How do plant-based milks compare to cow's milk nutritionally? An audit of the plant-based milk products available in Australia

Aim: This cross-sectional study aims to explore the nutritional composition, cost, country of origin and fortification status of plant-based milk products available for purchase in Illawarra supermarkets and make various comparisons between types of plant-based milks and cow's milk. Methods: Plant-based milk information was collected from nutrition information panels on packaging and manufacturer websites. Product ingredient lists, including fortifiers, were analysed to estimate the nutrient composition of the identified plant-based milks, including nutrients beyond those listed by manufacturers. Descriptive statistics were used to summarise the characteristics of the plant-based milks identified in the audit. For non-normally distributed data, a Kruskal-Wallis H test with pairwise multiple comparisons and a Bonferroni adjustment were undertaken to explore the differences between various types of plant-based milk and cow's milk. Results: One hundred twenty-nine plant-based milk products were identified in the audit, primarily almond, oat and soy-based beverages. Of these, 80.6% were fortified with calcium; however, fortification with other micronutrients was less common, ranging from 27.1% being fortified with vitamin B12 and 3.1% being fortified with iodine. The median plant-based milk cost was AU$3.5/L (Q1-Q3: AU$2.8-4.5/L) and 87.6% of products were Australian made. Overall, particularly due to low fortification rates, plant-based milks identified in the audit had significantly lower levels of protein, sugar, iodine, phosphorus, zinc and vitamins A, B2 and B12 compared to cow's milk. However, there was no significant difference in protein content between soy milk and cow's milk. Conclusions: The nutritional content of plant-based milks identified in this audit varied, and in most instances, Australian plant-based milks were found to be nutritionally different to cow's milk.