Miracle cure coffee against all common diseases?
Nutritionists find panacea for common diseases: Coffee protects against: diabetes, depression, cancer, Alzheimer's, gout, stroke and heart disease
Coffee is not only the favorite drink of many nations, the bean drink protects people from almost all common diseases. If one summarizes the study reports of the last years, then coffee resembles a medical miracle cure, for which the science searched so far in vain: the daily dose coffee protects against diabetes, depression, cancer, Alzheimer, gout, stroke and heart diseases (1). But the omnipotent protective effect of „Panazee coffee“ has a serious catch: „These reports are based on observational studies that allow only guesses, but never prove a cause-effect“, explains nutritionist Uwe Knop, „therefore, there is no scientifically proven evidence that coffee protects against any disease.“ Only clinical studies could provide this proof - but they do not (yet) exist.
Professor Gerd Antes, director of the German Cochrane Center in Freiburg, which assesses the quality of scientific research, has already stated several times (2) why nutrition research can not provide evidence. For Antes are „the nutritional sciences in a pitiable position“, because the researchers usually have to fall back on methodically unreliable observational studies. And „Studies in this area are dependent on many unknown or barely measurable influences“, explains Antes. In the end, no one can explain what a statistical link, such as' coffee drinkers, has a lower risk of diabetes´ based. Because it is because of the coffee, or because of the study participants sleep better and had less stress, nobody knows - too many lifestyle factors of the „complex human system“ may be responsible for the results. For Walter Krämer, Professor of Statistics at the University of Dortmund, the numerous coffee reports from observational studies „most likely only artifacts of a sloppy evaluated statistics“, which are brought to the public by means of striking-line press releases (3). And this „Press releases from academic centers or medical journals are often misleading and euphemistically transfigured“, Warns Professor Gabriele Meyer of the German Network Evidence-based Medicine (4). Such coffee-protection speculations from epidemiological investigations therefore only allow Kramer to conclude: „Much noise about next to nothing!“
Nutritional studies - nothing except hypotheses?
Nutritional observational studies provide only hypotheses that sound exciting on the one hand but often over-interpreted on the other hand - because there is often no distinction between correlation and causality. „Cause-and-effect dependency (causality) is claimed where only relationships (correlations) may be stated, which need not be causally causal or can be as the connection between stork flight and birth frequency“, Meyer explains. Therefore, clinical research must review these hypotheses before „Coffee protects-front ... “-Headlines have their permission. For example, a recommendation to drink coffee for health promotion can not be made until clinical trials of it „effectiveness“ would prove. „Such studies are ongoing and we are looking forward to the results“, says Professor Peter Nawroth, Medical Director at the University of Heidelberg. Until then, nutritionist and coffee drinker Knop recommends: „Enjoy your coffee when it tastes good and gets you good - but do not believe in the numerous reports you 'lower' with more than four cups a day´ Your risk of diabetes, depression, cancer, Alzheimer's, gout, stroke and heart disease!“
Incidentally, the same applies to nutritional knowledge, which propagates its disease-promoting effect instead of health-protecting properties of foods. These „Tartarenmeldungen“ as „Red meat promotes heart attacks“ or „Chocolate increases the risk of depression“ are as much in the realm of speculation as the rumored coffee-diabetes-related. For here, too, there are no scientific proofs, but only statistical correlations „pitiable“ Observational studies. (Pm)
1) World: „Coffee protects against diabetes“
Netdoktor: „Coffee protects against stroke“
Springer Medizin: „Coffee protects against stroke“
Frankfurter Rundschau: „Coffee protects against skin cancer“
Focus: „Coffee protects against liver cancer“
Springer scinexx: „Coffee lowers heart attack risk“
Biermann Medicine: „Coffee protects against depression“
German Medical Journal: „Coffee protects against gout“
tz: „Science: Coffee protects against skin cancer, depression, dementia“
Focus: „Alzheimer's & Dementia - Coffee protects against forgetting“
Doctors newspaper: „A jack of all trades in prevention?“
(2) Frankfurter Allgemeine Sonntagszeitung, 01.April.2012, No. 13, p. 57: „Meat red, human dead“ / sueddeutsche de, 14.April.2011: „Food as a cure - False fruits“
(3) Walter Krämer, 2011: The Fear of the Week, p. 223: Ways and Errors of Epidemiology
(4) Press release „Evidence-based science journalism seems to be a utopia“, 17.April.2012, German Network Evidence-based Medicine e.V.
Picture: Peter Friday