A high protein supplement or diet is consumed by many individuals either to lose weight or to build muscle. An individual, who is a vegetarian, is using a high protein supplement to build muscles. After six months on the high protein supplement, he starts experiencing mild chest pain. His physician suspects that he may be in the early stages of coronary artery disease. The physician focuses on his fat intake, which appears to be normal. The patient's blood work reveals low levels of vitamins D and B6. The physician recommends increasing the intake of both vitamins. The patient's symptoms seem to improve. However, the physician is unable to explain what was happening. He was able to explain the patient's low vitamin D status due to a lack of vitamin D-containing foods. Can you suggest a nutritional explanation for why low B6 levels could lead to cardiovascular abnormalities? Is there any other vitamin you think could be involved and why?