Studies have showed that moderate coffee consumption on a daily basis is associated with a reduced risk of developing Alzheimer’s Disease (AD). Experiments on animal models have demonstrated that components in coffee can effectively reduce the build-up of certain proteins believed to cause AD.
One study that involved 1409 middle aged adults showed that drinking 3-5 cups of coffee on a daily basis was associated with a 65% reduction in the risk of AD. Meanwhile, a group of Canadian researchers found out that daily coffee consumption reduced the risk of AD by 31 % on a 5 year follow up investigation. Most studies agree that an increase in coffee consumption reduces incidence of AD, with the majority pointing out that the most beneficial amount is between 3-5 cups of java a day. However, individuals drinking more than 5 or less than 2 cups per day had a higher risk of AD.
Figure 1. Coffee lovers, rejoice. Many studies have found a strong link between drinking 3-5 cups of java on a daily basis with a reduced risk of AD. On the other hand, decaffeinated coffee does not appear to offer protection in AD. Scientists are certain that the component in coffee responsible for most of the benefits in AD is caffeine. From http://www.reelsmillbank.com/reels-blog/2015/8/18/what-makes-a-great-cup-of-coffee
The compound in coffee that is believed to be responsible for reducing the risk and onset of AD is no other than the world’s most common psychoactive drug, caffeine. That substance that wakes you up in the morning could actually prevent you developing Alzheimer’s. Scientists are convinced that AD is characterised by the formation of protein plaques that contribute to the great neuronal loss in certain brain regions, leading to dementia and other symptoms. Experiments in mice with AD have showed that diets high in caffeine are capable of reducing the build-up of harmful protein plaques characteristic of the disease.
When proteins are produced, they then need to undergo further processing in order to function correctly. A protein present in neuronal synapses known as amyloid precursor protein (APP) is processed by a group of enzymes called secretases, which are essentially biological scissors. Usually, APP is cut by alpha secretase, resulting in a functioning protein, but in AD, APP is misprocessed by beta and gamma secretase, causing the production of ‘sticky’ amyloid beta (Aβ) peptide. Aβ forms plaques outside of neurons which trigger inflammation and neuronal dysfunction which eventually leads to the death of neurons.
Although high caffeine consumption appears to prevent AD, experiments on animal models are suggesting that it could also improve the outcome of patients already affected by the disease. A team of researchers worked using mice that had been genetically engineered to develop amyloid plaques in the brain, just like the ones present in the brains of AD patients. They fed a group of mice with water containing caffeine (equivalent to 4 cups of coffee) on a daily basis for 5 months. Meanwhile another group of mice were given water with no caffeine for the same length of time. The mice that were treated with caffeine had significantly lower levels of Aβ in a region of the brain known as the hippocampus, compared to untreated mice.
Figure 2. Mice that were given caffeine on a daily basis for 5 months showed significantly lower levels of Aβ plaques in the hippocampus compared to untreated mice. Therefore, if we consume around 3-5 cups of coffee on a daily basis, the caffeine could potentially reduce the build-up of Aβ in our brains, lowering our chances of developing AD.
Furthermore, the researchers found out that the caffeine treated mice showed an improvement in memory compared to untreated ones. Caffeine appears to reduce Aβ accumulation in the brain through multiple mechanisms, such as by blocking the actions (inhibiting) of beta and gamma secretase. By inhibiting these enzymes, less Aβ is produced, meaning that the build up of this peptide is slower than its removal from the brain and over time Aβ plaques would become smaller.
Caffeine appears to be the most important substance in coffee in the fight against AD, but scientists are certain that other components that have not yet been elucidated also play a role. Currently, the only treatment available in AD only helps to mask the symptoms but does not target the underlying cause of the disease. Daily coffee consumption from middle age (40-50 years) appears to be an effective strategy to reduce the chances of developing AD. But more importantly, moderate coffee consumption may benefit patients with early AD, not only helping to treat the symptoms but also the underlying cause of this devastating disease.