Hypothyroidism is when the thyroid gland does not produce enough thyroid hormones to meet the needs of the body. The thyroid is underactive.
The opposite is hyperthyroidism, where the thyroid produces too much thyroid hormone. However, the link between hyperthyroidism and hypothyroidism is complex, and one can lead to the other, in certain circumstances.
Thyroid hormones regulate metabolism, or the way the body uses energy. If thyroxine levels are low, many of the body’s functions slow down.
About 4.6 percent of the population aged 12 years and above in the United States has hypothyroidism.
The thyroid gland is found in the front of the neck below the larynx, or voice box, and has two lobes, one on each side of the windpipe.
It is an endocrine gland, made up of special cells that make hormones. Hormones are chemical messengers that relay information to the organs and tissues of the body, controlling processes such as metabolism, growth, and mood.
The production of thyroid hormones is regulated by thyroid-stimulating hormone (TSH), which is made by the pituitary gland.
This, in turn, is regulated by the hypothalamus, a region of the brain. TSH ensures that enough thyroid hormones are made to meet the needs of the body.
Fast facts on hypothyroidism
Here are some key points about hypothyroidism. More detail and supporting information is in the main article.
The thyroid gland produces two thyroid hormones, TS3 and TS4.
These hormones regulate the body’s metabolism.
The most common cause of hypothyroidism in the U.S. is Hashimoto’s disease.
Symptoms of hypothyroidism include fatigue, cold intolerance, and joint and muscle pain.
Hypothyroidism refers to the underproduction of hormones in the thyroid gland. It has a wide range of symptoms.
Thyroid hormones affect multiple organ systems, so the symptoms of hypothyroidism are wide-ranging and diverse.
The thyroid creates two thyroid hormones, triiodothyronine (T3) and thyroxine (T4). These regulate metabolism, and they also affect the following functions:
heart and nervous system functions
Symptoms of hypothyroidism commonly include, but are not limited to:
slowed heart rate, movements, and speech
joint and muscle pain, cramps, and weakness
thin, brittle hair or fingernails
pins and needles
heavy periods, or menorrhagia
puffy face, feet, and hands
balance and co-ordination issues
loss of libido
recurrent urinary and respiratory tract infections
If left untreated, the following symptoms can manifest:
puffiness in the face
thinned or missing eyebrows
slow heart rate
If it develops in children or teenagers, the signs and symptoms are generally the same as adults.
However, they may also experience:
delayed development of teeth
poor mental development
Hypothyroidism develops slowly. Symptoms may go unnoticed for a long time, and they may be vague and general.
Symptoms vary a great deal between individuals, and they are shared by other conditions. The only way to obtain a concrete diagnosis is through a blood test.
Treatment for hypothyroidism focuses on supplementing the thyroid hormone.
To replenish levels, doctors usually prescribe synthetic thyroxine, a medication that is identical to the T4 hormone.
Dosage is determined by the patient’s history, symptoms, and current TSH level. Doctors will regularly monitor the patient’s blood to determine if the dosage of synthetic T4 needs to be adjusted.
Regular monitoring will be required, but the frequency of blood tests will likely decrease over time.
Iodine and nutrition
Iodine is an essential mineral for thyroid function. Iodine deficiency is one of the most common causes of goiter development, or abnormal enlargement of the thyroid gland.
Maintaining adequate iodine intake is important for most people, but those with autoimmune thyroid disease can be particularly sensitive to the effects of iodine, meaning that it can trigger or worsen hypothyroidism.
They should inform their doctor if they are sensitive to the effects of iodine.
People with hypothyroidism should discuss any major dietary changes with their doctor, especially when starting a high fiber diet, or eating lots of soy or cruciferous vegetables.
Diet can affect the way in which the body absorbs thyroid medication.
During pregnancy, iodine requirements increase. Using iodized salt in the diet and taking prenatal vitamins can maintain the required levels of iodine.
Iodine supplements are available for purchase online.
Hypothyroidism can normally be managed appropriately by following the advice of a qualified healthcare practitioner. With appropriate treatment, thyroid hormone levels should return to normal.
In most cases, medications for hypothyroidism will need to be taken for the rest of the patient’s life.
There is no way to prevent hypothyroidism, but people who may have a higher risk of thyroid problems, for example, women during pregnancy, should check with their doctor about the need for additional iodine.
Screening is not recommended for those who do not have symptoms, unless they have the following risk factors:
a history of autoimmune disease
previous radiation treatment to the head or neck
family history of thyroid problems
use of medications known to affect thyroid function
These people can be tested for early signs of the condition. If tests are positive, they can take measures to prevent the disease from progressing.
There is no evidence that a particular diet will prevent hypothyroidism, and there is no way to prevent hypothyroidism unless you live in a region with low iodine levels in the diet, for example, some parts of Southeast Asia and Africa.
No specific diet is recommended for hypothyroidism, but individuals should follow a varied, well-balanced diet that is not high in fat or sodium.
In addition, those with autoimmune Hashimoto’s may benefit from following a gluten-free diet. Research suggests a link between celiac disease and autoimmune thyroid disease, and both have inflammatory components. Avoiding gluten may help in nonceliac autoimmune diseases, but it is important to speak to a doctor first before cutting out foods that contain gluten.
Other foods and nutrients may be hazardous, especially if consumed in large quantities.
soya, as it can affect thyroxine absorption
iodine, found in kelp and other seaweeds, and in supplements, including some multivitamins
iron supplements, as they can affect thyroxine absorption
cruciferous vegetables, such as cauliflower, kale, and cabbage may contribute to a goiter, but only in very large amounts
Consuming additional iodine can interfere with the balance involved in treatment. If hyperthyroidism develops, iodine can be hazardous.