Importance of vitamin D, calcium and exercise to bone health with specific reference to children and adolescents

Abstract

The optimisation of skeletal health during the life cycle is critical, especially if we are to reduce the continuing rise in osteoporosis -1 in 2 women and 1 in 5 men over the age of 50 years will suffer an osteoporotic fracture. The foundations of adult bone health are laid down in the early years; therefore, optimisation of bone health in the young is fundamental. Although genetics play a major role, accounting for 70-75% of bone strength, other lifestyle and nutrition factors are known to be highly influential. Calcium (Ca) and vitamin D play critical roles in bone mineralisation as well as generally being key nutrients in health. All living cells require Ca to survive, with the majority (99%) of Ca being found in bones and teeth and the remainder in soft tissues and body fluids. Vitamin D is the generic term for two molecules: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). The former is derived by ultraviolet (UV) irradiation of ergosterol, which is distributed in plants and fungi. The latter is formed from the effect of UV irradiation on the skin. The principal role of vitamin D is to support the serum Ca concentration within narrow limits. Vitamin D is crucial for maximising gut absorption of calcium via vitamin D dependent Ca receptors. It is estimated that adequate vitamin D status increases Ca absorption to 30-40% of intake compared with only 10-15% absorption without adequate vitamin D. Intakes of Ca are a concern among certain groups of the population, for example a high proportion (>12%) of teenage boys and girls fail to meet the lower reference nutrient intake for Ca. For vitamin D, there are no dietary reference values for the age group 4-64 years as it is considered that UV exposure provides sufficient quantities of vitamin D, but there is now mounting evidence of widespread vitamin D insufficiency in the population. Weight-bearing physical activity is beneficial to the skeleton but clarification is needed of the exact type, intensity and duration required for optimal bone mass. The role of othermicronutrients on bone metabolism remains to be fully quantified. This review investigates the current evidence of the impact of dietary and lifestyle factors on bone health, with specific reference to children and adolescents and with a focus on vitamin D, Ca and weight-bearing exercise. © 2007 The Authors; Journal compilation © 2007 British Nutrition Foundation

Factors Associated with Vitamin D Deficiency in European Adolescents: The HELENA Study

“…These findings are not surprising and confirm others indicating higher concentrations during sunny months (35,36). However, seasonality should be considered together with latitude as UVB radiation of the appropriate wavelength, especially during winter time (37), might be absent in the latitudes of the hemisphere not close to the Ecuador. Moreover, the comparison with other studies in Europe are difficult because of the lack of standardization (7).…”

Nutrition, health and schoolchildren

“…Most of the skeletal mass is laid down during childhood and adolescence. It is estimated that by post‐puberty (16 years onwards), approximately 80–90% of peak bone mass is achieved (Lanham‐New et al . 2007).…”

“…Bone density continues to increase for several years after the cessation of growth until peak bone mass is achieved. The exact age at which peak bone mass is attained remains controversial and is generally believed to be between 18 and 35 years of age (Lanham‐New et al . 2007).…”

Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment

“…As shown in Table 2, there are few dietary sources of vitamin D. The major providers are fat spreads (which are fortified with vitamin D), fish, eggs, pastry products, fortified breakfast cereals and meat (56) . Recent changes in EU regulations have resulted in a number of cereal manufacturers removing the vitamin D fortification (57) .…”