Nutritional research: observational studies make sense?

Nutritional research: observational studies make sense?

Uwe Knop: Nutritional research: observational studies do not bring any solutions

In a recent publication by the BMJ, US medical professor John Ioannidis, Stanford University, sums up the dilemma of nutritional science: Many study results are "completely unbelievable" - and even "another million observational studies" would not provide definitive solutions [1]. The effects of individual nutrients are "zero", especially for the hardest endpoint of study, overall mortality. Research in this area "seems hopeless". The BMJ publication underpins statements by the German Cochrane director, Professor Gerd Antes: "The nutritional sciences are in a pitiful situation." [2]

In Germany, too, numerous scientists have pointed out the basic problem in recent years that nutritional observation studies provide no evidence - in addition to Professor Gerd Antes, for example, Dr. Klaus Koch, Head of Health Information at IQWiG, Professor Walter Krämer, Economic and Social Statistics, University of Dortmund, Professor Peter P. Nawroth, Director of Internal Medicine and Clinical Chemistry, Heidelberg University Hospital or Professor Gabriele Meyer, Chair of the German Evidence-Based Medicine Network (DNEbM) [ 2]. "At the German Society for Nutrition DGE, however, these findings still seem unknown - which is clear in the new DGE brochure on fruit and vegetables [3]: The 5-day propaganda that plant-based foods' promote and protect health ´, will be continued on the basis of observational studies - even though there is no basic evidence for the health-promoting effect of fruits and vegetables, nor is there any evidence that the 5-day campaign promotes the health of citizens, ”explains nutritionist Uwe Knop. Nobody knows whether the state plant propaganda propaganda is related to the increasing number of clinical cases of gastrointestinal diseases, which have been documented by the federal health reporting system since the campaign started [4].

Doubts about nutritional recommendations Even the DGE only made it clear in September 2013 that it could not be said that fruits and vegetables protect against cancer and cardiovascular diseases - rather non-specific effects are responsible [5]. "Such contradictory statements make people doubt the general credibility of nutritional recommendations - which was only recently confirmed by a study by the University of Minnesota" [6], says Knop, "and rightly so, because the 'ecotrophological universal credo' is: nothing You don't know the exact details… ”(UK)

[1] Implausible results in human nutrition research - Definitive solutions won't come from another million observational papers or small randomized trials, BMJ 2013; 347
[2] "Flesh red, human dead", Frankfurter Allgemeine Sonntagszeitung, 1.4.12, p. 57 / "Food as a remedy - false fruit", SZ sueddeutsche online, 14.4.11 / "Medical studies are often based on untested assumptions", Spiegel online: July 23, 2012 / "Dietary rules: Where's the data?" Novo Argumente, April 3, 2013
[3] Vegetables and Fruits - All-Rounders in Health Protection, DGE Flyer, 1st Edition 2013
[4] 5-a-day campaign: It's fermenting, EU.L.E.N-Spiegel, 1-2 / 2013
[5] Eating without remorse, Frankfurter Rundschau, 09/30/13
[6] Adverse Outcomes Associated With Media Exposure to Contradictory Nutrition Messages, Journal of Health Communication: International Perspectives, Published online: 11.10.13
Excerpt on the topic: "Belief (s) instead of knowledge" (nutritional observation studies explained in the style of "broadcast with the mouse", from: "Eat what you want", rowohlt e-book, Oct. 2013, Uwe Knop )
Image: Jörg Brinckheger /

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