The extent to which variations in the intakes of some specific nutrients by healthy, apparently well-nourished, children and adolescents affect bone mass accumulation, has received increasing attention over the past 15 years.
This particular interest essentially stems from the growing awareness of two related important evidences: 1)fragility fractures occurring during adult life is a major public health problem; 2)the amount of bone acquired at the end of the growth phase is an important determinant of the risk of fragility fractures. These fragility fractures are mainly due to osteoporosis, writes Professor Jean-Philippe Bonjour.
Osteoporosis is one of the most serious diseases facing the aging population. It affects one in three women and one in eight men during their lives. Most subjects who suffer from the disease are in the last third of their lives. As the world's population ages, more and more people will suffer from this debilitating and sometimes fatal disease. Therefore, it is essential to develop a worldwide strategy for osteoporosis management and prevention. Over the past 25 years, measures of prevention have been aimed mainly at reducing the bone loss occurring at the menopause and/or that related to aging.
Another preventive strategy is to build up the strongest bone possible during infancy, childhood and adolescence. With respect to the impact of nutrients on bone mineral mass acquisition most studies have focused on the intake of calcium. However, other nutrients such as proteins should also be considered.
Nutrition is one of the many factors that influences bone mass accumulation during growth.
The list of other determinants classically includes heredity, sex, endocrine factors (sex steroids, calcitriol, IGF-I), mechanical forces (physical activity, body weight) and exposure to risk factors.
Quantitatively, the most prominent determinants appear to be genetically related. These factors appear to be inter-related. However, robust prospective data on these putative inter-relations are still lacking. Some observations suggest that the response to specific bone acting nutrients, such as calcium, inorganic phosphate, vitamin D an essential nutrient when its cutaneous production is insufficient and proteins may be modulated by certain gene polymorphisms, or by the degree of physical activity, or still by factors that determine the onset of pubertal maturation.
Key points:
* Peak bone mass is an important determinant of osteoporotic fracture risk.
* Bone mass accumulation from infancy to post puberty involves interrelated actions of genetic, endocrine, mechanical and nutritional factors.
* Like standing height, bone mineral mass during growth follows a trajectory that can be influenced by environmental factors.
* Increasing calcium intakes and/or mechanical loading can shift the age-bone mass trajectory upward.
* Protein intake, probably by influencing IGF-1, can also positively influence bone mass accrual.
Extracts from chapter 7 of Nutritional Aspects of Bone Health (£49.95), by Professor Jean-Philippe Bonjour and Dr Susan New.
Enter 44 or at www.scientistlive.com/efood
Royal Society of Chemistry is based in London and Cambridge, UK. www.rsc.org/books
