A large long-term study led by researchers at the University of Toronto and Harvard University provides strong evidence that children who consume sugar-sweetened beverages and fruit juice have higher risk of hypertension later in life.
The research, published in Circulation , suggests that dietary patterns in children can have a significant impact later in life and may help bolster guidelines around fructose consumption.
"This research shows that our habits, our diets and lifestyles in early years matter for developing hypertension or other cardiometabolic risk factors later in life," says Vasanti Malik, associate professor in the Temerty Faculty of Medicine's department of nutritional sciences and principal investigator on the study. "It also shows that the source and form of the sugar consumed is really important, and we should focus on reducing liquid sources of sugar in the diet in place of whole fruit."
Hypertension, also known as high blood pressure, increases the risk of cardiovascular disease and related conditions. Global rates of hypertension are increasing, and researchers are also seeing hypertension emerge earlier in life; however, it can often be prevented and managed through lifestyle changes, such as a healthier diet.
While previous research suggests a relationship between overconsumption of sugars — especially fructose — and risk of cardiometabolic disease, the researchers were able to use longitudinal data from the Growing Up Today Study (GUTS) to compare the long-term effects of consuming sugar-sweetened beverages (defined as pop, fruit drinks and sports drinks), fruit juice and whole fruit.
GUTS is an ongoing cohort study with more than 25,000 participants, who have provided data on diet, lifestyle, and health status regularly starting between the ages of nine and 16. The study has followed participants for nearly 25 years.
The study by Malik and her colleagues, which included first author and doctoral student Michelle Nguyen, found that about six per cent of participants reported a diagnosis of hypertension, with a median age of onset of 36 years. The researchers found that total fructose consumption was not associated with hypertension risk; however, higher intake of sugar-sweetened beverages was significantly associated with a higher risk of hypertension, which increased with each serving per day.
The relationship with fruit juice was slightly more complicated, showing some benefits at low intake amounts but increased hypertension risk at higher amounts.
The study also specifically examined sports drink consumption and hypertension risk. Malik says that these drinks often have a 'health halo' through their association with sports, but that in reality, they are strongly associated with increased hypertension risk and should be more clearly addressed in dietary guidelines.
Importantly, the analysis found that consumption of whole fruit was not associated with higher risk of hypertension, despite the amount of fructose found in fruit. Replacing one serving per day of sugar-sweetened beverages with whole fruit, milk or water or one serving per day of fruit juice with whole fruit were both associated with lower risk of hypertension.
Malik notes that although fruits, fruit juices and sugar-sweetened beverages all contain fructose, the difference in risk is likely due to the differences in overall nutrient composition and metabolic effects.
"Whole fruits include fibre and range of nutrients that are essential to a healthy diet, not just fructose," says Malik, who is also a researcher at U of T's Joannah & Brian Lawson Centre for Child Nutrition . "The source and form of the sugar are important for hypertension risk. We have to think about the whole food source, not just the nutrient on its own."
Malik says the study's results reinforce that dietary guidelines should encourage consuming whole fruit while limiting fructose in liquid form, even at young ages.
"Sugar consumption is just one aspect of diet, and it's important to be mindful of other factors in the diet and overall healthy lifestyle," she says. "This work really emphasizes that developing healthful patterns in childhood and maintaining them over time is important to our health later on."
The study was supported by the U.S. National Institutes of Health.
