“'A Vegemite sandwich made with whole grain bread and cheese or avocado is a great healthy option,' Mary Cluskey, associate professor of nutrition at Oregon State University, told HuffPost.

The one exception, she said, was “very strong” Vegemite sandwiches. “It definitely made me feel more Australian because I was eating what everybody else was eating,” she said.

A product of war Vegemite has German U-boats to thank for its invention. When the first world war began in 1914, Australians were big fans of Marmite, the British yeast extract spread.

Adding a spread like Vegemite significantly increases sodium intake, with a simple Vegemite sandwich estimated to supply around 50 per cent of a child’s daily limit.

For non-Australians, the mention of "a Vegemite sandwich" in Australian band Men at Work's 1983 hit song "Down Under" may be their only exposure to the stuff.