Optimising repeated exposure: Determining optimal exposure frequency for introducing a novel vegetable among children

Fruit and vegetables are important components of a healthy diet, but unfortunately many children are not consuming enough to meet the recommendations. Therefore, it is crucial to develop strategies towards increasing the acceptance of this food group. This study aims to investigate the effect of different repeated exposure frequencies on fruit and vegetable acceptance using a novel vegetable, daikon, among 3-6-year-old children. One hundred and fifty-nine children participated in this study. Eight kindergarten teams were assigned to one of the following groups: Three different intervention groups with varying exposure frequencies, but all receiving seven exposures: Twice a week (n = 47), once a week (n = 32) and once every second week (n = 30), and a control group (n = 50). Liking and familiarity of daikon and other vegetables (cucumber, celery, celeriac, broccoli, cauliflower and beetroot) were assessed at baseline, post-intervention and two follow up sessions (3 and 6 months) to test for potential generalisation effects and observe the longevity of the obtained effects. Intake of daikon was measured at all exposures and test sessions. Results showed significant increases (p ≤ 0.05) in liking and intake of daikon for all three frequencies and the control group. Over the exposures, intake of daikon increased until the 4th exposure for all the groups, where a plateau was reached. No systematic generalisation effects were found. Repeated exposure was a successful approach to increase liking and intake of a novel vegetable with all exposure frequencies to be effective, and no particular exposure frequency can be recommended. Even the few exposures the control group received were found to be sufficient to improve intake and liking over 6 months (p ≤ 0.05), indicating that exposures to low quantities of an unfamiliar vegetable may be sufficient.