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What if your headaches, brain fog, and mood changes could be linked back to low thyroid levels? You may not know that for some people, hypothyroidism is the cause of these symptoms, along with other surprising symptoms.

The thyroid gland produces hormones involved in regulating metabolism, energy, and overall well-being. However, these hormones’ influence goes far beyond the better-known physical signs like weight gain, brittle hair, or feeling cold. Many people are unaware that low serum thyroid hormone levels can also impact the central nervous system (CNS) and affect you mentally.

Understanding the connection between hypothyroidism and the CNS helps us recognize neurologic changes you may think are caused by something else. In this article, we’ll discuss CNS symptoms to look out for and ways to improve your thyroid function and health.

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The brain and spinal cord make up your central nervous system. The brain and spinal cord work together to serve the following essential functions:

• Detection: When your body feels a sensation like the pain from stubbing your toe, a message travels across nerve cells (neurons) up your spinal cord and to your brain.
• Reception and perception: Your brain receives these messages and perceives them as touch, taste, smell, sight, or sound. It can even receive multiple messages at once.
• Integration: In a fraction of a second, your brain combines messages from different parts of your body and integrates them to prepare a response.
• Response: After processing a message, your brain sends a response back through your spinal cord and peripheral nerves to react. For example, you are scrunching up your toes in pain after stubbing them.

Any change in how your body functions may interrupt your CNS. In one study, participants recently diagnosed with hypothyroidism saw a change in nerve response during testing. This suggests your CNS is affected, even in the early stages of hypothyroidism.

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We know the thyroid and the hormones it releases affect several body systems. But how do changes in your thyroid levels affect the brain and spinal cord? What are the mechanisms of thyroid hormone in relation to the CNS? Knowing how thyroid hormones interact with them helps answer this question.

Thyroid hormones and the blood-brain barrier

A highly selective barrier called the blood-brain barrier (BBB) surrounds and protects your brain. This barrier prevents most substances in the bloodstream from entering the brain tissue where it doesn’t belong. But, thyroid hormones are essential for proper brain function and have unique mechanisms to cross the BBB.

Thyroxine (T4), the inactive form of the hormone, relies on specific transporters in the cells of the BBB to enter the brain tissue. Once inside the brain, T4 is converted into the active form triiodothyronine (T3).  The activated T3 can then directly enter neurons through targeted transporters and enter your tissues where needed.

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The action of thyroid hormone on the CNS begins before birth. Studies have found babies born to women with maternal thyroid hormone deficiency hypothyroidism have a higher risk of seizure disorders, attention deficit hyperactivity disorder (ADHD), autism spectrum disorder, and other brain development problems and psychiatric conditions. Testing for and treating thyroid disorders during pregnancy could help prevent these changes.

For adults, much of the research on thyroid hormones and the CNS focuses on its effect on the brain. For instance, one study shows that these hormones influence the brain’s ability to form new and modify existing connections, which is crucial for learning and memory.

Another review of multiple studies shows several thyroid hormone-related changes in the adult brain. These included:

• Research shows that hypothyroidism can interfere with neurotransmitters or chemical messengers responsible for communication between neurons in your brain and spinal cord, leading to slowed neural transmission. This is the result of segmental demyelination of peripheral nerves, the loss of myelin from specific segments or regions along myelinated nerve fibers.
• Increased oxidative stress and inflammation make it more likely to develop Alzheimer’s.
• Changes to how genes are expressed can impact your brain.

Hypothyroidism has also been shown to cause problems with visual processing. Specifically, it can lead to:

• Prolonged latency: This means it takes longer for the visual system to respond to visual stimuli. The time it takes for the brain to detect and process visual information is delayed.
• Decreased amplitude: The strength or intensity of the brain’s electrical response to visual input is reduced. The brain’s signals related to vision are weaker than normal.

When this occurs, you may notice changes in your mood, cognition, behavior, movements, and other neurologic manifestations. Balancing thyroid hormones may help avoid or reverse the signs and symptoms of changes to your central nervous system.

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Understanding the impact thyroid hormones have on the function of the CNS highlights the importance of keeping their levels at goal. Even subclinical hypothyroidism, where thyroid levels are only slightly lower than normal, could lead to significant neurological symptoms.

In a small study, individuals with hypothyroidism showed changes in their brain’s structure and function. Pictures taken of their brains found a reduction in the size of the hippocampus, the area of the brain that controls learning, emotion, and memory. Researchers believe this could explain the changes in memory patients with hypothyroidism often experience.

The Rotterdam study found a decrease in blood flow to the brain in patients with hypothyroidism. This could increase the risk of strokes, dementia, and Alzheimer’s’ affecting memory, mood, and movement.

For patients with autoimmune Hashimoto’s disease, hypothyroidism can lead to inflammation in the brain and spinal cord. A case report found that this inflammation affects several functions, can slow cognitive function, and adversely affects mood and behavior.

Your Guide To The Genetics Of Thyroid Function

Knowing your risk for thyroid disease can help you stay in front of complications. Learn in this guide how genes impact your risk for hypothyroidism.

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Now that we know the role thyroid hormones play in supporting the CNS, what are the effects of hypothyroidism on the CNS? What symptoms should you watch for if your thyroid hormone levels are low? Some common symptoms of hypothyroidism may point to changes in your thyroid, such as cold intolerance or developing a swollen thyroid gland. On the other hand, other non-specific CNS symptoms could be related to many health conditions.

Non-specific neurological symptoms seen in hypothyroidism include:

• Anxiety
• Brain fog
• Depression
• Dementia
• Difficulty concentrating
• Fatigue
• Headaches
• Insomnia
• Memory problems
• Mood swings
• Movement disorders
• Seizures

Some people may experience just one or a combination of these symptoms, ranging in severity.  Usually, these symptoms will continue until the underlying problem is treated. The good news is if your symptoms are caused by hypothyroidism, they may be reversed with treatment!

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For many people, replacing your thyroid hormones is enough to get rid of unwanted signs and symptoms of hypothyroidism. Depending on your thyroid levels and the severity of symptoms, your healthcare provider may prescribe thyroid hormone replacement medication. Your options include a synthetic form of the T4 hormone, called levothyroxine, a combination of levothyroxine, and a synthetic form of T3, known as liothyronine, or natural desiccated thyroid, known as NDT. 

You should work with a healthcare provider to determine the best medication. There’s no one-size-fits-all approach. What’s most important is finding the right dose of thyroid medication to help you manage your symptoms. Regular check-ins and monitoring will help you find the safest dosage of the best medication for you, ensuring your body receives the amount of thyroid hormone it needs.

If your levels don’t support starting medication, talk with your healthcare provider about natural ways to increase your thyroid levels. Making changes to your diet, managing stress, and getting enough sleep can be just what you need.

THYROID GUIDE

Stress 101: How to Avoid a Flare-Up

Practical tools to lower your chance of an autoimmune flare-up due to stress.

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The connection between your central nervous system and hypothyroidism is complex. But you don’t have to figure it out on your own. Paloma Health providers are here to help you live your best life with proper hypothyroidism management.

The CNS-related symptoms discussed in this article could come from several health conditions, including the thyroid. Testing your thyroid levels could, therefore, be a significant step on the way to relief. Order your Paloma Health at-home testing kit today to find out how well your thyroid functions! Each blood test kit painlessly uses a drop of blood from a fingerpick to measure common thyroid biomarkers. A review of your test results will determine if you need further evaluation by a thyroid specialist.

Paloma Health is committed to taking a patient-centered approach to your overall well-being. We offer a team of healthcare professionals who provide an integrative approach to optimize your thyroid function. Book a free consultation today to get you started on the path to living well.

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