Le Figaro: Coffee may have protective effect on Alzheimer and Parkinson' s Diseases
Posted Feb 15 2011 6:59am
The debate on the virtues of caffeine and coffee is regularly revived at a rate of (many) scientific publications.The latest, published in theJournal of Pediatrics, is concerned about his heavy drinking among children and its disruptive effects on sleep.
This study points out that American children consume a significant amount of caffeine through the colas and other sodas.Of 228 children aged 5 to 12 years, 75% use it daily average of 52 mg per day in 5-7 years, the equivalent of a cup of tea.The average consumption is 109 mg per day for 8-12 years, the equivalent of a cup of coffee.Being American children, we can assume that their consumption is higher than that of young French.But in the absence of national standards, it is better to refer to the maximum dosage specified by the Canadian Ministry of Health: no more than 45 mg / day for 7 years, no more than 85 mg / day for 12 years.
Not everyone is equal before the caffeineChemically, caffeine is a methylxanthine such as theophylline and theobromine tea chocolate ... This explains its molecular structure effects bronchodilators (relaxing the bronchial tubes), potentially interesting in asthmatics.And above all its virtues and psycho-awakening, praised by many consumers.At least by those who are sensitive because we are not equal before the caffeine.For some, it would have stimulant effects, among other anxiogenic action.Some enzymes are involved in the body that vary genetically and influence its metabolism."Caffeine, which has anxiogenic effects, is transformed by an enzyme in liver paraxanthine, a metabolite that is him, anxiolytic, explains ProfessorDr.Jean Costantin, a pharmacologist at the University Hospital of Rouen (1).This enzyme anxiolytic effects is very active in people who feel particularly psychostimulant effects of caffeine.It is much less in others, which will be very sensitive especially to the anxiogenic effects of coffee. "Unsurprisingly, coffee lovers rather belong to the first group ...
It is also well known that caffeine accelerates the heart rate slightly, which makes it inadvisable for people prone to tachycardia.It is also mildly hypertensive."But the epidemiological data are somewhat contradictory, says epidemiologist Tobias Kurth (INSERM U708, Paris).We need more precise studies to understand the cardiovascular effects of caffeine. "
Trials in humans Other benefits attributed to the usual dose caffeine (about 400 mg / day) are no longer in doubt."It goes through the blocking of adenosine A2a receptors located on dopaminergic neurons destroyed by the disease," said Astrid Nehlig neurochemistry (INSERM 666, Strasbourg).But here again, the virtues are not universal, at least among women."This preventive effect concerns only those who are not taking hormone replacement therapy (HRT) or drink some coffee, rather than HRT with an increased risk," notes the researcher (2).
The relative effectson cognitive decline and Alzheimer's diseaseremain however unclear."Caffeine causes, animal model, in the brain decreased amyloid plaques (plaques in the brain of Alzheimer patients, Ed), and it reduces the amnesic effects of this disease," says neurobiologist David Blum (Inserm U837, Lille).Our goal now is to move towards a human trial, combining biological markers of Alzheimer's disease and imaging. "Equally debated is the relationship between coffee and cancer."More than five hundred studies have been devoted to the topic without associations have been demonstrated," said Astrid Nehlig.Assumed the risk of pancreatic cancer or bladder because of the roasting seems ruled out.But the vast heterogeneity and variable scientific value of studies precludes any conclusions.Is the pleasure of a good coffee.A pleasure that will further diversify, since after the American chewing gum with caffeine, the Swiss ... just invented caffeinated soap!What start the day off right.
Via Le Figaro: Le café est-il bon ou mauvais pour la santé ?