Tuesday, 14 March 2017

Dementia, Caffeine and Prevention

Dementia is a horrible set of neurodegenerative diseases, affecting not only our physical bodies and abilities, but also our mental health and abilities, to the point of destroying everything that we are. Fortunately, dementia rates among people over 60 years old are declining, at least in the USA. From 1986-1991, 3.6% of people over 60 had dementia. In 2004-2008, it was only 2% of over-60s. Overall, there has been a 20% drop in dementia rates per decade since 1977. Another found a drop in dementia rates among over-65s from 11.6% in 2000 to 8.8% in 2012, benefitting around one million people. But how can we join in with these benefits? Well, a common so-called "vice" may actually be another way to help prevent dementia.

This vice is coffee, not decaf, but the regular caffeinated variety. So how does it work? In a study on mice, which are biologically similar to humans, researchers found that mice genetically "destined" to produce the mis-folded tau proteins seen in Alzheimer's disease did not produce enough of an enzyme known as NMNAT2. Because of this, they tested over 1,280 compounds to see if they had any effects on NMNAT2 production in brain cells. Caffeine was one of the most active substances in increasing NMNAT2, and when they tested it on the mice, they began to produce normal levels of the enzyme. Of course, this is just an animal study; we need human research to confirm these effects.

Source: Julius Schorzman
There in fact have been population studies on the effects of caffeine and dementia, including Alzheimer's disease. One of these is the CAIDE study. Previous research found inconsistent results, but 3 of the 5 studies were in agreement that coffee drinking can help prevent dementia and cognitive decline. Another two that combined coffee and tea consumption also found positive effects on cognition. In the CAIDE study, drinking 3-5 cups of coffee every day in "midlife" was linked with a 65% reduction in Alzheimer's and other forms of dementia later in life. Researchers thought that this may be because of the antioxidant, insulin-sensitising benefits of coffee, or the caffeine itself.

Caffeine is more than an intoxicant, in fact, there is a lot of science behind its effects against dementia - this is far from "wishful thinking" by busy doctors who want an excuse for their coffee habit. There is a strong inflammatory component of the development of Alzheimer's disease, and part of this is over-reactivity of the glial cells, which act as part of the brain's immune system. Caffeine's effects on the adenosine receptors in the central nervous system have been found to reduce this over-reaction, and so inhibit inflammation. The blood-brain barrier (BBB) has also been shown to play a role in Alzheimer's disease; if it is too "leaky", it can speed the buildup of harmful proteins. And yes, caffeine may protect BBB integrity, partly by calming the glial cells. Animal studies have shown that all of this reduction in inflammation may translate to the prevention of memory problems. Despite a lack of human clinical trials, all of this helps to validate the benefits of caffeine seen in population studies. In conclusion, it may not be best to completely give up coffee in order to improve your health, as moderate caffeine consumption could prevent you from nasty neurodegenerative diseases later.

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