South Asians are up to 6 times more likely to have type 2 diabetes than the general population. Experts suggest this may explain why Covid-19 disproportionately affects this ethnic group.

India: home to almost a fifth of the world’s population, a rapidly growing economy, and with around 70 million sufferers, is dubbed ‘the world’s capital of diabetes’. And with cases rising, India’s unlikely to be losing its title in the foreseeable future.

However, diabetes is not just India’s nemesis, but poses a challenge for the entirety of South Asia and those of South Asian origin. So why are South Asians more susceptible to type 2 diabetes?  The short answer is a genetic predisposition, heightened by lifestyle choices and plagued by racial health inequalities.

The long answer requires us to examine the science behind our body’s response to sugar and the alarming way this response can be disturbed from a young age.

Diabetes mellitus, ‘diabetes’, is characterised by abnormally high blood glucose (sugar). Interestingly, the word ‘mellitus’, meaning sweetened with honey, in Latin, does not refer to the blood, but describes the taste of sugary urine that is produced in uncontrolled diabetes – a quirk used by 17th century physicians who would taste their patient’s urine to diagnose the condition.

Fortunately for us, the invention of urine dipsticks means diabetes diagnosis no longer requires our tongues. In fact, most diagnoses are now made with a simple blood test.  

In a healthy individual, blood glucose is generally kept low by the hormone insulin. Insulin is released by the pancreas when our blood glucose is too high, for example, after we’ve eaten.  It allows glucose to be taken up by the body’s cells and therefore not only provides our cells with a fuel source, but in doing so, reduces the glucose in the blood.

Think of this relationship as a parent (insulin) giving their child (the cell) a command. As the child grows into a teenager, they start to ignore what you tell them, which may result in you shouting at them before finally surrendering.

In type 2 diabetes, this is exactly what occurs; the body’s cells become insulin resistant i.e. they don’t respond to insulin and don’t absorb glucose, so the pancreas begins to secrete more insulin with the intention that strengthening the signal might reinstate the response.

Eventually, insulin production by the exhausted pancreas declines, to result in a significantly raised blood glucose concentration. Excess glucose internally damages our nerves, blood vessels and immune system. However, even the visible symptoms of diabetes are often overlooked. These symptoms include: increased thirst and appetite, more frequent urination, unexplained weight loss and tiredness.

The origin of insulin resistance is multifactorial, although it has been strongly correlated with the amount of abdominal fat. Research that compares the DNA of South Asians with Caucasians finds that South Asians may be more susceptible to develop insulin resistance because they harbour gene variants which promote fat accumulation and hinder the efficacy of insulin signalling.

South Asians have also been shown to ‘burn off’ less fat during exercise than White Europeans. The origins of insulin resistance in South Asians may also be traced to the womb. Several studies have identified a link between low birth weight (often due to maternal undernutrition) and signs of insulin resistance in adulthood.

This phenomenon is put down to ‘developmental programming’, which describes the way a fetus adapts to its future environment to maximise its chances of survival.

It can become problematic however when the environments before and after birth do not match. For instance, if a fetus has adapted to conditions of undernourishment by slowing its processing of nutrients and growth, developmental programming is not advantageous if their bodies become overburdened with calories later in life.

Whatever the specific mechanism may be, South Asians are predisposed to type 2 diabetes. This predisposition may be aggravated by a diet high in carbohydrates (sugar complexes) and fat, which both contribute to insulin resistance. Whilst traditional South Asian food itself is carbohydrate rich, an additional surge in the popularity of fast food puts young South Asians at greatest risk for later type 2 diabetes development. Indeed, South Asian teenagers exhibit greater insulin resistance and abdominal fat than their white counterparts, which are more suggestive of full-blown type 2 diabetes developing in adulthood.

Most worryingly however is that South Asian teenagers and young adults are often unaware of their programmed pancreatic failure, largely from a lack of education on ethnicity-specific health risks. An obscured knowledge of these risks may even extend to health workers, particularly in countries where South Asians are an ethnic minority.

For example, many of us are familiar with Body Mass Index (BMI) as a measure of how healthy our weight is but BMI classification can be misleading for specific ethnic groups as it fails to recognise ethnicity related risks. A BMI of 18-25 Kg/m2 is widely considered ‘healthy’, but for South Asians, having a BMI of 23 or above raises the risk of adverse outcomes.

Furthermore, the notion that type 2 diabetes is a later onset disease must be viewed with caution for South Asians (and increasingly, in general, given the obesity epidemic). Ideally, South Asians should have their blood glucose monitored from the age of 25, so that early lifestyle intervention can prevent diabetes-related complications.

Whilst health professionals are increasingly being made aware of ethnicity-related health risks, mitigating the risk for type 2 diabetes requires ourselves, as South Asian individuals, to take responsibility for our health.

With signs of type 2 diabetes appearing in childhood and with insulin’s function being disrupted by excessive fat, we need to take precautionary measures, like maintaining a BMI of <23, controlling our calorie intake, monitoring blood glucose and learning to recognise the symptoms of diabetes.

The philosopher Erasmus once said, ‘prevention is better than cure’ but diabetes has no cure. Prevention is our greatest weapon, so what are you waiting for?