Osteoporosis & vitamin K Dr Paul Clayton 2006
The critical involvement of vitamin K in calcium balance has been known for some
time in clinical science. But it is still largely ignored by a medical
profession that remains mired in pharmaceutical thinking.
A well-conducted meta-analysis has been reported in a respected journal. It has
shifted the debate forward to the point where we can no longer continue to
ignore the 'forgotten vitamin'. In this new study, the authors could hardly
have stated their case any more strongly. They stated that 'Increased intake of
vitamin K, both from diet and supplements, has a significant impact on bone
health and (is linked to) striking reductions of nearly 80% in hip fractures'.
The fact that there are various forms of vitamin K has lead to some confusion in
the past. K1 (phytonadione) is found in green leafy vegetables such as spinach,
broccoli and kale. K1 from these foods is the major form of vitamin K in the
British diet. It accounts for up to 90% of our K intake.
The other 10% consists of Vitamin K2 (menaquinone). It is actually a group of
related compounds with different numbers of side chains. The main members of
this group are called MK -4, -7, -8 and -9 respectively. MK-4 is found in meat.
MK-8 and -9 are found in fermented foods such as blue cheese. The best source
of MK-7 is the Japanese fermented soy bean dish known as natto*.
The meta-analysis summed the results of 7 major trials with K supplementation,
and concluded that vitamin K (in this case MK-4) was significantly protective.
It was associated with improved bone mineral density and reduced fracture rates
at all sites measured. The findings matched the positive results of Japanese
studies with MK-7.
Osteoporosis costs Britain over £5 million per day. Compared to that, K
supplements cost pennies. Thus wide-spread supplementation would be a
spectacularly cost-effective way of improving the nation's health. Food
fortification would present problems, as K is contra-indicated in patients
taking anti-coagulants. But for everyone else, a daily dose of K makes
excellent sense.
*Not to be confused with the Himalayan mountain K2, and the recently exhumed
K-9, a robotic extra in the TV series Dr Who!
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