Abstract
Metformin (MET) is currently being used in several trials for cancer prevention or treatment in non-diabetics. However, long-term MET use in diabetics is associated with lower serum levels of total vitamin B12. In a pilot randomized controlled trial of the Mediterranean diet (MedDiet) and MET, whose participants were characterized by different components of metabolic syndrome, we tested the effect of MET on serum levels of B12, holo transcobalamin II (holo-TC-II), and methylmalonic acid (MMA). The study was conducted on 165 women receiving MET or placebo for three years. Results of the study indicate a significant overall reduction in both serum total B12 and holo-TC-II levels according with MET-treatment. In particular, in the MET group 26 of 81 patients and 10 of the 84 placebo-treated subjects had B12 below the normal threshold (<221 pmol/L) at the end of the study. Considering jointly all B12, Holo-TC-II, and MMA, 13 of the 165 subjects (10 MET and 3 placebo-treated) had at least two deficits in the biochemical parameters at the end of the study, without reporting clinical signs. Although our results do not affect whether women remain in the trial, B12 monitoring for MET-treated individuals should be implemented.
Highlights
Metformin (MET) is the first-line treatment for type-2 diabetes and has been used for decades to treat this chronic condition [1]
On the basis of World Health Organization (WHO) guidelines, we examined the sample’s deficit conditions at the end of the interventions (Table 2): WHO guidelines on B12 status define “adequate” B12 values as higher or equal to 221 pmol/L, “low” from 148 to 221 and “B12 deficiency” if lower than 148
In line with previous studies in diabetics, our data indicate that long-term use of MET lowers circulating B12 levels in healthy women with tracts of metabolic syndrome (MS)
Summary
Metformin (MET) is the first-line treatment for type-2 diabetes and has been used for decades to treat this chronic condition [1]. Observational studies have suggested that diabetic patients treated with MET had a significantly lower risk of developing cancer or lower cancer mortality than those untreated or treated with other drugs [3,4]. For this reason, a number of clinical trials are in progress in different solid cancers. The aim of the present study was to assess the effect of three years of MET treatment in a randomized, controlled trial considering both B12 levels and biomarkers of its metabolism and biological effectiveness
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