GUM disease really is caused by not brushing your teeth regularly – and cannot be blamed on your genes, according to new research.

Scientists have claimed for years hereditary factors play a role in the development of the condition which can be serious, even leading to heart disease and dementia.

But a study of 485 pairs of twins has found bugs that cause tooth decay are picked up from what we consume, rather than running in families.

Writing in the journal Cell Host and Microbe, the researchers say the condition of a person's teeth depends on their dietary and oral hygiene habits.

Dr Karen Nelson, president of the J. Craig Venter Institute in the US, said: “Limiting sugar consumption and acid build-up in the mouth have been part of the dogma of the dental community for some time.

“This work introduces specific taxa of bacteria that can be acquired through the environment and that have the ability to induce cavities.”