Department of Internal Medicine II, Centre for Complementary Medicine, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany.
Department of Internal Medicine II, Centre for Complementary Medicine, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany.
Nutrition. 2024 Sep;125:112498. doi: 10.1016/j.nut.2024.112498. Epub 2024 May 7.
Healthy plant-based diets, such as the lacto-ovo-vegetarian and the vegan diet, offer numerous benefits to human health. Poorly designed plant-based diets, however, bear the risk for vitamin- and micronutrient deficiencies. Vitamin B12 (B12, cobalamin) is a nutrient of particular concern in both diets, and should be readily supplemented on a continuous basis to ensure adequate B12 levels and to prevent deficiencies.
This case reports describes the history of a healthy man in his mid-30s who adopted a vegan diet approximately 10 y ago. Well informed about the risks of vitamin B12 deficiency on a plant-based diet, he regularly supplemented methylcobalamin for years (single oral dose: 500 µg, 3-4 times a week) in order to maintain an adequate vitamin B12 status. In late 2023, however, he decided to cease B12 supplementation for undisclosed reasons. Subsequent to this decision, we closely monitored his B12 status and longitudinally measured serum B12, homocysteine, and holotranscobalamin (holo-TC). Total serum folate was also determined as it is a modifier of homocysteine concentration. A gradual decrease in holo-TC and vitamin B12 levels was observed after 4 weeks and supplements had to be re-introduced after 16 weeks. Homocysteine increased concomitantly up to 18.2 μmol/L after 20 weeks.
While a short-term B12 supplement intake cessation might be well tolerated by vegans with an adequate B12 status, an interruption of more than 8 weeks could signify B12 loss approaching suboptimal status. This case report reiterates the need for continuous B12 supplementation in persons following an unfortified plant-based diet.
健康的植物性饮食，如乳蛋素食和纯素食，对人类健康有诸多益处。然而，设计不当的植物性饮食存在维生素和微量营养素缺乏的风险。维生素 B12（B12，钴胺素）是这两种饮食中特别需要关注的营养素，应该持续补充，以确保充足的 B12 水平并预防缺乏。
本病例报告描述了一位健康的 30 多岁男性的病史，他大约 10 年前开始采用纯素食饮食。他非常了解植物性饮食中维生素 B12 缺乏的风险，因此多年来一直定期补充甲钴胺（单剂量：500µg，每周 3-4 次）以维持足够的维生素 B12 状态。然而，2023 年末，他出于未知原因决定停止补充 B12。在此决定后，我们密切监测他的 B12 状态，并进行了纵向测量血清 B12、同型半胱氨酸和全钴胺素（holo-TC）。还测定了总血清叶酸，因为它是同型半胱氨酸浓度的调节剂。在 4 周后，观察到 holo-TC 和维生素 B12 水平逐渐下降，在 16 周后不得不重新补充。同型半胱氨酸在 20 周后增加到 18.2μmol/L。
虽然短期停止 B12 补充可能会被 B12 状态充足的素食者耐受，但中断超过 8 周可能表明 B12 损失接近亚最佳状态。本病例报告再次强调了在食用未经强化的植物性饮食的人群中持续补充 B12 的必要性。
