Comparison of sugar intakes between vegetarian and non-vegetarian adolescent females

Abstract

Background: Sugar consumption has been associated with an increased risk of obesity and non-communicable diseases. Adolescents are high consumers of sugar in New Zealand (NZ), particularly added sugar. With NZ’s high obesity rates, a diet associated with lower weight status, such as that of a vegetarian diet, warrants further research. No known studies in NZ have compared the sugar intakes and food sources of sugar between vegetarian and non-vegetarian adolescent females.

Objectives: To gather data on the sugar intakes of vegetarian and non-vegetarian adolescent females using 24-hour diet recalls. To analyse and compare the food sources of sugar within vegetarian and non-vegetarian diets. To compare the sugar intakes of vegetarians and non-vegetarians with international recommendations.

Design: A convenience sample of females aged 15 to 18 years were recruited from schools across NZ to participate in this cross-sectional observational study between February and September 2019. Targeted recruitment of vegetarian females took place from July 2019. Thirty-one vegetarians (8 vegan) and 219 non-vegetarians, consented and had their sugar intakes assessed using 24-hour diet recall interviews. Telephone repeat recalls were collected from 85% of the population. Demographic, health, dietary habits, and attitudes and motivations towards food choice data were collected through self-administered online questionnaires. Data collectors recorded anthropometric measurements. Dietary data were entered into Foodworks which use NZ Food Composition Tables to calculate nutrient intakes and adjusted to reflect usual intake using the Multiple Source Method. Intakes of vegetarian and non-vegetarian total and individual sugars, and food sources of sugar were analysed and compared. Total sugar was categorised into assumed added sugar and natural sugar. Added sugar was unavailable in the FOODfiles 2014 database so assumed as total sugar less maltose, lactose, and the sum of glucose and fructose adjusted by 0.67 to account for sucrose intrinsic to fruit. Natural sugar was total sugar less assumed added sugar.

Results: There were no differences in sugar intake between vegetarians and non- vegetarians when expressed as total sugar or assumed added sugar. Vegetarians consumed less lactose compared to non-vegetarians with a mean (95% confidence interval (CI)) difference of 3.1 (0.5, 5.6) grams/day. Non-vegetarians consumed more natural sugar than vegetarians with a mean (95% CI) difference of 9.4 (1.8, 17.0) grams/day. Fruit, non- alcoholic beverages, sugar/sweets, milk and cakes and muffins were the five top food sources of sugar for the study population. Vegetarians consumed a lower proportion of total sugar from non-alcoholic beverages (6.8% vs 12.5%), and a higher proportion from vegetables (8.7% vs 5.7%), than non-vegetarians. An estimated 82% of the population met the United States Department of Agriculture sugar recommendation that added sugar should be <10% total energy (TE), and 44% met the World Health Organisation recommendation that free sugars contribute < 5% TE when using added sugar intake as a surrogate marker.

Conclusion: The current study shows relative sugar intakes of vegetarians were no different to non-vegetarians, however, absolute intake of natural sugar and lactose were lower. The results of this research suggest neither a vegetarian or non-vegetarian diet for NZ female adolescents is associated with a superior sugar profile. Any favourable health benefits related to the sugar intakes of a vegetarian diet are likely attributed to the food sources from which vegetarians obtain sugar, rather than their relative sugar intakes. In dietetic practice, this means a focus should be placed on the quality of sugar sources, rather than its total consumption.