Effects of short-term methionine and cysteine restriction and enrichment with polyunsaturated fatty acids on oral glucose tolerance, plasma amino acids, fatty acids, lactate and pyruvate: results from a pilot study

Abstract

Objective: In this 7-day pilot study we randomized healthy, normal-weight men and women to either a dietary intervention with methionine and cysteine restriction enriched in PUFA (Met/Cyslow + PUFA, n = 7) or with high contents of methionine, cysteine and SFA (Met/Cyshigh + SFA, n = 7). The objective was to describe the short-term responses in oral glucose tolerance, amino acid profile, total fatty acid profile, pyruvate and lactate following a Met/Cyslow + PUFA diet vs. Met/Cyshigh + SFA.

Results: The diet groups consisted of five women and two men, aged 20-38 years. After the 7-d intervention median pre- and post-oral glucose tolerance test (OGTT) glucose concentrations were 5 mmol/L and 4 mmol/L respectively in the Met/Cyslow + PUFA group. In the Met/Cyshigh + SFA group, median pre- and post-OGTT glucose concentrations were 4.8 mmol/L and 4.65 mmol/L after the 7-d intervention. The responses in the amino acid profiles were similar in both groups during the intervention with the exception of serine. Fatty acids decreased from baseline to day 7 in both groups. Plasma lactate and pyruvate were similar for both groups with an increase to day 3 before approaching baseline values at day 7.

Trial registration: ClinicalTrials.gov: NCT02647970, registration date: January 6th 2016.

Keywords: Cysteine restriction; Fatty acids; Methionine restriction; Oral glucose tolerance; Pyruvate; SCD.

Conflict of interest statement

None declared.

Figures

Fig. 1

Boxplots showing glucose concentrations before (fasting) and 2 h after an oral glucose tolerance test at baseline and day 7 of the intervention. Met/Cys,methionine and cysteine, OGTT oral glucose tolerance test, PUFA polyunsaturated fatty acids, SFA saturated fatty acids

Fig. 2

Shows the amino acid concentrations for each individual (grey lines) and the mean concentrations (black lines). Gln+Ga glutamine + glutamate, Met/Cys methionine and cysteine, PUFA polyunsaturated fatty acids, SFA saturated fatty acids

Fig. 3

Shows the total fatty acid concentrations for each individual (grey lines) and the mean concentrations (black lines). Met/Cys methionine and cysteine, C12 lauric acid, C14 myristic acid, C16:0 palmitic acid, C16:1 palmitoleic acid, C18 stearic acid, C18:1 oleic acid, C18:2 linoleic acid, C18:3-n3 α-linoleic acid, C18:3-n6 γ-linoleic acid, C20:3-n6 Dihomo-γ-linoleic acid, C20:4-n6 Arachidonic acid, C20:5-n3 Eicosapentanoic acid, C22:6-n3 Cervonic acid