Drawing data from Project EAT (Eating Among Teens), a prospective, population-based study designed to examine determinants of dietary intake and weight status, the responses of over 1,500 young adults (45% male) were analysed by investigators from the University of Minnesota, Minneapolis. The mean age of participants was 15.9 years at baseline and 20.5 years at follow-up.
During the transition from middle adolescence (high school) to young adulthood (post-high school), females and males respectively reduced their daily calcium intakes by an average of 153 mg and 194 mg. Although 38% of females and 39% of males increased their intake of calcium over 5 years, the majority of the sample reduced their intake of calcium over 5 years. During middle adolescence, more than 72% of females and 55% of males had calcium intakes lower than the recommended level of 1,300 mg/day. Similarly, during young adulthood, 68% of females and 53% of males had calcium intakes lower than the recommended level of 1,000 mg/day.
The researchers found that reports of mealtime milk availability, positive health/nutrition attitudes, taste preference for milk, healthful weight control behaviours and peer support for healthful eating when the participants were teenagers were associated with higher calcium intake in young adulthood. Time spent watching television and lactose intolerance during middle adolescence were associated with lower calcium intake in young adulthood.
Writing in the article, Dr. Nicole I. Larson, Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, and colleagues state, "The findings of this study indicate that future interventions designed to promote improvements in calcium intake should encourage the families of adolescents to serve milk at meals. In addition, interventions targeted to female adolescents should build concern for healthful eating, develop confidence in skills for healthful eating and reduce exposure to television advertisements. Interventions targeted to male adolescents should emphasise opportunities to taste calcium-rich food, the promotion of healthful weight management behaviours and supporting peers to engage in healthful eating behaviours."