Dietary Fibre intakes and the main food sources of fibre in New Zealand adolescents
Background: The mean fibre intakes for 15-18-year old females from the last national nutrition survey (2008/09 New Zealand Adult Nutrition Survey) was 16.0 grams/day, well below the Adequate Intake (AI) for this age group of 22.0 grams/day. Adolescent male’s fibre was at 21.9 g/day, which was also below the AI for their age group of 28 g/day. Given the role of dietary fibre in optimal health promotion, an update on the dietary fibre intakes of New Zealand adolescents is justified as it is unknown how intakes may have changed over time.Objective: To assess the dietary fibre intakes and identify the main food groups contributing to fibre intake with secondary aims of examining the association between fibre and bodyweight and correlation with bowel habits.Methods: The Survey of Nutrition Dietary Assessment and Lifestyle (SuNDiAL) study is two-year multi-centre, cross-sectional survey in New Zealand that was conducted in 2019 and 2020. Data were collected across three points; February-April 2019, July- August 2019 and February-April 2020 throughout New Zealand. Nationwide, adolescents aged 15-18 were recruited from high schools from eight locations nationwide in Dunedin, Wellington, Christchurch, Rotorua, Tauranga, New Plymouth, Wanaka and Auckland. Anthropometric measures were measured using standard protocols and used to calculate body mass index z- scores. Sociodemographic and bowel habits were self-reported with an online semi- quantitative questionnaire through REDCap. Dietary data were obtained via two interviewer- led 24-hour multi-pass dietary recalls on non-consecutive days, with a second recall via phone or video call. The dietary data were entered into FoodWorks 9 (Xyris Software, Australia) for each participant and analysed for nutrient content to estimate mean fibre intakes. Results: Two hundred and sixty six female and 135 male participants were enrolled. Of the sample, 344 participants completed one 24-hr recall with 281 of those completing a second recall. The mean dietary fibre intake of adolescent females was 24.1 g/day (95% CI: 22.2, 25.9), which was higher than the AI for their age group (22g /day). Mean dietary fibre intake in adolescent males was 24.0 g/day (95% CI: 22.1, 25.8), which was lower than their AI (28 g/day). The top five food sources contributing to fibre intake were bread; grains and pasta; fruits; vegetables and breakfast cereals in both males and females. Bread made the greatest contribution to fibre in males, and fruits and vegetables and bread contributed in equal amounts in females. Dietary fibre intake was positively associated with energy intake, however, a higher fibre intake was associated with a lower bodyweight in females and in males after energy adjustment. A bowel habits questionnaire was completed by 129 males and 124 females. Overall, males and females both tended to have frequent and regular bowel motions regardless of fibre intake (R² = 0.0099). Conclusion: Adolescent females had higher mean fibre intakes their AI whilst adolescent male’s dietary fibre intake was lower than their AI. Given the influence of dietary fibre on chronic disease prevention, encouraging adolescents, males in particular, to increase fibre-dense foods may help in achieving their AI for dietary fibre.
Advisor: Venn, Bernard
Degree Name: Master of Dietetics
Degree Discipline: Human Nutrition
Publisher: University of Otago
Keywords: Dietary; Fibre; NewZealand
Research Type: Thesis