In line with previous studies, researchers found that consuming sugar and sugary drinks ‘significantly raises’ cardiovascular disease risk: such as the risk of stroke, heart failure and atrial fibrillation.
But they also found the relationship between added sugar and cardiovascular risk is more complicated than previously assumed – based on not just the amount of sugar consumed, but also its source and context.
Large scale study
Researchers collected data from two major cohort studies: the Swedish Mammography Cohort and the Cohort of Swedish Men. These studies had diet questionnaires filled out between 1997 and 2009, creating a picture of participants’ diets over time. Once researchers removed participants with independent risk factors and adjusted the cohorts to the same inclusion criteria, they were lift with a sample of 69,705 people. Participants were aged 45-83 years old.
Cardiovascular disease is the leading cause of death globally, attributed to around 32% of all deaths, according to the National Institutes of Health.
That was reflected in the Swedish data: over the study period – which ended in 2019 – 25,739 participants were diagnosed with a cardiovascular disease.
While most studies on sugar intake have tended to focus on sugary-drink consumption, the researchers decided to delve into how different types of sugar intake had affected the risk of different types of cardiovascular disease.
So researchers looked at three classes of sugar consumption: sweetened beverages (sweetened sodas and fruit drinks but not fruit juices), toppings (honey, table sugar, jams and marmalades), and bakery, dairy and confectionery treats (pastries, ice cream, sweets and chocolates).
Sugar consumption
Most studies on sugar consumption and CV risk have primarily focused on sugar-sweetened beverage consumption rather than overall added sugar intake.
However, sugar-sweetened beverages make up only ~14% of added sugar intake in Sweden (and ~25% in the US) - so researchers in Sweden widened their research.
And they looked at seven cardiovascular diseases: two different types of stroke, heart attacks, heart failure, aortic aneurysms, atrial fibrillation, and aortic stenosis.
Sugar-sweetened beverages
Publishing their results in the journal Frontiers in Public Health, researchers found that consuming sweet drinks was worse for 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.
One explanation for that is overconsumption. Liquid sugars in sweetened beverages typically provide less satiety than solid forms – meaning drinking them doesn’t result in feeling full.
Another context is how such beverages are consumed. As this is often in social settings or at special occasions, sugary-beverages are consumed more regularly and not necessarily simply for thirst.
Why is sugar bad for you?
Although mechanisms explaining the associations between added sugar intake and CVD risk are not well-established, several biological mechanisms have been proposed.
One hypothesis is based on the distinct metabolism of fructose (a component of sucrose). Fructose is converted to glycerol-3-phosphate, which serves as a backbone for triacylglycerol synthesis, leading to increased triacylglycerol synthesis and ultimately increased CVD risk – although studies tend to focus on very high intakes of fructose rather than normal dietary intakes.
Meanwhile, relationships between added sugar intake and CVD risk factors such as dyslipidaemia, hypertension, and obesity, have been shown in both randomized controlled trials and observational studies, and could help explain the associations found between added sugar intake and some of the studied CVDs.
Could consuming a little bit of sugar be good for you?
One surprise thrown up from the research was that consuming occasional sugary treats – such as pastries, ice cream, sweets and chocolates - was actually associated with better outcomes than no treats at all.
While this might not make a lot of sense, the researchers suggest considering this in the overall context of dietary behaviors.
Individuals who consume extremely little sugar may have very restrictive diets, or may be limiting sugar due to pre-existing health conditions.
And researchers highlight a unique cultural factor in Sweden: the tradition of ‘fika’. This is where people get together with friends, relatives or coworkers for coffee and pastries.
That means that this finding, in particular, needs further research to see if it is replicated across other populations.
However, it does suggest that an extremely low sugar intake doesn’t have any beneficial results for cardiovascular health, although researchers emphasize this needs to be better understood.
Observational study
But this strange finding shows that there many be other factors at play - and beverage industry bodies advise caution when approaching the study.
“A key limitation of the study is that it is observational, making it impossible to establish a causal link,” said Nicholas Hodac, Director General of UNESDA.
“As noted by the authors, the divergent results highlight the importance of considering dietary behaviors and lifestyle patterns, including other demographic and culturally specific elements which also affect health outcomes.
“This is illustrated by the finding that the highest risk of a negative health outcome was observed among individuals with the lowest intake of added sugars, suggesting that other factors may contribute to this increased risk.”
UNESDA also points out that sodium (salt) intake was not taken into consideration in the study, despite high consumption being a risk factor for cardiovascular disease.
These concerns are echoed by the British Soft Drinks Association.
“This is an observational study which cannot prove cause,” said a spokesperson. “All soft drinks are safe to consume as part of a balanced diet.”
Sugar reduction
Voluntary actions from the European soft drinks industry include reducing the average sugar content in drinks, and expanding portfolios of low-/no-calorie beverages. Since 2000, the industry boasts an average sugar reduction of 33.9% across Europe, with investment in promoting low/no-calorie beverages. It has also increased the availability and range of smaller pack sizes to promote moderate consumption through portion control.
In the UK, more than seven out of every 10 soft drinks sold in the UK was low or no sugar in 2023, according to data provided by the BSDA. Between March 2014 and March 2020, take home sugar from soft drinks fell by 43.5%.
Cardiovascular disease
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.
“The findings of this study on the associations between added sugar and CVD risk indicate that the associations vary depending on the disease and the source of added sugar, demonstrating the importance of studying them separately,” write the authors in the study.