Thyrotoxicosis, Hyperthyroidism and Obesity

Hyperthyroidism takes place when the thyroid gland makes too much thyroid hormone. This condition is often referred to as an overactive thyroid. (1) As one of the most important organs in the body’s endocrine system, the thyroid gland is located in front of the neck just below the larynx. (2) The endocrine system is a complex set of glands and organs in the body which release hormones that regulate a lot of things, but mainly metabolism. (3) The various organs involved are the thyroid, brain, heart, liver, pancreas, pituitary glands and hypothalamus, just to name a few. (4)

Thyrotoxicosis is a term used for a thyroid crisis (or a storm), which can severely increase hyperthyroidism symptoms due to infection or stress. Fever, decreased mental alertness, and abdominal pain may occur and emergency care is required immediately. (5)

Radioactive iodine treatment for hyperthyroidism can cause obesity

Hyperthyroidism happens when too much hormones are released from the thyroid over a very short (acute) or long (chronic) period of time. (6) Mostly, hyperthyroidism is caused by a variety of diseases, but some links have been made between obesity and this condition of the thyroid. Weight gain can follow treatment of hyperthyroidism with radioactive iodine. (7) A recent clinical trial showed that in over 82% of patients from a sample of about 1159, radioactive iodine treatment for hyperthyroidism caused them to gain weight. Males, those with severe hyperthyroidism and people with prior weight loss are more susceptible to weight gain as a result of radioactive iodine treatment.

Insulin resistance in hyperthyroidism treatment

The way this mechanism works is important to understand, because of its implications for dietary and lifestyle choices. The radioactive iodine that is used to treat hyperthyroidism can cause insulin resistance in the patients. (8) It is important to understand the consequence of insulin resistance, because it is one of the precursors and main factors in developing type 2 diabetes. (9) Insulin is normally released by the pancreas and the intestines in a healthy human body and it serves a number of purposes, but the main ones to do with obesity and metabolic disorder are the regulation of blood-sugar and the regulation of cholesterol. (10) In many ways, insulin is a ‘messenger molecule’ that tells other molecules in the body what to do. When a person becomes insulin resistant, then their body is no longer able to regulate blood-sugar properly and this excess of triglycerides begins to be converted to stored body-fat. (11) Likewise, an insulin-resistant person cannot regulate their cholesterol and levels of this may go soaring or may be too low, depending on each patient’s unique situation. (12)

Insulin resistance, over an extended period of time, can cause type 2 diabetes mellitus. (13) The body becomes completely immune to the effects of insulin and the pancreas gives up. This can also cause severe problems in the pancreas, as well as cancer. So not only is there a risk of gaining weight following radioactive iodine treatment for hyperthyroidism, but excessive obesity due to insulin resistance can lead to a spiral that eventually is the path to diabetes.

Reversing obesity and balancing hormones

In metabolic syndrome, which is a disorder of many different parts of the metabolism, of which the most visible sign is obesity, there are a large number of organs and hormones at work. Any imbalance in this system can lead to severe problems. First, it is not only the pancreas and insulin that plays a part. The liver creates triglycerides and cholesterol, but it can do so in excessive amounts due to a poor diet based entirely on sugar and carbohydrates. (14) Excessive amounts of blood-sugar can cause hypertension and even hardening of the arteries (atherosclerosis). High- or low cholesterol is also a huge risk that comes with imbalances in the endocrine system and metabolism. Additionally, excess body-fat releases too much of the hormones leptin and adipocytokines which are responsible for regulating appetite and other functions. (15) When all of these hormones are out of balance, performing far more functions than they are supposed too for the person’s body-type and height, then serious metabolic disorders can result.

The link back to the thyroid

The thyroid is an organ or a gland that is part of the endocrine system. (16) It is very easy to let the endocrine system get out of balance due to improper diet and lack of exercise. Overweight and obese people are known to have fertility issues, which are the result of hormone imbalances brought on by excess body-fat. (17) Once one part of the endocrine system is compromised, it has an effect on the other parts too.

It is important to understand that the thyroid is primarily responsible for regulating metabolism. (18) Because of this, any disorders in the metabolism due to insulin resistance, out of control cholesterol, high blood-sugar levels and high leptin and adipocytokine levels can have negative feedback on the thyroid as well. The thyroid is also responsible for regulating growth and development, so especially in children a proper diet and regular physical activity is important for proper thyroid function and proper development. (19)

Genetic link

Although problems with the thyroid are usually genetic, they can be related to other factors as well. Children born with thyroid problems or with a non-functioning thyroid can undergo immediate surgery and also live for the rest of their natural lives, but they need to take thyroid medication to supplement the hormones that are supposed to be produced by the thyroid. (20) These people also have a higher chance of developing insulin resistance and type 2 diabetes, because of the effects of radioactive iodine on insulin in the body.

But if there is nothing wrong with your thyroid and you are overweight, then consider losing weight as soon as possible. Losing weight and regular exercise will return your body to the ideal body mass index for your height and allow you to enjoy a longer life free of the risk of diabetes, heart disease and other worse illnesses related to the metabolism and endocrine system.