Insulin Resistance
Insulin Resistance
Insulin Resistance is the root of many health concerns, particularly those that ApoE4s are susceptible to. A person can be insulin resistant without being Type 2 Diabetic, but Type 2 Diabetes by definition includes insulin resistance. There are many factors which can play in to insulin resistance, but a person is particularly vulnerable to developing insulin resistance if they are sedentary and eat a poor diet.
Introduction to Insulin Resistance and associated terms
Blood Sugar - the amount of glucose present in the blood. Blood Sugar Glucose is the body’s primary source of energy. The body works to keep blood glucose regulated to a near constant level (metabolic homeostasis). Foods that greatly interrupt this homeostasis by rapidly increasing blood sugar are called high glycemic. Foods that are high glycemic tend to be those containing sugar and carbohydrates, especially simple carbohydrates, although excess protein will also raise blood sugar levels (gluconeogenesis).
Insulin – A hormone made by the pancreas that allows the body to use or to store glucose. When stored, it becomes fat. Fat is stored in fat cells, called adipocytes. Insulin works to keep the blood sugar steady, neither too high too high (hyperglycemia) or too low (hypoglycemia).
Type 2 Diabetes -- A metabolic disorder characterized by high blood sugar, insulin resistance, and low insulin. Also referred to as T2D or Type 2 Diabetes mellitus. In T2D, the pancreas doesn’t produce sufficient insulin because either the insulin resistance is too high or the ability of the pancreas to produce a compensating amount of insulin (compensatory hyperinsulinemia) reaches a point where it drops. Unlike Type 1 Diabetes, T2D is largely preventable (often associated with obesity) and even reversible, seeReversing T2D start guide. T2D is preceded by pre-diabetes.
Pre-Diabetes – A period of many years when the blood sugar level is higher than normal but not yet high enough to be type 2 diabetes. Without diet and/or lifestyle intervention, pre-diabetes will become T2 diabetes. During this long phase, the blood glucose levels slowly rise and insulin resistance similarly rises, but the body produces enough insulin to overcome this resistance, so blood glucose remains relatively normal.
Insulin Resistance – When the body’s cells fail to respond normally to insulin, they become “resistant” to the insulin hormone, leading to high blood sugar. In turn, the beta cells of the pancreas increase their production of insulin, contributing to a high blood insulin level. A person can be insulin resistant without having T2D. With insulin resistance, the fat cells expand to a point where they can’t get any bigger (adipocyte hypertrophy), they don’t get enough oxygen, they create inflammation, and the fatty acids look for other storage places, so they go into the abdominal cavity (visceral fat), other organs (liver, pancreas, kidneys), and muscle.
Insulin Sensitivity – When the body responds quickly to the effects of insulin and requires smaller amounts of insulin to lower blood glucose levels. Generally speaking, having good sensitivity to insulin is a sign of good health.
Non-Alcoholic Fatty Liver Disease (NAFLD) – Also referred to as Non-Alcoholic Steatohepatitis (NASH). A condition when a liver accumulates fat not due to alcohol which leads to abnormalities in liver function. This occurs under conditions of persistent high insulin. A fatty liver can precede Type 2 diabetes. If the liver becomes fat it becomes insulin resistant, so it’s not regulated by insulin appropriately, therefore throughout the night the liver secretes more and more glucose. When people with fatty liver wake up in the morning they will have high glucose even though they haven’t eaten for 8-10 hours. When the liver tries to decompress itself from fat, it makes triglycerides through de novo lipogenesis. A person with high triglycerides, low HDL, and small dense LDLs is likely to have fatty liver even if they are a lean/normal weight person.
TOFI – Thin Outside, Fat Inside. These are people who have a limited ability to store fat. They look thin, have acceptable Body Mass Index (BMI) level, but since they have limited capacity to store fat they can be horribly insulin resistant or T2 diabetic. It’s been hypothesized that everyone has a Personal Fat Threshold (PFT). When that PFT is exceeded, the development of T2D us likely. See Normal weight individuals who develop type 2 diabetes: the personal fat threshold Conversely, there’s also a small percentage of obese people who, through a process called hyperplasia just develop additional adipocytes (fat cells), thereby not reaching a PFT or developing insulin resistance or T2D.
Hemoglobin A1c – More commonly referred to as HbA1c or just A1c. This is a blood test which measures the average level of blood sugar (glucose) over the past 2 to 3 months.
HOMA-IR – Short for Homeostatic Model Assessment of Insulin Resistance, commonly referred to in medical literature. This is a method used to quantify insulin resistance and beta-cell function. It is calculated by taking the fasting glucose times fasting insulin divided by 405. (FG x FI/405) Desired range: 1.0 or lower. Over 2.5 is insulin resistance.
Type 1 Diabetes – (also known as Juvenile Diabetes, or insulin-dependent diabetes) When the body doesn’t produce enough insulin because its immune system is destroying the beta cells in the pancreas which is where insulin is made. The cause of Type 1 Diabetes is unknown.
Type 3 Diabetes – Not a medically recognized type of diabetes but an informal term for Alzheimer’s.
Oral Glucose Tolerance Test (OGTT) --. Common test used to diagnose diabetes and prediabetes by measuring the body's ability to use glucose. Involves fasting overnight, then the fasting blood sugar level is measured followed by consuming a sugary liquid drink and testing blood sugar levels periodically for the next two hours. This test has been debated within the ApoE4 forums for its comprehensiveness deferring to Dr Joseph Kraft’s test better accuracy in determining diabetes and prediabetes.
Dr Joseph Kraft – Referred to numerous times within the ApoE4 forums. Dr. Kraft’s test is similar to the oral glucose tolerance test (OGTT), but runs longer and adds insulin measurements. He found that 80% of those who had normal glucose responses had abnormal insulin responses. In other words, subjects who would be classified as “normal” under Fasting Glucose Tests, thereby not even progressing to an OGTT test, are not “normal” in their insulin response. For more info search see Dr Joseph Kraft or read his book "Diabetes Epidemic & You." Dr Catherine Crofts has also been referred to within the forums, she did her PhD work using Dr. Kraft's data. Discussions on both of these individuals can be found by using the advanced search function ApoE4.info Advanced Search Function..