Abstract
Background: Vegetarianism is characterised by the exclusion of flesh-based animal foods. Historically, this diet resulted in improved diet quality, typified by lower intakes of high fat, sugar, salt discretionary foods and higher intakes of fruits and vegetables compared to an omnivorous diet. However, intakes of protein-rich foods can be lacking in vegetarians. Vegetarianism appears to be increasing at the greatest rate amongst adolescent females, who have increased energy and nutrient needs. In New Zealand, there is little information on the dietary habits of vegetarian adolescents. It is unclear whether the modern vegetarian diet, where there is increased availability of processed high fat, sugar, and salt foods and vegetarian alternatives, remains more healthful than an omnivorous diet in this population.
Objective: To investigate frequency of intake of: protein-rich foods; fruit and vegetables; and discretionary foods among adolescent female vegetarians, and compare these with non-vegetarians.
Design: Cross-sectional survey of 248 females aged 15-18 years recruited from 13 high schools throughout New Zealand, and from targeted recruitment of vegetarians in Dunedin. Vegetarian status was self-reported at enrolment. Frequency of intake of animal and plant-based protein foods, discretionary foods, and fruit and vegetables were analysed through an online dietary habits questionnaire. Analysis was conducted in vegetarians (n=33) and non-vegetarians (n=215), with prevalence and 95% confidence intervals being used to compare between the two groups.
Results: Legumes were the most frequently consumed protein alternative in vegetarians with 57.6% (95% CI: 39.8-75.4) consuming 2-6 times a week. Other vegetarian protein alternatives were consumed infrequently at 3 times a month or less. More vegetarians excluded eggs than non-vegetarians (39.4% (95% CI: 21.8-57) vs 11.6% (95% CI: 7.3-15.9)). Among vegetarians, 66.7% (95% CI: 49.7-83.6) excluded cows milk, with 6% (95% CI: 0-14.7) including it once or more a day; compared to 20.9% (95% CI: 15.4-26.4) and 34.5% (95% CI: 28.0-40.8) respectively among non-vegetarians. Of vegetarians, 48.5% (95% CI: 30.5-66.5) excluded dairy, with 12.1% (95% CI: 0.37-23.9) including it once or more a day; compared to 8.9% (95% CI: 15.4-26.4) and 31.6% (95% CI: 25.4-27.9) among non-vegetarians. Vegetarians were more likely to choose chose plant-based milks 63.6% compared to non-vegetarians (17.2%). Vegetarians more frequently excluded discretionary foods than non-vegetarians. More vegetarians than non-vegetarians met and/or exceeded recommended serves per day of fruit (72.8% vs 56.3%) and vegetables (63.6% vs 31.2%)
Conclusion: The majority of vegetarians in this study appeared unlikely to meet national guidelines for meat alternatives and milk and milk products. In non-vegetarians, intakes of milk products also appeared insufficient to meet recommendations. This could potentially compromise intakes of important nutrients, particularly in vegetarians. Overall, vegetarians had more healthful dietary habits in terms of fruit, vegetables, and discretionary food intakes than non-vegetarians. However, vegetarian diets need to be well-planned to ensure intakes of protein containing foods and associated nutrients are not compromised. Further research into intakes of milk and milk products and vegetarian protein alternatives for comparison to national guidelines is needed to confirm potentially low intakes of these protein-rich foods and associated nutrients in this population.