July 16, 2009 — Consuming at least 7 servings per day of fruits and vegetables may reduce the risk for upper respiratory tract infection (URTI) during pregnancy, according to the results of a cohort study reported June 25 in the online issue of Public Health Nutrition.
"Pregnant women may require more fruits and vegetables than usual because of the extra demands on the body," senior author Martha M. Werler, MPH, ScD, from the Slone Epidemiology Center at Boston University in Massachusetts, said in a news release.
Werler, along with coauthor Lin Li, from the Department of Epidemiology at Boston University, asked 1034 North American women to report retrospectively on their fruit and vegetable consumption during the 6 months before their pregnancy and episodes of URTI during the first half of pregnancy. Cox proportional hazards models allowed calculation of multivariable-adjusted hazard ratios (HRs).
Compared with women in the lowest quartile (median, 1.91 servings per day) of total fruit and vegetable intake, those in the highest quartile (median, 8.54 servings per day) had an adjusted HR of URTI of 0.74 (95% confidence interval [CI], 0.53 - 1.05) for the 5-month follow-up and 0.61 (95% CI, 0.39 - 0.97) for the 3-month follow-up. Intake of 6.71 servings per day was associated with a moderate risk reduction for URTI.
For the 3-month, but not the 5-month, follow-up, there was a dose-related decrease in URTI risk based on quartile of fruit and vegetable intake (P for trend = .03 at 3 months). However, there was no apparent association between either fruit or vegetable intake alone and the risk for URTI at 5 months or 3 months.
"Women who consume more fruits and vegetables have a moderate reduction in risk of URTI during pregnancy, and this benefit appears to be derived from both fruits and vegetables instead of either alone," the study authors write.
Limitations of this study include reliance on recall of diet and URTI, possible misclassification of exposure because of the timing of data collection, and possible residual confounding.
"If diets enriched with fruits and vegetables truly have a preventive or protective effect against URTI in pregnant women, the public health implications may be considerable given that URTI as well as treatments for URTI symptoms may affect fetal development," the study authors conclude. "However, the limitations discussed above make it necessary to replicate our findings through studies specially designed to address this question."
The National Institute of Dental and Craniofacial Research supported this study. The study authors have disclosed no relevant financial relationships.
Public Health Nutr. Published online June 25, 2009.