For millions, the kettle or expensive kitchen-top coffee machine goes on within seconds of the alarm ringing. But nutrition experts say that instinctive first sip could be a mistake – and that there is a far better time to drink your morning coffee if you actually want it to work.
Spanish nutritionist Pablo Ojeda has set out what he calls the ‘45-minute rule’, arguing that caffeine is most effective if you wait at least half an hour after waking up – not immediately.
And another medical expert goes further, suggesting you should wait a full 90 minutes.
Why coffee works in the first place
Coffee remains one of the most widely consumed drinks in Europe, prized for its caffeine hit. According to Gregorio Varela, Professor of Nutrition, writing in Coffee and a Healthy Lifestyle for the Spanish Nutrition Foundation, caffeine is an alkaloid that ‘easily penetrates all the body’s cells, and scientific evidence tells us that it stimulates the transmission of impulses between neurons’.
He adds that ‘a daily amount of coffee of less than 300 milligrams, that is, between two and three cups, relieves fatigue, delays tiredness, and promotes cognitive function’.
Research also suggests coffee:
- Influences the cardiovascular, respiratory and gastrointestinal systems
- Has a mild diuretic effect, although 24-hour urine output is similar to those drinking caffeine-free liquids
- Can improve the absorption and effect of analgesics, particularly in migraine relief
- Is a significant source of antioxidants, which help combat oxidative stress linked to cardiovascular and neurodegenerative diseases such as Alzheimer’s and Parkinson’s
- Provides dietary fibre in the form of non-digestible polysaccharides with a prebiotic effect that supports gut microbiota
The ‘45-minute rule’ explained
Ojeda challenges the common habit of drinking coffee the moment you wake up. “The best option to experience the effects of caffeine isn’t what everyone does, which is when we wake up,” he says.
His reasoning centres on cortisol – the body’s natural stress and alertness hormone: “When we wake up, we have very high levels of cortisol (the stress hormone), so drinking coffee wouldn’t make sense to wake us up even more or to have more energy.”
Instead, he advises: “Drink it half an hour or 45 minutes after waking up, and not immediately after.”
In short, let your body’s natural wake-up system do its job first – then add caffeine.
Why some say wait 90 minutes
Dr Marta González-Corró, a medic with a Master’s in Nutrition and Food from the University of Barcelona, advises waiting even longer.
“It is better to have your first coffee 90 minutes after waking up and not during the hours when you naturally produce cortisol,” she says.
She notes that cortisol peaks typically occur:
- Between 8am and 9am
- Between 12pm and 1pm
- Between 5.30pm and 6.30pm
‘At these times, you already have circulating cortisol in your blood and don’t need to drink coffee; you already have cortisol activation,’ she explains.
She also warns: ‘If you’re very fond of coffee and drink it during hours when you naturally produce cortisol, you’ll produce less cortisol over time and become more dependent on coffee to stay alert and energetic.’
Caffeine blocks adenosine – the chemical that makes you feel sleepy. Over time, she says, regular intake can lead the body to produce more adenosine, meaning you need more caffeine to achieve the same effect.
“Ideally, it’s better to have your first coffee 90 minutes after waking up,” she said.
Is coffee after lunch a bad idea?
In Spain and across Europe, coffee after a meal is a firm tradition. But Ojeda says it is ‘neither the best nor the most advisable time’.
He explains that ‘coffee can inhibit the absorption of some nutrients and prevent them from being absorbed’.
Both coffee and tea can interfere with the absorption of: Iron; Calcium; and Vitamin C. Drinking coffee straight after an iron-rich meal, for example, may reduce iron absorption.
For those concerned, herbal tea or water with lemon or ginger may be preferable, particularly as vitamin C enhances iron uptake from plant-based foods. Caffeine also speeds up digestion, which can reduce the absorption of certain micronutrients in people who are already deficient.
And for those prone to heartburn or reflux, coffee after spicy or fatty meals may worsen symptoms because it acts as a stimulant and can increase discomfort.
The gym exception
Dr González-Corró says coffee on an empty stomach can be appropriate if you are about to exercise. In that setting, caffeine acts as an ergogenic aid – helping improve endurance and reduce perceived effort during physical activity.
If your morning includes a run or gym session, that early coffee may still have a place.
Coffee and the brain
Caffeine’s effects extend to the central nervous system. Dr González-Corró explains that drinking coffee before learning something can increase mental clarity, concentration and alertness via dopamine release in the frontal lobe. Consuming caffeine after learning may enhance memory consolidation.
Some studies suggest moderate caffeine intake may be linked to a reduced risk of Alzheimer’s and Parkinson’s disease, possibly through dopamine-related pathways. There is also evidence that caffeine taken with aspirin may help reduce migraine.
However, experts stress the key word is moderation. For most adults, that means no more than around 300mg of caffeine a day – roughly two to three cups of coffee.
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This story originally appeared on Express.co.uk
