Haddad Ella H, Jaceldo-Siegl Karen, Oda Keiji, Fraser Gary E
Center for Nutrition, Healthy Lifestyle and Disease Prevention, School of Public Health, Loma Linda University, Loma Linda, CA, USA.
Curr Dev Nutr. 2020 Jan 22;4(2):nzaa008. doi: 10.1093/cdn/nzaa008. eCollection 2020 Feb.
Elevated plasma methylmalonic acid (MMA) is a functional biomarker of vitamin B-12 status but limited information is available on its prevalence in US vegetarians.
The study examines the prevalence of plasma MMA ≥0.27 µmol/L in those consuming vegetarian diets, its associations with vitamin B-12 intake and biomarkers, and the modifying effect of vegetarian patterns on these associations.
In this cross-sectional study ( = 785), concentrations of MMA, vitamin B-12, holotranscobalamin (holoTC), and homocysteine (Hcy) were determined in participants of the calibration substudy of the Adventist Health Study 2 (AHS-2). Vitamin B-12 intake from food, fortified food, and supplements was assessed by six 24-h recalls. Regression models were used to estimate ORs of having high MMA as related to vitamin B-12 status biomarkers, vitamin B-12 intake, and dietary pattern.
The prevalence of low vitamin B-12 status defined by serum vitamin B-12 <148 pmol/L, holoTC <35 pmol/L, MMA ≥0.27 and ≥0.37 μmol/L, or Hcy ≥15 μmol/L, and the OR of having high MMA did not differ by dietary pattern, possibly due to intake from fortified food and supplements. Total daily vitamin B-12 intake in the second tertile range of 4.4-14.5 μg/d reduced the likelihood of elevated MMA by 69%; and a doubling of vitamin B-12 intake was associated with a 4.3% decrease in plasma MMA. The association between log plasma MMA and biomarkers was modified by diet, with the vegan pattern showing an ∼3-fold stronger association with log serum vitamin B-12 and Hcy than did the nonvegetarian pattern.
The prevalence of vitamin B-12 intake <2.0 μg/d was 15.2% in vegans, 10.6% in lacto-ovo-vegetarians, and 6.5% in nonvegetarians. Given the irreversible neurological consequences of vitamin B-12 inadequacy, the importance of regular supplemental vitamin B-12 intake in adult and elderly individuals is stressed.
血浆甲基丙二酸（MMA）水平升高是维生素B-12状态的一种功能性生物标志物，但关于其在美国素食者中的流行情况，现有信息有限。
本研究调查素食者中血浆MMA≥0.27µmol/L的患病率，及其与维生素B-12摄入量和生物标志物的关联，以及素食模式对这些关联的调节作用。
在这项横断面研究（n = 785）中，对基督复临安息日会健康研究2（AHS-2）校准子研究的参与者测定了MMA、维生素B-12、全转钴胺素（holoTC）和同型半胱氨酸（Hcy）的浓度。通过6次24小时膳食回顾评估食物、强化食品和补充剂中的维生素B-12摄入量。采用回归模型估计与维生素B-12状态生物标志物、维生素B-12摄入量和饮食模式相关的高MMA的比值比（OR）。
根据血清维生素B-12<148pmol/L、holoTC<35pmol/L、MMA≥0.27和≥0.37μmol/L或Hcy≥15μmol/L定义的低维生素B-1状态的患病率，以及高MMA的OR在不同饮食模式下没有差异，这可能是由于强化食品和补充剂的摄入。每日维生素B-12总摄入量处于4.4 - 14.5μg/d的第二个三分位数范围内，可使MMA升高的可能性降低69%；维生素B-12摄入量翻倍与血浆MMA降低4.3%相关。血浆MMA对数与生物标志物之间的关联受到饮食的调节，纯素食模式与血清维生素B-12对数和Hcy的关联比非素食模式强约3倍。
纯素食者中维生素B-12摄入量<2.0μg/d的患病率为15.2%，蛋奶素食者为10.6%，非素食者为6.5%。鉴于维生素B-12缺乏会导致不可逆转的神经后果，强调了成年和老年个体定期补充维生素B-12的重要性。
