Browsing by Author "Gillies NA"

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    Protein Intake at Twice the RDA in Older Men Increases Circulatory Concentrations of the Microbiome Metabolite Trimethylamine-N-Oxide (TMAO)
    (MDPI (Basel, Switzerland), 2019-09-12) Mitchell SM; Milan AM; Mitchell CJ; Gillies NA; D'Souza RF; Zeng N; Ramzan F; Sharma P; Knowles SO; Roy NC; Sjödin A; Wagner K-H; Zeisel SH; Cameron-Smith D
    Higher dietary protein intake is increasingly recommended for the elderly; however, high protein diets have also been linked to increased cardiovascular disease (CVD) risk. Trimethylamine-N-oxide (TMAO) is a bacterial metabolite derived from choline and carnitine abundant from animal protein-rich foods. TMAO may be a novel biomarker for heightened CVD risk. The purpose of this study was to assess the impact of a high protein diet on TMAO. Healthy men (74.2 ± 3.6 years, n = 29) were randomised to consume the recommended dietary allowance of protein (RDA: 0.8 g protein/kg bodyweight/day) or twice the RDA (2RDA) as part of a supplied diet for 10 weeks. Fasting blood samples were collected pre- and post-intervention for measurement of TMAO, blood lipids, glucose tolerance, insulin sensitivity, and inflammatory biomarkers. An oral glucose tolerance test was also performed. In comparison with RDA, the 2RDA diet increased circulatory TMAO (p = 0.002) but unexpectedly decreased renal excretion of TMAO (p = 0.003). LDL cholesterol was increased in 2RDA compared to RDA (p = 0.049), but no differences in other biomarkers of CVD risk and insulin sensitivity were evident between groups. In conclusion, circulatory TMAO is responsive to changes in dietary protein intake in older healthy males.
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    Vitamin B and One-Carbon Metabolite Profiles Show Divergent Associations with Cardiometabolic Risk Markers but not Cognitive Function in Older New Zealand Adults: A Secondary Analysis of the REACH Study.
    (Elsevier B.V., 2023-12-07) Gillies NA; Milan AM; Cameron-Smith D; Mumme KD; Conlon CA; von Hurst PR; Haskell-Ramsay CF; Jones B; Roy NC; Coad J; Wall CR; Beck KL
    BACKGROUND: Vitamin B inadequacies and elevated homocysteine status have been associated with impaired cognitive and cardiometabolic health with aging. There is, however, a scarcity of research investigating integrated profiles of one-carbon (1C) metabolites in this context, including metabolites of interconnected folate, methionine, choline oxidation, and transsulfuration pathways. OBJECTIVES: The study aimed to examine associations between vitamins B and 1C metabolites with cardiometabolic health and cognitive function in healthy older adults, including the interactive effects of Apolipoprotein E-ε4 status. METHODS: Three hundred and thirteen healthy participants (65-74 y, 65% female) were analyzed. Vitamins B were estimated according to dietary intake (4-d food records) and biochemical status (serum folate and vitamin B12). Fasting plasma 1C metabolites were quantified by liquid chromatography with tandem mass spectrometry. Measures of cardiometabolic health included biochemical (lipid panel, blood glucose) and anthropometric markers. Cognitive function was assessed by the Computerized Mental Performance Assessment System (COMPASS) and Montreal Cognitive Assessment (MoCA). Associations were analyzed using multivariate linear (COMPASS, cardiometabolic health) and Poisson (MoCA) regression modeling. RESULTS: Over 90% of participants met dietary recommendations for riboflavin and vitamins B6 and B12, but only 78% of males and 67% of females achieved adequate folate intakes. Higher serum folate and plasma betaine and glycine concentrations were associated with favorable cardiometabolic markers, whereas higher plasma choline and homocysteine concentrations were associated with greater cardiometabolic risk based on body mass index and serum lipids concentration values (P< 0.05). Vitamins B and homocysteine were not associated with cognitive performance in this cohort, though higher glycine concentrations were associated with better global cognitive performance (P = 0.017), episodic memory (P = 0.016), and spatial memory (P = 0.027) scores. Apolipoprotein E-ε4 status did not modify the relationship between vitamins B or 1C metabolites with cognitive function in linear regression analyses. CONCLUSIONS: Vitamin B and 1C metabolite profiles showed divergent associations with cardiometabolic risk markers and limited associations with cognitive performance in this cohort of healthy older adults.