In December 2019 researchers from the USA published the results of their study to assess the dietary protein quality in athletes who are consuming either a vegetarian or non-vegetarian diet. It is known that vegetarian diets may have a lower protein quality compared to omnivorous diets and it is thought that the current recommended dietary allowance for protein may not be adequate for some vegetarian populations. A total of 38 omnivores and 22 vegetarians were involved in the study. Dietary information was collected via 7-day food diaries. The available protein in each individual’s diet was assessed by assigning a DIAAS (Digestible Indispensable Amino Acid Score). Average available protein was then compared with the individual’s lean body mass and strength. Results showed that DIAAS scores were 11% higher and available protein 43% higher for omnivorous than vegetarian athletes. It was also seen that the lean body mass was 14% higher in the omnivorous individuals than vegetarian individuals. An analysis revealed that there was a significant association between available protein and strength and also between available protein and lean body mass. The researchers concluded that athletes consuming a vegetarian diet may need to increase protein intake by an average of 10 g daily to reach the lower recommended intake for protein of 1.2 g/kg/day and an additional 22 g daily to achieve the upper end of the recommended intake range of 1.4 g/kg/day.
Ciuris C et al. A Comparison of Dietary Protein Digestibility, Based on DIAAS Scoring, in Vegetarian and Non-Vegetarian Athletes. Nutrients. 2019 Dec 10;11(12). pii: E3016.