Coffee has many effects on the body, some less known than others.
Most people know that coffee keeps you awake and that it modulates cardiovascular parameters such as blood pressure and heart rate.
But not many people know that coffee has the potential to stimulate the production of gastric acid or that it lowers risks for Parkinson’s disease, preserves memory and reduces risks for Alzheimer’s.
1) Coffee blocks receptors in the brain to keep you awake and alert
Most people know that coffee helps keep you awake, but how coffee keeps you awake is something they usually don’t know.
To keep you awake, coffee blocks receptors in the brain, adenosine receptors to be more exact.
This blocks the release of the neurotransmitter adenosine which signals to the body to rest and sleep.
This causes other neurotransmitters with opposite effects to be released, signaling to the body to stay awake, be alert and vigilant.
2) Drinking coffee increases dopamine levels in the brain and makes you want to drink more coffee
When coffee blocks adenosine receptors in the brain it inhibits the release of the neurotransmitter adenosine.
This helps keep you awake, but it’s not the only effect. When it blocks adenosine receptors, it automatically stimulates dopamine receptors.
This causes an increase in dopamine levels in the brain.
Dopamine is a neurotransmitter that influences behavior and has the reputation to encourage addictive behavior.
When you drink coffee, dopamine levels in the brain increase and this makes you want to drink more coffee. Of course, if absolutely don’t like coffee, having it once won’t make you love it.
3) Coffee is stimulating on the brain and energizing for the body
One of the first effects of coffee is blocking adenosine receptors in the brain which suppresses the release of the neurotransmitter adenosine.
But the effects don’t stop there: blocking adenosine receptors stimulates other types of receptors in the brain such as glutamate, noradrenaline and acetylcholine and raises levels of these three neurotransmitters as a counter-effect.
What effects does this have on the body? Lower adenosine levels counteract sleep so you don’t feel drowsy and don’t feel like resting.
Higher glutamate levels fires up nerve cells and signals to the brain and body to be active. Noradrenaline is also stimulant and higher levels makes you vigilant and feel energized, present and alert.
Acetylcholine activates muscles initiating movement.
All of these effects of coffee combined translate into feeling stimulated and energized.
4) Coffee boosts motivation and productivity
Drinking coffee acts on the brain by increasing levels of several neurotransmitters including glutamate, noradrenaline, acetylcholine and dopamine.
This translates into very specific effects on the brain and body.
Glutamate fires up nerve cells and counteracts drowsiness and sleepiness, increasing nervous system activity and making you alert.
Noradrenaline enhances vigilance and concentration which can help you focus on tasks and perform optimally.
Acetylcholine activates muscles by initiating contractions in muscle cells. Dopamine increases motivation by enhancing satisfaction.
By stimulating the brain and body to be alert, focused and motivated, coffee incentivizes and boosts productivity.
5) Coffee stimulates the stomach lining to produce gastric acid
Studies show bioactive components in coffee, including caffeine, stimulate the secretion of gastric acid (source).
By stimulating the secretion of gastric acid, coffee can make you feel hungry. At the same time, it can aggravate existing stomach issues such as acid reflux (GERD), gastritis and stomach ulcer.
Both regular coffee with caffeine and caffeine-free (decaffeinated) coffee have this effect on the stomach (source).
What further makes coffee bad for stomach issues is the fact that it ‘reduces the competence of the lower esophageal sphincter’ (source), the ring-like muscle that closes off the stomach and prevents gastric acid and stomach contents to escape the stomach.
Regular consumption can weaken the muscle and cause gastric acid to escape the stomach and rise up into the esophagus, causing more severe acid reflux episodes in GERD.
6) Coffee increases blood flow to the heart
Adenosine is a neurotransmitter that induces drowsiness and makes the body want to rest and sleep.
Receptors for adenosine are found in the brain, but also other parts of the body such as the heart. In the heart, the role of adenosine is to regulate cardiovascular parameters such as heart rate, heart rhythm, blood pressure and blood flow.
By blocking adenosine receptors and subsequently also adenosine release, coffee suppresses the depressant effects of the neurotransmitter on the heart muscle cells.
At the same time it blocks adenosine release, coffee stimulates the release of stimulant neurotransmitters such as glutamate, noradrenaline and acetylcholine.
This causes an increase in the conduction of electrical impulses which animate heart electrical activity, accelerate heart rate and raise blood pressure, increasing coronary blood flow.
7) Coffee improves memory
By blocking adenosine receptors in the brain and heart, coffee suppresses the depressant effect of the neurotransmitter adenosine.
At the same time, it stimulates receptors for excitatory neurotransmitters such as glutamate, noradrenaline, dopamine and acetylcholine.
This, in turn, stimulates heart activity and cardiovascular parameters such as heart rate and blood pressure, increasing blood flow in blood vessels.
Better blood flow contributes to better oxygenation of the brain which is believed to be one of the mechanisms behind the benefits of coffee for memory.
8) Coffee can potentially lower risks of dementia (Alzheimer’s disease)
According to research, Alzheimer’s disease and other forms of dementia cause degeneration of synapses, the connections between nerve cells, and the death of nerve cells.
In turn, this causes brain atrophy which is pregnant in areas of the brain involved in memory and spatial orientation, hence the symptoms typical of the disease (source).
Constituents occurring naturally in coffee such as caffeine and theophylline suppress adenosine receptors in the brain and inhibit the release of the neurotransmitter adenosine.
This has the counter-effect of stimulating other neurotransmitters such as glutamate.
Glutamate is needed by nerve cells when they make connections called synaptic connections.
Not just this, but glutamate strengthens synaptic connections between nerve cells.
Stronger synaptic connections play an important role in learning and memory.
Because glutamate strengthens synaptic connections and constituents in coffee have the effect of stimulating glutamate production, it has been proposed that coffee intake can help reduce risks of cognitive decline associated with Alzheimer’s disease.
Another possible mechanism of action has been proposed: biologically active constituents in coffee such as neuro-stimulants (e.g. caffeine, theophylline) and antioxidants may protect against nerve cell damage and exert important anti-inflammatory and antioxidant effects conducive to reduced oxidative stress markers. By protecting against nerve cell damage, coffee may contribute to reduced risks of cognitive decline such as that seen in dementia.
9) Coffee lowers Parkinson’s risks
According to research, Parkinson’s disease ‘is a neurodegenerative disorder characterized by the progressive neurodegeneration of the dopaminergic neurons in the substantia nigra pars compacta and in the corpus striatum’ (source).
An ‘increase in oxidative stress contributes to the loss of dopaminergic neurons’ (source) which increases risks of degenerative disease such as Parkinson’s.
Neuro-stimulants and antioxidants abound in coffee. One prime example is caffeine. According to research, ‘caffeine is a compound capable of inhibiting lipid peroxidation as well as the formation of reactive oxygen species (ROS)’ (source).
Moreover, ‘the constant consumption of caffeine acts on neurotoxicity by improving mitochondrial function and oxidative stress’ (source).
Caffeine shows a great potential for counteracting the degeneration of the nervous system, including dopaminergic nerve cells.
The neuroprotective effect of caffeine, but also other constituents in coffee, is believed to be behind the reduction in Parkinson’s risks in regular coffee consumers.
Moreover, caffeine stimulates dopamine receptors in the brain which has been proposed to potentially help counteract the loss of dopaminergic function specific to Parkinson’s disease and both reduce risks of the disease and delay progression.