Dr. Michael Gregor of www.nutritionfacts.org has an interesting video that talks about research into whether phytates from whole foods, such as beans and grains, results in Osteoporosis:
http://www.youtube.com/watch?v=Bmg9kLe3tQI
Previous studies on puppies showed a bone softening effect from phytates and subsequent studies on rats (fed an excessive equivalent of 10 loaves of bread per day) confirmed that phytates are anti-nutrient.
However, subsequently, in a study on several people partaking of a high phytate diet, bodies become accustomed to phytates with no adverse effect.
Since then, a new study asked, do people who avoid high phytate food have better bone mineral density?
The results were interesting in that those eating a lot of phytates ended up with greater bone density. The phytates had a protective effect. Low consumption of phytates was found to be a risk factor for osteoporosis. A follow up study found the same results: more phytates = greater bone density and a lower risk of fracture.
The reason seems to be that phytates block formation of bone eating cells similar to Fosamax, but without the side effects such as horribly disfiguring osteonecrosis of the jaw.