Eating cheese late at night, the rumour goes, will give you strange dreams. As far back as 1964, a researcher noted that a patient stopped having nightmares when he dropped his habit of eating one or two ounces of cheddar cheese every evening.
More recently, the now-defunct British Cheese Board, who funded a study in 2005 and concluded that eating blue cheese causes vivid dreams, while cheddar makes people dream about celebrities. The study wasn’t exactly scientifically robust or published in a peer-reviewed journal, but the findings helped to perpetuate the belief that cheese can affect the content of our dreams.
Another indirect explanation is cheese’s high lactose content. A study that Nielson conducted in 2015 found that only 17% of people said their dreams seemed to be influenced by what they ate, but he says dairy products were the foods most frequently reported as causing disturbing dreams.
“It’s entirely possible that these effects were due to people having lactose intolerances,” [psychology professor Tore Nielson] says. “It’s likely an indirect effect in that lactose produces symptoms like gas, bloating and diarrhoea and influences dreams, as dreams draw on somatic sources like this.”