In 2021, there were 537 million adults living with diabetesabout 90% of whom had type 2 diabetes. When a person has type 2 diabetes, specialized cells in the pancreas called “beta cells” produce insufficient amounts of insulin.
Insulin is a hormone which travels through the bloodstream and tells other cells to remove excess sugar from the blood and use that sugar as energy, ensuring the body keeps doing whatever it needs to.
People with type 2 diabetes are ‘insulin resistant’, which means that cells do not properly recognize insulin. These people need more insulin than normal to regulate their blood sugar. When beta cells fail to compensate for the increased demand for insulin, blood sugar rises, which negatively affects organ function.
Globally, the South Asian community is made up of more than two billion people. In Canada, 14.4% of South Asians have type 2 diabetesthe highest prevalence of any other ethnic group in the country.
As a member of the South Asian community, it is extremely common for me (Lahari Basu) to learn that someone I know has been diagnosed with type 2 diabetes. When I joined Laboratory of Dr. Jenny Bruin at Carleton University to study diabetes for my PhD, I was intrigued by this question: why are South Asians disproportionately affected by type 2 diabetes?
This response lies in a web of genetic, behavioral and cultural factors.
Genetic variants
In 2013, researchers confirmed that South Asians are particularly resistant to insulin. Compared to Caucasians, South Asians had higher insulin concentrations in their blood after ingesting sugar. This means that South Asian people need more insulin to regulate their blood sugar levels, a hallmark of type 2 diabetes.
There are many possible explanations for this, but genetic variants could be one of the culprits. Variations or mutations in genes can alter cellular function. In the case of beta cells, genetic variants can lead to inappropriate levels of insulin secretion and insulin resistance.
It turns out that South Asians have acquired mutations in various genes necessary for the proper functioning of beta cells. They also have a higher prevalence of mutations in a gene called GRB14leading to increased insulin resistance.
Although not all South Asians have these mutations, a significant proportion do. There are also probably other gene variants that have not yet been discovered in this population. These genetic variants are beginning to paint an interesting picture of how genetic predisposition increases their risk of developing diabetes.
Physiological adaptations
Genetic variants explain only a small part of the increase in insulin resistance in South Asian individuals. This observed insulin resistance may also have a historical context.
South Asians have faced multiple famines throughout history. The recurrence of depletion of food sources and malnutrition has led to the development of a adaptation to starvation. This adaptation allowed them to efficiently process food and store fat during times of plenty, providing an advantage during famine.
Now, with urbanization and migration, this trait can be detrimental to South Asians. Adaptation does not bode well in a world of increased access to high-fat foods. Combined with modern diets, this adaptation can result in increased fat storage and abdominal obesity in South Asian peopleleading to an increased risk of insulin resistance and diabetes.
Cultural differences
Food plays an important social role in South Asian culture. As far back as I can remember, big family dinners were an integral part of my way of life and my cultural identity. For us, food is a way to communicate, to honor ancestors and to celebrate.
The staples of South Asian cuisine include white rice, flatbreads, and potatoes, with most dishes prepared in clarified butter. This diet is influenced by a time before refrigerators and plenty of food, focusing on shelf-stable and self-preserved foods. Diets high in carbohydrates and fats have been linked to increased insulin resistance and decreased metabolism (the process of converting food into energy).
Culture-centered treatment
There is clearly a complex relationship between South Asian ethnicity and diabetes risk. The interplay of culture and genetics presents a unique challenge for this community. For many, ignorance of diabetes can prevent them from getting the care they need.
Execution culture-based treatment programs can help approach diabetes management in a new light. Healthier versions of traditional foods, familiar languages and knowledge of cultural barriers can help South Asians with diabetes understand the severity of the disease, their susceptibility to it and how to manage their symptoms.
A call for research focused on South Asia
As a South Asian woman studying diabetes, learning about this phenomenon opened my eyes to how little we know about ethnic-specific diabetes risk. South Asians are severely underrepresented in clinical research. To truly understand the complex relationship between type 2 diabetes and South Asians, it is essential to conduct clinical studies specifically targeting this ethnic group.
A better scientific understanding of the link between South Asians and the rise in type 2 diabetes and the implementation of culture-centered management programs can help alleviate the mystery and stigma behind this phenomenon.
