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The Choice of a Metabolic Syndrome Generation: Soft Drink Consumption Associated With Increased Metabolic Risk

  • Authors: News Author: Michael O' Riordan
    CME Author: Charles Vega, MD
  • CME / CE Released: 7/25/2007; Reviewed and Renewed: 7/23/2008
  • Valid for credit through: 7/23/2009, 11:59 PM EST
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Target Audience and Goal Statement

This article is intended for primary care clinicians, cardiologists, endocrinologists, and other specialists who care for patients at risk of developing the metabolic syndrome.

The goal of this activity is to provide medical news to primary care clinicians and other healthcare professionals in order to enhance patient care.

Upon completion of this activity, participants will be able to:

  1. Identify the efficacy of educational intervention programs designed to curb soft drink consumption among children.
  2. Describe the effects of soft drink consumption on the risk of developing the metabolic syndrome in middle age.


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  • Michael O'Riordan

    Michael O'Riordan is a journalist for Medscape. Before becoming a journalist for, now part of the WebMD Professional Network, he worked for WebMD Canada. Michael studied at Queen's University in Kingston and the University of Toronto and has a master's degree in journalism from the University of British Columbia, where he specialized in medical reporting. He can be contacted at [email protected].


    Disclosure: Michael O'Riordan has disclosed no relevant financial relationships.

CME Author(s)

  • Charles P Vega, MD

    Associate Professor; Residency Director, Department of Family Medicine, University of California, Irvine


    Disclosure: Charles Vega, MD, has disclosed an advisor/consultant relationship to Novartis, Inc.

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The Choice of a Metabolic Syndrome Generation: Soft Drink Consumption Associated With Increased Metabolic Risk

Authors: News Author: Michael O' Riordan CME Author: Charles Vega, MDFaculty and Disclosures

CME / CE Released: 7/25/2007; Reviewed and Renewed: 7/23/2008

Valid for credit through: 7/23/2009, 11:59 PM EST


from Heartwire — a professional news service of WebMD

July 25, 2007 Drinking more than one soft drink daily is associated with a higher risk of developing adverse metabolic traits, as well as developing the metabolic syndrome, a new study has shown. Interestingly, it doesn't matter if the soda consumed is the diet variety, those with zero calories, as investigators showed these also increased the burden of metabolic risk in middle-aged adults.

"That was one of the more striking aspects of this study," lead investigator Dr Ramachandran Vasan (Boston University School of Medicine, MA) told heartwire . "It actually doesn't matter if the soft drink is regular or diet. There was an association of increased risk of developing the metabolic syndrome with both types of drinks."

Discussing the findings, which are published online July 23, 2007 in Circulation, Vasan said that the consumption of soft drinks has doubled to tripled between 1977 and 2001. During this same time period, soft-drink sizes have also increased to staggering proportions. With evidence that soft-drink consumption is linked with weight gain and obesity as well as an increased risk of diabetes, the investigators questioned whether soft-drink consumption in adults, in amounts that are seemingly innocuous, like one per day, posed any metabolic hazard.

The investigators, led by Dr Ravi Dhingra (Harvard Medical School, Boston, MA), related the incidence of metabolic syndrome and its components to soft-drink consumption in more than 6000 individuals participating in the Framingham Heart Study. Information on daily consumption of soft drinks was collected via a physician-administered questionnaire, with information on the type of soft drink diet or regular collected in later questionnaires. Metabolic syndrome was defined as the presence of three or more of following risk factors: excess waist circumference, high blood pressure, elevated triglycerides, low high-density lipoprotein (HDL)-cholesterol levels, and high fasting glucose levels.

In a cross-sectional analysis of the data, investigators report that those consuming more than one soft drink daily had a 48% higher prevalence of metabolic syndrome than those who drank less than one soft drink per day. In a longitudinal analysis of more than 6000 subjects free from metabolic syndrome at baseline, drinking more than one soft drink daily was associated with a 44% greater risk of developing metabolic syndrome and with developing four out of five components of metabolic syndrome. There was a trend toward an increased risk of developing high blood pressure, but this association did not reach statistical significance.

Odds Ratio of Developing Components of the Metabolic Syndrome and Metabolic Syndrome in Adults Consuming ≥ 1 Soft Drink Daily

Component of the metabolic syndrome Multivariable-adjusted odds ratio (95% CI)
Incidence of increased waist circumference (≥102 cm for men and ≥ 88 cm for women) 1.30 (1.09 - 1.56)
Incidence of impaired fasting glucose (≥ 5.5 mmol/L or diabetes) 1.25 (1.05 - 1.48)
Incidence of high blood pressure (≥ 135/85 mm Hg or on treatment) 1.18 (0.96 - 1.44)
Incidence of hypertriglyceridemia (≥ 1.7 mmol/L or on treatment) 1.25 (1.04 - 1.51)
Incidence of low HDL cholesterol (< 1.03 mmol/L for men and < 1.30 mmol/L for women or on treatment) 1.32 (1.06 - 1.64)
Incidence of the metabolic syndrome (3 of 5 components) 1.44 (1.20 - 1.74)

In a smaller sample of participants who had data available regarding the type of soft drink consumed, researchers observed that that those who consumed one or more drinks of diet or regular soda per day had a 50% to 60% increased risk of developing new-onset metabolic syndrome.

Odds Ratio of Developing the Metabolic Syndrome in Adults Consuming ≥ 1 Soft Drink (Diet or Regular) Daily

Component of the metabolic syndrome Multivariable-adjusted odds ratio (95% CI)
Diet soft drink, ≥ 1/d 1.53 (1.10 - 2.15)
Regular soft drink, ≥ 1/d 1.62 (0.96 - 2.75)

Despite the fact that diet soda has zero calories, the findings are not entirely surprising, said Vasan, as diet soft drinks have been previously linked with poor health outcomes in children, such as weight gain and high blood pressure. In terms of theories explaining the association between soft-drink consumption and the metabolic syndrome risk, Vasan said there are no definitive answers yet.

"Individuals who drink soda tend to have a greater intake of calories, they consume more saturated and trans fats, they consume less fiber and dairy products and have a more sedentary lifestyle," he said. "We adjusted for a number of these variables, but even after the adjustment, there was a significant association that was evident. It makes the case that maybe you can't fully adjust for lifestyle factors, and it might be a lifestyle/dietary background thing driving this."

In addition, Vasan said diet soda might also induce a conditioning response in which the soft drinks promote a dietary preference for sweeter foods. Also, because diet soda is liquid, this has the effect of individuals eating more at the next meal, mainly because liquids are not as satiating. And finally, the brown caramel in soda has been linked with tissue damage and inflammation, which might contribute to the increased risk. All of these theories, however, are debated in literature.

"Clearly, these findings are sufficiently intriguing that scientists now have to help us understand better why we see this association," said Vasan. "We are not inferring causality from this analysis. It is just an association, so we need to turn to the scientists who are better positioned to help us understand the association more."

Circulation. Published online July 23, 2007.

The complete contents of Heartwire , a professional news service of WebMD, can be found at, a Web site for cardiovascular healthcare professionals.

Clinical Context

Increased soft drink consumption has been associated with an increased risk for obesity and diabetes among children and adolescents, but educational programs may reduce the number of children choosing soft drinks. In a study of 644 children aged between 7 and 11 years by James and colleagues, the use of an educational program reduced the consumption of soft drinks by 0.6 glasses per day immediately compared with an increase of 0.2 glasses per day in a control group. The results, which were published in the May 22, 2004, issue of BMJ, also demonstrated that the rate of overweight and obesity increased in the control group by 7.5% during 1 year, compared with a respective decrease of 0.2% among children who received the educational program.

The potential harms of soft drink consumption among adults are less clear. The current analysis of the Framingham Offspring study cohort seeks to determine the relationship between drinking sodas and incidence of the metabolic syndrome.

Study Highlights

  • 5124 participants comprised the main study cohort, and they were queried regarding lifestyle habits, including soft drink consumption, approximately every 4 years between 1987 and 2001. Participants who completed at least 2 consecutive examinations were included in the current analysis, whereas those with metabolic syndrome at baseline were excluded.
  • The main study outcome was the relationship between the frequency of soft drink consumption and incident metabolic syndrome. Metabolic syndrome was defined by the presence of at least 3 of the following factors: waist circumference of at least 35 inches in women or 40 inches in men, fasting blood glucose level of at least 100 mg/dL or treatment of diabetes, blood pressure of at least 135/85 mm Hg or treatment of hypertension, serum triglyceride levels of at least 150 mg/dL or treatment with niacin or fibrates, and HDL cholesterol level less than 40 mg/dL in men or less than 50 mg/dL in women.
  • The main study outcome was adjusted for other factors, including age, sex, body mass index, diet, blood pressure, serum lipid and glucose values, physical activity, smoking status, and alcohol use.
  • Slightly more than half the study cohort were women, and the mean age was 52.9 years. Approximately 35% of subjects reported consuming at least 1 soft drink per day.
  • Rates of incident metabolic syndrome were 18.7% and 22.6% among subjects who drank less than 1 soda per day and subjects who drank at least 1 soda per day, respectively. The adjusted odds ratio (OR) of incident metabolic syndrome associated with higher soft drink consumption was 1.44.
  • Differentiating sodas into those that were low-calorie or contained caffeine did not significantly alter the main study outcome.
  • Compared with drinking less than 1 soda per day, drinking at least 1 soft drink per day significantly increased the risks for obesity (OR, 1.31), increased waist circumference (OR, 1.30), impaired fasting glucose (OR, 1.25), hypertriglyceridemia (OR, 1.25), and reduced HDL cholesterol levels (OR, 1.32).

Pearls for Practice

  • An educational program has been demonstrated to reduce soft drink consumption and the risk for overweight or obesity among children.
  • The current study shows that regular consumption of either diet or regular soda increases the risk of developing the metabolic syndrome and its individual components among middle-aged adults.


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