Bob Dylan provided the soundtrack to my adolescence.

Dylan, Leonard Cohen and Lou Reed — the great triumvirate of misery brought angst-ridden enlightenment to that bedroom in a cul-de-sac on a new-build housing estate in a West Country dormitory town.

When I was struck down one spring day in the early 1980s by glandular fever, I was told I would have to take the rest of the school year off. My dad came home with two albums to aid my recovery: Dylan’s folk opus, The Times They Are a’Changin’, and The Velvet Underground and Nico, which features some of Lou Reed’s bleakest songs. I spent my time reading the works of Kafka, topped up with Leonard Cohen’s poetry and even finished Dylan’s “novel”, Tarantula, which is officially unreadable.

Did I consider for one moment the Jewishness of Dylan, Cohen, Reed and Kafka? Even if I had, it would have meant very little. As far as I was aware, there was not a single Jewish family in our town. At school, the one half-Jewish boy was himself unaware of his heritage until he was bullied for having a vaguely Semitic-sounding surname.

The news that the National Portrait Gallery is to host the first exhibition of portraits by Bob Dylan has been greeted with something of a fanfare. This is no real surprise. The great man’s pastel portraits may not compare in aesthetic terms with Blonde on Blonde or Blood on the Tracks, but it is still an important cultural event.

Yet, the idea of making a special case of the Jewish figure in popular culture does make me uncomfortable. It would be absurd to suggest that I was drawn to the music of Dylan, Cohen and Reed because of its essentially Old Testament pessimism or the quasi-rabbinical nature of the writing.

Without denying the ethnic origins of these great songwriters, they are primarily American artists — deeply embedded within the folk and blues tradition with little connection with the Jewish musical traditions of Europe or North Africa. In their songs, they rarely refer to their Jewishness.

Philosemitism can so easily drift into its opposite.It would be stretching a point to suggest there is something sinister about this kind of cultural Jew-spotting. We are a long way from the Nazis’ 1937 “Degenerate Art” exhibition. But we should be careful about suggesting there is something essentially Jewish in any work of art.