HEALTH:
The Indian Paradox: Heart Disease and Indians
Immigrant Indians have the highest rates of coronary heart disease among all ethnic groups living in the United States. This is in spite of the fact that 50% of them are lifelong vegetarians. Most of them are also non-smokers, weigh less and have no higher cholesterol than their western counterparts. Yogesh Verma discusses some of the underlying reasons for this paradox.
India is a land of paradox. On the one hand, it’s a country with a lot of political violence; on the other hand, it’s also the world’s largest democracy. We worship Naari Shakti (woman power), yet many crimes are committed against women. Amid the starvation and malnutrition, urban India suffers from the rising burden of obesity. And then there is the “Indian Heart Disease Paradox.”
Most Indians living in the United States are conscious eaters who make deliberate efforts to maintain good health. Compared to our Western counterparts, we don’t eat as much meat (50% of the Indians living abroad are lifelong vegetarians) or smoke as much. We have a lower body mass index (BMI) and our cholesterol levels are no higher. Even so, we have the highest rate of coronary heart disease in the United States. Paradoxical, isn’t it?
Studies done in North America (Canada and the United States) and the United Kingdom show that Indians have the highest rates of coronary heart disease (CHD) of all ethnic groups. In the book Coronary Artery Disease the comparison is set out clearly: “The CAD rates among overseas Asian Indians worldwide are 50 to 400 percent higher than people of other ethnic origin irrespective of gender, religion, or social class.”
 In a study done from 1978 through 1985, data from about 13,000 participants in Northern California showed that Indians have four times more hospitalizations from coronary artery disease (CAD) than whites and six times more than Chinese people. The median age of first heart attack in Indians is 53 years, 10 years earlier than Westerners; the incidence of CAD in young Indians (under 50 years old) is about 12%–16%, higher than any other ethnic group; and about 5%–10% of heart attacks occur in Indian men and women younger than 40 years.
So why are Indians so susceptible to heart disease—and at such a young age—even though we fare well in all the conventional CHD risk metrics such as cholesterol levels, total fat consumption, smoking prevalence, and BMI? Is it our genes, or our diet, or perhaps our lifestyle? There is no clear-cut answer, but two key factors that predispose immigrant Indian populations to CHD are diet and stress.
The typical Indian diet comprises rice and wheat flour, along with lentils, vegetables, beans, and some dairy. Meat is an occasional indulgence. The biggest component of our calorie intake is carbohydrates—more specifically, carbs from wheat flour and rice.
(Above): Figure 1: Relative rates of hospitalizations for CAD in northern California for various ethnicities. [cadiresearch.org]
So what is the effect of a carb-rich diet on our metabolism? Carbohydrates get broken down into simple sugars in the gut then are absorbed in our blood. Our pancreas uses insulin to regulate the amount of sugar in our blood. Insulin is released in response to a surge of sugar, signaling the liver to convert the excess sugar into triglycerides and the fat cells to start storing the triglycerides. This is the primary mechanism for gaining fat; in fact, without insulin there would be no fat gain. People with untreated diabetes experience rapid weight loss even if they keep the same diet and lifestyle, simply because their pancreas is incapable of producing insulin.
When blood sugar spikes rapidly from a carb-rich meal, insulin is usually overproduced. After all the excess sugar is stored away as fat, the leftover insulin keeps storing the remaining blood sugar; your sugar level drops below normal so you feel low on energy and you get hungry. You eat another big carb meal and the whole process repeats. Over a period of years, the fat cells become resistant to the action of insulin, just as we become immune to traffic noise if we live by a highway. As a result, even more insulin is needed to do the same job.
At this point, a person is said to have developed insulin resistance or metabolic syndrome: their insulin and their glucose levels are simultaneously high. Metabolic syndrome is characterized by the following conditions: increased insulin levels, increased glucose levels, increased triglycerides and, increased abdominal fat.
The increased abdominal fat deposits happen because abdominal fat cells have four times as many insulin receptors as fat cells elsewhere in the body. Any free-floating triglyceride molecules most likely end up getting stored in the mid-section.
When left untreated, metabolic syndrome leads to Type 2 Diabetes, when the pancreas completely gives up producing insulin.
The second distinctive aspect of the Indian diet is our eating pattern. Typically we eat a light breakfast of some cereal or chai with toast. Lunch is somewhat bigger, with rice or roti and some vegetables, beans or lentils. Dinner is the biggest meal, followed by dessert. So how does this eating pattern affect our metabolism?
At this point it helps to know two concepts: Basal Metabolic Rate (BMR) and Activity Thermogenesis (AT). BMR is the minimum amount of energy required to sustain vital body functions. This is the amount of energy you burn even when resting or sleeping, so it’s also called resting metabolic rate (RMR). The activity thermogenesis is the amount of energy you burn doing daily activities, everything from picking up a spoon to washing your hands to exercising. Your daily calorie expenditure is a combination of BMR and AT. While BMR stays more or less constant throughout the day, AT expenditure depends on what you are doing at any given time. For most people AT is highest in the morning and tapers off as the day goes on.
Figure 2 shows our eating pattern and our glucose (or blood sugar) levels throughout the day. The first triangle represents a light breakfast: the blood sugar spikes slightly then is all used up as energy, as its well below the AT expenditure. The second triangle represents a moderate lunch: the red apex shows excess blood sugar beyond AT expenditure, which gets stored as fat. The third triangle represents a big dinner: all excess blood sugar beyond the AT expenditure ends up as stored fat.
(Above): FIGURE 2. Glucose response to a typical eating pattern for an Indian adult.
Put together overreliance on carbohydrates and our eating pattern and you get fat gain plus insulin resistance, leading to metabolic syndrome.
The current CHD metrics don’t capture the true risk of developing heart disease. Medical researchers now realize that better predictors of CHD risk are: Triglyceride levels, fasting glucose levels, and, waist to hip ratio (which captures real abdominal obesity, as opposed to BMI).
These are the exact three metrics Indians fail, which makes us susceptible to CHD. And all three of them point to a single cause: an overdriven carb/insulin response.
No wonder India is the diabetes capital of the world. According to the World Health Organization, cardiovascular disease is now the leading cause of death in India, accounting for 29% of all deaths (in 2005). With almost 100 million people affected, India is set to become the heart disease capital of the world. Two thousand people die of stroke every day.
On a closer look, the Indian Heart Disease Paradox isn’t a paradox at all!
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Yogesh Verma is a physicist working in San Francisco Bay Area, designing and manufacturing optics for military and aerospace applications. He is a health blogger at inutrifit.com. He lives in Pleasanton, Calif.
