Insulin increases heart disease risk
Insulin's effects on cardiovascular risk factors
As a 'healthy diet' which raises blood glucose is eaten, the raised glucose forces a rise in levels of insulin in the blood. This is not a healthy progression for the following reasons. Insulin:
- increases risk of thrombosis (blood clots),
- increases arterial plaque formation (the 'furring up' of arteries leading to heart attacks and strokes),
- prevents plaque regression,
- stimulates connective tissue synthesis and also stimulates the production of insulin-like growth factor 1 (IGF-1).
- Insulin levels both before and after meals raise systolic and diastolic blood pressures significantly.
- Insulin increases blood pressure by forcing the kidneys to retain sodium and by enhancing the flow of sodium and calcium into artery walls.
- Insulin also damages the walls of blood vessels, increasing permeability of the capillary walls leading to the smaller blood vessels and capillaries leaking and rupturing.
All of these factors increase the risk of a heart attack and stroke.
Many studies have demonstrated that a breakdown of the
endothelium
, the inner lining of arteries and veins, occurs early in the insulin-resistant
state and can predict future cardiovascular events. Similarly, insulin
resistance has been associated with the metabolic syndrome, which also
increases the risk of adverse cardiovascular outcomes.
Chronic high levels of insulin in the blood are a consequence of the chronic
high levels of blood glucose found in a person eating a '
healthy diet
'.
This insulin damage cannot occur in a person who eats a low-carbohydrate,
high-fat diet.
References
1. Meigs JB, Mieeleman MA, Nathan DM, et al. Hyperinsulinemia, hyperglycemia, and impaired hemostasis. The Framingham offspring study. JAMA 2000; 283:221-229.2. Rosen Q. Serum insulin-like growth factors and insulin-like growth factor-binding proteins: clinical implications. Clin Chem 1999; 45: 1384-90.
3. DeFronzo RA, Eleuterio F. Insulin resistance: a multifaceted syndrome responsible for NIDDM, obesity, hypertension, dyslipidemia, and atherosclerotic cardiovascular disease. Diabetes Care 1991; 14: 173-91
4. Pyorala M, et al. Hyperinsulinemia and the risk of stroke in healthy middle-aged men: the 22 year follow-up results of the Helsinki Policemen Study. Stroke 1998; 29: 1860-1866.
5. Kamide K. et al, Insulin resistance is related to silent cerebral infarction in patients with essential hypertension. Am J Hypertens 1997; 10: 1245-1249
6. Biessels GJ. Cerebral complications of diabetes: clinical findings and pathogenic mechanisms. Neth J Med 1999; 54: 35-45
