Dastur D K, Quadros E V, Wadia N H, Desai M M, Bharucha E P
Br Med J. 1972 Jul 29;3(5821):260-3. doi: 10.1136/bmj.3.5821.260.
Vitamin B(12), thiocyanate, and folate levels in the blood were estimated in 69 apparently normal subjects, of whom 26 were non-vegetarian non-smokers, 19 non-vegetarian smokers, 15 vegetarian non-smokers, and nine vegetarian smokers. The serum total (cyanide-extracted) B(12) level (value A) ranged from 105 to 728 pg/ml, with a mean of 292 pg/ml. The highest values were found in non-vegetarian non-smokers and the lowest in vegetarian smokers. There was no significant difference in value A between smokers as a group and non-smokers as a group. On the other hand, in vegetarians value A was very significantly lower than in non-vegetarians regardless of their smoking habits.It is suggested that A may represent both the protein-bound and free forms of vitamin B(12) in the blood, and B mainly the free B(12), which may be the physiologically active form. The plasma thiocyanate level varied from 1.0 to 15 mumol/100 ml, being, as expected, much higher in smokers (mean 8.20 mumol/100 ml) than in non-smokers (mean 2.02 mumol/100 ml). There was a rough correlation between falling B(12) levels and rising thiocyanate levels. The serum folate level ranged from 2.75 to 15.75 ng/ml, and was slightly but significantly higher in vegetarians (mean 6.60 ng/ml) than in non-vegetarians (mean 4.79 ng/ml), reflecting the greater content of folate in a vegetarian diet.
对69名表面上健康的受试者的血液中的维生素B12、硫氰酸盐和叶酸水平进行了评估，其中26名是非素食不吸烟者，19名是非素食吸烟者，15名是素食不吸烟者，9名是素食吸烟者。血清总（经氰化物提取）B12水平（值A）在105至728 pg/ml之间，平均为292 pg/ml。最高值出现在非素食不吸烟者中，最低值出现在素食吸烟者中。吸烟者组和不吸烟者组之间的值A没有显著差异。另一方面，无论吸烟习惯如何，素食者的值A均显著低于非素食者。有人认为，A可能代表血液中维生素B12的蛋白质结合形式和游离形式，而B主要代表游离B12，它可能是生理活性形式。血浆硫氰酸盐水平在1.0至15 μmol/100 ml之间，正如预期的那样，吸烟者（平均8.20 μmol/100 ml）的水平远高于不吸烟者（平均2.02 μmol/100 ml）。B12水平下降与硫氰酸盐水平上升之间存在大致的相关性。血清叶酸水平在2.75至15.75 ng/ml之间，素食者（平均6.60 ng/ml）略高于非素食者（平均4.79 ng/ml），这反映了素食饮食中叶酸含量更高。
