Duel studies conducted in the US and Sweden found people who drink more than four and upwards of six cups of coffee a day were significantly less likely than people who drank fewer cups to develop MS, an autoimmune disease that can be painful and debilitating, according to research published online March 4 in the Journal of Neurology Neurosurgery and Psychiatry.
Specifically, the research showed two case-controlled studies that matched 1,620 adults with MS in Sweden to 2,788 healthy counterparts and 1,159 people with MS in the US to 1,172 healthy Americans found people who drank more than 900 ml, or about six cups, of coffee daily were 26% to 31% less likely to develop MS.
While the study is observational, and therefore cause and effect conclusions cannot be drawn, the “intriguing” findings “add to the growing evidence for the beneficial health effects of coffee” the role of which in the development of MS “clearly warrants further investigation,” Faculty of Medicine, University of British Columbia, members write in an accompanying editorial.
In particular, they suggest future research should focus on finding the potential mechanism of action linking coffee consumption to a reduced risk of developing MS.
The study authors agree – noting the most likely mechanism of action is caffeine, the impact of which has been investigated on MS resulting in “inconsistent” results in the past.
Based on their findings and previous animal research, they hypothesize that caffeine protects against developing MS by upregulating adenosine 1A receptors to provide a protective effect against experimental autoimmune encephalomyelitis.
“Furthermore,” they add, “in vitro caffeine treatment of human monocytoid cells increased the expression of adenosine 1A receptors and reduced pro-inflammatory cytokine production.”
In addition, they note, in animal models caffeine appears to protect against Alzheimer’s disease by inhibiting blood-brain barrier leakage. This would lend itself to supporting the protective nature of caffeine against MS.
However, the fact that no association was observed between increasing amounts of tea or soda, which also both have caffeine, and MS development could be a mark against the compound as the mechanism of action.
Indeed, the researchers note, “coffee contains more than a thousand biologically active compounds,” and another could be responsible for the dose-dependent relationship between the consumption of coffee and reduced risk of developing MS.
The conflicting and inconsistent results, underscore the difficulty of “untangling the nature of associations between dietary factors and disease risk,” according to the accompanying editorial.
The researchers agree and urge future studies to look at whether caffeine or another molecule in coffee underlies the findings. Such an evaluation could, eventually, lead to new therapeutic targets, they conclude.