Opinion | Trump is set to release his health records. Why not his taxes?

Is there a law that requires the President to release his tax returns? PO1 Holland: Will you release your health and tax records to all?

MSG Marshall - What a lie that is, and like I said earlier its not required. Obama never released his records and college transcripts like many president have in the past, I wonder why?

"No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty five Years, and been fourteen Years a Resident within the United States."

I'm confused! Where in the US Constitution, the document we swore to defend, does it state that a candidate and/or president has to release their income tax records? Considering the Income Tax wasn't codified until 1913, I fail to see this as an issue.