Is coffee good or bad for you? Is it healthy or not? The answer to that question is, it depends on several things! It depends on the individual’s health status and genetics, the quantity of coffee being drunk, when it is being drunk and how it is served. So there are quite a few considerations.
Coffee, because of its caffeine content, is a stimulant. The way this works is through its relationship with a compound, adenosine, that we naturally produce throughout the day. Adenosine acts as an inhibitory neurotransmitter; it slows down nerve cell activity, dilates blood vessels, inhibits processes relating to wakefulness and hence promotes drowsiness. Levels of adenosine increase until a level is reached making us sleepy. Adenosine’s actions are effective when it locks into receptors on the cell surface; a bit like putting a key into a lock where adenosine is the key and the receptor is the lock.
However, caffeine is also able to bind to these receptors and when it does prevents the adenosine binding to them. Hence caffeine has a stimulating impact making us more alert, energised and focussed by blocking adenosine’s actions. Once caffeine has been metabolised, in other words, broken down by the body, adenosine is once again able to bind to the receptors and exert its inhibitory actions. This can make us feel suddenly tired and sleepy as we move from being stimulated by the caffeine to relaxed by adenosine.
During the time when caffeine is bound to the receptors, adenosine continues to be produced. The slower the caffeine is metabolised and the longer it is locked into the receptors the more adenosine builds up and hence the more available when the receptors are free again. This results in an energy ‘crash’. That crash can make us rush for the next cup of coffee to keep us alert again. Caffeine’s blocking of the adenosine receptors also impacts the availability of dopamine, the neurotransmitter that impacts our mood making us feel good and motivated. The caffeine boosts the action of dopamine so we experience the “feel good factor”.
How quickly we metabolise caffeine can be impacted by our genetics. A slow metaboliser of caffeine may only be able to tolerate small amounts of coffee without feeling anxious and restless. Some people can hardly tolerate any intake at all where others seem to be able to drink coffee all day long! So coffee can boost your energy and improve your mood and its effects are fast-acting but the impact it has is very individualised.
As well as making us feel alert and energised, coffee has other beneficial benefits due to its polyphenol content. These are compounds in plants that provide their colour and also protection against microbes and their environment but give us health benefits when we ingest them. Coffee polyphenols protect against oxidative damage and inflammation.
Studies have shown there is a decreased risk of neurological diseases like Alzheimer’s Disease and Parkinson’s Disease in coffee drinkers. Coffee polyphenols have also been shown to increase the production of the compound brain-derived neurotrophic factor (BDNF). BDNF supports neuroplasticity by promoting nerve growth and differentiation and is important for learning and memory.
On average the half-life of caffeine in healthy adults is around 5-6 hours, that’s the time for your body to eliminate half of it. Therefore drinking coffee after 4 pm can interfere with sleep, although the half-life is varied depending upon not only genetics but other factors that alter caffeine’s metabolism. For example, smoking speeds up the metabolism and hence smokers often do not feel the impact of caffeine intake.
How you drink your coffee is important. If you are adding syrups and other sweeteners then the impact on your blood sugar levels will be significant. These are simple sugars that should be avoided on a regular basis. Consistently high blood sugar levels may lead to diabetes, obesity and poor cardiovascular health.
So is coffee good or bad for you?
Whether you consume coffee and how much you consume to maximise the health benefits are personal to you. We all have different genetic profiles and have our own tolerance levels. We also all have different health statuses and personal situations. Using coffee as a regular stimulant because you aren’t getting enough sleep or are under chronic stress is not a healthy habit.
As a general guide, 2-3 cups of unsweetened espresso coffee a day taken before 4 pm could make you feel more alert, energised, protect the brain from oxidative damage and support neuroplasticity resulting in improved cognitive function and reduced risk from neurological disease. However, listen to your body and do what is right for you because we are all unique! Instead of reaching for the coffee to give you an energy boost read our 4 nutrition tips to boost your energy.
For further understanding on how genes & environmental factors determine individual responses to caffeine watch this video by Lifecode Gx .