- Zhao L et al. Sugar-sweetened and artificially sweetened beverages and risk of liver cancer and chronic liver disease mortality. JAMA. 2023;330:537-46.
Around two-thirds of all US citizens consume soft drinks or sweetened fruit juices every day. At the same time, the incidence of liver cancer in the USA has risen sharply in recent decades. The known risk factors include chronic hepatitis infections, metabolic disorders such as type 2 diabetes and obesity, as well as excessive alcohol consumption. A team led by epidemiologist Longgang Zhao from the University of South Carolina, Columbia, wanted to know whether sugar could also be added to the list of risk factors for liver disease.
For their study, the researchers drew on the Women's Health Initiative, a large prospective study of around 160,000 postmenopausal women in 40 clinical centres in the USA, which started in 1993. From this cohort, they recruited almost 100,000 participants and asked them about their drinking behaviour. Questionnaires were used to determine the consumption of sugar-sweetened and artificially-sweetened beverages; pure fruit juices with no added sugars were not considered. Consumption was categorised as:
One portion corresponded to a 355-ml beverage can.
The primary endpoints were:
During a mean follow-up period of 20.9 years, 207 women developed liver cancer and 148 died of chronic liver disease. Compared to the consumption of 3 or fewer servings of sugar-sweetened beverages per month, those who consumed 1 or more servings per day had a 1.85-fold higher risk of liver cancer. The risk of death from chronic liver disease was 1.68 times higher in the group with the highest consumption of sweetened beverages than in the group with moderate consumption. In contrast, artificially sweetened beverages did not increase the risk of liver cancer or liver-related mortality, even in large quantities.
Another interesting observation: replacing a sugar-sweetened drink with 1 serving of coffee or tea was associated with a lower liver cancer incidence, although the result was not significant. Similar observations have already been made in a cohort study of the US general population.
As a possible explanation for the negative effects of sugar-sweetened beverages on the liver, the authors discussed, among other things, the promotion of obesity and insulin resistance, which in turn represent a risk factor for liver disease. Other additives in sweet drinks could also play a role. However, these pathophysiological derivations remain hypothetical and require further investigation.
The study shows once again that the heavy consumption of sugary drinks carries high health risks and probably damages the liver. Sugar substitutes could at least be a healthier alternative. The best drinks, according to the study, were coffee or tea – unsweetened, of course. In general, it seems advisable to avoid consuming added sugars in drinks as much as possible. After all, there is already more than enough in today's diet.