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

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/Cys(low) + PUFA, n = 7) or with high contents of methionine, cysteine and SFA (Met/Cys(high) + 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/Cys(low) + PUFA diet vs. Met/Cys(high) + 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/Cys(low) + PUFA group. In the Met/Cys(high) + 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 6(th) 2016.