<p><a href="https://peterattiamd.com/antoniobianco/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=251117-pod-antoniobianco&utm_content=251117-pod-antoniobianco-podfeed"> View the Show Notes Page for This Episode</a></p> <p><a href="https://peterattiamd.com/subscribe/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=251117-pod-antoniobianco&utm_content=251117-pod-antoniobianco-podfeed"> Become a Member to Receive Exclusive Content</a></p> <p><a href="https://peterattiamd.com/newsletter/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=251117-pod-antoniobianco&utm_content=251117-pod-antoniobianco-podfeed"> Sign Up to Receive Peter's Weekly Newsletter</a></p> <p>Antonio Bianco is a world-renowned physician-scientist and expert in thyroid physiology and metabolism. In this episode, Antonio explores the complex biology of thyroid hormone production, conversion, and regulation—highlighting how deiodinase enzymes modulate hormone activity at the tissue level and why that matters for interpreting lab results. He discusses the shortcomings of relying solely on TSH as a marker of thyroid function, the ongoing debate around combination therapy with T3 and T4 versus standard T4 treatment, and how genetics, tissue sensitivity, and individual variability influence thyroid hormone metabolism. The conversation also examines how hypothyroidism affects energy, mood, cognition, and longevity; why some patients remain symptomatic despite "normal" labs; and how future research could reshape treatment paradigms.</p> <p><strong>We discuss:</strong></p> <ul type="disc"> <li>How the thyroid produces, stores, and activates hormones like T4 and T3 to finely regulate thyroid activity [2:45];</li> <li>How fasting alters thyroid hormones to conserve energy [12:45];</li> <li>Action of the deiodinases: how D1, D2, and D3 enzymes control the activation and inactivation of thyroid hormones [19:15];</li> <li>The normal function of thyroid hormone and the roles of the hypothalamus, pituitary gland, and deiodinases in maintaining hormonal balance [23:30];</li> <li>Why understanding thyroid physiology is essential for proper diagnosis and treatment of hypothyroidism [33:45];</li> <li>Testing for thyroid hormones: understanding free vs. total levels, the limitations of current T3 assays, best practices, and more [36:00];</li> <li>Genetic and sex-based variability in thyroid hormone regulation and their limited clinical significance [43:45];</li> <li>Hyperthyroidism: causes, symptoms, diagnosis, and treatment options [46:00];</li> <li>Hypothyroidism: diagnosis and autoimmune causes of hypothyroidism [56:30];</li> <li>More on hypothyroidism: diagnostic biomarkers, antibody patterns, and non-autoimmune presentations [1:05:00];</li> <li>Thyroid hormone replacement therapy [1:15:15];</li> <li>More on thyroid replacement strategies: exploring the evidence gaps, mortality signals, effects on lipids, and more [1:28:00];</li> <li>Hypothyroidism basics: causes, antibody implications (including pregnancy), and how to make the diagnosis before choosing therapy [1:35:15];</li> <li>Thyroid medication: compounded controlled-release T3, brand name versus generic, and what Antonio prescribes to newly diagnosed hypothyroid patients [1:42:45];</li> <li>Redefining treatment success: why normalizing TSH isn't always enough for patients with hypothyroidism [1:54:45];</li> <li>Case studies: analysis of two unusual cases of thyroid disease [1:57:00];</li> <li>Dangers of supplementing with high levels of iodine, and female-specific risk of thyroid disease [2:05:45];</li> <li>Case study of a patient who presents with elevated TSH but no symptoms [2:09:30];</li> <li>How future research could reshape treatment, and Antonio's new book called "Rethinking Hypothyroidism" [2:13:15]; and</li> <li>More.</li> </ul> <p>Connect With Peter on <a href="https://twitter.com/PeterAttiaMD">Twitter</a>, <a href="https://www.instagram.com/peterattiamd/">Instagram</a>, <a href="https://www.facebook.com/peterattiamd/">Facebook</a> and <a href="https://www.youtube.com/channel/UC8kGsMa0LygSX9nkBcBH1Sg">YouTube</a></p>
Actionable Insights
1. Request Mass Spec for T3/rT3
When measuring T3 and reverse T3, request a mass spectrometry (LC-MS) assay instead of immunoassay, especially for low levels, due to its superior accuracy and reliability.
2. Measure Biologically Active T3
Advocate for measuring T3 (the biologically active thyroid hormone) when assessing thyroid function, as its omission reflects an incomplete understanding of thyroid physiology.
3. Rely on Labs, Not Just Symptoms
When evaluating for hypothyroidism, rely primarily on TSH and Free T4 lab results rather than symptoms alone, as many symptoms are non-specific and can be caused by other conditions.
If you have hypothyroidism, even when treated, consider it a risk factor for cardiometabolic disease and ensure regular monitoring of cholesterol, LDL, and signs of early cardiovascular disease.
5. Re-evaluate Therapy if Symptoms Persist
If you continue to experience symptoms despite normalized TSH and Free T4, discuss with your doctor that the current therapy may not be ideal and explore further options.
6. Advocate for Better Hypo Treatment
Advocate for improved hypothyroidism treatment, including the development of reliable mass spec T3 assays and pharmaceutical slow-release T3 formulations, to address patient suffering beyond just normalizing TSH.
7. Start Hypo Treatment with T4
For initial hypothyroidism treatment, start with T4 monotherapy (levothyroxine), assuming deiodinases are functioning optimally to convert T4 to active T3.
8. Address Comorbidities First
If T4 monotherapy is ineffective, first rule out and address other comorbidities (e.g., menopause, anemia) causing similar symptoms before considering combination T4/T3 therapy for hypothyroidism.
9. Consider Synthetic T4/T3 Combo
If T4 monotherapy is insufficient, consider synthetic T4/T3 combination therapy, which allows for adjusting the T4 to T3 ratio (ideally around 3.5-4:1) to optimize treatment.
10. Adjust TSH Range with Age
Recognize that the normal TSH range increases with age; for individuals over 50, an elevated TSH (e.g., 6 at 70, 8 at 80) may be considered normal and not require treatment.
11. Screen Pregnant Women for TPO
Pregnant women should be screened for TPO antibodies in the first trimester, and if positive, should be referred to a high-risk obstetrician due to increased risk of miscarriage and prematurity, even without overt hypothyroidism.
12. Avoid High-Dose Iodine
Avoid supplementing with excessive amounts of iodine (above 150-250 micrograms daily), as high doses can trigger autoimmune thyroid disease and hyperthyroidism in some cases.
13. Selenium/Vitamin D for Hashimoto’s
If you have Hashimoto’s disease, consider supplementing with selenium, vitamin D, or other antioxidants to potentially reduce TPO levels and prolong the thyroid’s natural function.
14. Monitor TSH with Family History
If you have a family history of hypothyroidism, a rising TSH, and positive TPO antibodies, monitor TSH every three months to make an early treatment decision, even if minimally symptomatic.
15. Diagnose Secondary Hypo by Low Free T4
If you suspect secondary hypothyroidism (normal TSH with symptoms), ensure your Free T4 is below normal; if so, pursue imaging of the pituitary or hypothalamus to rule out underlying issues.
16. Check FDA for Drug Recalls
Regularly check the FDA website for recalls on thyroid medications, including desiccated thyroid extract and levothyroxine, to ensure the safety and potency of your treatment.
17. Choose High-Volume Surgeons
When considering surgery, especially for specialized procedures like thyroidectomies, seek surgeons who perform a high volume of cases (e.g., at least 100 per year) to ensure expertise.
18. Discuss Post-Iodine Cancer Screening
If you’ve had Graves’ disease and received radioactive iodine treatment, consult your doctor about potential increased cancer risk and discuss appropriate additional cancer screenings.
19. Track Personal Baseline TSH
Keep records of your baseline TSH levels from when you were healthy, as this can serve as a personalized target if you develop hypothyroidism.
20. Ensure Daily Iodine Intake
Consume a reasonable amount of iodine daily through diet (e.g., seafood) or supplemented kitchen salt to support thyroid function.
21. Generic Levothyroxine is Comparable
Do not assume branded levothyroxine (Synthroid) is superior to generic versions; studies show comparable efficacy, and pharmacists may switch to generics without notification.
22. Normalize TSH, Free T4
The primary goal of thyroid hormone replacement therapy is to normalize TSH and Free T4 levels, aiming for biochemical euthyroidism, even if some symptoms persist.
23. Monitor for Co-Occurring Autoimmunity
If diagnosed with one autoimmune disease, be aware of the increased risk of developing other autoimmune conditions and discuss this with your doctor for comprehensive monitoring.
24. T3 Not for Hypo Diagnosis
Do not rely on T3 levels for diagnosing hypothyroidism, as the body prioritizes maintaining normal T3 even in early stages; focus on TSH and Free T4 instead.
25. Trust TSH, Free T4 Assays
Trust TSH and Free T4 immunoassay results, especially when consistently using the same lab, but be cautious with T3 and reverse T3 immunoassay results, particularly at low levels.
26. Master Physiology for Treatment
Deeply understand the underlying physiology of a condition to discern genuine therapies from potentially harmful or ineffective treatments.
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