Because human bone mass peaks when a person is in their 30s, consuming sufficient amounts of calcium, protein and vitamin D -- all found in dairy products -- during the teen and young-adult years is considered key to lowering the risk of osteoporosis and some other health issues in later life. According to nutrition experts at Harvard University, calcium can also be found in certain greens, fortified soy milk, and supplements.

About 1,300 milligrams of calcium a day is recommended for high school-aged children and 1,000 millgrams a day for young adults, according to a news release from the journal.