In 2014, I once again had zero health issues, sick days or doctor visits (same as for 2013). My health has always been very good but it is worth noting that over the last 6 years of cycling regularly I have had no illnesses, sick days or doctor visits. Nor have I taken any medicine or supplements (excluding a few aspirins for hangovers). My current BMI is 22 and very stable which compares pretty favourably with people of a similar age (born in 1975) and background.
Naturally, one can't claim that daily cycling will be a remedy for all existing health issues, but it is fair to say that the daily exercise that cycling for transport provides can be a significant contributor to maintaining good health. See: Built-in exercise is a major benefit of cycling for transport