12 Jul 2019

Sugary drinks and cancer

From Lately, 10:20 pm on 12 July 2019

A new study published in the British Medical Journal (BMJ) says sugary drinks could increase the risk of cancer.

French scientists followed more than 100,000 people for five years and concluded that drinking an extra 100mls of sugary drinks a day - about 2 cans of coke a week - could increase the risk of developing cancer by 18 percent.

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Photo: RNZ / Diego Opatowski

Auckland University health researcher, Dr Simon Thornley has sounded warnings about the risks of sugary drinks, saying they are more harmful than sweet food and that New Zealanders' consumption of sugary drinks has increased at a time when it is falling in other countries.

He told Karyn Hay the new evidence did not surprise him.

“I think it fits in with what we already know, or what we think we know. We know that sugar is related to a lot of things which are related to cardiovascular disease, like getting fat around the middle, high blood pressure, diabetes, and we know that those things are also related to cancer.”

He says the study’s notional quantity of 100mls didn’t reflect reality.  

“Most of us don't drink in units of 100mls, most of us drink in units of about 330 mls, which is about a can.

“If you translate that increase, a 20 percent increase translates to a 90 percent increase in risk from a can of coke, because it's 1.2 raised to the power of 3.3.”

He says the researchers looked at all sugary drinks; including ones sometimes considered healthy.

“You could see that risks were also raised with fruit juice. And this is something that we've been saying for a long time, because fruit juice has as much sugar as soft drinks, and yet it is kind of considered to be healthy and often given to kids.”

Sugary drinks are particularly bad for us, compared with biscuits or lollies for example, because of our physiology.

“Well, from looking at the physiology, what happens when you have a sugary drink is that your liver gets flooded with fructose, and it gets overwhelmed. And that high concentration of fructose which comes from the rapid absorption into the body, into the bloodstream, we think is particularly harmful and we see it the scientific studies.”

Auckland Regional Public Health Service epidemiologist Dr Simon Thornley

Dr Simon Thornley Photo: LinkedIn

New Zealanders have a very sweet tooth, he says.

“We have roughly, on average, 40 teaspoons of sugar a day. So that it's not all soft drinks for kids about a quarter of it comes from soft drinks.

“But we know the trends are not going down. In fact, they're increasing, if anything, because the decline in soft drinks sales are being offset by an increase in sports drinks and an increase in fruit juice.”

Although the French study said sugary drinks “may” increase the risk of cancer, Dr Simon Thornley says the evidence is overwhelming.

“And so I'd say that the weight of scientific evidence points strongly in that direction, biochemists and cell biologists have been talking for years about the increased risk of cancer from sugar and that sugar makes cancer cells multiply more rapidly. And that there is a very strongly biologically plausible argument that that's the case.”

Sugar is highly addictive and affects the same receptors in the brain as alcohol and tobacco, he says. He believes a sugar tax, such as the one in the UK, is a “no brainer”. The UK tax included incentives for producers to reduce sugar concentration, he says.

“The impact on sugar intake has been absolutely dramatic In the UK they've taken thousands of tons of sugar out of the food supply by making this tax incentive for producers. “”

He has been lobbying for a similar tax here, but says the Government’s response has been lukewarm.

“We've talked to the Minister of Health about it and we've been very disappointed at the government's response, they say they working with the food industry, but they don't want to be coercive.”

He says health minister David Clarke seems more attuned to industry voices.

“He says he's going to look at the evidence that is coming out. But he certainly hasn't been particularly attentive to the evidence that we've presented to him. He seems to be more responsive to the industry's evidence, which I think is very disappointing for Labour government.”

Related stories:

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  • Advantages of a sugar tax
  • A panel of experts discuss the practical and social dilemmas associated with tackling diet-related disease in New Zealand