Effect of Vegetarianism and Smoking on Vitamin B12, Thiocyanate, and Folate Levels in the Blood of Normal Subjects

Abstract

SummaryVitamin B,,, thiocyanate, and folate levels in the blood were estimated in 69 apparently normal subjects, of whom 26 were non-vegetarian non-smokers, 19 nonvegetarian smokers, 15 vegetarian non-smokers, and nine vegetarian smokers. The serum total (cyanideextracted) B1, 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 proteinbound and free forms of vitamin B1, in the blood, and B mainly the free B12, which may be the physiologically active form. The plasma thiocyanate level varied from 1-0 to 15 Imol/100 ml, being, as expected, much higher in smokers (mean 8 20 ILmol/100 ml) than in non-smokers (mean 2-02 ,umol/100 ml). There was a rough correlation between falling B12 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/mi), reflecting the greater content of folate in a vegetarian diet.

Expired air carbon monoxide and serum thiocyanate as objective measures of cigarette exposure.

“…CO is raised by exposure to the products of incomplete combustion; gas heaters and automobile engines are common sources of exposure.14 The factors in addition to smoking that may elevate serum SCN levels include industrial exposure to cyanides in electroplating, precious metal refining, case hardening of steel, and gas manufacturing.15 Some foods also produce SCN, including the cabbage family, turnips, garlic, horseradish, mustard, and almonds.3 Vegetarians have slightly higher SCN concentrations than non-vegetarians but the increase is not as large or consistent as that seen in smokers. 5 Both expired air CO and serum SCN are elevated threefold when the mean levels of subjects smoking more than 20 cigarettes per day are compared with those of non-smokers. The mean expired CO level of these relatively heavy smokers, 21ppm, is compatible with previous reports9' 11, 12.…”

“…The main disadvantage of this approach is the overlap that is observed in the distributions of the SCN levels of smokers and non-smokers. [1][2][3][4][5][6][7] A second test is the measurement of blood carboxyhemoglobin concentration,812 elevated in smokers because cigarette smoke contains carbon monoxide (CO). Technical…”

Does metformin increase the serum total homocysteine level in non‐insulin‐dependent diabetes mellitus?

“…We matched for important determinants of the serum total homocysteine level, i.e. sex, age, serum creatinine and current smoking habits [21,[26][27][28][29][30][31][32][33]. Finally, we decided to restrict this study to a Caucasian population, because there is evidence for differences in homocysteine metabolism amongst races.…”

Hematinic Deficiency and the risk of Oral Epithelial Dysplasia

“…Some of the carcinogenic substances present in tobacco smoke 'primarily organic nitrites, cyanates, and isocyanates', have been shown to interact with folate and vitamin B 12 coenzymes, transforming them into biologically inactive compounds [32,38]. These chemical interactions may have physiological significance is supported by reports of lower circulating folate [39,40] and B 12 [41] levels in smokers and the buccal mucosal cells of tobacco smokers were shown to have a decreased concentration of folate [35].…”