Dr. Genuis from the University of Alberta has some great ideas from his research. I've combined his research with some of my own to come up with a better way for those who want to prevent bone loss.
It comes down to getting enough weight bearing exercise (sorry swimmers) and the right nutrition.
Yes you need calcium but you also need Vitamin D (supplement), strontium, vitamin K, and essential fatty acids.
The sun around here is not going to cut it for Vitamin D. The wavelength of light we get is fine for giving you a burn but apparently is not great at converting to Vitamin D3. This is one you will need to supplement. I like the Vit D3 drops for convenience.
Strontium is found in spinach, whole grains, and seafood.
Vitamin K is in green leafy vegtables, broccoli, Kale, cabbage, asparagus and olive oil
Omega 3 fatty acids are good for so many things. You can add bone strength to the list. Fish or fish oils in supplement form are "essential!" Omega 6 will do the opposite so stay away from safflower oils, corn based chips and snacks, potato chips and pork. Foods like nuts also have Omega 6 but they have off-setting benefits as well so go ahead and eat them in moderation.
I prefer a run or weight training but in a pinch a few heel drop sets can fill the gap.
Get Strong! Dr. D.