Does vitamin K2 help your bones and blood vessels?
For bones in women after the menopause the evidence is reasonably strong; combining K2 with vitamin D gives the greatest effect. For blood vessels the signals are interesting, but firm evidence from completed studies is still lacking.
Vitamin K2 demonstrably helps slow bone loss after the menopause. If this is a concern for you, discuss it with your doctor before starting. In one study, women took 180 micrograms of MK-7 (a form of vitamin K2) per day for three years and lost less bone density in the lower back and hip neck than women who took nothing. Many studies combined confirm that bone density in the lower back improved clearly. Fewer bone fractures were also seen, but that result was less certain when one outlying study was included. If you combine K2 with vitamin D, the effect on overall bone density is greater than with K2 alone.
On the label, look for 'vitamin K2 as MK-7' or 'menaquinone-7', with the dose stated in micrograms. There is also an older form, MK-4 (menatetrenone), which was used in studies at 45 milligrams per day; that will appear in milligrams on the label. Your body weight or your exact age within the post-menopausal group makes little difference to the effect, according to the available studies. How long you take it does matter: the studies that showed a benefit ran for at least one to three years.
For blood vessels, vitamin K2 sounds promising, but the large studies with solid outcomes, such as heart attacks or a demonstrated reduction in vessel calcification, have not yet been completed. The underlying mechanism is biologically plausible: K2 activates a protein in the vessel wall that keeps calcium deposits in check, and in people who use blood thinners that block vitamin K, vessel calcification noticeably increases. Direct proof, however, is still lacking. Because the right amount and duration are unknown, we do not currently recommend vitamin K2 for blood vessels.
Vitamin K2 appears to be safe: sixteen studies found no difference in side effects compared with a dummy pill, and the American food safety authority recognises its safety. If you use blood thinners such as warfarin or acenocoumarol, you must not take K2 on your own initiative. K2 can directly affect how those medicines work. Consult your doctor first.
The bone evidence comes from multiple studies in which participants were randomly given either K2 or a dummy pill, including a summary of sixteen such studies. That is solid for bone density; the fracture effect is somewhat less stable. For blood vessels the evidence is thinner: the underlying mechanism is well described, but large studies looking at heart attacks and deaths are not yet complete. In one blood vessel study, a vitamin K2 manufacturer had a financial interest.
Should you take vitamin D together with vitamin K2?
For osteoporosis, there is reasonable evidence that vitamin K2 and D3 together do more for bone density than either one alone; for healthy people without bone problems, the necessity of the combination has not been demonstrated. Do not use vitamin K with blood thinners, and always discuss high vitamin D doses with your doctor.
Does vitamin D prevent me from breaking bones?
Vitamin D alone does not demonstrably reduce the chance of bone fractures. Combined with calcium it does help, especially in older adults and people with a deficiency.
What does sunlight do for your bones, apart from vitamin D?
Sunlight helps your bones through vitamin D, but a separate bone benefit outside that pathway has not been demonstrated and has not been studied; for your bones, what matters most here is how much vitamin D you produce.
Do you really need calcium supplements for strong bones?
Whether you need calcium supplements depends strongly on your age and situation: for healthy women before the menopause there is no evidence of benefit, while women over 50 may benefit from calcium plus vitamin D, provided you weigh the increased risk of kidney stones and the uncertain cardiac risk with your doctor.
Do carbonated drinks damage your bones?
Regularly drinking large amounts of sugary carbonated drinks is associated with lower bone density, especially in women and during puberty. Moderate consumption appears less harmful, but it is preferable to replace soft drinks with beverages that support bone development.
Which supplements are proven to help strengthen bones?
For bone strengthening, the combination of calcium and vitamin D is the best supported by evidence, especially in cases of deficiency or elevated fracture risk. Vitamin K2 shows encouraging results in postmenopausal women, but discuss the right dose and combination with your doctor, as too much of any supplement also has downsides.