Diabetes are more common among middle classes due to nutrition endured by their ancestors. According to a new study by an Indian professor, diabetes are likely to develop among middle classes in India and other developing countries.

The research, published in the journal Cell Metabolism, shows eating a ‘normal’ diet can make animals obese if their ancestors had been undernourished for several generations.

The middle classes from developing countries are more susceptible than westerners to Type-2 diabetes, obesity and cardiovascular disease in today’s changing environment which may be a result of the nutrition endured by their ancestors, it says.

The results could explain projections that more than 70% of the global burden of Type-2 diabetes will fall on individuals from developing countries by 2030, researchers of University of Sydney, the National Centre for Cell Science and the DYP Medical College in Pune, India said.

India will have 80 million people with diabetes by 2030, according to the World Health Organisation (WHO).

Unsurprisingly, increasing prosperity in developing countries has been accompanied by a sudden increase in caloric intake. However their populations’ epigenetic makeup, whereby changing environmental factors alter how people’s genes are expressed, has not compensated for these dietary changes.

This means their bodies are still designed to cope with undernourishment so they store fat in a manner that makes them more prone to obesity and its resulting diseases than populations accustomed to several generations of a normal diet.

This scenario was recreated in a 12-year study of two groups of rats by Associate Professor Anandwardhan A Hardikar’s team at the University of Sydney.

The first group was undernourished for 50 generations and then put on a normal diet for two generations. The second (control) group maintained a normal diet for 52 generations. When the descendants of the first group were exposed to a normal diet, this did not reverse the epigenetic modifications made by their undernourished forebears.

These rats were eight times more likely to develop diabetes and multiple metabolic defects when compared to the control group, it was found.

“Their adverse metabolic state was not reversed by two generations of nutrient recuperation through a normal diet. Instead this newly prosperous population favoured storage of the excess nutrients as fat leading to increased obesity, cardiovascular disease and metabolic risk for diabetes when compared to their ‘developed world’ counterparts,” Hardikar said, adding that lower Vitamin B12 levels in the undernourished rats could also be an indicator of this trend.

“Human studies from Ranjan Yajnik’s group at KEM Hospital in Pune, India have demonstrated that low circulating B12 and high folate levels are associated with insulin resistance and Type-2 diabetes,” Hardikar, a PhD in Zoology from the University of Pune, added.