Donald Trump shares bizarre tweet asking about Iowa, corn, and brain 'issues'

Republican presidential front-runner Donald Trump shared an unusual tweet on Thursday asking if Iowans' had suffered some sort of brain issue due to controversial agricultural practices.

The tweet noted a new poll released earlier in the day that found retired neurosurgeon Ben Carson overtaking Trump in a survey of likely Iowa caucus-goers.

"#BenCarson is now leading in the #polls in #Iowa. Too much #Monsanto in the #corn creates issues in the brain?" the tweet asked, possibly tongue-in-cheek.

Monsanto Company is a massive multinational agricultural company that was among the first to embrace genetically engineered foods, a hot-button issue that has generated criticism and some conspiracy theories.

The poll, from Quinnipiac University, gave Carson a 28% to 20% lead over Trump among likely Iowa caucus-goers. Outside of that poll, Trump has led almost every other national and state-based survey in the last 100 days.

Here's Trump's tweet: