Metabolic profiles of male meat eaters, fish eaters, vegetarians, and vegans from the EPIC-Oxford cohort

Comparison of Collection Methods for Fecal Samples for Discovery Metabolomics in Epidemiologic Studies

BACKGROUND

The gut metabolome may be associated with the incidence and progression of numerous diseases. The composition of the gut metabolome can be captured by measuring metabolite levels in the feces. However, there are little data describing the effect of fecal sample collection methods on metabolomic measures.

METHODS

We collected fecal samples from 18 volunteers using four methods: no solution, 95% ethanol, fecal occult blood test (FOBT) cards, and fecal immunochemical test (FIT). One set of samples was frozen after collection (day 0), and for 95% ethanol, FOBT, and FIT, a second set was frozen after 96 hours at room temperature. We evaluated (i) technical reproducibility within sample replicates, (ii) stability after 96 hours at room temperature for 95% ethanol, FOBT, and FIT, and (iii) concordance of metabolite measures with the putative "gold standard," day 0 samples without solution.

RESULTS

Intraclass correlation coefficients (ICC) estimating technical reproducibility were high for replicate samples for each collection method. ICCs estimating stability at room temperature were high for 95% ethanol and FOBT (median ICC > 0.87) but not FIT (median ICC = 0.52). Similarly, Spearman correlation coefficients (rs) estimating metabolite concordance with the "gold standard" were higher for 95% ethanol (median rs = 0.82) and FOBT (median rs = 0.70) than for FIT (median rs = 0.40).

CONCLUSIONS

Metabolomic measurements appear reproducible and stable in fecal samples collected with 95% ethanol or FOBT. Concordance with the "gold standard" is highest with 95% ethanol and acceptable with FOBT.

IMPACT

Future epidemiologic studies should collect feces using 95% ethanol or FOBT if interested in studying fecal metabolomics. Cancer Epidemiol Biomarkers Prev; 25(11); 1483-90. ©2016 AACR.

Vegan-vegetarian low-protein supplemented diets in pregnant CKD patients: fifteen years of experience

BACKGROUND

Pregnancy in women with advanced CKD becoming increasingly common. However, experience with low-protein diets in CKD patients in pregnancy is still limited. Aim of this study is to review the results obtained over the last 15 years with moderately restricted low-protein diets in pregnant CKD women (combining: CKD stages 3-5, proteinuria: nephrotic at any time, or > =1 g/24 at start or referral; nephrotic in previous pregnancy). CKD patients on unrestricted diets were employed for comparison.

METHODS

STUDY PERIOD

January, 2000 to September, 2015: 36 on-diet pregnancies (31 singleton deliveries, 3 twin deliveries, 1 pregnancy termination, 1 miscarriage); 47 controls (42 singleton deliveries, 5 miscarriages). The diet is basically vegan; since occasional milk and yoghurt are allowed, we defined it vegan-vegetarian; protein intake (0.6-0.8 g/Kg/day), keto-acid supplementation, protein-unrestricted meals (1-3/week) are prescribed according to CKD stage and nutritional status. Statistical analysis was performed as implemented on SPSS.

RESULTS

Patients and controls were similar (p: ns) at baseline with regard to age (33 vs 33.5), referral week (7 vs 9), kidney function (CKD 3-5: 48.4 % vs 64.3 %); prevalence of hypertension (51.6 % vs 40.5 %) and proteinuria >3 g/24 h (16.1 % vs 12.2 %). There were more diabetic nephropathies in on-diet patients (on diet: 31.0 % vs controls 5.3 %; p 0.007 (Fisher)) while lupus nephropathies were non-significantly higher in controls (on diet: 10.3 % vs controls 23.7 %; p 0.28 (Fisher)). The incidence of preterm delivery was similar (<37 weeks: on-diet singletons 77.4 %; controls: 71.4 %). The incidence of other adverse pregnancy related outcomes was non-significantly lower in on-diet patients (early preterm delivery: on diet: 32.3 % vs controls 35.7 %; birth-weight = <1.500 g: on diet: 9.7 % vs controls 23.8 %). None of the singletons in the on-diet series died, while two perinatal deaths occurred among the controls (p = 0.505). The incidence of small for gestational age (SGA <10th centile) and/or extremely preterm babies (<28th week) was significantly lower in singletons from on-diet mothers than in controls (on diet: 12.9 % vs controls: 33.3 %; p: 0.04 (Fisher)).

CONCLUSION

Moderate protein restriction in the context of a vegan-vegetarian supplemented diet is confirmed as a safe option in the management of pregnant CKD patients.

Identification of Altered Metabolomic Profiles Following a Panchakarma-based Ayurvedic Intervention in Healthy Subjects: The Self-Directed Biological Transformation Initiative (SBTI)

The effects of integrative medicine practices such as meditation and Ayurveda on human physiology are not fully understood. The aim of this study was to identify altered metabolomic profiles following an Ayurveda-based intervention. In the experimental group, 65 healthy male and female subjects participated in a 6-day Panchakarma-based Ayurvedic intervention which included herbs, vegetarian diet, meditation, yoga, and massage. A set of 12 plasma phosphatidylcholines decreased (adjusted p < 0.01) post-intervention in the experimental (n = 65) compared to control group (n = 54) after Bonferroni correction for multiple testing; within these compounds, the phosphatidylcholine with the greatest decrease in abundance was PC ae C36:4 (delta = −0.34). Application of a 10% FDR revealed an additional 57 metabolites that were differentially abundant between groups. Pathway analysis suggests that the intervention results in changes in metabolites across many pathways such as phospholipid biosynthesis, choline metabolism, and lipoprotein metabolism. The observed plasma metabolomic alterations may reflect a Panchakarma-induced modulation of metabotypes. Panchakarma promoted statistically significant changes in plasma levels of phosphatidylcholines, sphingomyelins and others in just 6 days. Forthcoming studies that integrate metabolomics with genomic, microbiome and physiological parameters may facilitate a broader systems-level understanding and mechanistic insights into these integrative practices that are employed to promote health and well-being.

Plasma acylcarnitines and risk of cardiovascular disease: effect of Mediterranean diet interventions

BACKGROUND

Previous studies have suggested that metabolite profiles of elevated acylcarnitines were associated with increased risk of cardiovascular disease (CVD) in populations with established coronary disease. However, to our knowledge, this association has not been evaluated in the context of primary cardiovascular prevention.

OBJECTIVES

We evaluated the association between 28 plasma acylcarnitine species and risk of incident CVD and the potential modifying effect of Mediterranean diet (MedDiet) interventions.

DESIGN

We measured plasma acylcarnitines with the use of high-throughput liquid chromatography-tandem mass spectrometry at baseline and after 1 y of follow-up, both individually and classified into short-, medium-, or long-chain scores, in a case-cohort study within the Prevención con Dieta Mediterránea (PREDIMED) study, which is a randomized Mediterranean dietary intervention for primary cardiovascular prevention. A randomly selected subcohort (n = 751) and all available incident CVD cases (n = 229) after 4.8 y of follow-up were included in the current study.

RESULTS

After adjustment for age, sex, body mass index, and other CVD risk factors, participants in the highest quartile of baseline short- and medium-chain acylcarnitines had a higher risk of CVD than did participants in the lowest quartile [HRs: 1.80 (95% CI: 1.11, 2.91; P-trend 0.01) and 1.55 (95% CI: 1.01, 2.48; P-trend = 0.04), respectively]. Increased short-chain acylcarnitines after 1 y were associated with higher risks of total CVD and stroke. Participants with higher baseline concentrations of short-, medium-, and long-chain acylcarnitines who were randomly assigned to the control group had a higher risk of CVD than did subjects with lower concentrations of acylcarnitines who were assigned to the MedDiet group.

CONCLUSIONS

Our data support the conclusion that metabolite profiles characterized by elevated concentrations of acylcarnitines are independently associated with risks of total CVD and stroke alone in participants at high risk of CVD. MedDiet interventions may mitigate the adverse associations shown between higher concentrations of acylcarnitines and CVD. This trial was registered at www.controlled-trials.com as ISRCTN35739639.