Sugar has a direct effect on risk factors for heart disease and is likely to impact blood pressure, independent of weight gain, a new research has warned.
Dr Lisa Te Morenga, Professor Jim Mann and colleagues from New Zealand's University of Otago conducted a review and meta-analysis of all international studies that compared the effects of higher versus lower added sugar consumption on blood pressure and lipids (blood fats or cholesterol) – both of which are important cardiovascular risk-factors.
They located dietary intervention trials published in English-speaking journals between 1965 and 2013, comparing diets where the only intended differences were the amount of sugars and non-sugar carbohydrates consumed by the participants, and which measured the effects of these diets on lipids and blood pressure.
They found 37 trials reporting effects on lipids and 12 reporting effects on blood pressure. The findings from the individual trials were then pooled to determine the overall effects from all the studies.
"Our analysis confirmed that sugars contribute to cardiovascular risk, independent of the effect of sugars on body weight," said Te Morenga.
"Although the effects of sugars on blood pressure and lipids are relatively modest, our findings support public health recommendations to reduce added sugar in our diets as one of the measures which might be expected to reduce the global burden of cardiovascular diseases," Te Morenga said.
Te Morenga said previous research showed that there did not appear to be any special metabolic effect of sugars making people more likely to gain weight on high-sugar diets compared with low sugar diets when the total amount of carbohydrates and energy remains the same.
"However our latest study did find significant effects of sugars on lipids and blood pressure among these types of energy-controlled studies. This suggests that our bodies handle sugar differently to other types of carbohydrates.
"We were also relatively surprised that there was a positive association between sugars and cardiometabolic risk factors given that a large body of the research which met our inclusion criteria is funded by the food industry. This is because such trials are less likely to find a significant association between sugars and health outcomes," Te Morenga said.
"In subgroup analyses we showed that by excluding the trials funded by the food/sugar industry, we found larger effects of sugar on lipids and blood pressure," said Te Morenga.
"Our work provides further evidence to support these recommendations which have been disputed by the food industry," she said.
The findings were