Purpose: It 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. Methods: Data 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. Results: At 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. Conclusion: Vegans 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.

Scope: Vegans might have a higher exposure to mycotoxins due to their heightened consumption of typical mycotoxin containing food sources. Yet, data on internal exposure among vegans in comparison to omnivores are currently lacking.Methods and Results: This cross‐sectional study includes 36 vegans and 36 omnivores (50% females, 30–60 years). A set of 28 and 27 mycotoxins is analyzed in 24‐h urine and serum samples, respectively, by validated multi‐mycotoxin methods (HPLC‐MS/MS). Ochratoxin A (OTA), 2’R‐OTA, and enniatin B in serum as well as deoxynivalenol‐glucuronide in 24‐h urine are quantified in 57–100% of the samples. Serum OTA levels are twofold higher in vegans than in omnivores (median 0.24 ng mL⁻¹ vs 0.12 ng mL⁻¹; p < 0.0001). No further significant differences were observed. Serum OTA levels are associated with intake of “vegan products” (r = 0.50, p < 0.0001) and “pasta & rice” (r = 0.33, p = 0.006). Sensitivity analyses advise cautious interpretation. Furthermore, serum levels of 2’R‐OTA are related to coffee consumption (r = 0.64, p < 0.0001).Conclusion: The results indicate a higher exposure of vegans to OTA, but not to other mycotoxins. However, larger studies with repeated measurements are required to better evaluate the exposure to mycotoxins from plant‐based diets.

Biomarker measurements in spot urine are often adjusted for creatinine to control for dilution resulting from individual hydration. We here report on results of a study involving age- and sex-matched vegans and omnivores (n = 36 each). The daily urinary excretion of 2,3-dihydroxypropylmercapturic acid (DHPMA, a diet-independent endogenous C3-metabolite used as an example compound) was found not to be different in vegans and omnivores (median 433 μg/24 h each), however, creatinine-adjusted levels were 26% lower in omnivores (median 285 μg/g creatinine) than in vegans (median 383 μg/g creatinine, p = 0.003). This difference results from the higher urinary excretion of creatinine in the omnivores compared to vegans (median 1.51 vs. 1.21 g/24 h, p = 0.009). Linear regression showed - besides the fat-free mass - a significant impact of the factor diet (vegans vs. omnivores). This may be due to the consumption of meat and fish as exogenous sources of creatinine. A literature search revealed broad evidence for this interpretation, as creatinine is formed from creatine during heating of meat and fish. Accordingly, consumption leads to temporary increase of serum/plasma creatinine and urinary creatinine excretion, resulting in higher levels in omnivores compared to vegans/vegetarians. An adjustment of the urinary DHPMA concentrations using specific gravity revealed 13% lower values in omnivores (median 225 μg/L) than in vegans (median 260 μg/L, p = 0.07). Compared to creatinine-adjustment, adjustment for specific gravity introduces a smaller but still obvious difference between omnivores and vegans. Especially with respect to future studies comparing vegans, vegetarians and omnivores, researchers should be aware of the risks of severe misinterpretations if biomarker measurements in spot urine are adjusted for creatinine.

Purpose: To examine the association between fructose intake in adolescence and fatty liver indices (hepatic steatosis index (HSI), fatty liver index (FLI)) in young adulthood. Methods: Overall, 246 participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study who had a fasting blood sample in adulthood (18–36 years), at least two 3-day weighed dietary records for calculating fructose intakes and other fructose-containing sugars (total (TS), free (FS), added sugar (AS)) as well as two complete 24-h urine samples for calculating sugar excretion (fructose excretion (FE), fructose + sucrose excretion (FE + SE)) in adolescence (males: 9.5–16.5 years; females: 8.5–15.5 years) were analysed using multivariable linear regression analyses. Results: On the level of dietary intake, no prospective associations were observed between adolescent fructose intake and both adult fatty liver indices, whereas higher FS intakes were associated with lower levels of HSI (P_trend = 0.02) and FLI (P_trend = 0.03). On the urinary excretion level, however, a higher FE (P_trend = 0.03) and FE + SE (P_trend = 0.01) in adolescence were prospectively related to higher adult FLI values. No associations were observed between adolescent sugar excretion and adult HSI. Conclusion: The present study does not provide unambiguous support for a detrimental impact of adolescent fructose intake on adult liver health. Nonetheless, further examinations estimating exposure by means of urinary excretion as well as dietary intake levels appear warranted.

Both veganism and high dietary acid load are linked to unfavorable bone health. However, the specific role of dietary alkali or acid load for the bone health of vegans is so far unknown. Thus, the renal biomarker for dietary acid or alkali load, i.e., urinary potential renal acid load (uPRAL), was measured in 24 h urine samples of 34 vegans and 35 omnivores (50.7% males). Bone health was assessed via calcaneal quantitative ultrasound. Associations between uPRAL and bone health indices were examined using multivariable general linear models. Compared to omnivores, vegans had a significantly lower uPRAL (mean difference = −34.5 mEq/24 h, p < 0.0001), a lower 24 h urinary phosphate excretion (p = 0.0004), a lower 24 h urinary sulfate excretion (p = 0.01), and a higher urine pH value (p < 0.0001). Broadband ultrasound attenuation (BUA) was lower among vegans versus omnivores (p = 0.037), yet it was not associated with uPRAL irrespective of adjustments. This study confirms different acid-base profiles of vegans and omnivores, with a pronounced alkaline excess among vegans and a rather low acid load among a group of omnivores with moderate protein intake. Within this spectrum of alkaline to low acid load, no association with bone health was found.

To examine health risks and benefits of a vegan diet, the RBVD study was conducted in 2017 and followed up in 2021. The present paper evaluated dietary nutrient intake and status together with systemic cardiometabolic health-related biomarkers and examinations among vegans and omnivores in 2017 and 2021. Our study included n = 24 vegans and n = 26 omnivores (aged 30–60 years at baseline), who participated at both time points. Dietary nutrient intake was determined by 3-day weighed food records and an interview about supplement use. Nutrient status and health-related biomarkers were measured in blood and 24-h urine samples. Despite similar energy intake, fibre intake was higher and saturated fat intake was lower in vegans compared to omnivores at both time points. Vitamin B ₁₂ status did not differ between both groups at any time. Compared to omnivores, vegans had higher blood concentrations of folate and 25-hydroxyvitamin D in 2021, and lower vitamin A and B ₂ concentrations in 2017. Blood concentrations of magnesium and copper were similar in both groups at both time points, while urinary calcium excretion was lower in vegans compared to omnivores in 2021. Selenium and zinc serum concentrations were consistently lower in vegans. Compared to omnivores, vegans had lower serum total and LDL cholesterol as well as plasma HbA1c at both time points. Over a four-year period, significant nutritional intake, status and health biomarker differences were observed between vegans and omnivores. Future research is needed to clarify the associated long-term health risks and benefits.