Vitamin K

This fat-soluble vitamin is important because of its ability to help create a protein that causes blood to clot, but it also helps to boost the metabolism by bonding calcium to bones (which increases bone mass). Less brittle bones reduce the likelihood of bone fractures during exercise or other activity. Though the vitamin is produced from the bacteria that live in your intestine, it can also be found in leafy greens, avocado, and kiwi. Ask your doctor before changing your vitamin K intake if you take the medication warfarin (Coumadin).