Hypothyroidism is a condition in which the thyroid gland fails to produce enough hormone. The main function of the thyroid gland is to regulate the body's metabolism; it affects all parts of the body. Many of the symptoms of hypothyroidism are associated with other illnesses, and are often overlooked or misdiagnosed by physicians. Hypothyroidism is very common, although many people are unaware that they have hypothyroidism, and often go untreated for many years.
The thyroid gland is a butterfly-shaped organ situated on the front of the neck that secretes two hormones, thyroxine (also known as T4) and triiodothyronine (called T3), that are important in the control of metabolism. Hypothyroidism is a condition in which the thyroid gland does not produce adequate levels of these critical hormones.
Hypothyroidism is very common and is estimated to affect 3-5% of the adult population. It is more common in women than in men, and the risk of developing hypothyroidism increases with advancing age.
Hypothyroidism is most commonly a result of an autoimmune condition known as Hashimoto's thyroiditis, in which the body's own immune cells attack and destroy the thyroid gland. Since the activity of the thyroid gland is controlled by other hormones from the pituitary gland and the hypothalamus of the brain, defects in these areas can also cause underactivity of the thyroid gland. Previous surgeries on the thyroid or a history of irradiation to the neck are other causes of hypothyroidism.
Symptoms of hypothyroidism can be mild or severe, but are often very subtle. People with a mild form of the condition may not have any symptoms at all. The most serious form of hypothyroidism is called myxedema, which can lead to coma and even death. An underactive thyroid gland affects all organs and functions within the body, leading to both physical and emotional symptoms. Some of the most common symptoms of hypothyroidism in adults are:
Tiredness and weakness; feeling "run down"
Weight gain or difficulty losing weight
Constipation
Depression
Thinning or brittleness of the hair or nails
Cold intolerance
Sleepiness
Memory loss
Muscle aches and pains
Those affected by more advanced cases of hypothyroidism may notice dryness or thickening of the skin; slow speech; abnormal menstrual cycles; puffiness of the face, hands, or feet; and decreased capacity for taste and smell.
If you are experiencing symptoms of hypothyroidism, your doctor can order simple blood tests to diagnose the condition. An underactive thyroid gland is in most cases easily and completely treated by daily administration of thyroid hormones in tablet form.
Question: Hypothyroidism diet: Can certain foods increase thyroid function?
Is there any truth to the hypothyroidism diet? Can certain foods increase thyroid function?
Answer: Generally, there's no hypothyroidism diet. Although claims about hypothyroidism diets abound, there's no evidence that eating or avoiding certain foods will improve thyroid function in people with hypothyroidism.
If you have hypothyroidism, take thyroid hormone replacement as directed by your doctor — generally on an empty stomach. It's also important to note that too much dietary fiber can impair the absorption of synthetic thyroid hormone. Certain foods, supplements and medications can have the same effect.
Avoid taking your thyroid hormone at the same time as:
Walnuts
Soybean flour
Cottonseed meal
Iron supplements or multivitamins containing iron
Calcium supplements
Antacids that contain aluminum or magnesium
Some ulcer medications, such as sucralfate (Carafate)
Some cholesterol-lowering drugs, such as cholestyramine (Questran) and colestipol (Colestid)
To avoid potential interactions, eat these foods or use these products several hours before or after you take your thyroid medication.
With the exception of certain conditions, the treatment of hypothyroidism requires life-long therapy. Before synthetic levothyroxine (T4) was available, desiccated thyroid tablets were used. Desiccated thyroid was obtained from animal thyroid glands, which lacked consistency of potency from batch to batch. Presently, a pure, synthetic T4 is widely available. Therefore, there is no reason to use desiccated thyroid extract.
As described above, the most active thyroid hormone is actually T3. So why do physicians choose to treat patients with the T4 form of thyroid? T3 [liothyronine sodium (Cytomel)] is available and there are certain indications for its use. However, for the majority of patients, a form of T4 [levothyroxine sodium (Levoxyl, Synthroid)] is the preferred treatment. This is a more stable form of thyroid hormone and requires once a day dosing, whereas T3 is much shorter-acting and needs to be taken multiple times a day. In the overwhelming majority of patients, synthetic T4 is readily and steadily converted to T3 naturally in the bloodstream, and this conversion is appropriately regulated by the body's tissues.
The average dose of T4 replacement in adults is approximately 1.6 micrograms per kilogram per day. This translates into approximately 100 to 150 micrograms per day.
Children require larger doses.
In young, healthy patients, the full amount of T4 replacement hormone may be started initially.
In patients with preexisting heart disease, this method of thyroid replacement may aggravate the underlying heart condition in about 20% of cases.
In older patients without known heart disease, starting with a full dose of thyroid replacement may result in uncovering heart disease, resulting in chest pain or a heart attack. For this reason, patients with a history of heart disease or those suspected of being at high risk are started with 25 micrograms or less of replacement hormone, with a gradual increase in the dose at 6 week intervals.
Ideally, synthetic T4 replacement should be taken in the morning, 30 minutes before eating. Other medications containing iron or antacids should be avoided, because they interfere with absorption.
Therapy for hypothyroidism is monitored at approximately six week intervals until stable. During these visits, a blood sample is checked for TSH to determine if the appropriate amount of thyroid replacement is being given. The goal is to maintain the TSH within normal limits. Depending on the lab used, the absolute values may vary, but in general, a normal TSH range is between 0.5 to 5.0uIU/ml. Once stable, the TSH can be checked yearly. Over-treating hypothyroidism with excessive thyroid medication is potentially harmful and can cause problems with heart palpitations and blood pressure control and can also contribute to osteoporosis. Every effort should be made to keep the TSH within the normal range.