio Growers. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
• Comment:  It’s obvious that the funders had no role.  I’ll bet they are quite unhappy with the results.

This second study came out last year but I’ll take any of these I can get.  Please do send.

But if I’m just counting since March, the ratio is 37 studies favoring the sponsor’s interest, to 1 that doesn’t.  Coincidence?  I’m not convinced.

Despite my long interest in and dubious opinion about the benefits of Golden Rice (genetically modified to contain the beta-carotene precursor of vitamin A), I somehow completely missed the huge and highly embarrassing uproar over a study demonstrating the effectiveness of this rice in raising vitamin A levels in young children.

This particular uproar began with publication of the study in the American Journal of Clinical Nutrition in 2012.  Last week the journal announced that it has retracted the study—on ethical, not scientific, grounds.

To explain:  Dr. Guangwen Tang, a long-time researcher at Tufts University, and her colleagues at Tufts, in China, and at Baylor and the NIH, compared the effectiveness of vitamin A capsules, Golden Rice, and spinach in raising vitamin A levels in the blood of Chinese schoolchildren.  They reported that Golden Rice proved just as effective as capsules, and somewhat better than spinach, in inducing higher vitamin A levels, just as it is supposed to do.

Golden Rice, of course, is the poster child for the benefits of GMOs, extolled by many as the solution to the developing world’s high prevalence of vitamin A deficiency (I’m dubious because I view vitamin A deficiency as a social problem requiring policy and cultural shifts).

Soon after, Greenpeace, which is decidedly anti-GMO, challenged the ethics of the study, charging that the children were being used as “guinea pigs.”

As reported in Nature,

none of the children, their parents or school teachers was aware that Golden Rice was involved, according to a 45-minute investigative news programme broadcast on 8 December on CCTV, China’s state television channel.  The informed-consent form said that the rice contained β-carotene, but not that it was genetically modified or that it was Golden Rice. Nor did it highlight uncertainty around any potential risks of ingesting such rice…Moreover, Wang didn’t apply for ethical evaluation of the trial, instead fabricating the approval documents, according to CDC. And Tang brought Golden Rice from the United States to China illegally, without due declaration to the relevant Chinese authorities, it said.

According to a report on NPR, Tufts University did a year-long investigation and agreed that ethical standards had been violated:

the study was not “conducted in full compliance with … policy or federal regulations”… the researchers did not adequately explain the nature of golden rice and made some changes in the study without getting approval from the committee at Tufts that is supposed to review all research involving human subjects.  Guangwen Tang will be banned from conducting research on human subjects for two years. For two years after that, any research that she conducts will be under the direct supervision of another investigator.

A report on the case in ScienceInsider explains the ethical problem raised by the study’s informed consent form :

U.S. guidelines stipulate that such forms use plain language understandable to lay people, and the IRB [the Tufts Institutional Review Board] agreed to let Tang say that “Golden Rice is a new rice which makes beta-carotene,” without using the loaded words “genetically modified.” (The consent form for a very similar study by Tang among adults in Boston, published in 2009, didn’t use that term either.) Given the sensitivities over transgenic food, which existed in China as well, that was the wrong decision, according to the external panel.

In 2014,  Dr. Tang sued the ASN:

ASN twice asked Tang and her six co-authors to withdraw the paper voluntarily, which they declined to do. The society recently decided to retract the paper on its own…but it has agreed to a 90-day stay after Tang filed her lawsuit, to see if the matter can be settled out of court.

But the court ruled in favor of ASN.  Hence, the retraction.  ASN issued a press release:

In a ruling by the Massachusetts Superior Court, Judge Salinger…cleared the way for the American Society for Nutrition (ASN) to retract the article “β-Carotene in Golden Rice is as good as β-carotene in oil at providing vitamin A to children”…ASN is very pleased that the Massachusetts courts have upheld the organization’s First Amendment rights and have allowed ASN to move forward with the retraction of the article.

In its online retraction notice, ASN states the reasons:

1. The authors are unable to provide sufficient evidence that the study had been reviewed and approved by a local ethics committee in China in a manner fully consistent with NIH guidelines….
2. The authors are unable to substantiate through documentary evidence that all parents or children involved in the study were provided with the full consent form for the study.
3. Specific eligibility issues were identified in regard to 2 subjects in the study.

Last week, Retraction Watch published a lengthy summary of this case that includes a long statement from Tufts University:

No questions were raised about the integrity of the study data, accuracy of the research results or safety of the research subjects…Tufts University has always been and remains deeply committed to the highest ethical and scientific standards in research.  In September 2012, w …convened an external review committee to interview those involved and to review documentation of the study…There was no evidence found of falsification or fabrication of the data that underlie the study’s primary findings. Those reviews did, however, determine that the research had not been conducted in full compliance with Tufts research policies and federal research regulations.

The retraction is a huge embarrassment, not only for the researchers involved but also for Tufts University’s Friedman School of Nutrition Science and Policy, Tufts’ Institutional Review Board, the American Journal of Clinical Nutrition, and the American Society for Clinical Nutrition.

The study was funded by NIH, USDA, as well as a program in China.  NIH takes research ethics very seriously and expects the researchers it funds to adhere to the highest possible standards for research on human subjects.  Because the study did not follow standard ethical guidelines, especially with regard to research on children, Tufts had no choice but to investigate and impose sanctions, and the journal had no choice but to retract the paper.

This case reinforces my views about GMOs in general and Golden Rice in particular.

The controversies are not (or not usually) about the science.  They are very much about ethics and other questions of values.

I’ve been posting summaries of studies funded by food companies or trade groups, all of which come up with results that the sponsor can use for marketing purposes.

In each of these posts, I ask for examples of industry-funded studies that produce results contrary to the interests of the funder.

In response, I received this comment from Mickey Rubin, Vice President for Nutrition Research, National Dairy Council.

He gave me permission to reproduce his letter: 

Dear Marion,

By way of introduction, my name is Mickey Rubin and I am a scientist at the National Dairy Council. I understand that you know Greg Miller, and I asked him for your contact information so I could write to you directly after reading with great interest your most recent post on industry-funded nutrition research, in which you selected a sample of 5 studies/papers sponsored by industry all showing favorable outcomes. Although none of the papers you selected were sponsored by the organization I represent (although there is one dairy industry sponsored review paper in the list), what struck me is your focus on the favorable vs. unfavorable dichotomy, rather than the reality of what much nutrition science research results in: null findings.

It seems that there are fewer and fewer nutrition studies published that report the null, or find no effect. I agree with you that the reason we don’t see more of these studies in the literature has to do with bias, but I suspect that it is publication bias as much as any other bias. From my interactions with nutrition researchers, I gather it is quite difficult and sometimes impossible to get a study with no significant effects published regardless of funding source, to say nothing of allegiance bias by some researchers hesitant to publish findings that may go against their own hypotheses. Dr. Dennis Bier of Baylor College of Medicine and editor in chief of the American Journal of Clinical Nutrition has presented eloquently on this issue previously. You may also be aware of David Allison’s papers on other types of bias. So I think it is important to discuss all types of bias, and not just industry bias. You of course wouldn’t want your discussion on bias to be biased to just one type.

At National Dairy Council we have an extensive program of nutrition research that we sponsor at universities both nationally and internationally. While I can’t speak for all of industry, we strongly encourage the investigators of all of our sponsored studies to publish the findings, no matter the results. Thus, we would expect our sponsored studies to have a similar “success” rate as those sponsored by the National Institutes of Health. In fact, that is exactly what one recent analysis – not sponsored by the dairy industry – found, reporting that there was no evidence that dairy industry funded projects were more likely to support an obesity prevention benefit from dairy consumption than studies sponsored by NIH.

We feel this transparency is not only critical to the credibility of the research we sponsor, but we also feel it is important that our research contributes to nutrition science knowledge as a whole. We hope that other scientists take the findings from studies we sponsor and build upon them, and if it is by using research dollars from other sources, even better! I’ll be the first to stand up and say that one favorable study on milk, as an example, does not close the books on the subject. We need many studies in many different labs sponsored by multiple agencies in order to produce a portfolio of knowledge. I suspect that is certainly an example of where you and I are in agreement.

That all said, please allow me to provide some examples of studies the National Dairy Council has sponsored that are published and, rather than showing a clear benefit, do not refute the null hypothesis. These are all studies published within the last 4 years. It’s not meant to be comprehensive, but rather just a sample similar to what you provided. I could also provide you a list of studies we have sponsored that have shown favorable results for dairy, but you seem to have that covered, and I’ll instead wait until one of our sponsored studies appears in a subsequent blog post J.

Thanks for taking the time to read. I appreciate the dialogue.

Here’s his list of papers:

Studies with null finding:

Bendtsen et al. 2014: http://www.ncbi.nlm.nih.gov/pubmed/24168904

• No unique benefit of dairy protein over other proteins for weight maintenance

Maki et al. 2013: http://www.ncbi.nlm.nih.gov/pubmed/23901280

• No effect of three servings of dairy on blood pressure

Chale et al. 2013: http://www.ncbi.nlm.nih.gov/pubmed/23114462

• Whey protein supplementation offered no additional benefit over resistance training alone in older individuals

Lambourne et al. 2013: http://www.ncbi.nlm.nih.gov/pubmed/23239680

• No change in body weight or composition in adolescents performing resistance training and supplemented with milk, juice, or control

Van Loan et al. 2011: http://www.ncbi.nlm.nih.gov/pubmed/21941636

• Recommended dairy servings offered no additional weight loss benefit over calorie restriction without dairy servings 

Studies with mixed findings (some outcomes changed, others null):

Maki et al. 2015: http://www.ncbi.nlm.nih.gov/pubmed/25733460

• The main finding from the study was that dairy intake had no effect on glucose control whereas sugar sweetened product consumption contributed to a worsening of glucose control in at-risk adults.

Dugan et al. 2014: http://www.ncbi.nlm.nih.gov/pubmed/24236646

• Waist circumference and BMI were lower in women after consuming the dairy diet as compared to the control diet. Fasting glucose was lower in men following the dairy diet as compared to the control diet. There were no differences in blood pressure, serum lipids, fasting insulin, or insulin resistance between the treatments.

Here’s what I wrote in response:

I am familiar with charges of bias against independently funded researchers (“White-hat Bias”), which equates industry biases with biases that result from career objectives and other goals.  I do not view the biases as equivalent.  Industry-sponsored research has only one purpose: to be used in marketing to sell products.   As I have said repeatedly, it is easy to design studies that produce desired answers.

When I was in graduate school in molecular biology, we were taught—no, had beaten into us—to do everything we could to control for biases introduced by wishful thinking.  I don’t see that level of critical thinking in most studies funded by food companies.

You may be correct about the influence of publication bias with respect to dairy studies, but how do you explain the situation with sugar-sweetened beverages?  Studies funded by government and foundations typically indicate strong correlations between habitual consumption of sugary beverages and metabolic problems, whereas studies funded by the soda industry most definitely do not.   The percentages are too high to be due to chance: 90% of independently funded studies show health effects of soda consumption whereas 90% of studies funded by soda companies do not.  This is troubling.

We’ve seen the results of studies funded by tobacco and drug companies.  Are food-industry studies different?  I don’t think so.   What seems clear is that industry-induced biases are not recognized by funding recipients, a problem in itself.

That’s why I’m posting these studies as they come in and begging for examples of industry-funded studies that do not favor the interests of the donor.

Thanks to Mickey Rubin for writing and for permission to reproduce his letter.

Let the discussion continue!

Here is my latest roundup of industry-sponsored research producing results or opinions that favor the sponsor’s commercial interests.

Sugars and obesity: Is it the sugars or the calories?  Choo FL, Ha V, Sievenpiper JL.  Nutrition Bulletin, May 19, 2015.  DOI: 10.1111/nbu.12137

Conclusion: The higher level evidence reviewed in this report does not support concerns linking fructose-containing sugars with overweight and obesity.

Conflicts of interest: All three authors report scholarship or research support from such entities as the Canadian
Sugar Institute, PepsiCo, Coca-Cola, Dr Pepper Sapple, Corn Refiners Association, World Sugar Research Organization.

Cranberry Juice Consumption Lowers Markers of Cardiometabolic Risk, Including Blood Pressure and Circulating C-Reactive Protein, Triglyceride, and Glucose Concentrations in Adults.  Janet A Novotny, David J Baer, Christina Khoo, Sarah K Gebauer, and Craig S Charron. J. Nutr. 2015; 145:1185-1193 doi:10.3945/jn.114.203190.

Conclusion: LCCJ [low-calorie cranberry juice] can improve several risk factors of CVD [cardiovascular disease] in adults, including circulating TGs [triglycerides], CRP (c-reactive protein], and glucose, insulin resistance, and diastolic BP [blood pressure].

Sponsor: Ocean Spray Cranberries, Inc. and the USDA.  JA Novotny received funding from  and C Khoo is employed by Ocean Spray Cranberries, Inc.

Effect of cheese consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials. Janette de Goede, Johanna M. Geleijnse, Eric L. Ding, and Sabita S. Soedamah-Muthu

Conclusion: Despite the similar P/S ratios of hard cheese and butter, consumption of hard cheese lowers LDL-C and HDL-C when compared with consumption of butter.

Funding. The senior author received unrestricted research grants from the Global Dairy Platform, the Dairy Research Institute, and Dairy Australia for the present meta-analysis. One other author, E.L.D., has consulted for the Dairy Research Institute.

Protein Summit 2.0: Evaluating the Role of Protein in Public Health: Proceedings of a conference held in Washington, DC, October 2, 2013.  American Journal of Clinical Nutrition, June 2015 Supplement.

Program organizer: Shalene McNeill, National Cattlemen’s Beef Association, and a Contractor to The Beef Checkoff.

Sponsors: The Beef Checkoff, Dairy Research Institute, Egg Nutrition Center, Global Dairy Platform, Hillshire Brands, National Pork Board

My comment: Journal supplements are typically paid for by outside parties—government agencies, foundations, private organizations, or food companies.  The papers in this supplement discuss various aspects of protein and health.  All emphasize the benefits of animal protein in human diets, as might be expected, given the sponsors.

Two examples:

Commonly consumed protein foods contribute to nutrient intake, diet quality, and nutrient adequacy.  Stuart M Phillips, Victor L Fulgoni III, Robert P Heaney, Theresa A Nicklas, Joanne L Slavin, and Connie M Weaver.  Am J Clin Nutr June 2015 vol. 101 no. 6 1346S-1352S.

Conclusion: dietary recommendations to reduce intakes of saturated fat and solid fats may result in dietary guidance to reduce intakes of commonly consumed food sources of protein, in particular animal-based protein.

The role of protein in weight loss and maintenance.  Heather J Leidy, Peter M Clifton, Arne Astrup, Thomas P Wycherley, Margriet S Westerterp-Plantenga, Natalie D Luscombe-Marsh, Stephen C Woods, and Richard D Mattes.

Conclusion:  Collectively, these data suggest that higher-protein diets…provide improvements in appetite, body weight management, cardiometabolic risk factors, or all of these health outcomes.

For the record: Industry sponsorship does not necessarily mean that the reported conclusions are wrong.  It just means that the papers require even more than the usual level of critical analysis.

I am happy to post industry-sponsored studies that do not produce results that can be used to market the sponsor’s products.  Please send if you find any.