Is there anything in the United States Constitution that justifies or contradicts the drinking age law?

[BK_FAN#2]

There are several sound social arguments for both sides of this issue. One is that, at 18, with all of the other obligations, responsibilities, and rights, the 18-20 year old adult demographic is discriminated against unfairly. Another states that science says the human brain (primarily cerebral cortex) is not fully developed until roughly the age of 25. These are both respectable arguments in my opinion, but I want to know if any of you are aware of anything in the constitution that would support or go against the United States drinking age being 21 years of age. I know the US constitution has been historically ambiguous, but is there anything that would lead you to think one age was more constitutional than the other?