I'm also wondering how much genetics plays a part? I've been on Coumadin for almost 15 years and my cardio is not concerned with osteoporisis with me. Women in general, need to make sure they consume an adequate amount of calcium. I read, don't remember where, that some believe that the "surge" in osteoporosis in women is due to a diet that really lacked calcium. Weight was stated as a big reason many women don't consume dairy much. My MIL has bad osteoporosis - only been on Coumadin for a few months after a hip replacement. My SIL (her daughter) is fighting off osteoporosis. Both are HUGE coffee drinkers and rarely every drink milk.
As far as vitamins with K in them, the danger isn't in taking the vitamin, because your dose will be adjuststed accordingly. The danger is in not taking them for a week or so after your dose has included your K vitamin intake.
I have never been concerned about Vit K in any of the food I eat. (Maybe that's why I'm on a larger dose). Most people do not stray outside their normal eating habits. If you wrote everything down that you eat, for a year, and then looked at your list, you probably would see that everything you eat would only fill up a month on the calendar before you start repeating.
Eat what you want. We say to be consistant - but in reality, most people are. We just don't want someone pigging out on spinach 3 times a day for a week and then stopping.