Djokovic has long been known to eat a gluten and dairy-free diet, while following a largely plant-based nutritional regime - which he has regularly cited as a recipe for his success.

As the World Health Organization notes: “Unhealthy diet is one of the leading risks for the global burden of disease, mainly for noncommunicable diseases such as cardiovascular diseases, diabetes, and cancer.”

Olive oil is synonymous with the Mediterranean diet, and the health benefits of both are well documented.

The researchers analysed the diets of more than half a million women over 16 years and found dark leafy greens, bread and non-dairy milks containing calcium also had a protective effect.

Learning more about his children's condition, church minister William realised they all shared problems with noise and had very restricted diets.