Diabetes and Neuropathy
Our long standing war on diabetes in the United States is turning into more of a ‘massacre’. Diabetes is responsible for a vast number of secondary illnesses and disorders. Diabetic patients battle controlling their levels of glucose (or blood sugar) on a daily basis. As a result, they suffer from high levels of glucose in their blood over an extended period of time, which carries enormous consequences. When we look at the number of people afflicted with diabetes, we find that 60-70% of all diabetics will develop polyneuropathy. Researchers have long been studying how prolonged exposure to high blood glucose causes nerve damage.
With regards to neuropathies, chronically elevated glucose levels can damage blood vessels that carry oxygen and nutrients to the nerves. This can lead to anoxia, a lack of oxygen to the nerve cells and blood vessels, resulting in poor circulation and nerve damage. This is a large part of the reason that most neuropathy sufferers have, not only, pain but also, abnormal changes in the skin on the legs. These changes can include purple discolorations, extremely dry, flaky skin and extremely taunt skin. All are signs that the skin has lost proper circulation and thus oxygenation and nutrients; it also signifies that the skin is beginning to die.
New evidence correlates Metabolic Syndrome with small fiber damage leading to neuropathy.
Metabolic syndrome, also known as Metabolic Syndrome X, is the name applied to a group of risk factors that raises your risk for cardiovascular disease, stroke and diabetes. It is becoming more prevalent in the United States with each passing year. Researchers have found that one thing is for certain, all of the risk factors associated with metabolic syndrome are related to obesity.
The six conditions described below (taken from the ‘American Heart Association’ guidelines and NIDH) are metabolic risk factors. You must have at least three metabolic risk factors to be diagnosed with metabolic syndrome.
- Elevated Waist Circumference (Apple Shaped Body):
Men — greater than 40 inches (102 cm)
Women — greater than 35 inches (88 cm)
- Elevated triglycerides: Equal to or greater than 150 mg/
- Reduced HDL (“good”) cholesterol:
Men — Less than 40 mg/dL
Women — Less than 50 mg/dL
- Elevated blood pressure: Equal to or greater than 130/85 mm Hg or use of medication for hypertension
- Elevated fasting glucose: Equal to or greater than 100 mg/dL or use of medication for hyperglycemia
- Insulin Resistance: Hemoglobin A1C levels equal to or greater than 6.0
The tests that may be done to diagnose metabolic syndrome include the following:
- Blood pressure measurement
- Glucose test
- Hemoglobin A1c (HbA1c)
- HDL cholesterol level
- LDL cholesterol level
- Total cholesterol level
- Triglyceride level
The two most important risk factors for metabolic syndrome are:
- Extra weight around the middle and upper parts of the body, also known as central obesity.
- Insulin resistance
What is Insulin Resistance?
Insulin, a hormone made by the pancreas, helps the body get glucose into the cells. Glucose, a form of sugar, is the main energy source or fuel for the cells within your body, much like gasoline is to your car. During the process of digestion food is broken down into glucose, which then travels in the bloodstream to cells throughout the body. When glucose is circulating in the bloodstream it is called blood glucose, also known as blood sugar. After a meal, your blood glucose level rises signaling the pancreas to release insulin.
One of the actions of insulin is to cause the cells of the body, particularly the muscle and fat cells, to remove glucose from the blood by opening up a door or channel into the cell. Insulin has the ability to do this by binding to a specific receptor on the surface of the cell. Think of this receptor site as being a lock on a door and insulin is the key that unlocks the door, allowing it to open. Insulin (the key) slides into the lock (receptor site on a cell). If the lock is not damaged, the key should open the door to the cell, so that glucose get in. If the lock, (the cell receptor site) is damaged, the key may fit in but it will not turn and unlock the door. If this happens, glucose can’t get into the cell, where it can be used as energy. This leaves high levels of glucose circulating in the blood. We call this Insulin Resistance. With increased levels of glucose in the blood, the pancreas is signaled to produce more insulin in the hope that additional ‘keys’ may open the cell door. Once the cell is resistant to insulin, this will set off an alarm in the pancreas causing it to continually produce increased levels of insulin. Eventually, the pancreas will be unable to keep up to the demands of the body’s need for more insulin and it will fail. This will cause excess glucose to build up in the bloodstream, setting the stage for Type II Diabetes. If a person becomes insulin resistant and does not take the necessary steps to reverse it (and yes it can be reversed!), they will end up with diabetes. It’s not a matter of ‘If’ they develop diabetes but more a matter of ‘When’ they develop diabetes.
A study published in the ‘New England Journal of Medicine (2005) revealed the correlation between small fiber neuropathy and metabolic syndrome. One study involving 548 patients with type 2 diabetes showed that those with metabolic syndrome were twice as likely to have neuropathy as those without.
Research findings strongly suggest that even pre-diabetes is a risk factor for small fiber neuropathy. Neurons don’t require insulin for glucose uptake, therefore, diabetics accumulate excess glucose in their nerves. Glucose in nerve cells can cause free radical damage. It also causes a large decrease in multiple nutrients and anti-oxicants, such as vitamin C, Taurine, carnitine and inositol. All of these nutrients are necessary for nerve conduction and transmission. Elevated glucose levels also leads to a decreased production in Nitric oxide (NO). A lack of NO production often times leads to vascular impairment, or simply put, damage to blood vessels. This will take you down a path, leading directly to neuropathies ‘door’.
It is equally important to realize that glucose levels in the blood can spike to nerve-damaging levels after a meal, even if your fasting and average blood glucose levels remain below normal levels. Normal levels are currently considered to be below 100 for fasting blood plasma and below 6.0 for HGBA1c (hemoglobin A1c), the test commonly used to measure insulin sensitivity). Studies have shown that many of the cases of small fiber peripheral neuropathy with symptoms of tingling, pain and loss of sensation in the feet and hands are due to glucose intolerance found before a diagnosis of diabetes or pre-diabetes has ever been reached. This damage is much easier to reverse with diet, exercise and weight loss, particularly because it is in the very early stages of neuropathy.