Dietary phytochemical index and subsequent changes of lipid profile: A 3-year follow-up in Tehran Lipid and Glucose Study in Iran

BACKGROUND High intakes of phytochemical-rich foods have beneficial effects on lipid profiles and cardiovascular disease (CVD). In this study, we assessed the association between the dietary phytochemical index (PI) and changes in lipid profile after 3-year follow-up among Iranian adults. METHODS This longitudinal study was conducted in 1983 subjects, aged 19-70 years, selected among participants of the Tehran Lipid and Glucose Study in Iran. Dietary data were collected by using a validated semi-quantitative food frequency questionnaire with 168 food items at baseline. PI was calculated based on daily energy derived from [(phytochemical-rich foods kcal/total daily energy intake kcal) × 100]. Lipid profile was measured at baseline and after 3 years and changes in serum lipid profiles were assessed during 3-year follow-up. RESULTS The mean age of participants was 40.4 ± 13.0 years; participants in the highest PI quartile category were more likely to be older. After 3 years of follow-up, total cholesterol was significantly lower in the highest quartile compared with lower quartile of PI in men (181 ± 3 vs. 189 ± 3, P for trend < 0.05). There were significant inverse association between dietary PI and 3 years changes of total cholesterol [β = -5.6, 95% confidence interval (CI) = -9.3, -1.8], triglycerides (β = -13.7, 95% CI = -24.6, -2.8), and non-high-density lipoprotein cholesterol (HDL-C) (β = -6.2, 95% CI = -10.8, -1.5), in highest quartile of PI in men. Lipid profiles showed no significant changes over the study period in women. CONCLUSION Higher dietary PI is associated with 3 years improvement of total cholesterol, triglycerides, and non-HDL-C. Higher consumption of phytochemical-rich foods is recommended to prevent CVD.