Daily commuting - are dietary supplements recommended? I've been commuting daily (Apart from holidays, illness and some other exceptions) for the past year, riding 12 miles daily (6 miles with 500ft height gain coming in, 6 miles 232ft height gain riding back) on a hybrid.

Recently there have been times when I've been feeling quite run down by the weekend, lacking energy. It could just be a virus doing the rounds, but it made me wonder if there was a specific diet or dietary supplement that would be of benefit to a daily commuteer.
The canonical recommendation is for "a complete and balanced diet". Whatever 'supplements' you might need depend on what your current diet is. The recommendations I've been given (I'm 50 and commute 24 miles/day) from a dietitian are vitamin D (because I live in Canada - I suspect that recommendation is obsolete currently while I'm commuting 2 hours/day in summer) and (based on blood test results) perhaps a bit more iron (I'm vegetarian). Some of the important components to consider, IMO, include water, salt, carbohydrates, and, rest/sleep. In summary, perhaps you should talk with a doctor or dietitian.

If you want to discover what your current diet is (which is presumably one important question before deciding how to supplement it - an alternative might be physical exam, blood tests), I quite recommend DietOrganizer.