Amino acid intake and plasma concentrations and their interplay with gut microbiota in vegans and omnivores in Germany

Stefan Dietrich,Iris Trefflich,Juliane Menzel,Cornelia Weikert,Klaus Abraham,Katharina J. Penczynski,Per Magne Ueland

doi:10.1007/s00394-021-02790-y

Abstract

PurposeIt has been estimated that most vegans meet the total protein requirements, but whether this is also true for individual essential amino acids (AAs) is unclear. Furthermore, a shift in protein intake is suggested to alter microbiota composition, but this association is unknown in terms of veganism or individual AAs. This cross-sectional study compared vegans and omnivores regarding dietary intake and plasma concentration of AAs. The prevalence of insufficient intake of essential AAs among vegans was determined using estimated average requirements (EAR) of WHO. Moreover, correlations between AAs intake and gut microbiota were investigated.MethodsData of 36 vegans and 36 omnivores (30–60 years) were analysed. AA intake, AA plasma concentrations and gut microbiota were ascertained by three-day weighed food protocols, gas/liquid chromatography-tandem mass spectrometry and 16S rRNA sequencing, respectively.ResultsAt almost the same energy intake, the intake of 9 AAs in vegans was significantly lower than in omnivores, with median differences of − 27.0% to − 51.9%. However, only one female vegan showed total protein and lysine intake below the EAR. Vegans showed lower lysine (− 25.0%), but higher glycine (+ 25.4%) and glutamate (+ 13.1%) plasma concentrations than omnivores. Correlation patterns between AA intake and bacterial microbiota differed between vegans and omnivores. In vegans 19 species and in omnivores 5 species showed correlations with AA intake.ConclusionVegans consumed apparently sufficient but lower AAs than omnivores. In addition, the different AAs intake seems to influence the microbiota composition. The use of short-term dietary data without considering usual intake limits these findings.

Highlights

IntroductionApart from these positive aspects, a vegan diet may poses the risk of nutritional deficiencies [2, 3]
A vegan diet, which excludes the consumption of all animal products, is becoming increasingly popular in Western countries for ethical, environmental and health-relatedEconomics, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany reasons [1]
21 (58.3) 6 (16.7) 9 (25.0) 2386 (2081–2737) 12 (33.3) 3 (8.3) 647.7 ± 333.6 6.73 ± 0.45 a Data are reported as percentage, mean ± standard deviation (SD) for normally distributed or median (IQR) for skewed variables amino acids (AAs) amino acid, BMI body mass index (p > 0.05) were observed; the proportion of current smokers and consumption of alcohol was slightly higher in omnivores than in vegans

Summary

Introduction

Apart from these positive aspects, a vegan diet may poses the risk of nutritional deficiencies [2, 3]. It is widely believed that a vegan diet is associated with an insufficient dietary intake of total protein and with an insufficient intake of essential amino acids (AAs). Since a long-term undersupply of essential AAs is associated with a negative health status, the World Health Organization (WHO) has published Estimated Average Requirements (EAR) as a guidance for the daily intake of total protein and essential AAs [5]. Some studies have reported that most vegans have total protein intakes which

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Conclusion