CRAVING COFFEE?
The hidden harms
It’s well known that Kiwis have a love affair with caffeine — but how many of us know about the potential hidden harm it could be causing us?
Scientists at Massey University and University of Auckland are leading a large- scale research programme aiming to build a detailed picture of the amount of caffeine we’re consuming, and how our varying rates of metabolism or genetic traits could be causing unseen problems.
More than 70 per cent of New Zealanders consume caffeine regularly, but most don’t understand the effect it can have on their sleep, mood and cognitive functions.
The last major assessment of caffeine risk in New Zealand reported negative effects, from dizziness, rapid heartbeat, irritability, anxiety, tremors and insomnia to diarrhoea, nausea and vomiting.
Single high doses of caffeine could affect the cardiovascular system by causing a rapid heartbeat and high blood pressure, and caffeine intake could also be associated with a slight deterioration in calcium balance.
Massey sports and exercise scientist Dr Ajmol Ali, who is leading the programme, said caffeine was an antagonist of adenosine, which helps induce sleep by blocking wakefulness and can lead to heightened perception of pain.
“So this means other neurotransmitters like dopamine go into the brain and keep us awake, reduce pain and give us that ‘ feel- good’ factor, and that’s why we ultimately think caffeine helps performance,” he said.
“However, some people experience strong effects of caffeine, and others don’t — and that got me interested and thinking, why could that be?”
One new study i s surveying the genotypes of hundreds of young Kiwis and quizzing them on their intake to seek out potential genetic dispositions.
It partly looks at the caffeinerelated gene CYP1A2, which has three variations that can determine whether an individual is a slow, intermediate or fast metaboliser of caffeine.
Slow metabolisers were considered to have a higher risk of the negative effects of caffeine, as it remains in the body longer, one variant has been associated with an increased risk of heart attacks.
Another gene that affects the metabolism of caffeine is ADORA2A, a variant of which has been found to be associated with panic disorder, along with caffeine- induced anxiety, sleep changes and caffeine sensitivity.
There has been an increase in consumption of caffeine, which was now in a greater variety of products marketed to a wider range of people.
Data from the US shows a doubling of visits to hospital emergency departments because of energy drink consumption, although there’s no published research yet to show the same is happening here.
There has also been an increase in reported cases of caffeine poisoning in New Zealand, and 25 per cent have been because of the consumption of energy drinks.
Ali was keen to investigate caffeine’s impact on the health system, but first saw the need to collect enough data to create risk profiles that could be based on sex, age, underlying health conditions, genetic traits and ethnicity.
The programme also looks at top athletes, who use caffeine to boost performance, cognition and perception.
Ali pointed to a 2011 study that analysed 21,000 urine samples from athletes and found around 75 per cent were using caffeine as an ergogenic aid.
Another project was looking at caffeine’s effects on children.