Atlantico: A recent study carried out in the United States did not fail to shake the world of nutrition: ice cream, in certain cases, could prove to be good for health since its daily consumption – when it remains moderate – could prove capable of reducing the risk of diabetes or suffering from heart problems. At least… According to the thesis of a student at Harvard. What can we say about his work?
Beatrice de Reynal: Manipulating epidemiological studies and improvising results without a reliable statistical protocol is a source of great hilarity, indeed. For example, allow yourself a link like “the biggest consumers of diet soda are obese so sweeteners make you fat”, rather than asking yourself “is it because they are obese that they choose diet cola”?
Parasitic effects show up all the time in science, especially in nutritional epidemiology, where the health conditions and eating habits of hundreds of thousands of people are tracked over years and years.
How teams of researchers process data, mix it with theory, then present the results as “what the science says”.
Similarly, this study is based on few robust scientific elements and therefore gives a hilarious result.
Ice cream reduces the risk of diabetes? Certainly, it has a lower glycemic index because of its fat content. But the author Ardisson Korat indicates that he has no plausible biological explanations… His thesis indicates that he was not the first to observe a “halo of health” around ice cream. Digging even deeper into these earlier studies, they point to high fat or low fat dairy products, and the link to insulin resistance. Not on ice cream. Bias No. 1.
These world-renowned studies fueled a stream of influential findings, including some of the data that helped pinpoint trans fatty acids, which can be dairy or industrial, the latter of which have since been phased out.
Between 1986 and 1998, the authors of an observational study by Harvard researchers reported that higher consumption of low-fat dairy products was associated with a lower risk of diabetes, but this is not the case. for those who consume full-fat dairy products.
This is unfortunately frequent in medicine as in nutrition, with disastrous consequences on public health, on the misleading information communicated to the general public, but also and above all, on the reputation of scientists in general. The number of participants in these studies is always low, and in addition, the dairy lobbies have put pressure on the authors, who have suddenly summed up “dairy products” as ice cream… Bias N°2
The end word
The theory goes: Perhaps some of the people in the study had developed health problems, such as high blood pressure or high cholesterol, and had started to avoid ice cream on doctors’ orders, or on their own. thank you. Meanwhile, people who didn’t have these health issues would have had less reason to give up their cookies and cream. In this scenario, it wouldn’t be that ice cream prevented diabetes, but that the risk of developing diabetes caused people not to eat ice cream. Epidemiologists call this “reverse causation.” Bias N°3
To test this idea, Hu and his co-authors set aside the dietary data collected after people received these kinds of diagnoses, then redid the statistics: the effect of ice cream halved…
In 2016 in the American Journal of Clinical Nutrition summarizes data from a dozen studies: as a person’s yogurt consumption increases to about a third of a cup a day, their risk of developing diabetes drops by 14%.
Yogurt which reduces the risk of diabetes, ice cream, no.
Since Americans love ice cream, the research is surprisingly numerous. We then spoke of the “milk fat globule membrane”, a three-layered biological envelope that envelops the fat in the milk of mammals. Some studies suggest that if this envelope remains intact, the metabolic effects are neutral….. But you can’t have that on ice cream, whereas you don’t have it on fresh cream.
Bias + bias + bias = inconsistent and false results.
Is it normal that he makes the experts react to this point?
It is quite normal that the experts – the real ones – react to the results of this study, these studies which should never have left the scientific sphere until they have been consolidated and verified.
It is the responsibility of professors, research lab bosses and all the teams not to let people believe that they have non-consensual results.
But it is also the responsibility of the press to publish reliable and verified data.
However, this case – which has been going on for several years! – also underlines the difficulty we all have, scientists, in questioning an idea that we believe to be sure and certain. When results seem to indicate that ice cream would be beneficial, the first thing is to agree to put into play what we believe to be certain. A good scientist is one who doubts and has the ability to question any data.
It is clear that the conclusions of this study conflict with the general idea of what a good diet could be. What does this say about our biases and their place in the world of science?
If you read the entirety of this article, the author explains very well how biases can pile up on top of each other to arrive at results that are inconsistent with the recognized knowledge of all scientists.
More serious: giving voice to incompetents with catchy titles and nutritional scoops is not acceptable today, when consumers demand transparency, truth and fairness.
Do they prevent certain researchers from exploring new paths, discovering new things?
Precisely: we read well, over this “ice cream saga”, that some scientists have been able to question while others have refused and preferred to evade the question, while letting it “leak” into the general public. . It is this behavior that is unacceptable. Imagine how many American patients dove into tubs of ice cream when they read the headline “ice cream prevents diabetes”!!
The English-language press, which has been looking into the issue since the publication of this study, now compares ice cream to yogurt. In your opinion, should we review our contemporary dietary recommendations in depth and breadth?
France is excellent in the field of nutrition and public health: our researchers and managers in this field are internationally renowned, and know how to put everything back on track.
They alerted on key points: the French paradox and the alleged benefits of olive oil (no, it only provides energy, neither Omega 3, nor any benefits, unless you consume olive oil). unfiltered and unrefined olive, which is not the case with the olive oils in the department).
They warned of their doubts about intense sweeteners, ultra-processed foods. Let’s trust them.
As for Ardisson Korat, he no longer responds: several Emails have not found an answer. His Tufts University, where he works, says he is not available…