Letter: For the record - 26 January 2019

• Vitamin B12 supplements may be synthesised from scratch, derived from animal products or extracted from bacteria (The Last Word, 5 January).

• We are still in the Quaternary Ice Age, and the previous interglacial period within it ended 115,000 years ago (22/29 December 2018, p 54).

• The image by artist Dan Holdsworth was in fact of the Argentière glacier in the Chamonix region of France (15 December 2018, p 28).

• Data point: statistician Joshua Loftus is at New York University (12 January, p 7).