Vitamin K linked to stronger bones for adolescents
implications on bone health, and a better status may protect them
from osteoporosis later in life, suggests a new study.
An improved status of the vitamin was found to improve bone mineral content and bone mass in the whole body, according to the study with 307 healthy children with an average age of 11.2 published in the British Journal of Nutrition. "As children grow the increase in bone mass may fail to keep up with the increase in height, or length of the bone, and as a consequence, this imbalance may result in fracture," said lead author Marieke Summeren from University Medical Centre Utrecht. "But the main threat of a long-term shortage of K vitamins is that peak bone mass may be compromised, and as we age and begin to lose bone density, the risk of fracture in later life is increased." Osteoporosis is characterized by low bone mass, which leads to an increase risk of fractures, especially the hips, spine and wrists. An estimated 75 million people suffer from osteoporosis in Europe, the USA and Japan. Women are four times more likely to develop osteoporosis than men. Potential reduction of osteoporosis has traditionally been a two-pronged approach by either attempting to boost bone density in high-risk post-menopausal women by improved diet or supplements, or by maximising the build up of bone during the highly important pubescent years. About 35 per cent of a mature adult's peak bone mass is built-up during puberty. The new study followed the children for years and correlated vitamin K status, measured as a ratio of undercarboxylated osteocalcin (ucOC) to carboxylated osteocalcin (cOC), to bone mineral content (BMC) and markers of bone metabolism. Osteocalcin is a vitamin K-dependent protein and is essential for the body to utilise calcium in bone tissue. Without adequate vitamin K, the osteocalcin remains inactive, and thus not effective. Summeren and co-workers report that large variations were observed in the vitamin K status of the children, both at the start and end of the two-year study. Nonetheless, an improved vitamin K status over the time period, as was observed in 281 children, was associated with a significant increase in BMC. "There are two types of vitamin K from dietary sources. Vitamin K1 is found in leafy green vegetables, and Vitamin K2, also called menaquinones, are predominately found in fermented cheeses, curd, and the fermented soy called natto," explained co-author Leon Schurgers from VitaK and Cardiovascular Research Institute at the University of Maastricht. "Vitamin K1 is mostly used by the liver where it is involved in the synthesis of certain blood clotting factors. Vitamin K2 is also equally active outside the liver, in tissues including bone. Thus it is important to have good sources of both types of vitamin K!" The research adds to a growing body of science linking the vitamin to improved boned health, particularly in post-menopausal women. The Maastricht-based researchers previously reported that daily supplements of vitamin K2 maintained hipbone strength in postmenopausal women, while placebo led to weakening (Osteoporosis International, doi: 10.1007/s00198-007-0337-9). The double-blind, placebo controlled study followed 325 healthy women with no osteoporosis for three years and also found that vitamin K2 supplements boosted the women's bone mineral content (BMC), compared to placebo. The new study also included researchers from VU University Medical Centre and the Danone Research Centre Daniel Carasso in France. Source: British Journal of Nutrition Published online ahead of print, doi:10.1017/S0007114508921760 "Vitamin K status is associated with childhood bone mineral content" Authors: M.J.H. van Summeren, S.C.C.M. van Coeverden, L.J. Schurgers, L.A.J.L.M. Braam, F. Noirt, C.S.P.M. Uiterwaal, W. Kuis, C. Vermeer