High consumption of sugar-sweetened beverages appeared to adversely affect blood pressure levels in a population-based study involving more than 2,600 people living in the United Kingdom and the United States.
The findings should help shore up the message to patients that consumption of soda and fruit juice needs to be limited for a healthy diet.
“If individuals want to drink sugar-sweetened beverages, we suggest they do so only in moderation [fewer than three 12-ounce cans per week],” the lead investigator of the study, Ian Brown, Ph.D., said in an interview.
The International Study of Macro/Micronutrients and Blood Pressure (INTERMAP) involved 2,696 people aged 40–59 years recruited from 10 population samples in the United Kingdom and United States. In addition to answering questions about the intake of beverages sweetened by fructose, glucose, and sucrose, participants were asked about their consumption of diet beverages and alcohol. Each subject also provided two 24-hour urine collection samples, according to Dr. Brown of the department of Eepidemiology and biostatistics at the Imperial College of London, and his colleagues.
Multiple regression analyses showed that for each serving of a sugar-sweetened beverage consumed per day, systolic blood pressure increased by 1.6 mm Hg. Diastolic blood pressure rose by 0.8 mm Hg, the investigators wrote.
A direct association also was observed between the intake of fructose-sweetened beverages and blood pressure. Fructose intake that was higher by 2 standard derivations was associated with a 3.4–mm Hg increase in systolic blood pressure and a 2.5–mm Hg increase in diastolic blood pressure, according to the findings (J. Hypertens. 2011 Feb. 28 [doi: 10.1161/HYPERTENSION AHA.110.165456]).
These associations between sugared beverage intake and blood pressure were strongest among individuals with higher urinary sodium excretion, the researchers added. The results remained statistically significant after the investigators accounted for differences in body mass.
The researchers concluded that higher blood pressure is associated with high consumption of glucose and fructose, as well as with higher levels of dietary sugar and sodium.
There was no significant correlation between diet soda intake and blood pressure levels.
The study was the first in people to suggest that there is an association between high sodium intake and high sugar-sweetened beverage intake and the overall effect on blood pressure, Dr. Brown said in an interview.
“It has been suggested by other scientists that consumption of high levels of sugars and salt may lead to sodium retention in the kidneys and/or volume expansion (i.e., an increased level of fluid in the body), which could lead to higher blood pressure,” Dr. Brown said.
The findings also suggest that people who consume more than one sugar-sweetened beverage daily tend to consume less of other types of nutrients including starch, fiber, protein (animal and vegetable), and polyunsaturated and monounsaturated fatty acids.
But critics of the study emphasized that the “level of blood pressure changes noted by the authors are inconsequential and well within standard measurement error,” according to a statement by the American Beverage Association.
In addition, “The results of [the analysis] obfuscate other important variables that are linked to high blood pressure,” the statement said.
The investigators reported having no conflicts of interest. Dr. Brown's analysis was supported by a U.K. Medical Research Council studentship. The INTERMAP Study as a whole was supported by a grant from the National Heart, Lung, and Blood Institute; the Chicago Health Resource Foundation; and national agencies in China, Japan, and the United Kingdom.