A systematic review of interventions aimed at increasing calcium intake in adults: where do we go from here?

Identification of effective intervention characteristics for increasing calcium intake is important given the widespread failure of adults to meet dietary guidelines for calcium in many developed countries. This paper synthesises, in a systematic review, all interventions published between 1980-2012, that were designed to increase calcium consumption in adults. Eighteen interventions were identified and subsequently analysed using Hendrie's intervention intensity scaling system (2012), permitting comparison of interventions of varying designs. Michie et al. (2011) refined CALO-RE taxonomy was used to classify behaviour change techniques used within the interventions. Five interventions yielded large effect sizes, with a mean change of 333.18 mg of calcium per day post-intervention. Although the number of behaviour change techniques was unrelated to intervention effectiveness, the interventions yielding the largest effects employed techniques that involved education regarding: a) the consequences of increasing calcium intake; b) how to increase calcium intake. This review highlights promising calcium consumption behaviour change characteristics, grounded in behaviour change theories, and emphasises the need for future research that incorporates more male samples.