It’s pretty simple. Researchers who have studied populations of people that don’t wear shoes have found next to no bunions in these people! Various studies have shown 0% of non-shoe wearing populations have bunions (or hallux valgus), while 2 other studies have shown as much as 1.9% (although it should be noted that the people in this study occasionally wore shoes.)
In fact, only 3% of people in non-shoe wearing populations have any kind of foot malady. Contrast that with the 73% of Americans who take the time to report foot pain! (2010 APMA Survey). In my opinion as someone who has studied this stuff my whole life, our modern footwear is almost the sole source of our foot problems.
Are bunions causes by over-pronation? Not really. Unless of course that is caused by a shoe with a tapered toe box (bunion creator) or an elevated heel which causes the foot to roll in in the first place. Supposed “over-pronation” has never been significantly linked to any injury.
Are bunions caused by tight fitting shoes? Absolutely! They’re also caused by supposed well fitting shoes that aren’t shaped like feet (i.e. 99% of all shoes).Most people have never even thought about it, but almost all shoes are shaped more like pizza slices or torpedoes than they are healthy human feet!
Are bunions caused by high heels? Yes. But they’re also caused by low heels. A heel of any height causes your big toe to move inward, which pushes the bunion out.
Do your feet and bunions a favor—get a pair of shoes that are actually shaped like your feet and that have no heel elevation. Altra, Lems Shoes, & VivoBarefoot all make great shoes for this!
If your big toe joint is still flexible, consider Correct Toes to help re-shape your feet over time. Use them while active, like when walking or driving, for best effect. http://www.correcttoes.com
http://refs.ahcuah.com/papers/shulman.htm (Shows 0% Hallux Valgus or Bunions in Chinese and Indian Populations that don’t wear shoes)
A few citations:
Hoffman, P. 1905. Conclusions drawn from a comparative study of the feet of barefooted and shoe-wearing peoples. The Journal of Bone and Joint Surgery, 3, 105-136.
Lam Sim-Fook and Hodgson, A. R. 1958. A comparison of foot forms among the non-shoe and shoe-wearing Chinese Population. 7. Bone 7t Surg., 40A, 1058.
Shine, I. B. 1965. Incidence of hallux valgus in a partially shoe-wearing community. British Medical Journal, 1, 1648-1650.
Kato, T. and Watanabe, S. 1981. The etiology of hallux valgus in Japan. Clinical Orthopedics and Related Research, 157, 78-81.