Adequate calcium intake levels suggested for the United States of America are higher than those accepted internationally, and extend the increased needs of adolescents to young adults. Peak bone mass continues to increase until age of 24 years. Results of bone density measurements support the need for calcium intake beyond that required for calcium balance and retention for growth.
However, the situation in most Asian countries suggests that their populations may have sufficient calcium retention and bone mass despite lower levels of intake.
Calcium intake may need to be adjusted for dietary factors (e.g. observed animal protein, sodium intake, vitamin D intake) and for sun exposure, since both affect calcium retention.