Probiotic pills could hold the key to ending malnutrition across the globe within the next two decades, according to the billionaire Bill Gates.

Probiotics, or “good” bacteria, are thought to help maintain a healthy gut and are commonly added to foods such as Yakult or Actimel yoghurt.

Many view these so called “functional foods” as a gimmick but Mr Gates, who is giving the annual Hawking Fellowship Lecture at Cambridge University Union on Monday, believes the science that underpins them could save millions of lives.

Writing in The Telegraph, Mr Gates said if he could only work to solve one problem it would be malnutrition.

“It’s the greatest health inequity in the world – but thanks to new scientific breakthroughs, I believe we will find a way to solve it within 20 years”, he said.

He argues that better scientific understanding of the human microbiome – specifically the microorganisms which inhabit the gut – will enable the development of “smartly engineered” probiotic pills which will help us to retain more of the nutrients in the foods we eat.

“In the future, we’ll be able to create next-generation probiotic pills that contain ideal combinations of bacteria – even ones that are tailored to your specific gut,” said the 63-year-old Microsoft founder turned philanthropist.