Can't lose weight? New research on thyroid may solve your problem
Posted Mar 23 2009 3:02pm
Diets rarely help people to lose weight permanently, so exercise gives you your best chance to lose excess weight and keep it off. However, some people cannot lose weight, no matter how much they exercise. Researchers at the University of Pittsburgh showed that overweight people who do not lose weight when they follow an exercise program are likely to suffer from low thyroid function, and therefore should be able to lose weight if they take thyroid hormones ( Medicine & Science in Sports & Exercise, February 2009). I think this is a very important study so this issue of the eZine is a little longer than usual.
When you eat, blood sugar levels rise. Your pancreas responds by releasing insulin into your bloodstream which drives sugar into cells where it can be used for energy. As you gain weight, fat cells fill with fat. This blocks insulin receptors so your cells cannot respond adequately to insulin and blood sugar rises to higher levels. This causes your pancreas to release even more insulin. Too much insulin can harm you. It acts on your brain to make you hungry, eat more and gain more weight. It constricts the arteries leading to your heart to cause heart attacks.
As I explained last week, muscles become extraordinarily responsive to insulin when you exercise so you need far less insulin to drive sugar from your bloodstream into cells. Insulin levels go way down with exercise, but the effect gradually tapers off in about 18 hours. So you have to exercise every day to maintain the benefit of lowered insulin levels, and overweight people who exercise every day usually lose weight.
However, some overweight people cannot lose weight no matter how much they exercise. This study shows that many of these people have low thyroid function which prevents the cells from responding to insulin and drives both insulin and blood sugar to very high levels.
Doctors do not diagnose low thyroid function by measuring thyroid hormone levels. Instead, they do a blood test called TSH that measures the brain's response to thyroid hormone levels. The brain produces TSH to stimulate the thyroid gland to make more thyroid hormone. TSH rises to high levels when the brain senses that there is not enough thyroid hormone in the body.
For many years, doctors have argued among themselves whether to treat people who have normal levels of thyroid hormones and very high levels of TSH (called subclinical hypothyroidism). This exciting new study shows that people who have high levels of TSH but have normal levels of thyroid hormone have muscles that do not respond to insulin adequately when they exercise. This means that they develop high levels of insulin and blood sugar, become overweight, diabetic, and often die of heart attacks.
If you are person who has extreme difficulty losing weight, ask your doctor to draw a blood test called TSH. If it is above 3.0, you probably will benefit from taking thyroid hormone. However, you must be careful not to take too much because overdoses of thyroid cause osteoporosis. Your thyroid dose should be adjusted to keep your TSH values between 0.3 and 3.0. Free weekly Fitness & Health eZine