Juda Polak was a son of Isaac Polak and Sara Loonstijn. He married in Amsterdam on 24 October 1906 to Grietje Verduin, daughter of Levie Abraham Verduin and Vrouwtje Philip Rood. Besides Grietje, there were also her brothers Isaac, Barend and Jacob Verduin.
Juda and Grietje had one daughter Sara, who married Leon Verduin.
Grietje Verduin passed away on 13 May 1930 and Juda Polak remarried in Amsterdam on 4 June 1931 to Esther Klein.
City Archive of Amsterdam, archive card of Juda Polak.
In addition, a Jokos file (number 9797) on this person is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.The Jokos file reveals that a claim was lodged for compensation for valuables surrendered to the Lippmann-Rosenthal looting bank (L-claim, number 9453/12579).