I know this is just a single case study but it seems to confirm Peat's recommendations to take vitamin K2 to lower blood pressure. The dosage used was sort of low (100 micrograms), which tells me it was probably MK-7 that was used and not MK-4. Either way, something to keep in mind for people with low blood pressure and for those that want to lower their high blood pressure.
http://www.ncbi.nlm.nih.gov/pubmed/22821789
http://www.ncbi.nlm.nih.gov/pubmed/22821789