I suffer from osteoporosis: can I improve it with diet?

I am 60 years old and I have had serious osteoporosis for 12 years and I would like to find a specialist who can help me improve with the right diet. Having the family problem of osteoporosis, I started taking bisphosphonates at 48, followed by an osteoporosis prevention and treatment center. Not seeing any improvement after 7 years I turned to alternative medicine. After a little improvement, my situation has fallen back years. The motivation you gave me? My body does not assimilate calcium. Now I am looking for a nutrition specialist who is convinced that WITH DIET you can make a difference. Can you help me? I live between Brindisi and Milan. Thanks so much for your help and congratulations on the site.