Massive intake of caffeine can affect hydration, ion absorption by kidneys

By Sarah MacDonald
News Reporter

Tim Hortons’ new giant cup size may be helping students get an extra jolt, but it’s also raising concerns related to increased caffeine intake.

“You actually become dependent on caffeine,” said Matthew Ramer, a bioscience professor at Humber. “Your body has become used to that stimulant — to that caffeine.”

The 24-ounce extra large cup was introduced on Jan. 23. To accommodate the new size, all of Tim Hortons’ old sizes were downgraded – the small became an extra small, and so on.

Higher levels of caffeine are primarily found in coffee – 125mg per five ounces – according to Susan Somerville, program co-ordinator of food and nutrition at Humber.

However, tea, chocolate, energy drinks and some medications like cough syrup, also include caffeine.

Somerville said caffeine is not an addictive substance, and that any effects from consumption wear off after a week.

But the move to use cup sizes similar to those sold in Tim Hortons chains in the United States is worrisome, said Ramer.

“This is not necessarily a good trend to have larger and larger sizes. I mean, we started years ago with a small and now a small is what a large used to be. You’re getting more and more volume,” he said.

Consuming more liquids affects the biological breakdown of the fluid in your body, specifically in the kidneys, said Ramer.

The ability to transport important ions into your kidneys is essential, but caffeine blocks the process of sodium and water reabsorbing back into the blood, which may cause dehydration.

“You’re not actually absorbing as much water as you should be,” said Ramer. “You still want to keep drinking coffee and you’re thinking, ‘why am I still thirsty?’”

But students don’t seem to mind the increased amount of caffeine in these new cup sizes.

“I think that’s okay because I would get the biggest one,” said Marissa Cho, 19, a first-year marketing student. “I drink tea more than coffee, at least one extra-large a day.”

Health Canada suggests adults ages 18-25 consume a maximum of 400mg of caffeine in a day, the equivalent of about three extra small Tim Hortons’ coffees.