Study reveals common ingredient linked to higher risk of heart disease

A cohort study of UK Biobank participants has found a relationship between increased usage of free sugars with the rising possibility of heart diseases.

Free sugars are those sweeteners that are added and those naturally present in honey and fruit juice. Sounds confusing? Sugars are classified as 'free' as they're not inside the cells of the food we consume.

When fruit is turned into fruit juice, the sugar is released from their cells, and they become free sugars. They lose fiber content as well.

The study aimed to assess the link between types and sources of dietary carbohydrates and cardiovascular incidence. Furthermore, the team looked at the associations of carbohydrate intakes with triglycerides within lipoprotein subclasses. According to a press release, the results act as proof to effect a change in the global dietary recommendation and reduce free sugar consumption to below five percent of total daily energy.

The research was based on data from 110,497 individuals acquired from the UK Biobank who had completed at least two dietary assessments. The team led by Rebecca Kelly of the University of Oxford, the UK tracked "individuals for more than 9 years and found that total cardiovascular disease (heart disease and stroke combined), heart disease, and stroke occurred in 4,188, 3,138, and 1,124 participants, respectively," said the release. 

Quality, rather than quantity of the sugar consumed, matters  

The study concluded that total carbohydrate intake does not have a direct link to cardiovascular disease outcomes. The team further analyzed the types and sources of carbohydrates consumed and found that "higher free sugar intake from foods such as sugary drinks, fruit juice, and sweets, was associated with increased risk of all cardiovascular disease outcomes."

The results are striking, as each five percent extra intake of total energy from free sugars leads to a seven percent rise in cardiovascular diseases. Furthermore, the team found that the incidence of heart disease was six percent higher, while the risk of stroke was ten percent higher. 

Further analysis showed that consuming five extra grams of fiber per day was "associated with four percent lower risk of total cardiovascular disease, but this association did not remain significant after accounting for body mass index (BMI)."

A higher intake of non-free sugars recommended

As a solution, researchers suggest the replacement of free sugars with non-free sugars – "mostly those naturally occurring in whole fruits and vegetables – and a higher fiber intake may help protect against cardiovascular disease."

According to the British Heart Foundation, "Adults and children aged over 11 should eat no more than around 30g of free sugars a day. A standard chocolate bar equals 25g of free sugar, 150 ml of fruit juice equals 12g of free sugar, and a 330 ml can of cola equals 35g of free sugar."

The study was published in BMC Medicine.

Abstract

Recent studies have reported that the associations between dietary carbohydrates and cardiovascular disease (CVD) may depend on the quality, rather than the quantity, of carbohydrates consumed. This study aimed to assess the associations between types and sources of dietary carbohydrates and CVD incidence. A secondary aim was to examine the associations of carbohydrate intakes with triglycerides within lipoprotein subclasses. A total of 110,497 UK Biobank participants with ≥ two (maximum five) 24-h dietary assessments who were free from CVD and diabetes at baseline were included. Multivariable-adjusted Cox regressions were used to estimate risks of incident total CVD (4188 cases), ischaemic heart disease (IHD; 3138), and stroke (1124) by carbohydrate intakes over a median follow-up time of 9.4 years, and the effect of modeled dietary substitutions. The associations of carbo‑hydrate intakes with plasma triglycerides within lipoprotein subclasses as measured by nuclear magnetic resonance(NMR) spectroscopy were examined in 26,095 participants with baseline NMR spectroscopy measurements. Total carbohydrate intake was not associated with CVD outcomes. Free sugar intake was positively associated with total CVD (HR; 95% CI per 5% of energy, 1.07;1.03–1.10), IHD (1.06;1.02–1.10), and stroke (1.10;1.04–1.17). Fibre intake was inversely associated with total CVD (HR; 95% CI per 5 g/d, 0.96;0.93–0.99). Modeled isoenergetic substitution of 5% of energy from refined grain starch with wholegrain starch was inversely associated with total CVD(0.94;0.91–0.98) and IHD (0.94;0.90–0.98), and substitution of free sugars with non-free sugars was inversely associated with total CVD (0.95;0.92–0.98) and stroke (0.91;0.86–0.97). Free sugar intake was positively associated with triglycerides within all lipoproteins. Higher free sugar intake was associated with higher CVD incidence and higher triglyceride concentrations within all lipoproteins. Higher fiber intake and replacement of refined grain starch and free sugars with wholegrain starch and non-free sugars, respectively, may be protective against incident CVD.