Sugary drinks significantly raise cardiovascular disease risk, but occasional sweet treats don’t, scientists find

A little of what you fancy does you good… unless it’s a fizzy drink. Scientists studying the impact of sugar on the risk of cardiovascular disease have found that eating too much added sugar increases your risk of stroke or aneurysm, but eating a few treats is associated with a lower risk of cardiovascular diseases. Meanwhile, drinking sweetened beverages raises your risk of stroke, heart failure, and atrial fibrillation.  

“The most striking finding from our study is the divergent relationship between different sources of added sugar and cardiovascular disease risk,” said Suzanne Janzi, PhD candidate at Lund University and corresponding author of the article in Frontiers in Public Health. “This surprising contrast highlights the importance of considering not just the amount of sugar consumed, but its source and context.” 

A spoonful of sugar 

Although most public health bodies recommend limiting sugar consumption to protect your teeth and improve your diet, there has previously been limited evidence regarding the impact of sugar intake on cardiovascular diseases. These diseases are the leading cause of death and disease in Europe, and changing your diet is a comparatively easy way to reduce your risk. 

To understand how sugar consumption affects cardiovascular disease risk, and whether consuming different kinds of sugar changes those risks, the scientists collected data from two major cohort studies, the Swedish Mammography Cohort and the Cohort of Swedish Men. These studies had diet questionnaires administered in 1997 and 2009, allowing the scientists to monitor participants’ diets over time.  

Once exclusions had been made to ensure the two cohorts shared the same inclusion criteria and to remove independent risk factors for cardiovascular diseases, the scientists were left with a sample of 69,705 participants. They looked at three classes of sugar consumption — toppings like honey, treats like a pastry, or sweetened beverages like fizzy drinks — and seven cardiovascular diseases: two different types of stroke, heart attacks, heart failure, aortic aneurysms, atrial fibrillation, and aortic stenosis. 

The participants were monitored until they died, were diagnosed with one of the cardiovascular diseases, or reached the end of the follow-up period in 2019. During this period, 25,739 participants were diagnosed with a cardiovascular disease.  

The scientists then used this data to break down how the different types of sugar intake affect the risk of different cardiovascular diseases.  

Affairs of the heart 

They found that consuming sweet drinks was worse for your health than any other form of sugar: drinking more sweetened drinks significantly increased the risk of ischemic stroke, heart failure, atrial fibrillation and abdominal aortic aneurysm.  

“Liquid sugars, found in sweetened beverages, typically provide less satiety than solid forms — they make you feel less full — potentially leading to overconsumption,” said Janzi. “Context also matters — treats are often enjoyed in social settings or special occasions, while sweetened beverages might be consumed more regularly.” 

Different cardiovascular diseases were affected differently by increased sugar intake, possibly because consuming additional sugar affected participants’ individual risk profile differently. Increased sugar in general raised the risk of ischemic stroke and abdominal aortic aneurysm, as well as increasing the risk of heart failure in participants with a normal BMI.  

However, the highest risks of a negative health outcome arose in the lowest intake category for treats. Consuming occasional treats was associated with better outcomes than no treats at all.   

“This might reflect underlying dietary behaviors — individuals consuming very little sugar might have very restrictive diets or might be limiting sugar due to pre-existing health conditions,” suggested Janzi. “While our observational study cannot establish causation, these findings suggest that extremely low sugar intake may not be necessary or beneficial for cardiovascular health.” 

However, the scientists noted that more work will be needed to understand the mechanisms involved in the differential effects of different types of sugar consumption. They also pointed out that diet is highly demographically and culturally specific.  

“Our findings are based on a Swedish population, which may have dietary habits and lifestyle factors that differ from those in other populations,” said Janzi. “Particularly relevant in this context is the social custom of ‘fika’ — regular coffee and pastry breaks that are deeply embedded in Swedish culture. These results may not directly translate to other populations with different dietary cultures.”