The ‘cheesy’ vitamin that boosts bones

CAPSULES containing a vitamin found in cheese and chicken livers could protect against the ravages of a bonethinning condition that causes misery to half of women over 50.

A top hospital has launched a clinical trial into the use of Vitamin K supplements for those with osteoporosis – the condition in which poor bone strength increases the risk of fractures and, for some, makes even standing and walking painful.

Researchers at the Osteoporosis Screening & Research Unit at King’s College London and Guy’s and St Thomas NHS Foundation Trust are recruiting 150 postmenopausal women who have been diagnosed with osteoporosis for the trial of the vitamin and its effects on bone health.

Vitamin K is a fat-soluble vitamin comprising t wo types, K1 and K2. Vitamin K1 has long been known as a treatment for babies who have blood-clotting abnormalities at birth.

‘We think K2 has a more direct effect on bones,’ says Dr Geeta Hampson, who is leading the new study that will give Vitamin K to women with low levels of it.

In Japan, a compound of Vitamin K2 called menatetrenone (MK4) is already being used for osteoporosis. It is not licensed for medical use in the EU, but Dr Hampson was given approval from UK watchdogs the Medicines and Healthcare products Regulatory Agency in February.

The women will take the vitamin in oral form for 18 months before their bone density is assessed with a bone scan.

Vitamin K1 is found in leafy vegetables such as spinach and kale and Vitamin K2 is found in some cheeses, egg yolk and butter, but neither food nor supplements are believed to contain sufficient quantities to improve bone density.

The bones are continually renewed in a process known as ‘bone turnover’, but osteoporosis occurs when cells called osteoclasts break down the bones faster than bone-building cells called osteoblasts can replace them.

The disease is genetic, and the risk of developing it rises rapidly in women after menopause when decreasing levels of the hormone oestrogen further weaken bones. Bisphosphonates, or ‘antiresorptive’ drugs, are currently the main treatment and work by slowing the activity of osteoclast cells.

They are taken in conjunction with supplements to boost levels of calcium – the most prevalent mineral in bones – and Vitamin D, which helps its absorption.

RESEARCHERS also believe that Vitamin K activates the function of a bonederived protein called osteocalcin that is produced by osteoblasts. ‘We think that by improving the function of the proteins involved in bone mineralisation, the bone will hang on to more calcium which may make our bones stronger,’ says Dr Hampson.