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The role of micronutrients and impact of fortified foods in the diets of teenagers in Ireland
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Date
2024
Authors
Walsh, Niamh M.
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Publisher
University College Cork
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Abstract
During the teenage years, adequate micronutrient intake is crucial for physical and cognitive development. Strategies to meet high nutritional needs can involve food based dietary guidelines (FBDG) or fortification of foods and recommendations for nutritional supplements.
The aims of this thesis were to estimate current micronutrient intakes in the diets of teenagers in Ireland, investigate the dietary determinants of vitamin D and calcium and examine the role of fortified foods in teenagers.
The analyses for this thesis were based on data from the National Teens’ Food Survey II (NTFS II), a nationally representative study which collected data on food and nutrient intakes of 428 teenagers (13-18y) in the Republic of Ireland between 2019-2020. Dietary data were collected using weighed food diaries and nutrient intakes were estimated using UK and Irish food composition data. Mean daily intakes (MDI) and usual intakes of food groups and nutrients were estimated using SPSS©. The prevalence of inadequate and excess intakes were estimated using estimated average requirements (EAR) and the tolerable upper intake level (UL). Dietary determinants of vitamin D and calcium intake were investigated by examining the food groups and consumption patterns which contributed to the difference in intakes between the high and low intake groups. A fortified food consumer was defined as someone who consumed fortified foods at least once during the recording period.
A large proportion of teenagers in Ireland had inadequate intakes of micronutrients, particularly vitamin D (94%), calcium (51%), vitamin C (48%), and zinc (48%). There was little risk of excessive intakes with few exceeding the UL for folic acid (4%), copper (<1%), and zinc (<1%). The key sources of micronutrients included natural animal and plant sources and fortified foods, with supplements contributing to 0-6% of intakes.
Considering the dietary determinants of vitamin D intake, 100% in the low intake group had intakes <EAR compared to 82% in the high intake group, with a difference of 6.8μg/d in the MDI of vitamin D between groups. Approximately 87% of this difference was attributable to nutritional supplements, ready-to-eat breakfast cereals (RTEBC), fish, vitamin D fortified milk, and eggs, with a higher proportion of consumers of these foods in the high intake group. Increasing the proportion of teenagers consuming vitamin D containing supplements, fish, and eggs, and consuming RTEBC alongside vitamin D fortified milk would be beneficial for vitamin D intakes.
For calcium, the difference in the MDI of calcium between the high and low intake group was 739mg/d, with 100% of those in the low intake group having intakes <EAR compared to 29% in the high intake group. Milk, cheese, grains, rice, pasta and savouries, breakfast cereals, and bread and rolls were attributable for 79% of the difference between intake groups. Consumers with higher calcium intakes were more likely to consume milk, cheese, and RTEBC and did so more frequently and (except for RTEBC) in larger amounts. Therefore, promoting the consumption of five portions of dairy per day as per FBDGs, and the consumption of RTEBC would be beneficial in increasing calcium intakes in this group.
Fortified foods made up 13% of all foods consumed, with RTEBC, dairy products/non-dairy alternatives, soft drinks/energy drinks, and cereal/protein bars the most frequently fortified items, with vitamin D, riboflavin, niacin, vitamin B6, vitamin B12, folic acid, iron, thiamin, and calcium most commonly added. The majority (87%) of teenagers in Ireland consumed fortified foods with the consumption of nutrient-specific fortified foods associated with a reduced prevalence of inadequate intakes for all micronutrients.
These findings will be useful for research related to nutrition, public health, and food safety, and support the work of agencies that are responsible for food and nutrition policy and regulation.
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Keywords
Teenagers , Micronutrients , Fortified food , Adequacy , Excess
Citation
Walsh, N. 2024. The role of micronutrients and impact of fortified foods in the diets of teenagers in Ireland. PhD Thesis, University College Cork.