Dietary fructose and risk of metabolic syndrome in adults: Tehran Lipid and Glucose study

BACKGROUND Studies have shown that the excessive fructose intake may induce adverse metabolic effects. There is no direct evidence from epidemiological studies to clarify the association between usual amounts of fructose intake and the metabolic syndrome. OBJECTIVE The aim this study was to determine the association of fructose intake and prevalence of metabolic syndrome (MetS) and its components in Tehranian adults. METHODS This cross-sectional population based study was conducted on 2537 subjects (45% men) aged 19-70 y, participants of the Tehran Lipid and Glucose Study (2006-2008). Dietary data were collected using a validated 168 item semi-quantitative food frequency questionnaire. Dietary fructose intake was calculated by sum of natural fructose (NF) in fruits and vegetables and added fructose (AF) in commercial foods. MetS was defined according to the modified NCEP ATP III for Iranian adults. RESULTS The mean ages of men and women were 40.5 ± 13.6 and 38.6 ± 12.8 years, respectively. Mean total dietary fructose intakes were 46.5 ± 24.5 (NF: 19.6 ± 10.7 and AF: 26.9 ± 13.9) and 37.3 ± 24.2 g/d (NF: 18.6 ± 10.5 and AF: 18.7 ± 13.6) in men and women, respectively. Compared with those in the lowest quartile of fructose intakes, men and women in the highest quartile, respectively, had 33% (95% CI, 1.15-1.47) and 20% (95% CI, 1.09-1.27) higher risk of the metabolic syndrome; 39% (CI, 1.16-1.63) and 20% (CI, 1.07-1.27) higher risk of abdominal obesity; 11% (CI, 1.02-1.17) and 9% (CI, 1.02-1.14) higher risk of hypertension; and 9% (CI, 1-1.15) and 9% (1.04-1.12) higher risk of impaired fasting glucose. CONCLUSION Higher consumption of dietary fructose may have adverse metabolic effects.