Insulin in Type 2 Diabetes may be harmful. Why? Because natural insulin levels in Type 2 Diabetes are typically high until the very late stages. High insulin levels develop as a result of insulin resistance, which is the root cause of Type 2 Diabetes. Simply put, insulin resistance means your own insulin becomes less effective in doing its job. In response to this insulin resistance, the pancreas produces more and more insulin. This large amount of insulin is not good for your body as explained below.
Now if you start taking insulin shots, you increase your insulin levels a whole lot more. It is like adding fuel to the fire!
Is Insulin Produced in Type 2 Diabetes?
Simple answer is YES. However, there may an occasional thin Type 2 diabetic who does not produce enough insulin.
Unfortunately, many patients wonder if insulin is produced in Type 2 diabetes. This confusion is understandable because Type 2 diabetic patients may presume their body does not produce insulin and that’s why they take insulin shots. However, most likely their pancreas is producing insulin in high amounts, but insulin resistance is so severe that even a high level of natural insulin is unable to control their blood sugar. Typically, a physician wants to control your blood sugar without paying any attention to your insulin resistance. As a result, most patients require ever increasing doses of insulin to control their blood glucose levels. Unfortunately, their insulin resistance continues to worsen due to lack of its treatment.
Please understand that insulin shots DO NOT treat insulin resistance.
Harmful Effects of Too Much Insulin in Type 2 Diabetes
Numerous scientific studies show that high levels of insulin in Type 2 Diabetes may have harmful effects.
High Insulin in Type 2 Diabetes May Increase Blood Pressure
A high level of insulin in Type 2 Diabetes may cause high blood pressure. Several researchers have confirmed this association between high insulin levels and the development of high blood pressure.(1)
Elevated Insulin in Type 2 Diabetes May Cause Narrowing of Blood Vessels
A High level of insulin in Type 2 Diabetes may cause narrowing of the blood vessels, including the coronary arteries. In this way, high insulin is associated with coronary artery disease. This association has been documented by several excellent clinical studies—The Helsinki Policeman Study (2), the Paris Prospective Study (3), and the Danish Study (4).
How Can Insulin Cause Heart Disease?
Insulin stimulates the growth of muscle cells in the walls of the arteries. Consequently, there is thickening and stiffness of arterial walls. The net result is narrowed blood vessels (5).
High blood pressure – due to high insulin – further adds to the narrowing of the blood vessels. Narrowed blood vessels set the stage for heart attacks and strokes.
High Insulin in Type 2 Diabetes May Cause Growth of Cancer
A high level of insulin in Type 2 Diabetes may lead to the growth of cancers. Why? Because insulin causes growth. Several clinical studies have shown a high prevalence of cancer in people with insulin resistance, especially cancer of breast, colon, and prostate.
An excellent, large clinical study, known as the Nurses Health Study (6) documented a relationship between insulin resistance and breast cancer. This study included 111,488 American female nurses who were free of cancer in 1976. These was a follow-up through 1996 for the occurrence of Type 2 Diabetes and through 1998 for the development of breast cancer. Researchers discovered a higher incidence of breast cancer in women with Type 2 Diabetes, as compared to those who did not have diabetes.
Another study – from the University of Texas M.D. Anderson Cancer Center in Houston – showed that Type 2 diabetics on insulin were 5 times more likely to develop pancreatic cancer compared to those who did not use insulin. On the other hand, Metformin – a drug that treats insulin resistance – reduced the risk for developing pancreatic cancer by 62%. (7)
Why Insulin Shots in Type 2 Diabetes May be Harmful
Now imagine if a typical obese Type 2 diabetic patient – who is already producing a large amount of insulin as a result of insulin resistance – starts to take insulin shots to control elevated blood sugars. Usually, you need large doses of insulin to control high blood sugars in obese Type 2 diabetic patients. Giving large doses of insulin in these individuals is like adding fuel to the fire, isn’t it? That patient is already at high risk for heart disease, hypertension and cancer growth due to a high insulin level. Adding more insulin may control elevated blood sugar, but will increase the risk for high blood pressure, heart attack and cancer. The reverse is also true: If you treat Type 2 diabetes by treating its root cause, insulin resistance, then you can reduce the risk of heart attack and cancer.
Other Harmful Effects of Insulin Shots in Type 2 Diabetes
Insulin also causes weight gain, retention of water and low blood sugar (hypoglycemia). As you are aware, low blood sugar can be life-threatening.
The myopic approach to control blood sugar by insulin can be disastrous for many Type 2 diabetic patients because most Type 2 diabetic patients already have high levels of insulin. Their blood sugars are high due to a very high level of insulin resistance, not because their body does not produce insulin. Insulin shots do not treat insulin resistance, but simply add to the already high levels of insulin. Then, high levels of insulin may contribute to many other complications: Low blood sugar, high blood pressure, swelling of feet, weight gain, heart disease, stroke and cancer risk.
An occasional thin patient with Type 2 diabetes may need a small dose of insulin.
You must never stop insulin or any other medication, without consulting your health care provider.
Be aware this article is about Insulin in Type 2 Diabetes and not in Type 1 diabetics. Patients with Type 1 diabetes depend on Insulin Treatment to survive for the rest of their life.
- Manicardi V, Camellini L, Bellodi G, Coscelli C, Ferrannini E. Evidence for an association between high blood pressure and hyperinsulinemia in obese men. J Clin Endocrinol Metabolism 1986; 62(6):1302–4.
- Pyorala K., Savolainen E, Kaukola S, Haapakoski J. Plasma insulin as coronary heart disease risk factor: relationship to other risk factors and predictive value during 9 1/2-year follow-up of the Helsinki Policemen Study. Acta Med Scand Suppl 1985; 701:38–52.
- Eschwege E, Richard JL, Thibult N, et al. Coronary heart disease mortality in relation with diabetes, blood glucose and plasma insulin level. The Paris Prospective Study, ten years later. Horm Metab Res Suppl 1985; 15:41–46.
- Moller LF, Jespersen J. Fasting serum insulin level and coronary heart disease in a Danish cohort: 17-year follow-up. J Cardiovasc Risk 1995; 2:235–240.
- Despres J-P, Lamarche B, et al. Hyperinsulinemia as an independent risk factor for ischemic heart disease. N Engl J Med 1996; 334:952–957. Salomaa V, Riley W, Kaark JD, et al. Non–insulin dependent diabetes mellitus and fasting insulin concentrations are associated with arterial stiffness index, the ARIC study. Circulation 1995; 91:1432–1443. 239
- Michels KB, Solomon CG, Hu FB, et al. Type 2 diabetes and subsequent incidence of breast cancer in the Nurses’ Health Study. Diabetes Care 2003; 26:1752–1758.
- Li D, Yeung SC, Hassan MM, Konopleva M, Abbruzzese JL. Antidiabetic therapies affect risk of pancreatic cancer. Gastroenterology. 2009 Aug;137(2):482-8