Magnesium-rich diets during pre-adolescence are positively associated with bone mineral density in young adulthood, particularly in the heel bone.
"Studies have shown that magnesium-rich diets in pre-adolescents are positively positively affect bone density in young adulthood, particularly in the heel bone." (said at 0:56:08)
A 10-year longitudinal study from the National Heart, Lung, and Blood Institute Growth and Health Study examined 63 young adult women (aged 18-19) and found that dietary magnesium intake assessed during pre-adolescence (aged 9-11) was positively correlated with calcaneal (heel bone) quantitative ultrasound parameters (speed of sound and bone velocity). However, claiming that magnesium-rich diets 'positively affect' bone density overstates the available literature: the evidence comes from a small observational convenience sample (n = 63) using quantitative ultrasound rather than dual-energy X-ray absorptiometry (DXA) bone mineral density, and the authors explicitly noted that the small sample size precluded strong inferences.
- partial: Influence of pre-adolescent diet on quantitative ultrasound measurements of the calcaneus … (Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA 1999)
"Stepwise multiple regression analysis, controlling for race, height and weight, demonstrated that pre-adolescent intake of calcium and magnesium were positively related to QUS parameters (calcium with broadband ultrasound attenuation, and magnesium with speed of sound and bone velocity)." (abstract, results, passage verified)
pubmedfull study (doi)