How thyroid impacts heart health
The purpose of this post is to highlight the vital role of your thyroid in protecting your heart.
Most people appreciate that diet and exercise play crucial roles in managing cholesterol levels. However, few realize the significant impact that thyroid health can also have on cholesterol. Let's explore the intricate relationship between your thyroid and your cholesterol.
Understanding how your thyroid influences your cholesterol
Your thyroid gland, a small butterfly-shaped organ in your neck, produces hormones that regulate metabolism throughout your entire body. These hormones affect nearly every organ system in your body, including how your body processes cholesterol.
Here is how it happens:
- Thyroid hormones impact the LDL receptors in your liver which influence your ability to eliminate the cholesterol you no longer need. Thyroid hormones increase the expression of LDL receptors on your liver, which increase your ability to eliminate the cholesterol.
- LDL receptors on the liver are often compared to catcher’s mitts because they ‘catch’ the LDL, bring it to the liver for conversion to bile and then eliminate it via the stool, thus disposing of cholesterol.
- Note, anyone who’s on a PCSK-9 inhibitor (one of the newer medications to lower cholesterol) might be intrigued to know they work in a similar way - by increasing the number of LDL receptors on the liver (1).
- When thyroid function is low (hypothyroidism) there are fewer LDL receptors on the liver, which results in increased levels of LDL and total cholesterol in the blood.
- Thyroid hormones also influence cholesterol production by regulating HMG-CoA reductase, aka the rate-limiting enzyme involved in cholesterol synthesis.
- You’ve likely heard of people taking statins to lower cholesterol, right? Well, statins work by inhibiting HMG-CoA reductase enzymes. FYI - statins are ‘technically’ referred to as HMG-CoA reductase inhibitors.
- And, thyroid hormones influence cholesterol metabolism by enhancing the breakdown and removal of cholesterol from the body.
Therefore, when thyroid function is less than optimal you don’t break down or eliminate the cholesterol you no longer need very well, and you’re likely to make more of it too, which results in elevated total cholesterol, increased levels of LDL cholesterol, and higher triglyceride levels (2).
Research has shown that up to 13% of people with hypothyroidism also have high LDL cholesterol levels (2). The connection is so strong that most doctors now recommend thyroid testing for anyone newly diagnosed with high cholesterol (3).
Your thyroid plays a more significant role in heart health than you may realize. By understanding this connection, you can take a more comprehensive, functional medicine approach to managing your cholesterol levels and overall health.
5 practical steps to stay mindful of the crucial link between your thyroid & heart health (4):
- If you have a thyroid condition, monitor both thyroid and cholesterol levels regularly
- For hypothyroidism, thyroid hormone replacement therapy can significantly lower cholesterol levels in many patients (5). In some cases, cholesterol levels may return to normal once thyroid function is restored.
- If you’re newly diagnosed with high cholesterol, request thyroid testing
- The good news is that treating thyroid disorders often helps normalize cholesterol levels.
- If your cholesterol is elevated, and you want to minimize the need for medication(s), work with someone well versed in functional medicine to explore the underlying causes for the elevation.
- This thyroid-heart connection is a perfect example of functional medicine in-action, also referred to as a ‘root-cause’ approach. Rather than just diving straight in and endeavoring to improve the cholesterol profile we, as functional medicine practitioners, are trained to look for the underlying mechanisms involved, review the biochemistry, nutritional status and all the other factors (from stress management to sleep, to gastrointestinal function etc.) and we work address the reasons the numbers may be elevated in the first place.
- Know how to assess your thyroid status & how to interpret the test
- The primary way to evaluate your thyroid health is via a straight-forward, normal (no special lab required) blood test, where you assess thyroid stimulating hormone (TSH).
- The standard, normal, TSH range is between 0.45 - 4.5, which is a pretty wide range!
- FYI - You could have a TSH @ 4.4 and still be considered ‘normal’, but if you’re working with a functional medicine practitioner we prefer that number below 2.5.
- Note, many things can influence thyroid function, so I like my clients to just make note of it if it’s higher than 2.5 and then monitor it before jumping to the conclusion that it needs attention. This is a nuance that’s beyond the scope of this newsletter, and is worthy of further exploration and discussion with your medical provider/practitioner.
- Know how to optimize your thyroid health
- Optimize everything I refer to as the B.I.G. stuff - Blood Sugar, Inflammation, and Gastrointestinal Health. Note, each of these categories involve enhancing your food and lifestyle choices including your stress management strategies, sleep quality, minimizing exposure to toxins, etc.
Remember, a healthy thyroid is essential to a healthy heart!
References:
- Page, M. M. (2016). PCSK9 inhibitors - mechanisms of action. Australian Prescriber, 39(5), 164-167. doi: 10.18773/austprescr.2016.060
- High cholesterol & thyroid disease, WebMD, https://www.webmd.com/cholesterol-management/cholesterol-thyroid-disease
- Willard, D. L. et al (2014). Thyroid function testing in patients with newly diagnosed hyperlipidemia. JAMA Intern Med, 1; 174(2), 287-9. Doi: 10.1001/jamainternmed.2013.12188
- Wang, J-J. et al (2022). Assessment of causal direction between thyroid function and cardiometabolic health: A Mendelian randomization study. Journal of Geriatric Cardiology, 19(1), 61-70. doi: 10.11909/j.issn.1671-5411.2022.01.004
- Kotwal, A. et al (2020). Treatment of thyroid dysfunction and serum lipids: A systematic review and meta-analysis. Journal of Clinical Endocrinology Metabolism, 1; 105 (12). doi: 10.1210/clinem/dgaa672