Dietary intakes and nutritional adequacy of Australians consuming plant-based diets compared to a regular meat-eating diet

Abstract

Background/objectives: Despite the healthful nature of plant-based diets (PBDs) there is potential for nutritional inadequacies. This study aimed to compare dietary intakes and nutritional adequacy in Australians following PBDs compared a regular meat-eating diet.

Subjects/methods: A cross-sectional study of adults (n = 240) aged 30-75 yrs, habitually following dietary patterns for ≥6 months; vegan, lacto-vegetarian, pesco-vegetarian, semi-vegetarian or regular meat-eater (n = 48 per group). Dietary intakes were assessed using validated food frequency questionnaires and dietitian-administered diet histories. Multivariable regression adjusted for sex, age, BMI, race, energy intake and physical activity.

Results: Compared to regular meat-eaters, vegans and lacto-ovo vegetarians had significantly lower intakes of protein (4-5 EN%), saturated fat (2-4 EN%), trans fat, cholesterol, vitamin B₁₂, iodine, riboflavin, niacin, sodium, and long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA), and higher carbohydrate (5-7 EN%), fibre, vitamin E, folate, magnesium, iron, and n-6PUFA, whereas, pesco-vegetarians and semi-vegetarians had intermediate intakes. Individuals following PBDs consumed significantly more daily serves of vegetables (1-1.5 serves), fruit (1 serve, vegan only), legumes/nuts (0.5-1 serves), and less discretionary choices (0.5-1 serves) compared to regular meat-eaters. All dietary patterns were adequate in protein, exceeded in fat, inadequate in carbohydrate and met recommended serves of fruit and vegetables, but not grains. Inadequate serves were observed for meat/poultry/eggs/beans/nuts among PBDs except pesco-vegetarians, and dairy among semi-vegetarians and regular meat-eaters. Vegans and lacto-vegetarians were inadequate in vitamin B12, LCn-3PUFA, iodine, and in addition calcium among vegans, iodine in pesco-vegetarians, and LCn-3PUFA in semi-vegetarians and regular meat-eaters.

Conclusion: PBDs, while higher in beneficial nutrients and wholefood groups than regular meat-eaters, may lead to nutritional inadequacies if not planned appropriately.