Department of Pathology, Deenanath Mangeshkar Hospital and Research Center, Pune, 411004, India.
Department of Clinical Biochemistry and Institute of Clinical Medicine, Aarhus University Hospital, DK-8200 Aarhus N, Denmark.
Nutrients. 2019 Oct 6;11(10):2382. doi: 10.3390/nu11102382.
Lactovegetarians ( = 35) with low vitamin B12 (B12) status were intervened for eight weeks capsules containing cyano-B12 (CN-B12), (2 × 2.8 µg/day), or equivalent doses of endogenous B12 (mainly hydroxo-B12 (HO-B12)) in whey powder. Blood samples were examined at baseline, every second week during the intervention, and two weeks post-intervention. The groups did not differ at baseline in [global median (min/max)] plasma B12 [112(61/185)] pmol/L, holotranscobalamin [20(4/99)] pmol/L, folate [13(11/16)], the metabolites total homocysteine [18(9/52)] µmol/L and methylmalonic acid [0.90(0.28/2.5)] µmol/L, and the combined indicator of B12 status (4cB12) [-1.7(-3.0/-0.33)]. Both supplements caused significant effects, though none of the biomarkers returned to normal values. Total plasma B12 showed a higher increase in the capsule group compared to the whey powder group ( = 0.02). However, the increase of plasma holotranscobalamin ( = 0.06) and the lowering of the metabolites ( > 0.07) were alike in both groups. Thereby, the high total plasma B12 in the capsule group was not mirrored in enhanced B12 metabolism, possibly because the B12 surplus was mainly accumulated on an "inert" carrier haptocorrin, considered to be of marginal importance for tissue delivery of B12. In conclusion, we demonstrate that administration of whey powder (HO-B12) or capsules (CN-B12) equivalent to 5.6 µg of B12 daily for eight weeks similarly improves B12 status but does not normalize it. We document that the results for plasma B12 should be interpreted with caution following administration of CN-B12, since the change is disproportionately high compared to the responses of complementary biomarkers.
素食者（= 35）的维生素 B12（B12）状态较低，接受了八周的干预，摄入含有氰钴胺素（CN-B12）（2×2.8µg/天）的胶囊，或乳清粉中内源性 B12（主要为羟钴胺素（HO-B12））的等效剂量。在干预期间每两周和干预结束后两周采集血样。在基线时，两组间[总体中位数（最小/最大）]血浆 B12 [112（61/185）] pmol/L、全钴胺素[20（4/99）] pmol/L、叶酸[13（11/16）]、代谢物总同型半胱氨酸[18（9/52）]µmol/L 和甲基丙二酸[0.90（0.28/2.5）]µmol/L 以及 B12 状态的综合指标（4cB12）[-1.7（-3.0/-0.33）]均无差异。两种补充剂均有显著效果，但没有一种生物标志物恢复正常。与乳清粉组相比，胶囊组的总血浆 B12 增加更高（=0.02）。然而，血浆全钴胺素的增加（=0.06）和代谢物的降低（>0.07）在两组中相似。因此，胶囊组中高的总血浆 B12 并没有反映在增强的 B12 代谢中，这可能是因为 B12 过剩主要积累在被认为对 B12 组织输送意义不大的惰性载体转钴胺素上。总之，我们证明了乳清粉（HO-B12）或胶囊（CN-B12）的给药，相当于每天 5.6µg 的 B12，持续八周，同样改善了 B12 状态，但并未使其正常化。我们记录到，在给予 CN-B12 后，血浆 B12 的结果应谨慎解释，因为与互补生物标志物的反应相比，变化不成比例地高。
