Effect of oral contraceptive agents on vitamin nutrition status

Abstract

Effects of low estrogen combination type oral contraceptives on some of the biochemical parameters used for assessing vitamin nutritional status were investigated in a group of women who had used the pill for 6 to 12 months. Another group of women was examined initially and then at one or more points of time within the first 6 months of treatment. Following changes were observed in women treated with oral contraceptives: 1) increased excretion of kynurenic acid and xanthurenic acid following tryptophan load; 2) increased EGOT activity and also an increase in vitro stimulation of EGOT with added PALP; 3) increased plasma vitamin A levels; 4) fall in erythrocyte folate levels; 5) fall in erythrocyte transketolase activity with no change in vitro stimulation with TPP; and 6) fall in erythrocyte riboflavin concentration associated with a decrease in erythrocyte glutathione reductase activity and increase in vitro stimulation with FAD. Most of these changes were observed during the first few cycles of oral contraceptive treatment.

Oral contraceptive use: impact on folate, vitamin B6, and vitamin B12 status

“…For example, in most studies there were no controls for dietary folate intake, vitamin supplement use, smoking, or alcohol use. [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] In addition, other factors not considered by many investigators include differences in the specific type of hormone used in the OCs, 58,59 compliance with the OC regimen, 44,58,59 and duration of OC use. 50,58 Folate status in these earlier studies was, in most cases, based solely on a comparison of serum folate concentration between groups of OC users and non-users.…”

“…32 More recently conducted studies, designed to evaluate the effect of OC use on folate status, have included measures of RBC folate concentration; however, as with studies measuring only serum folate concentration, the results have been equivocal. [46][47][48]50,51,[60][61][62] In the studies from which it was concluded that OC use negatively affected folate status, none controlled for all potentially confounding variables, including differences in dietary intake and use of folic acid-containing supplements. 46,48,60,62 Of those studies that controlled for dietary intake, with one exception, 62 no difference in RBC folate concentration between OC and non-OC users was detected.…”

“…It is likely that the inconsistency between these early studies may be due to lack of control of potentially confounding variables. For example, in most studies there were no controls for dietary folate intake, vitamin supplement use, smoking, or alcohol use 39–57 . In addition, other factors not considered by many investigators include differences in the specific type of hormone used in the OCs, 58,59 compliance with the OC regimen, 44,58,59 and duration of OC use 50,58 .…”

“…In the studies from which it was concluded that OC use negatively affected folate status, none controlled for all potentially confounding variables, including differences in dietary intake and use of folic acid‐containing supplements 46,48,60,62 . Of those studies that controlled for dietary intake, with one exception, 62 no difference in RBC folate concentration between OC and non‐OC users was detected 47,50,58–61 . Similarly, in one well‐controlled study with rats, no effect of single or combined hormones was found on tissue folate concentrations 63 .…”

Failure of Pyridoxine to Improve Glucose Tolerance in Diabetics

“…The vitamin B 6 status of the patients was assessed by measuring the stimulation of EGOT activity in vitro in the presence of excess pyridoxal phosphate (PALP effect). A PALP effect greater than 40% was considered to be evidence of vitamin B6 deficiency, and a PALP value less than 35% was considered to indicate adequate vitamin B6 nutriture (15).…”