Folic acid and Vitamins C, K and B12 can prevent bruising, according to WebMD. These vitamins can be obtained through the diet or by taking dietary supplements.
WebMD indicates that excessive bruising is caused by a lack of blood clotting. Vitamins C, K, B12 and folic acid can help with bruising problems because they help the body effectively clot blood. It is also important to avoid supplements and foods that increase bruising, such as fish oil, vitamin E, garlic, ginger, and ginkgo biloba, notes WebMD. In addition to vitamin supplements, good dietary sources for vitamins that prevent bruising include whole gains, fruits, vegetables, lean meats and dairy.