As noted in a recent press release from the National Institutes of Health, middle-aged adults who drank more than one soft drink daily, either diet or regular, have a more than 40% greater rate of either having or developing metabolic syndrome, a cluster of conditions that increase the risk for heart disease, according to new data from the National Heart, Lung, and Blood Institute (NHLBI )of the National Institutes of Health.
A person is considered to have metabolic syndrome if he or she has three or more of the following five risk factors: waist circumference greater than or equal to 35 inches (women) or 40 inches (men); fasting blood glucose of greater than or equal to 100 mg/dL, triglycerides greater than or equal to 150 mg/dL; blood pressure greater than or equal to 135/85 mmHg; and high-density lipoprotein (HDL, or "good") cholesterol below 40mg/dL for men or below 50 mg/dL for women.
Results from the Framingham Heart Study's "Soft Drink Consumption and Risk of Developing Cardio-Metabolic Risk Factors and the Metabolic Syndrome in Middle Aged Adults in the Community," were published online in Circulation earlier this week.
"Other studies have shown that the extra calories and sugar in soft drinks contribute to weight gain, and therefore heart disease risk," said Dr. Elizabeth G. Nabel, director, NHLBI. "This study echoes those findings by extending the link to all soft drinks and the metabolic syndrome."
While the authors acknowledge that the increased risk of metabolic syndrome associated with high-calorie, high-sugar regular soft drinks might be expected, the similar risk found among those drinking diet sodas is more challenging to understand, they say. It is worth noting that dietary patterns are similar across drinkers of both regular and diet soft drinks.
"Although our study adjusted for lifestyle factors, it is known that people who regularly drink soft drinks—even diet sodas—are also known to eat foods that are higher in calories and fat, and get less physical activity," said Dr. Ramachandran Vasan, professor of medicine, Boston University School of Medicine, and senior author of the paper.
"High soft drink consumption may in fact be a marker for metabolic syndrome risk, but more study is needed," said Dr. Ravi Dhingra, instructor in medicine, Harvard Medical School, and lead author.
Data was collected in two ways, via a physician-administered questionnaire that captured average daily of consumption of 12-oz. soft drinks, and a self-administered food-frequency questionnaire that captured the frequency of diet versus regular soft drink intake. Both questionnaires were recorded during Framingham Heart Study visits scheduled in 1987 to 1991 and 1995 to 1998, and accounted for nearly 9,000 person observations.
"Our results point to the importance of long-term observational studies such as the Framingham Heart Study, which allow us to take a closer look at how aspects of diet are inter-related with health risks," said Dr. Caroline Fox, medical officer, Framingham Heart Study and study co-author.
