Coke No Sugar uses aspartame - so is it safe?

Don't go gulping down litres of the new Coke No Sugar range - it's no health drink, a nutrition expert has warned.

Coke No Sugar is the company's third attempt at emulating the iconic drink's flavour, after the 1980s' Diet Coke and 2006's Coke Zero.

Coca-Cola says it's closer to the taste of the real thing, but without the calories. But that does make it safe to drink?

Healthy Food Guide editor Niki Bezzant says it can only be considered healthy if you're drinking it instead of the sugar-filled Coca-Cola Classic.

"Coke with sugar in it is bad for you. Sugary drinks have got no redeeming features. There's no nutrition in them. They're nothing but empty calories.

"If you're choosing a sugar-free drink like this one over a sugary drink, then it's a healthier option. Obviously the healthiest option is to have water."

The sweeteners in Coke No Sugar, just like Coke Zero and Diet Coke, are aspartame - listed on the can as sweetener 951 - and acesulfame potassium, otherwise known as sweetener 950 or 'Ace K'. Aspartame is perhaps the most common artificial sweetener in the world, sold under the brand names Equal and NutraSweet.

Both products are considered safe by food authorities here, in the US and in Europe. Because it's around 200 times sweeter than sugar, only a very small amount of aspartame needed to make a drink taste nice - about 185mg (in contrast, a can of Coke Classic has 27g of sugar). It would take 18 cans for the average person to exceed the US Food and Drug Administration's daily recommended maximum.

If you drink fewer than 18 cans a day, according the Mayo Clinic the only proven risks aspartame poses are to people:

  • with the genetic disorder phenylketonuria or muscle disorder dyskinesia
  • taking certain medications
  • who have a sleep or anxiety disorder, which aspartame can worsen.

Recent studies looking at suspected links between aspartame and cancer have largely come up empty.  

A less immediate risk of consuming any artificial sweetener is weight gain. It sounds counterintuitive, but studies have shown consuming sweet products without the calories increases your appetite and makes real sugar even tastier.

"Inside the brain's reward centres, sweet sensation is integrated with energy content," Associate Professor Greg Neely from the University of Sydney said last year.

"When sweetness versus energy is out of balance for a period of time, the brain recalibrates and increases total calories consumed."

All Coke variants are acidic says Ms Bezzant, so are bad for your teeth regardless of their sugar content.

"Try and get yourself towards where you're having more water than anything else."

Coca-Cola's position is that its sweeteners are "perfectly safe".

"We know that consumers, their tastes are changing, their preferences are changing, our concerns are changing, right?" says Sandhya Pillay, general manager of Coca-Cola New Zealand.

"We want to eat and drink less sugar."

All about the money?

Ms Bezzant says Coke's move has little do with health, and more about capturing the emerging sugar-free market.

"They're going where the demand is," she told The AM Show. "Everyone's wanting to have less sugar in their diet. This is Coke being a savvy business."

Ms Pillay says Coca-Cola's sugar-free range currently makes up about a third of the company's sales, but that's rising fast - about at least 12 percent in the last year.

"We're in the business of treats - that's part of our portfolio. But now you're going to have an option."

Coke No Sugar goes on sale on June 12. In the meantime, both Diet Coke and Coke Zero will still be available. It's not clear if they'll eventually be discontinued. "We've been so focused on getting this to market, because it's been five years in the making, we haven't even had conversations about that yet," says Ms Pillay.

In countries where a similar 'Coke Zero Sugar' offering has been unveiled in the past year, the 10-year-old Coke Zero range has been discontinued.