Free sugars in the diet – those that are not found inside cells in food – increase the risk of stroke and heart attack, according to a macro study in which 110,000 people in the United Kingdom have been followed over ten years. In contrast, no harmful effect has been observed from the sugars naturally found in fruit or other carbohydrates.
Free sugars are “any sugar that is added to a food or drink; or also the sugar that is already in honey, syrup or fruit juice,” reports the British Heart Foundation. “When you make fruit juice, the sugars leave the cells and become free sugars. Fiber is lost and it is easier to consume excess sugar without realizing it.” In the case of dairy products, their carbohydrates are not considered free sugars.
According to the results of the new study, if the proportion of dietary calories provided by free sugars increases by 5%, the risk of suffering a myocardial infarction in the following ten years increases by 6% and that of stroke by 10%. . Fiber, on the other hand, has a protective effect: for every increase of five grams of fiber in the daily diet, the risk of cardiovascular disease is reduced by 4%.
“Replacing refined starches and free sugars with whole starches and non-free sugars can protect against cardiovascular disease,” the researchers conclude in the journal BMC Medicine, where they presented their results.
The research, led by the University of Oxford, has been based on 110,000 volunteers from the UK Biobank project, which studies the influence of diet and other environmental factors on the development of diseases. They had an average age of 55 years when they enrolled in the study. They had no diagnosed cardiovascular disease or diabetes and answered exhaustive questionnaires about their diet between 2010 and 2012. In the following ten years, 3,138 myocardial infarctions and 1,124 strokes were recorded among the volunteers.
The results show that the greater the amount of free sugars in the diet, the higher the level of triglycerides in the blood, which may explain the greater risk of heart attack in the adult population analyzed. Previous studies have observed that higher sugar consumption is also associated with a higher risk of obesity.
Regarding the possible harmful effect of free sugars on the cardiovascular health of children, adolescents and young adults, “we cannot draw conclusions since our study was carried out in middle-aged adults,” states Rebecca Kelly, first author of the study, by email. job. “A different study would have to be carried out to find out.”
The World Health Organization (WHO) has recommended since 2015 that both adults and children “reduce their daily consumption of free sugars to less than 10% of their total energy consumption; a reduction below 5% would provide additional health benefits.”
5% of daily calories is equivalent to about 25 grams of sugar for an adult, says the WHO. A 150-milliliter container of fruit juice provides about 12 grams of sugar and a 330-milliliter can of cola provides 35, reports the British Heart Foundation, which recommends “choosing sugar-free drinks; do not drink more than one glass of fruit juice; do not add sugar to tea or coffee; and avoid sugary snacks or limit yourself to small portions.”
Although the total amount of carbohydrates in the diet has not been shown to affect cardiovascular health, “the quality of carbohydrates may be more important than the quantity,” the research authors note in BMC Medicine. The new study is the first to focus on the role of free sugars, and joins others that have examined added sugars, which are a common form of free sugars.
