Effects of Individual Dietary Intervention on Nutrient Intake in Postpartum Japanese Women: A Randomized Controlled Trial

No dietary intervention that focuses on the diet quality of postpartum women has been developed in Japan, although most postpartum women experience an insufficient intake of vitamins and minerals. We aimed to examine whether dietary intervention, based on the health belief model, at both 1 and 3 months postpartum affects nutrient intake and food group consumption at 6 months postpartum. A randomized controlled trial was conducted at a university hospital in Tokyo between 2015 and 2016. Healthy women at 1 month postpartum were randomly allocated to either an intervention group (n = 100) or a control group (n = 94). Dietary intervention included dietary assessment, individual feedback, and dietary guidance. The dietary intakes between the two groups were compared using the Mann-Whitney U test. At 6 months postpartum, the energy-adjusted intakes of protein, total dietary fiber, potassium, magnesium, phosphorus, zinc, vitamin B₆, and β-carotene were significantly higher in the intervention group than in the control group. The changes in energy-adjusted intakes of total dietary fiber and iron from 1 month postpartum to 6 months postpartum were significantly different between the two groups. Dietary intervention based on the health belief model improved nutrition at 6 months postpartum, although the impact was limited.