PUBLIC HEALTH NUTRITION AND EPIDEMIOLOGY The association of dietary phytochemical index and cardiometabolic risk factors in adults: Tehran Lipid and Glucose Study

AbstractBackground: Phytochemicals are natural non-nutritive bioactive compoundsfound in fruits, vegetables, whole grains, nuts and legumes, as well as otherplant foods. In the present study, we assessed the dietary phytochemicalindex (PI) in relation to cardiometabolic risk factors among Iranian adults.Methods: This cross-sectional study was conducted within the framework ofthird phase of Tehran Lipid and Glucose Study 2006–2008. For the presentstudy, 2567 subjects aged 19–70 years (1129 men and 1438 women) wereselected randomly. Dietary data were collected using a validated semi-quan-titative food frequency questionnaire with 168 food items. The PI was calcu-lated based on daily energy derived from phytochemical-rich foods. Theodds ratios of abdominal obesity, impaired fasting glucose, hypertriglyceri-daemia, low high-density lipoprotein-cholesterol and hypertension wereassessed across PI quartile categories.Results: The mean (SD) age of participants was 39.4 (13.2) years. Partici-pants in the upper quartile of PI were older, and had a lower weight andwaist 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, participantsin the upper quartiles had a 66% lower risk of abdominal obesity [95% con-fidence interval (CI) = 0.23–0.51] and a 36% lower risk of hypertriglyceri-daemia (95% CI, 0.47–0.86), after adjustment for potential confounders.Conclusions: Higher intakes of phytochemical-rich foods are associated witha lower risk of abdominal obesity and hypertriglyceridaemia as the maincardiometabolic risk factors.IntroductionThe prevalence of cardiovascular risk factors, such asobesity, hypertension, dyslipidaemia and insulin resistancesyndrome, has increased over the last two decades indeveloping countries (Boutayeb & Boutayeb, 2005). Themajor factors contributing to this trend are an increasingsedentary lifestyle, and an on-going nutrition transitionwith the progressive shift to a westernised diet, low inwhole grains, legumes and vegetables (Popkin, 2002).Several prospective and case–control studies, as well asecological data, have indicated that a higher intake ofvegetables and fruits (Ness & Powles, 1997; Mirmiranet al., 2009), legumes (Bazzano et al., 2001; Darmadi-Blackberry et al., 2004) and whole grains (Mellen et al.,2007; Seal, 2006) is associated with a lower risk of cardio-vascular risk factors. The protective effects of these plantbased foods are mediated through mono- and polysatu-rated fatty acids, antioxidant vitamins, minerals, plantprotein, fibre and phytochemicals. Currently, there is