According to a 2009 study, application of two common herbicides to several varieties of sweet corn significantly increased the amounts of key nutrients carotenoids in the corn kernels. Corn is among the few vegetable crops that are good sources of zeaxanthin carotenoids, which help ward off diseases of the eye.

“Kernel lutein and zeaxanthin levels significantly increased 15.6% after mesotrione+atrazine early postemergence applications, as compared to the control treatment.  … This is the first report of herbicides directly up-regulating the carotenoid biosynthetic pathway in corn kernels, which is associated with the nutritional quality of sweet corn. Enhanced accumulation of lutein and zeaxanthin is important because dietary carotenoids function in suppressing aging eye diseases such as macular degeneration, now affecting 1.75 million older Americans.”

Authors: Dean A. Kopsell, et al.
Affiliation: Plant Sciences Department, University of Tennessee
Title: Increase in nutritionally important sweet corn kernel carotenoids following mesotrione and atrazine applications.
Publication: Journal of Agricultural and Food Chemistry. Published June 19, 2009 on http://pubs.acs.org.