--this is part and parcel of a mindset that assumes one can achieve a great deal of control over one's health by being proactive. Taking supplements is an autonomously proactive way to take charge of one's health, but so are assiduously following an exercise program, not smoking, not drinking to excess, being very aware and choosy about food, and so on. So it does not surprise me that supplement takers also do a lot of other things to promote their health.

I think the interesting next step might be to determine why certain people develop this mindset and others, more fatalistic perhaps, do not--and what other behaviors and/or personality aspects these mindsets are associated with/caused by.