Part I of a two-part series

Most people know that smoking cigarettes is a bad habit, but they may not know how it can lead to type 2 diabetes, Dr. Janette Wheat, University of Arkansas at Pine Bluff associate professor and Cooperative Extension Program human development specialist, said.

Insulin helps blood sugar enter cells, but nicotine changes cells so they don’t respond to insulin, which increases blood sugar levels, she said. Also, chemicals in cigarettes harm cells and cause inflammation which makes cells stop responding to insulin. And lastly, those who smoke tend to have a higher risk of belly fat, which increases the risk for type 2 diabetes even if they are not overweight.

According to a Centers for Disease 2019 report, smokers are 30 to 40 percent more likely to get type 2 diabetes than nonsmokers; the more one smokes, the higher the risk.

The CDC says insulin is key in developing type 2 diabetes. This vital hormone, that humans cannot survive without, regulates blood sugar (glucose) in the body, Dr. Wheat said. In a nutshell, here is how it works.

Food eaten is broken down into glucose which enters the bloodstream and signals the pancreas to release insulin. The insulin helps glucose enter cells so it can be used for energy and also signals the liver to store glucose for later use. Glucose enters cells, and glucose levels in the bloodstream decrease signaling insulin to decrease, too. Lower insulin levels alert the liver to release stored glucose so energy is available even if one hasn’t eaten for a while.

“That is how it is supposed to work,” Dr. Wheat said. “But, the system can quickly get out of whack.” Here’s what happens, according to the CDC when the system goes awry.

A lot of glucose enters the bloodstream so the pancreas pumps more insulin to get glucose into cells. Over time, cells stop responding to all the insulin and become insulin resistant. The pancreas keeps making more insulin to try to get cells to respond. Eventually, the pancreas can’t keep up and the glucose keeps rising.

“Breaking the smoking habit is one of the best things you can do to become more healthy. Managing diabetes is challenging, and smoking can make it more so,” Dr. Wheat said. “Nicotine increases blood sugar levels and makes them harder to handle. People with diabetes who smoke often need larger doses of insulin to keep their blood sugar close to target levels.”

Diabetes causes serious health complications such as heart disease, kidney failure, blindness and nerve damage often leading to amputation of a toe, foot or leg.

“If you have diabetes and smoke, you are more likely to have complications, and they will be more severe,” Dr. Wheat said, adding that over time, high blood sugar from diabetes can damage blood vessels as well as nerves in and around the heart. Cigarette smoking can damage blood vessels, too, by increasing plaque that builds up on artery walls.

Ideally, Dr. Wheat said, one should quit smoking. No matter how long someone has smoked or how much, quitting will help them be healthier. The CDC reports that as soon as one stops, their body begins healing itself. In 20 minutes, heart rate and blood pressure drops. In 12 hours, carbon monoxide in blood drops to normal, Dr. Wheat said. In two weeks to three months, circulation and lung function improve and in a year the risk for heart disease is half of someone who smokes.

Quitting smoking also helps a body use insulin better which can make blood sugar levels easier to manage, the doctor said.   

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