The Association of Dietary Phytochemical Index and Cardiometabolic Risk Factors in Adults: Tehran Lipid and Glucose Study

Background: Phytochemicals are natural non-nutritive bioactive compounds found in fruits, vegetables, whole grains, nuts and legumes, as well as other plant foods. In the present study, we assessed the dietary phytochemical index (PI) in relation to cardiometabolic risk factors among Iranian adults.

Methods: This cross-sectional study was conducted within the framework of third phase of Tehran Lipid and Glucose Study 2006-2008. For the present study, 2567 subjects aged 19-70 years (1129 men and 1438 women) were selected randomly. Dietary data were collected using a validated semi-quantitative food frequency questionnaire with 168 food items. The PI was calculated based on daily energy derived from phytochemical-rich foods. The odds ratios of abdominal obesity, impaired fasting glucose, hypertriglyceridaemia, low high-density lipoprotein-cholesterol and hypertension were assessed across PI quartile categories.

Results: The mean (SD) age of participants was 39.4 (13.2) years. Participants in the upper quartile of PI were older, and had a lower weight and waist circumference. The mean (SD) of the PI was 17.3 (5.6), 25.5 (6.4), 32.7 (8.3) and 42.8 (10.5) in the first, second, third and fourth quartiles, respectively. Compared with those in the lower quartile of PI, participants in the upper quartiles had a 66% lower risk of abdominal obesity [95% confidence interval (CI) = 0.23-0.51] and a 36% lower risk of hypertriglyceridaemia (95% CI, 0.47-0.86), after adjustment for potential confounders.

Conclusions: Higher intakes of phytochemical-rich foods are associated with a lower risk of abdominal obesity and hypertriglyceridaemia as the main cardiometabolic risk factors.