Review: Vitamin B6 is beneficial in the premenstrual syndrome
ACP J Club. 1999 Nov-Dec;131:60. doi:10.7326/ACPJC-1999-131-3-060
Wyatt KM, Dimmock PW, Jones PW, O'Brien PM. Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ. 1999 May 22;318:1375-81. [PubMed ID: 99267356]
In women with the premenstrual syndrome (PMS), is vitamin B6 (pyridoxine) effective for relieving overall and depressive premenstrual symptoms?
Studies were identified by searching MEDLINE (1966 to 1998), EMBASE/Excerpta Medica (1988 to 1996), PsycLIT (1974 to 1997), CINAHL (1982 to 1997), and the Cochrane Controlled Trials Register with the terms premenstrual syndrome, pyridoxine, PMT, LLPDD, and PMDD. Bibliographies of relevant articles were scanned, and pharmaceutical companies were contacted.
Published and unpublished studies in any language were selected if they were randomized, double-blind, placebo-controlled trials for which data could be obtained. Studies involving multi-vitamin supplements were included if the supplement contained ≥ 50 mg of vitamin B6.
Data were extracted on participants, dose and preparation of vitamin B6, outcome measures, results, withdrawals and side effects, and quality scores. The main outcome was subjective improvement in overall premenstrual symptoms, and a secondary outcome was improvement in depressive premenstrual symptoms. Predetermined quality scores ≥ 3 on the Jadad scale and ≥ 6 on the authors' rating scale were used to classify high-quality studies.
10 RCTs with 12 comparisons met the inclusion criteria. Sample sizes ranged from 31 to 434 women (mean 98 women). Doses ranged from 50 mg/d (3 comparisons) to 600 mg/d (1 comparison). Quality scores on the Jadad scale were 1 (3 studies), 2 (4 studies), and 3 (3 studies) points. On the authors' quality rating scale, scores were 3(2 studies), 4 (5 studies), 5 (2 studies), and 6 (1 study) points. Quality scores were not used to exclude studies in the analysis because few high-quality studies were found. Pooled results showed that vitamin B6 was effective for relieving premenstrual symptoms (combined odds ratio [OR] 1.57, 95% CI 1.40 to 1.77). 1 study led to statistically significant heterogeneity when the 10 studies were pooled (P < 0.001). When this study was removed, the combined OR was 2.32 (CI 1.95 to 2.54). 5 studies reported data on depressive menstrual symptoms and showed a benefit for vitamin B6 (combined OR 2.12, CI 1.80 to 2.48). 1 study led to heterogeneity (P < 0.001), and removal of this study resulted in a combined OR of 1.69 (CI 1.39 to 2.06). The 3 high-quality studies according to the Jadad scale showed a benefit for vitamin B6, whereas the 1 high-quality study according to the authors' quality rating did not show an effect.
In women with the premenstrual syndrome, randomized, double-blind, placebo-controlled trials show that vitamin B6 relieves overall premenstrual and depressive symptoms. However, most of the studies fail to meet some methodologic criteria.
Source of funding: None.
For correspondence: Dr. K.M. Wyatt, Academic Department of Obstetrics and Gynecology, North Staffordshire Hospital, Stoke on Trent ST4 6QG, England, UK. FAX 44-1782-552472.
Pathophysiologists know little about what causes PMS and even less about the reason for its psychological manifestations. Pyridoxine—a co-enzyme for the biosynthesis of dopamine and serotonin—may block the development of the depressive symptoms of PMS, but little explanation on how it alleviates the somatic symptoms can be found. The meta-analysis by Wyatt and colleagues of 10 randomized controlled trials promotes vitamin B6 as a possible therapeutic choice. Although none of the randomized controlled trials met all of the criteria for high-quality studies, the meta-analysis provides convincing data that vitamin B6, given in doses of 50 mg once or twice a day, may alleviate PMS symptoms in general and depressive symptoms in particular without causing harm.
Many therapeutic regimens have been presented as alleviators of PMS: Exercise 3 to 4 times per week, particularly during the luteal phase; a high-protein diet; potassium-sparing diuretics; a decrease in oral contraceptive estrogen levels; an increase in exogenous progesterones; psychoactive drugs (e.g., alpraxolam or fluoxetine); and hypothalamic-pituitary-ovarian axis modulators (e.g., danazol and bromocriptine) have all been recommended (1). In comparison with some of the pharmacologic choices presented here, vitamin B6, 50 mg once or twice a day, has the potential to help without causing much harm.
Diane M. Harper, MD, MSc, MPH
Dartmouth-Hitchcock Medical SchoolLebanon, New Hampshire, USA