Everything You Need to Know About Thyroid and Heart Health

Most people have heard of butterflies in the stomach, but did you know that you have an actual butterfly-shaped gland in your neck? An estimated 20 million Americans have a thyroid disorder. What’s worse, approximately 60 percent of people with thyroid disease have no idea they have it! This is concerning because thyroid disorders can significantly impact overall health. It might be a small gland, but the thyroid has a huge impact on the heart. 

What is the thyroid?

Many people associate the thyroid gland with weight, attributing extra unwanted pounds to an underactive thyroid. While the thyroid does regulate the body’s metabolism, this tiny gland also does so much more. 

The thyroid sits towards the front of the neck, right below the voice box. It’s approximately 2 inches long. A small strip of tissue called the isthmus connects the two symmetrical lobes. 

Part of the endocrine system, the thyroid gland produces hormones that influence many functions throughout the body. Thyroid hormones have many jobs, including: 

  • Regulating heart rate, blood pressure, and breathing
  • Controlling body temperature
  • Regulating metabolism, affecting weight loss and gain
  • Influencing the speed of digestion 
  • Assisting with menstrual cycles
  • Helping growth and muscle strength 
  • Influencing cholesterol levels 
  • Impacting the nervous system 

How does the thyroid work?

The thyroid uses iodine from food to produce two primary hormones: 

  • Triiodothyronine (T3)
  • Thyroxine (T4)

Two important endocrine glands control the thyroid in the brain: the hypothalamus and the pituitary gland. First, the hypothalamus tells the pituitary gland to release thyroid-stimulating hormone (TSH). In turn, TSH tells the thyroid how much T3 and T4 to release. 

A healthy thyroid will keep the T3 and T4 levels balanced, helping the body stay in homeostasis. 

Thyroid malfunctions

Sometimes the thyroid runs into trouble and doesn’t work the way it’s supposed to. Thyroid disorders can range from inflammation to cancer, although most dysfunction occurs due to an imbalance in hormone production. The two most common thyroid disorders are: 

Hyperthyroidism is when a person’s thyroid is overactive, releasing too much T3 and T4 into the bloodstream. Too much thyroid hormone speeds up the body. The most common form of hyperthyroidism is Grave’s disease. Individuals with hyperthyroidism may experience: 

  • Nervousness or irritability
  • Anxiety
  • Sweating
  • Racing heart
  • Brittle hair and nails 
  • Tremors
  • Sleeping difficulty
  • Muscle weakness 
  • Frequent urination and bowel movements 
  • Weight loss
  • Lighter menstrual cycles  
  • Initial energy, followed by exhaustion 

Hypothyroidism is a condition where a person’s thyroid underperforms. As the production of T3 and T4 slows, so do the body’s functions. Hashimoto’s disease is an autoimmune disease of the thyroid that causes hypothyroidism. Symptoms of hypothyroidism include: 

  • Slow heart rate
  • Excess fatigue
  • Dry skin and hair 
  • Intolerant to cold temperatures 
  • Constipation 
  • Weight gain
  • Puffy face/bags under eyes
  • Depression 
  • Raised cholesterol 
  • Memory difficulties 
  • Heavier, longer menstrual cycles 

Can the thyroid cause heart problems?

Thyroid hormones impact all body systems, including essential cardiac and vascular functions. Malfunctions of the endocrine system can cause ripple effects for the cardiovascular system and beyond. 

As you might expect, hyperthyroidism results in over-excitability of the heart. In addition to a fast heart rate (tachycardia), an overactive thyroid can lead to high blood pressure and arrhythmias, such as AFib. Heart palpitations are one of the most common symptoms of hyperthyroidism, and many with the disease go on to develop atrial fibrillation. When left untreated, hyperthyroidism can lead to heart failure. 

In untreated hypothyroidism, the heart muscle may not pump as vigorously. As a result, blood vessels stiffen, and blood pressure rises. Over time, the heart weakens, which can lead to heart failure. Further, as all body systems slow, the liver clears less cholesterol from the blood, resulting in more circulating LDL cholesterol in the body. Higher levels of LDL cholesterol may increase the risk of heart disease. People with hypothyroidism are also at risk for electrical dysfunctions of the heart, such as prolonged QT intervals. 

Individuals with cardiac symptoms or lipid abnormalities should carefully evaluate their thyroid. Those with over or underactive thyroid symptoms should watch for signs of heart disease and get their cholesterol checked. 

Will taking cholesterol-lowering drugs help my thyroid?

Cholesterol has gotten a bad rap over the years, but it’s essential for many functions that contribute to thyroid health. For example, cholesterol helps form the cell membrane of the thyroid, builds receptors for thyroid hormones throughout the body, and helps the pituitary gland function well. 

Cholesterol-lowering statin drugs may cause more harm than good. Statins have been shown to falsely lower TSH, increase the risk of thyroid cancer, and lower CoQ10. Not only that, cholesterol-lowering drugs have significant side effects. Therefore, it’s best to treat hypothyroidism directly, and the cholesterol will respond accordingly. 

How can I tell if my thyroid is working correctly? 

When thyroid problems are suspected, most doctors order only a thyroid-stimulating hormone (TSH) test. While this is an appropriate first step, it does not tell the whole picture. The thyroid itself does not produce TSH, so this test may not clearly depict what’s happening in the body. A thorough thyroid evaluation should include the following blood labs: 

  • TSH
  • T3
  • T4
  • Free T3
  • Reverse T3
  • Thyroid antibodies

How can I improve my thyroid health?

There are many ways to ensure that your thyroid functions optimally. Adding the following foods to the diet will improve thyroid health:

  • Sea vegetables such as wakame, nori, dulse, and kelp
  • Wild-caught shellfish such as shrimp, clams, and oysters
  • Brazil nuts
  • Grass-fed organ meat such as liver, kidney, heart, and even thyroid itself
  • Avocado
  • Fish such as sardines, anchovies, and wild salmon 

In one of the first studies to examine the impact of diet on thyroid function, scientists recently discovered that eating foods high in saturated fats and protein is associated with better thyroid function. On the other hand, foods high in sugar harm the thyroid. Isn’t it interesting that the same foods good for the heart are beneficial for the thyroid? 

Next steps

Maybe you’ve noticed your heart beating quickly or skipping a few extra beats. Perhaps you’ve been more anxious than usual. Or maybe you’ve been exhausted, and your blood pressure is a bit high. 

You might be wondering if you have a cardiac condition. While contacting your doctor should be your first step, you might want to ask for a review of your heart and thyroid. If a thyroid imbalance is to blame, addressing the root cause might help reduce or eliminate the cardiac symptoms.

Eat Well · Live Well · Think Well 


Medical Review 2022: Dr. Lauren Lattanza NMD

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