Drinking just one sugary drink a day – such as Coca-Cola or fruit juice – could significantly increase the risk of liver cancer, concerning research today revealed.
Liver cancer is the fastest-rising cause of cancer-related deaths in the UK.
The disease claims around 6,400 lives every year in the UK, with global cases expected to increase by 55 per cent by 2040.
World-leading experts have previously linked artificial sweeteners such as aspartame to the disease, after it was listed as ‘possibly carcinogenic’.
Now US researchers say sugar-laden drinks may pose a greater risk when it comes to liver cancer.
The scientists, who analysed the diets of more than 1.5million adults, found that for each additional sugar-sweetened drink per day, the risk of certain liver cancers increased by up to 15 per cent.
There was no clear increased risk for artificially sweetened drinks.
The researchers concluded that sugary drinks may be more harmful than ‘diet’ alternatives – challenging previous assumptions about artificial sweeteners.
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‘Intake of sugar-sweetened beverages has been associated with a number of deleterious health outcomes, including weight gain, diabetes and liver disease – all of which are risk factors associated with liver cancer,’ the study’s lead author said.
‘Based on this study, and prior research, individuals may benefit from reducing their intake.’
In the new study, researchers from the National Cancer Institute tracked 1,518,411 participants from the US and Europe, aged 57 on average.
Every four years, participants filled out food frequency questionnaires which tracked their consumption of artificially-sweetened and sugary drinks.
They were grouped into five categories for both beverage types ranging from rarely drinking them to consuming more than one a day.
Factors that could skew the results such as diabetes status, sex, BMI, alcohol intake, regular use of painkillers and coffee intake were also accounted for.
Over a follow-up of around 18 years, 2,811 participants were diagnosed with liver cancer.
Of these, 1,699 developed hepatocellular carcinoma, the most common type of the disease, which starts in liver cells.
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A further 444 developed intrahepatic cholangiocarcinoma, a rarer cancer which starts in the bile ducts inside the liver.
Initially, researchers found no clear link between sugary drinks and overall liver cancer.
However, when they removed one large study from the analysis, a clear link emerged.
In that study, nearly a quarter of participants had diabetes – far higher than in others.
This mattered because people with diabetes are more likely to limit their intake of sugary drinks, but already face a much higher risk of liver cancer.
This skewed the results, making it look like people who drink fewer sugary drinks have a higher cancer risk – when in reality this was driven by diabetes.
Once this study was removed, sugary drinks were shown to increase the risk of hepatocellular carcinoma by around 10 per cent with every additional daily drink.
For intrahepatic cholangiocarcinoma, the risk was slightly higher with each additional drink raising the risk by 15 per cent.
Sugary drinks like Coca-Cola and sweetened fruit juices are already known to contribute to adverse health outcomes such as obesity, high blood pressure and type 2 diabetes – all of which are linked to a higher risk of liver cancer.
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They can also increase the risk of metabolic dysfunction-associated steatotic liver disease (MASLD) – which occurs when excess fat builds up inside the liver.
This process is thought to be driven primarily by fructose – a sugar processed in the liver that encourages fat production.
Some studies have also suggested that fructose may damage the gut lining, allowing harmful substances to enter the bloodstream and reach the liver.
The team concluded this suggests sugary drinks may raise liver cancer risk through multiple biological pathways, not just via obesity and diabetes.
However, writing in the journal JAMA Network Open, they cautioned it’s almost impossible to completely separate the effect of sugary drinks from those of obesity and diabetes.
In 2023, World Health Organisation (WHO) bosses ruled that aspartame would be classed as a possible carcinogen. But its guidance – that an 11 stone adult can drink 14 cans of a diet drink per day – didn’t change.
Since then, a number of studies have linked both diet and sugary drinks to liver disease – a key driver of liver cancer.
One study of more than 123,000 British adults found those who guzzled sugar-sweetened drinks had a 50 per cent increased risk of developing the condition.
The British Liver Trust estimates MASLD may now affect one in five people in the UK- though experts have warned the true figure could be as high as 40 per cent.
Worryingly, around 80 per cent of cases go undiagnosed, as the disease often has no obvious symptoms – or it has symptoms that are mistaken for less serious problems.
