South Asians have one of the highest risks of heart disease among all populations in the United States and Dr. Ronesh Sinha believes that he knows the reason why — insulin resistance.
“Insulin resistance is so common in South Asians that I now assume all South Asians are to some degree insulin resistant until proven otherwise,” the Indian American physician says in his new book, “The South Asian Health Solution.”
“Excess insulin causes most of the heart disease (major macrovascular complication) seen in South Asians,” he says. “You don’t have to be diabetic to develop these macrovascular complications. You can have perfectly normal blood sugar levels and still drop dead from a heart attack or become paralyzed by a stroke due to the more subtle signs of insulin resistance.”
Chapter headings in the book are arranged by topic and include inflammation and insulin resistance, cholesterol, blood pressure, body weight, fat and weight loss, the right carbohydrate approach for South Asians, exercise, approaches for energy, stress management, health for South Asian women and children, anti-aging and improving the health of the elderly.
“Obesity is a global health issue, but South Asians continue to lead the race to the top — or shall we say the bottom — of the health curve,” Sinha says in the book.
The Indian American physician, who practices at the Palo Alto Medical Foundation in Los Altos, Calif., has worked more than a decade with Silicon Valley companies to help their employees improve health outcomes.
He told India-West that genetic factors, a more sedentary lifestyle and diet all play their parts in increased incidence of heart disease among South Asian populations.
Increased insulin “makes blood vessels stiffer and causes them to retain more salt and water, thereby elevating blood pressure,” he says. “Elevated blood pressure damages the ECL (endothelial cell layer), which then promotes inflammation.”
Insulin resistance also increases triglycerides, lowers HDL (good cholesterol), and increases type B LDL cholesterol (the bad cholesterol that triggers inflammation), he points out in the book.
Many Indians are vegetarians, but a vegetarian diet can put people at even greater risk for heart disease, Sinha says, because of the consumption of large amounts of carbohydrates, which produce higher levels of fat, especially in the belly area.
“A characteristic feature of the South Asian diet is the abundance of carbohydrates, especially in the vegetarian diet,” he says. “The core of most South Asian diets is a combination of flat breads, rice and lentils. These foods alone are enough to promote excess fat deposition and insulin resistance in inactive South Asians.”
“The impulse (among South Asians and other ethnic groups) to overfeed family members and guests with excess carbohydrates, especially sweets, is an ingrained gesture of warmth and hospitality that goes beyond rationality,” he bluntly states in the book.
“Pregnant South Asian women are experiencing an epidemic of gestational diabetes (diabetes during pregnancy),” the book says.
“In fact, 30% to 60% of mothers with gestational diabetes will go on to develop adult onset diabetes after delivering their babies.”
South Asians in Silicon Valley are often riveted to their computers or other devices, leading to them serving as poor role models, Sinha, whose wife, Shally Sinha, is a pediatrician practicing in Fremont, told India-West.
“The sedentary epidemic is not just confined to adults, but has hit South Asian children, who often model their behavior after inactive parents,” he added.
“Virtually every South Asian patient I see has some degree of vitamin D deficiency, and the average levels tend to run much lower than those of most other ethnic groups. This is due to a combination of darker skin pigment and a predominantly indoor lifestyle,” he says in the book.
Another mistake, Sinha adds, is that the role of cholesterol is misunderstood, even among medical professionals.
“Most high-risk, insulin resistant South Asians have cholesterol levels lower than 200, because while a standard cholesterol test directly measures the amount of triglycerides and HDL in you blood, it does not measure the LDL cholesterol,” he says in the book.
Many of the foods with high cholesterol content, such as shrimp, eggs and meat, “typically have no adverse impact on cholesterol profiles and are far less harmful than the excessive carbohydrates prevalent in the South Asian diet.”
“High triglycerides latch onto HDL and LDL lipoproteins, turning them into oily, greasy, appetizing particles voraciously consumed by hungry enzymes called lipases (hepatic and endothelial lipases to be exact). Once lipases devour these LDL and HDL particles, they shrink in size, producing the smaller and dangerous type B LDL.”
“Triglycerides over 150 mg/dL and especially over 200 mg/dL are strongly associated with more dangerous type B LDL. Ignore the outdated ‘normal’ reference range on most standard lab reports that make 150 or 200 mg/dL the cutoff, and instead aim for a goal level of less than 100 mg/dL,” Sinha says.
“High triglycerides have become so common in South Asians that I once had a physician colleague tell me that he doesn’t worry unless the triglyceride level peaks at over 300! I call this high triglyceride desensitization. Just because high triglycerides are common, doesn’t mean such numbers are safe.”
Sinha puts forward a “metabolic 6-pack” of steps for people to follow to lower their risk of heart disease.
They are: 1) trim waist circumferences to less than 35 inches in males and 31 inches in females; 2) drop triglyceride levels to less than 100 mg/dL; 3) raise HDL cholesterol above 40 mg/dL for males and above 50 mg/dL for females; 4) reduce systolic blood pressure (the top number) at or below 120 and diastolic blood pressure (the bottom number) at or below 100 mg/dL; 5) decrease fasting blood glucose below 100mg/dL; and 6) get hs-CRP (highly sensitive C-reactive protein, a marker for inflammation) below 1.0 mg/dL.