Lettuce, spinach, broccoli, cabbage and brussels sprouts are tops on the list of vitamin K-rich vegetables, which might help improve bone strength and lessen fractures. A study in the January 2000 American Journal of Clinical Nutrition followed more than 72,000 female nurses for a 10-year period. Those who consumed more than 146 micrograms of vitamin K per day (equal to one cup of lettuce) had fewer bone fractures than those who consumed less.