Sugary drinks might raise hypertension risk

Drinking sugar-sweetened sodas and fruit drinks is associated with higher blood pressure levels in adults.

To explore the potential for a link between sugar-sweetened drinks and high blood pressure, researchers in United States and United Kingdom analysed the consumption patterns of nearly 2,696 American and British men and women between the ages of 40 and 59 years. Diet diaries covering food, sugars, sugar-sweetened drinks and diet drinks were completed over a four-day period for each study participant. Detailed questionnaires focusing on a range of lifestyle, medical and social factors were also completed. Urine samples and blood pressure readings were taken throughout the study period.

It was observed that those who drank more than one sugar-sweetened beverage a day had the highest sugar consumption (whether glucose, fructose or sucrose) and the highest calorie consumption, at an average of about 400 extra calories a day. Those drinking more than one sugar-sweetened beverage a day also registered higher average body-mass indexes (BMI) compared with those who drank none, suggesting that those who consumed such drinks also consumed less healthy foods. They were consuming empty calories without the nutritional benefits of real food with reduced intake of potassium, magnesium and calcium.

For every serving (355-millilitres) of sugar-sweetened beverage consumed per day, there was a significant jump in both systolic and diastolic blood pressure readings (+1.6 mm of Hg and +0.8 mm of Hg, respectively), even after adjusting for differences in body mass.

Higher blood pressure was more pronounced in people who consumed high levels of both sugar and sodium. Drinking a diet beverage, however, was actually linked to a slight drop in blood pressure (although this finding did not meet statistical significance), while caffeine consumption appeared to have no impact on blood pressure.

The findings suggest that individuals who consume more soda and other sugar-sweetened soft drinks may have higher blood pressure levels than those who consume less. And the problem may be exacerbated by higher salt intake, an important cause of high blood pressure in itself, which can increase the incidence of heart attack and stroke.

The possible mechanisms by which sugars increase the blood pressure include an increase in the level of uric acid in the blood that may in turn lower the nitric oxide required to keep the blood vessels dilated, enhanced sympathetic nervous system activity, and sodium retention. However, future studies are needed to understand how this works because even though the data shows a pretty clear association between sugary drinks and high blood pressure, it doesn't definitively suggest a mechanistic link. These findings lend support for recommendations to reduce the intake of sugar-sweetened beverages, as well as added sugars and sodium in an effort to reduce blood pressure and improve cardiovascular health.

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