Therefore, increasing peak bone mass in young people during the time of skeletal maturation may

be the ‘best bet’ primary prevention strategy to reduce the likelihood of this disease [6]. While bone and body size have been identified NVP-BSK805 as the main determinants of bone mineral content (BMC) [7], physical activity (PA), nutritional factors, sex hormones and drugs have also been found to play a role in bone mineralization [6–8]. Positive relationships between dairy product intake and total BMC and BMD have been reported in women aged 18–50 y [6, 9]. However, it is uncertain which nutrient or combination of nutrients is responsible for changes in bone mass when dairy products are consumed because protein, calcium, phosphorus and vitamin D are known to be associated with bone health [6].

There is limited evidence of an effect of dietary calcium intake on BMC in children [10], young MEK inhibitor side effects women aged 19–35 y [11] and perimenopausal women aged 45 to 58 y with amenorrhoea for 2–24 months [12]. In adolescents aged 12 to 16 y [8], dietary calcium had no effect on BMC [8]. Physical activity (PA) on the other hand, has been shown to contribute to bone mass in many studies [10, 11, 13–16]. For example, BMC was found to be higher in the dominant arm of female tennis players [14] and in pre- and early-pubertal children with the highest levels of habitual PA [10] or involvement in a 2-year p38 MAPK inhibitors clinical trials school-based exercise program [5]. A study with 2384 young men attending the mandatory tests for selection to compulsory military service in Sweden found that history of regular physical was the strongest predictor and could explain 10.1% of the variation in BMD [17]. Type of PA has also been shown ZD1839 datasheet to contribute to bone mineralization. Whereas vigorous-intensity PA,

including resistance training programs and high-impact exercise has been shown to influence bone mass in some studies [7, 15, 18–20], others have shown that a minimum intake of calcium seems to be essential for PA to have an impact on bone mass [4, 21]. In contrast, strength training 3 d/wk for 12 months had no benefit on bone mineralization in postmenopausal women [21] and there was no association between bone mineralization and level and frequency of sports participation in adolescents aged 12 to 16 y [8]. Calcium and weight-bearing PA have been suggested to have their greatest effect early in life [4, 16, 22] and with consistently high calcium intake [4, 21, 23]. The recommended dietary intake (RDA) of calcium for men aged 19–30 y is 1000 mg/d [24] with most young men able to meet the RDA by consuming at least three servings of milk, cheese or yogurt daily. In Australia, the median intake of calcium in men 19–24 y was only 961.5 mg/d [25].