Nicotine is a plant compound that contains both stimulant and relaxation properties when ingested. Common recreational uses of nicotine include cigarette and cigar smoking and the use of chewing tobacco. Regardless of the source, nicotine is linked to an increase in blood glucose levels, as nicotine impairs insulin action and prompts the body to make extra glucose. Because of these effects, nicotine use has an impact on blood glucose control, making it problematic for individuals with diabetes.
Nicotine Increases Glucose Production
Nicotine causes an increase in the body's production of catecholamines, which include hormones such as epinephrine and norepinephrine. These hormones are produced when the body is under emotional and physical stress. They affect the body in several ways -- increasing heart rate, blood pressure, breathing rate and blood glucose levels, while also causing the breakdown of fat and the increase of blood fat levels. Catecholamine production can also decrease appetite and increase the amount of calories burned -- which may help explain why weight gain is common when people stop smoking.
Nicotine Affects Insulin Action
Smokers who have diabetes are more likely than their non-smoking counterparts to have impaired insulin action, also known as insulin resistance. Nicotine use is linked to an increase in abdominal fat, which is another way it can interfere with the effectiveness of insulin. Insulin is the hormone that removes excess glucose from the blood, so impaired insulin action is a major cause of high blood glucose levels. Insulin resistance causes the body to make more insulin to keep blood glucose controlled, and if the body cannot keep up with this increased demand for insulin, blood glucose levels increase. This can lead to prediabetes and diabetes, and may aggravate blood glucose control in someone with pre-existing diabetes.
The Effects of Stopping Nicotine
The impact of nicotine on blood glucose levels doesn't stop when nicotine is discontinued. A January 2010 study published in "Annals of Internal Medicine" reported that individuals without diabetes who quit smoking still experienced an increased risk for diabetes for two years after they quit. This extended risk may be related to the insulin resistance caused by the weight gain that's common after smoking cessation, but other factors may also be involved. The good news is that after two years of being nicotine-free, the risk of developing diabetes gradually decreases until the 12-year mark, when no increased risk is observed.
Because of nicotine's impact on both metabolism and appetite, smoking has long been associated with weight control. While weight control is important in diabetes, nicotine is not an effective means -- the damaging effects of nicotine far outweigh the potential benefits of weight maintenance. Nicotine use can substantially worsen glucose control, making use of nicotine ill-advised for anyone who has diabetes. Because blood glucose levels and weight may be affected by smoking cessation, it’s important to discuss plans to quit with a doctor and work with a diabetes care team for help with nutrition and blood glucose management.