4.1. Strengths and Limitations
The original MANGO study was not designed to investigate changes in vitamin B12 status specifically. However, this sub-study included three individual biomarkers of B12 status as well as a composite score (3cB12). The 3cB12 composite score is considered to give a better judgment of B12 status than use of the individual biomarkers [One of the limitations of this study is that samples were stored for between 3 and 5 years prior to analyses at a non-optimal, −20 °C, temperature. For serum vitamin B12, an almost linear decrease has been observed during the time of storage at −80 °C [