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Insulin Resistance
(General Information)
What is Insulin?
Insulin is a hormone secreted by the pancreas. It helps the body utilize blood
glucose (blood sugar) by binding with receptors on cells like a key would fit
into a lock. Once the key insulin- has unlocked the door, the glucose can pass
from the blood into the cell. Inside the cell, glucose is either used for
energy or stored for future use in the form of glycogen in liver or muscle
cells.
What is insulin resistance?
Insulin resistance occurs when the normal amount of insulin secreted by the
pancreas is not able to unlock the door to cells. To maintain a normal blood
glucose, the pancreas secretes additional insulin. In some cases (about 1/3 of
the people with insulin resistance), when the body cells resist or do not
respond to even high levels of insulin, glucose builds up in the blood resulting
in high blood glucose or type 2 diabetes. Even people with diabetes who take
oral medication or require insulin injections to control their blood glucose
levels can have higher than normal blood insulin levels due to insulin
resistance.
Why is insulin resistance in the news?
More and more people in the U.S. are becoming obese, physically inactive, or
both. Obesity and physical inactivity aggravate insulin resistance. Also,
people who are insulin resistant typically have an imbalance in their blood
lipids (blood fat). They have an increased level of triglycerides (blood fat)
and a decreased level of HDL (good) cholesterol. Imbalances in triglycerides
and HDL cholesterol increase the risk for heart disease. These findings have
heightened awareness of insulin resistance and its impact on health.
What is Syndrome X?
Another term heard in the news is Syndrome X. Syndrome X is a cluster of risk
factors for heart disease associated with insulin resistance. These risk
factors include: hypertriglyceridemia (high blood lipid), low HDL-cholesterol,
hyperinsulinemia (high blood insulin), often hyperglycemia (high blood glucose),
and hypertension (high blood pressure).
Who has insulin resistance?
Almost all individuals with type 2 diabetes mellitus (diabetes) and many with
hypertension, cardiovascular disease, and obesity are insulin resistant. These
diseases and conditions are predominantly found in countries with an improved
economic status such as the U.S. And in the U.S., these diseases and conditions
are among the leading contributors to morbidity and mortality. Also, about
20-25% of the healthy population may be insulin resistant.
What are the symptoms of insulin resistance?
There are no outward physical signs of insulin resistance. A glucose tolerance
test, during which insulin and blood glucose are measured, can help determine if
someone is insulin resistant. Many people who are insulin resistant produce
large enough quantities of insulin to maintain near normal blood glucose levels.
What causes insulin resistance?
No one knows for sure. Some scientists think a defect in specific genes may
cause insulin resistance and type 2 diabetes. Researchers continue to
investigate the cause. What we do know is that insulin resistance is aggravated
by obesity and physical inactivity both of which are increasing in the U.S.
Do all people with insulin resistance develop diabetes?
No. Science has not yet determined why some people with insulin resistance
eventually develop diabetes and others do not. By maintaining an appropriate
weight and a physically active lifestyle many individuals are able to reduce
their chances of becoming insulin resistant and developing diabetes.
What is the best diet for people with insulin resistance?
Research indicates that low fat diets may aggravate the effect of insulin
resistance on blood lipids. Therefore, for individuals who are insulin
resistant, a diet low in saturated fat (less than 10 percent of total calories)
and more moderate in total fat content (40% of total calories) may be
beneficial. This recommendation is different from the low-fat,
high-carbohydrate diet that many health organizations recommend to help prevent
heart disease. Specifically, they recommend decreasing fat intake to less than
30 percent of calories. Some groups recommend even lower levels of dietary fat.
It is also beneficial to maintain an appropriate body weight because obesity can
aggravate insulin resistance. To maintain an appropriate weight, regulate
caloric intake and maintain a physically active lifestyle. A registered
dietitian can assist with developing a proper diet plan for people with insulin
resistance, or a family history of type 2 diabetes.
Glossary
Blood Glucose -
Sugar in the blood that is used by the body cells for energy or stored as
glycogen for future energy needs.
Blood Lipid -
Fat that is present in the blood, includes triglycerides and cholesterol.
Cholesterol -
A waxy, fat-like substance produced by the liver and contained in selected foods
(e.g., egg yolks, coconut oil). Cholesterol is a form of lipid. The body
produces all the cholesterol it needs to function normally. 200mg/dl or less is
the desired blood level.
Glycogen -
Storage form for glucose in the body.
High Density Lipoprotein (HDL) -
Also called the "good" cholesterol because it removes cholesterol from the
bloodstream preventing it from accumulating in the vessels.
Insulin -
Hormone produced by the pancreas; essential for proper use of glucose in the
body.
Insulin Resistance -
Insulin resistance occurs when the normal amount of insulin secreted by the
pancreas is not able to remove glucose from the blood into the cells for use as
energy or storage for future use.
Low Density Lipoprotein (LDL) -
Also called the "bad" cholesterol because it carries most of the cholesterol in
the blood. If the LDL level is too high, cholesterol and fat can build up in
the arteries.
Pancreas -
Organ in the body that produces the hormone insulin.
Triglycerides -
One of the components of a lipoprotein (in addition to cholesterol and other
components). Triglycerides are the main constituents of stored fat.
Type 2 Diabetes Mellitus -
Often referred to as adult onset diabetes or noninsulin dependent diabetes
mellitus. Disease state in which glucose is not able to move efficiently from
the blood to the cells. There are two possible causes. First, the pancreas
produces enough insulin but the insulin is not effective in removing glucose
from the blood. Second, the pancreas eventually may not produce enough insulin
to properly remove glucose from the blood.
(From http://syndromex.stanford.edu)
See also
Insulin
Note:
This diabetes
health education project is supported
by Chong's Health Care at http://www.cljhealth.com, one of the leading companies in the discovery of
alternative
medicines for diabetes.
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