THE number of people ending up in hospital due to vitamin and mineral deficiencies or being underweight will surge with global warming, scientists have warned.

It is well-documented that as the Earth's climate change will increase the risk of food shortages and hunger in the world's developing countries as crop production becomes more difficult.

However, Australian researchers have examined for the first time the implications between heat exposure and hospitalisation in the developed world using data from Brazil.

READ MORE: Nothing would do more to ease strain on NHS than closing the gap between rich and poor 

They found that for every 1°C increase in daily mean temperature during the hot season, there was a 2.5 per cent increase in the number of hospitalisations for undernutrition.

Undernutrition - a form of malnutrition - covers people falling ill because they are dangerously thin or deficient in the essential vitamins and minerals needed for metabolism.

The research at Monash University in Melbourne was led by Yuming Guo, an associate professor of environmental epidemiology and biostatistics at the School of Public Health.

Prof Guo and his team analysed daily hospitalisation figures covering almost 80 per cent of Brazil between 2000 and 2015.

They studied the link between daily average temperatures and hospitalisation for undernourishment according to the International Classification of Diseases.

READ MORE: Putting calorie info on menus encourages diners to cut back - but only enough to lost 1Ib in 3 years 

The findings are published in the journal, PLOS Medicine.

They said: “The association between increased heat and hospitalisation for undernutrition was greatest for individuals aged over 80, and those five to 19 years.

“We estimated that 15.6% of undernutrition hospitalisations could be attributed to heat exposure during the study period.”

The study says increased heat may cause illness through undernourishment in a number of ways, including reducing appetite and encouraging excess alcohol consumption leading to dehydration.

They said high temperatures could also worsen absorption of nutrients in people with already impaired digestive systems, reduce motivation or ability to shop and cook, or disrupt thermoregulation - the process that allows your body to maintain its core internal temperature.

The study added: "Climate change is one of the biggest threats to the reduction of hunger and undernutrition, especially in low and middle-income countries.

"It has been estimated that climate change will reduce global food availability by 3.2% and thus cause about 30,000 underweight-related deaths by 2050.

"However, this may actually underestimate the real effect of climate change on future undernutrition-related morbidity and mortality, because it overlooks the direct and short-term effects of temperature rise.

“We estimated that over 15% of undernutrition hospitalisations could have been attributable to heat exposure in Brazil during the study period."