Protein content and amino acid composition in the diet of Danish vegans: a cross-sectional study

BACKGROUND: A growing proportion of the population are replacing their dietary animal protein with plant protein. A particular example of this trend is the vegan diet, which excludes all food items of animal origin. However, the DIAAS score for individual plant proteins is generally lower than that of animal proteins due to an unbalanced amino acid composition and lower bioavailability. Care must therefore be taken to meet the nutritional recommendations in the daily food intake. METHODS: A three-day dietary food record was carried out by 40 Danish vegans in a cross-sectional study. The data were analysed, with particular emphasis on protein requirements and the essential amino acid composition of the diet. RESULTS: The protein recommendations were met on all three days by 60% of the participants. In contrast, 18% did not meet the protein recommendations on any of the three days and 7% met the recommendations on only one of the days. Lysine was the most limiting amino acid (only 50% met the recommendations every day) followed by the sulphur-containing amino acids (recommendations met by 67.5%), leucine and valine (recommendations met by 70%). Combining both the amount of protein and the intake of the essential amino acids showed that less than half of the participants met the recommendations on all three days (47.5%) and 35% did not meet the recommendations on any days or on one day only. CONCLUSION: In conclusion, our study showed that many of the participants in the present study failed to meet the daily protein intake requirements, both on single days and on all three days. Furthermore, the food intake was found to have an inadequate amino acid composition and was particularly limited by the essential amino acids lysine, the sulphur-containing amino acids, and leucine and valine. This could be ascribed to the fact that only a limited number of protein sources were consumed during a day.