There are more than 72 million people living with diabetes in India as per the 2017 IDF diabetes atlas.
India has 49% of the world’s diabetes burden which is supposed to double by the year 2025. The urban poor are just as prone to diabetes as wealthier communities, according to an August 2017 study published in the Lancet Diabetes and Endocrinology journal.
Interestingly, in a study published in British Journal of Nutrition in 2008, the authors found that when identical foods were given to Asian Indians and UK Caucasian subjects, the Asian Indians elicited a greater glycemic response (greater glucose excursion) compared to their UK Caucasian counterparts. The authors attributed this to the ‘Asian Indian Phenotype’.
Several studies on migrant Indians across the globe have shown that Asian Indians have an increased risk for developing type 2 diabetes and related metabolic abnormalities compared to other ethnic groups. Although the exact reasons are still not clear, certain unique clinical and biochemical characteristics of this ethnic group collectively called as the “Asian Indian phenotype” is considered to be one of the major factors contributing to the increased preference towards diabetes. Despite having lower prevalence of obesity as defined by body mass index (BMI), Asian Indians tend to have greater waist circumference and waist to hip ratios thus having a greater degree of central obesity.
Studies on new-born suggested that Indian babies are born smaller but relatively fatter compared to Caucasian babies and are referred to as “the thin fat Indian baby”.
These findings suggest that Asian Indians are more prone to diabetes and related metabolic abnormalities.
Another way to explain the diabetes epidemic in India is through Neel’s ‘thrifty genotype’ hypothesis. This hypothesis proposes that some genes are selected over previous millennia to allow survival in times of famine by efficiently storing all available energy during times of feast. However, these very genes lead to obesity and type 2 diabetes when exposed to a constant high energy diet. In virtually all populations, higher fat diets and decreased physical activity and sedentary occupational habits have accompanied the process of modernization which has resulted in the doubling of the prevalence of obesity and type 2 diabetes in less than a generation.
In India, as urbanization and economic growth occurs, there are major deviations in the dietary pattern which are influenced by the varied cultural and social customs. Traditional dietary patterns are disappearing as Indians are adapting themselves to living in the more industrialized, urban environments that are brought about by globalization.
The major dietary changes that urbanization and affluence bring about are, substitution of unrefined wheat, rice or millets by highly polished wheat or rice and increased intakes of fat in higher income groups. High calorie intakes by high-income groups in India are largely due to high intakes of refined cereals and carbohydrates rather than fats and meat as in Europe and North America.
Over the past few decades, a huge number of the working population has shifted from manual labour associated with the agriculture sector to physically less demanding office jobs. With the advent of highly addictive computer and video games, sedentarinism is now affecting the children and youth as they tend to spend more time in front of television sets or computers than playing outdoors. It was observed that the prevalence of diabetes was almost three times higher in individuals with light physical activity compared to those having heavy physical activity.
It is thus clear that the diabetes epidemic experienced in India may be due to strong genetic factors coupled with urbanization and lifestyle changes leading to insulin resistance. The contributing factor for increased insulin resistance may be the Asian Indian phenotype consisting of higher rates of central obesity and increased visceral fat.
Sufficient evidence is now available to show that many of the environmental factors adversely related to glucose intolerance are modifiable through lifestyle changes.
Prevention of Type 2 diabetes will require measures to promote physical activity and reduce obesity in adults and children, alongside programmes to achieve healthy fetal and infant growth.
Considering that Indians appear to be generally more insulin resistant, it would be prudent to advise a healthy lifestyle across the different geographic regions and age groups, continue diets rich in fibre and possibly adopt stress reduction measures. Such an effort is urgently needed to tackle the explosion of diabetes and lower the burden due to diabetes in India.
 Henry et al British Journal of Nutrition (2008), 99, 840–845
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