Is Coffee Healthy?

Coffee can provide several health benefits, but can also have negative effects in some people. A number of factors can affect the way in which an individual tolerates the caffeine in coffee including how much and how often caffeine is consumed, the quality of coffee consumed, the way each individual processes caffeine, and your individual biochemistry (age, weight, body fat, genetics, stress levels). Each person’s sensitivity or tolerance to caffeine can vary. And this can change depending on stress and energy levels, health or medical conditions (including pregnancy), food intake, medication, liver and kidney function.

Caffeine metabolism

The bioactive compound in coffee, caffeine, is the most commonly consumed stimulant and psychoactive substance in the world. The caffeine content can vary from around 50-165mg.

The average half-life of caffeine is 5-7 hours (depending on the person), meaning that is how long it takes the caffeine to clear and stop having an effect on your body. However, it takes 1.15 days to fully clear caffeine from your system.

When caffeine is consumed it is metabolised by the liver and absorbed into the bloodstream. It then travels to the brain and blocks an inhibitory neurotransmitter called ‘adenosine’. When adenosine is blocked, it allows neurons in the brain to fire more and increase brain activity, as well as increased release of stimulatory neurotransmitters such as norepinephrine, adrenaline and dopamine.

This increased stimulation gives us short term improvement in brain cognitive function such as memory, focus, mood, reaction times and energy levels. Studies have also shown caffeine to increase metabolic rate, thermogenesis and fat oxidation short-term.

Cappuccino and long black coffee

Health benefits of coffee


Coffee contains a potent source of antioxidants, which provide numerous health benefits by scavenging free-radicals and reducing oxidative stress. The antioxidants are what is believed to provide benefits against lowering disease risk. However, fruits and vegetables are plentiful in antioxidants, so we don’t need coffee to get a good source of antioxidants.

Increased performance:

Studies have shown caffeine to be effective at improving athletic performance by increasing adrenaline (our fight or flight hormone), mobilising fat cells (which can be used for energy during exercise), increasing fat burning, and increasing stamina. It also increases brain function, focus, reaction times and energy levels.

Improved mood:

A study found drinking a few cups of coffee a day could improve mental health by helping to release neurotransmitters such as dopamine that make us feel good.

Lowered risk of chronic diseases:

Studies have shown long-term regular coffee consumption to be associated with a lowered risk of type-2 diabetes, stroke, cardiovascular disease, some cancers, Alzheimer’s and Parkinson’s diseases, as well as a longer life expectancy.

However, the results of these studies are not black and white. Some research found a lowered risk of mortality and disease rates, whilst others showed a higher risk or no change at all. What was discovered was that heavy coffee drinkers tended to be smokers and/or physically inactive, or may have drank their coffee with added sugar and/or milk, impacting their disease risk. Whether coffee is beneficial to health realistically comes down to overall lifestyle and diet quality.

Negative effects of coffee


As with any non-organic source, coffee bean crops are heavily sprayed with pesticides. If you buy coffee for home, stick to an organic coffee bean, and find a local café that uses organic coffee where possible.

Side effects:

Too much caffeine can lead to restlessness, insomnia, anxiety, dizziness, irritability, upset stomach (due to the acidity), rapid heartbeat and tremors. Caffeine also raises blood sugar levels (due to the action of adrenalin), which may affect management of diabetes. The amount which causes side effects can vary from person to person.


Not only does caffeine stimulate the nervous system and adrenal glands, but a dependency on caffeine for energy can signal a problem with adrenal health. Too much stress on the adrenal glands over a period of time can potentially lead to adrenal maladaptation or fatigue. Eliminating caffeine can even cause short-term withdrawal symptoms.


Coffee is a diuretic, meaning it increases water loss through urine. Just make sure you are hydrating with adequate water daily.

Medication interaction:

Caffeine can interact with some medications, so best to check with your Doctor.

The take home message is that caffeine affects each of us differently, so listen to your body to find your own tolerance levels. Be aware about how much coffee you drink, time of day you drink it, whether you are getting caffeine from other sources (check your supplements), and how you drink your coffee (i.e. are you adding sugar and milk?). Everything in moderation and to suit the individual.