@Cormoran I thought you may like to read this from the Royal Osteoporosis Society which is THE expert society in the UK on bone health.
theros.org.uk/media/v2pdyew4/ros-further-food-facts-and-bones-fact-sheet-december-2019.pdf
What are the benefits of vitamin K for my bones?
Vitamin K ‘turns on’ a protein called osteocalcin
which is necessary for bone building and bone
healing. Some studies have shown that people with
low intakes of vitamin K have lower bone density
and a higher risk of fractures, although results have
been varied and inconsistent. Vitamin K deficiency
is usually a consequence of a medical condition
which affects the absorption of food such as
Crohn’s or coeliac disease or severe liver disease.
Which foods contain vitamin K?
Vitamin K is present in commonly-eaten foods
and is easily absorbed. There are different forms
of vitamin K, with vitamins K1 and K2 being the
main ones. Vitamin K1 is obtained mainly from
plant sources, and vitamin K2 is produced from
some animal products and through the action of
naturally-occurring bacteria present in the gut.
These gut bacteria are involved in helping the body
produce, break down, convert and absorb different
types vitamin K.
Vitamin K1: is found in green leafy vegetables,
broccoli, spinach, cauliflower, asparagus, okra,
parsley, fruit, cereals and vegetable oils. Smaller
amounts are in meat, eggs, dairy and cheese.
Vitamin K2: most is provided by the bacterial flora
of the gut. It’s also found in fish, meat, liver and
eggs, soy foods and some fermented dairy, such as
cottage, ricotta, brie and Gouda cheeses, yoghurt
and Kefir (fermented milk). In general the UK diet
is not rich in vitamin K2. Japanese diets contain
higher amounts largely due to ‘Natto’ (a Japanese
dish of fermented soya beans).
Should I take a vitamin K supplement?
Evidence on the effects of vitamin K supplements
on bone health and strength isn’t strong, so
currently supplements are not recommended.
Studies have shown that a diet rich in vitamin K
foods is linked to lower risks of hip fractures in
older people, however taking vitamin K1 or K2
supplements did not always result in improved
bone strength.
I’ve read that vitamin K2 supplements may have a beneficial effect linked to taking calcium supplements. Is this true
It’s been suggested that vitamin K2 may play a
part in keeping blood vessels healthy and help to
prevent calcium build-up in arteries. So far, the
studies on this are inconclusive so at the moment
vitamin K2 as a supplement isn’t recommended.
Is there anything else I should know
about vitamin K?
Vitamin K also has a role in blood clotting and
so foods that contain high amounts of vitamin K,
such as liver and broccoli, can affect the action of
anticoagulant (blood thinning) medications such as
warfarin, and make them less efficient. Don’t leave
out these foods if you are taking an anticoagulant,
just make sure that you have a regular and constant
amount. This will help to ensure that vitamin K
levels in the bloodstream are fairly constant and
your blood will clot normally. If you are taking
warfarin, you shouldn’t take a vitamin K supplement
or make any major changes to your diet.
As I posted, in the UK the jury is still out on supplementation.
Maybe in other parts of the world it's a different treatment.
All very interesting.