Is there a link between hypothyroidism and chronic fatigue syndrome?

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Chronic fatigue syndrome

Chronic fatigue syndrome is a common disease marked by lengthy spells of weakness, fatigue and depression. Its diagnosis is predominantly based on symptoms and on ruling out any underlying medical condition, rather than on laboratory tests and physical examination. According to the Centers for Disease Control and Prevention (CDC), between 836,000 and 2.5 million people in the United States might currently live with chronic fatigue syndrome (CFS), which is also known as myalgic encephalomyelitis. Despite the fact that this condition is often tied to significantly decreased quality of life, many people do not get an official diagnosis, and those who do might not always receive adequate treatment; the causes of CFS are still unknown.That is why research about CFS is ongoing, with investigators striving to uncover the underlying biological mechanisms that characterize this condition.

What causes Chronic fatigue syndrome?

The cause of CFS is unknown. Researchers speculate that contributing factors may include:

viruses
a weakened immune system
stress
hormonal imbalances
It’s also possible that some people are genetically predisposed to develop CFS.

The relationship between hypothyroidism and chronic fatigue syndrome

New research demonstrates a link between chronic fatigue syndrome (CFS) symptoms and lower thyroid hormone levels. Published in Frontiers in Endocrinology, the study indicates that CFS, a condition with unknown causes, can be explained by lower thyroid hormones — but may be distinct from thyroidal disease. This finding can be seen as a first step to finding treatment for a debilitating illness for which there is no recognized treatment. Not surprisingly, many symptoms of hypothyroidism overlap with ME/CFS symptoms. They include (among others):

Fatigue
Weight gain
Depression
Brain fog and difficulty concentrating
Feeling cold (especially hands and feet)
Dry hair and skin
Thinning of the outer third of your eyebrows
Insomnia
Constipation

Low levels of thyroid hormones

In hypothyroidism, the thyroid gland — which is situated in the neck — is unable to produce enough thyroid hormones, which help with the regulation of many of the body’s metabolic functions. When not enough of these hormones are released, the body becomes more sluggish and is unable to function at its usual speed. Under such circumstances, to try to boost the thyroid gland’s activity, the pituitary gland — which is found at the base of the brain — releases higher levels of thyroid-stimulating hormone (TSH). The researchers behind the new study note that in CSF, as in hypothyroidism, the thyroid gland fails to release adequate levels of thyroid hormones. However, in this case, no extra TSH is released into the system. Following on from these clues, Ruiz-Núñez and colleagues inferred that CFS could manifest as a result of low thyroid hormone levels, independently from thyroidal disease. Remarkably, the CFS patients had lower serum levels of certain key thyroid hormones such as triiodothyronine (T3) and thyroxine (T4), but normal levels of thyroid-stimulating hormone.

These CFS patients, however, had relatively higher levels of another thyroid hormone called “reverse T3” or rT3. This appeared to be due to a shift in hormone production, where the body preferred to convert T4 to rT3 instead of producing T3. The low T3 levels found in CFS patients coupled with this switchover to rT3 could mean that T3 levels are severely reduced in tissue.

Further tests revealed that the participants with CFS had a lower urinary iodine status compared with their healthy counterparts. Low urinary iodine is associated with various deficiencies in the human body, as well as with thyroid gland-related issues.