Metabolic consequences of discretionary fortified beverage consumption containing excessive vitamin B levels in adolescents

Over the past decade, there has been a substantial increase in the number of beverage products containing added vitamins and minerals. Often viewed as a healthier choice by consumers, the metabolic impacts of excessive vitamin consumption are relatively unknown, especially in children. The aim of this study was to examine the effects of a widely available, vitamin fortified beverage (5h Energy Decaffeinated) on insulin sensitivity, metabolic hormones and serum metabolomic responses in adolescents. Twenty adolescents (13-19y, 10M/10F) completed two randomized trials, consuming either coloured water as placebo (PL) or a vitamin fortified, sugar free beverage (FB, 1.5ml/kg) 40min prior to a modified oral glucose tolerance test (OGTT, 1.75g/kg glucose). Samples were collected at baseline and at 30, 45, 60, 90 and 120min during the OGTT. No differences in blood glucose response were observed between the treatments. However, compared to PL, postprandial plasma C-peptide and insulin excursion was significantly greater with FB, resulting in a 28% decline in the insulin sensitivity index. This was accompanied by elevated GLP-1, glucagon and PYY responses with FB compared to PL. Serum metabolomics (1H-NMR) analysis also revealed perturbations to vitamin B-linked one carbon metabolism flux with FB consumption that became more pronounced over time. These included a transient reduction in homocysteine flux accompanied by increases in betaine, vitamin B6, vitamin B12, choline, folate and taurine. Although these impacts are likely short-lived, results show that beverages fortified with excessive amounts of vitamins are not metabolically inert, but likely result in greater insulin secretion, differential gut hormone secretion and elevated one-carbon flux to process the excessive vitamin loads.

过去十余年间，添加维生素与矿物质的饮品品类数量实现了显著增长。消费者普遍将这类产品视作更健康的选择，但过量摄入维生素所带来的代谢影响目前仍相对未知，尤其在儿童群体中。本研究旨在探究一款市面常见的维生素强化饮品——5h脱因能量饮料（5h Energy Decaffeinated）对青少年胰岛素敏感性、代谢激素水平及血清代谢组学响应的影响。本研究招募20名年龄介于13至19岁的青少年（男、女各10名）完成两项随机对照试验，受试者需在改良口服葡萄糖耐量试验（modified Oral Glucose Tolerance Test，OGTT，葡萄糖摄入剂量为1.75g/kg体重）前40分钟，分别饮用有色水安慰剂（PL组）或无糖维生素强化饮品（FB组，给药剂量为1.5ml/kg体重）。在该试验期间，分别于基线期及30、45、60、90、120分钟五个时间点采集血液样本。两组受试者的血糖响应未观察到显著差异。但与安慰剂组相比，FB组受试者的餐后血浆C肽与胰岛素波动幅度显著更高，致使胰岛素敏感性指数下降28%。与此同时，FB组受试者的胰高血糖素样肽-1（Glucagon-like Peptide-1，GLP-1）、胰高血糖素及多肽YY（Peptide YY，PYY）的响应水平均高于安慰剂组。血清代谢组学（1H-Nuclear Magnetic Resonance，1H-NMR）分析还显示，饮用FB组饮品会干扰与维生素B族相关的一碳代谢通量，且该干扰效应随时间推移愈发显著，具体表现为同型半胱氨酸通量出现一过性降低，同时甜菜碱、维生素B6、维生素B12、胆碱、叶酸及牛磺酸的水平均有所上升。尽管上述影响可能仅为短期效应，但研究结果表明，添加过量维生素的饮品并非代谢惰性物质，反而可能引发胰岛素分泌增加、肠道激素分泌异常，以及为代谢过量维生素负荷而出现的一碳代谢通量升高。