Dietary phytochemical index is inversely associated with the occurrence of hypertension in adults: a 3-year follow-up (the Tehran Lipid and Glucose Study).
OBJECTIVE
The epidemiological association of phytochemical-rich foods with the risk of hypertension is unclear. This study aimed to determine the association of dietary phytochemical index (PI) with the occurrence of hypertension (HTN) after 3 years of follow-up in Tehranian adults.


METHODS
This prospective study was conducted on 1546 nonhypertensive subjects, aged 20-70 years. Dietary intake was collected by validated semiquantitative food frequency questionnaire (FFQ). Dietary PI was calculated as (dietary energy derived from phytochemical-rich foods (kcal)/total daily energy intake (kcal)) × 100. Blood pressure was measured at baseline and after 3 years of follow-up and HTN was defined by Joint National Committee on prevention, detection, evaluation and treatment of high blood pressure criteria. The odds of HTN after 3 years in each quartile category of dietary PI were estimated by logistic regression model and adjusted for potential variables.


RESULTS
The mean age of participants was 38.0±12.0 years and 43% were male. The mean dietary PI was 29.1±11.8. After 3 years of follow-up, 265 (17.1%) new cases of HTN were identified. No significant changes were observed in the systolic and diastolic blood pressure across quartile categories of dietary PI. After adjustment for confounders, the odds (95% confidence interval) of HTN across quartiles of dietary PI were 1.00, 0.97 (0.62-1.38), 0.69 (0.45-1.07) and 0.52 (0.32-0.84) (P for trend=0.004).


CONCLUSIONS
Consumption of phytochemical-rich foods may prevent the development of HTN. Further investigations are, however, recommended.
1] Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran [2] Obesity Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
M
M
Golzarand
1] Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran [2] Obesity Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Z
Z
Bahadoran
Department of Clinical Nutrition and Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
P
P
Mirmiran
Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
S
S
Sadeghian-Sharif
Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
F
F
Azizi
D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D004032:Diet; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D006973:Hypertension / Q000517:prevention & control*; D007492:Iran; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D064209:Phytochemicals / Q000494:pharmacology / Q000627:therapeutic use*; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D010944:Plants / Q000737:chemistry*; D055815:Young Adult
D064209:Phytochemicals; D010936:Plant Extracts