Insulin is well-known as the blood sugar hormone, the one linked to diabetes. But it is much more than that. It is also an important hormone for heart health that influences a wide range of other hormones. Understanding insulin’s relationships and functions can help you map out ways to enjoy better health.
Insulin And Blood Sugar
You may already know that insulin is the hormone made by the pancreas for blood sugar management. Insulin is critical for controlling the rate at which blood sugar enters the cells of your body.
Every type 1 diabetic knows well that insulin is what keeps them alive, as necessary as water and air. Because all your cells must have glucose (sugar) to function, you also must have functioning insulin as well as cells that are sensitive to its impact. Type 1 diabetes occurs when the pancreas cannot make enough insulin to keep blood sugar under control.
When the cells of the body’s tissues become resistant to insulin, they are vulnerable to the disease known as type 2 diabetes. In this condition, insulin levels rise in the blood, but the cells lack sensitivity to the hormone’s presence and do not take up sugar.
Insulin And Your Heart Health
Metabolic syndrome  is called the “insulin resistance syndrome” and also a “prediabetes” condition. However, equally important to its effects on blood sugar are its relationships to cardiovascular disease. Cardiovascular disease and diabetes are linked through insulin resistance, obesity and inflammation. Metabolic syndrome is indicated by the presence of:
- Insulin resistance: Determined by finding high fasting insulin levels in the blood. You must ask for this test in addition to your standard lab work if you are at risk. (I’ll discuss this in greater detail in future articles.)
- Glucose intolerance: Determined by a fasting and then a one-hour post-glucose load blood sugar test.
- Lipid abnormalities: High triglycerides, low HDL cholesterol and high LDL cholesterol.
- Hypertension: If you have high blood pressure, get screened for high blood sugar and lipid abnormalities.
- Abdominal obesity: Also called VAT (visceral adipose tissue).
- Sedentary lifestyle: Limited physical activity contributes to VAT.
- Poor diet: Eating mainly processed, refined and otherwise nutrient-devoid foods.
- Elevated serum indicators of inflammation: C-reactive protein, fibrinogen or plasminogen activator inhibitor-1 level.
- Signs of early aging.
Metabolic Syndrome Alert
All of these factors play into a diagnosis of metabolic syndrome; but you probably haven’t heard as much about this condition as you have about heart disease, diabetes or cancer.
Here’s the important point about metabolic syndrome: We know that it takes time for disease to develop, so why wait until it is manifest to start reversing it? For example, a meta-regression analysis of published data from 20 studies of 95,783 individuals followed for 12.4 years was reported in a 1999 issue of Diabetes Care. The researchers concluded that there is a risk of heart attack even from minimally elevated blood sugar, well below the threshold for diabetes. 
Disease that will manifest five or 10 years from now has already started to develop today. The good news is that there are ways to detect it by analyzing your medical history, signs, symptoms and, of course, lab work. But few physicians think this far ahead in their assessments. It’s up to you to think ahead. I’ll teach you what to look for.
Insulin And Obesity
The two main risk factors for metabolic syndrome are abdominal obesity and insulin resistance. The accumulation of abdominal fat is proven to actively promote cardiovascular disease, hypertension, type 2 diabetes, high blood cholesterol and metabolic syndrome.  Compared with subcutaneous fat (below the skin), fat predominately in the belly is far more predictive of ill health. The fat cells (adipocytes) secrete bioactive substances called adipocytokines that cause inflammation. These adipocytokines — which include visfatin, tumor necrosis factor-alpha, plasminogen activator inhibitor type 1 and heparin binding epidermal growth factor — are major contributors to the development of diabetes mellitus and cardiovascular disease. 
Inflammatory foods like refined sugars, refined oils and other junk food stimulate the activity of adipocytokines. Also, it has been proven that as your belly fat expands, it expands the activity of disease-promoting chemicals even further.
Conversely, you can turn off adipocytokines by consuming nutrient-rich, whole, mostly raw food. And by reducing your waist circumference to normal size, you improve the sensitivity of cell receptors to insulin and allow glucose to enter the cells to be used.
The most accurate way to correlate your susceptibility to health risks from body fat is to measure your waist circumference. That more accurately shows your vulnerability rather than body mass index (BMI).
Bottom line: A healthy, flat belly is not just for looks — it’s worth years of life!
Insulin And Other Hormone Functions
Your adrenal gland hormones are affected by too much insulin in your bloodstream (hyperinsulinemia). High insulin levels and abdominal obesity contribute to more cortisol production, thus down-regulating your sex steroid production. In addition, high insulin levels cause SHBG (sex hormone binding globulin) to preferentially bind to testosterone, thus lowering your available free (effective) testosterone hormone. This becomes more significant as you age when your adrenal glands become the major source of sex hormone production.
Additionally, increased cortisol levels suppress melatonin levels, leading to poor sleep, cravings for comfort foods and poor energy levels. They also restrict serotonin levels, causing depressed mood, anxiety, sugar cravings and that sluggish sensation of feeling too fat.
Even your thyroid hormone is decreased by too much insulin in the bloodstream. Much like the other hormones, increased cortisol causes your thyroid hormone function to be reduced. First, your TSH from the pituitary gland decreases; also you get slowed conversion from T4 to more active thyroid hormone, T3; and you increase your reverse T3, the version of T3 that inhibits normal T3 at the receptor sites of your tissue cells.
Furthermore, when your thyroid hormone function is reduced, it slows the conversion of cholesterol to pregnenolone and impacts all the other sex steroid hormones while your insulin resistance increases.
Insulin And Other Conditions
You should also consider that these chronic conditions are linked to high insulin levels and insulin resistance:
- Polycystic ovary syndrome
- Cancer (breast, colon and others)
- Non-alcoholic fatty liver disease
- Elevated Liver Function tests (AST/ALT &/or GGT)
- Obstructive sleep apnea
I hope you see that insulin is not just a concern for diabetics. It’s for all of us who are aging. In my next article I’ll cover what tests to have when looking for early indicators of insulin resistance and metabolic syndrome.
All the best in your pursuit to feeling good for life,
Michael Cutler, M.D.
Easy Health Options
 American Heart Association website at http://www.americanheart.org/presenter.jhtml?identifier=4756
 Coutinho M, et al.The relationship between glucose and incident cardiovascular events. Diabetes Care, 1999. 22(2): p. 233-40.
 Despres JP. Is visceral obesity the cause of the metabolic syndrome? Ann Med. 2006;38(1):52-63.
 Matsuzawa Y. The metabolic syndrome and adipocytokines, FEBS Letter, 2006 May 22;580(12):2917-21.