Thyroid Trouble or Pre-Diabetes? Why Your A1C Might Be Lying to You

Thyroid Trouble or Pre-Diabetes? Why Your A1C Might Be Lying to You

If you’re a woman in midlife and just got lab results showing thyroid issues and a rising A1C, this episode is a must-read. Whether you’re premenopausal or postmenopausal, it’s more common than you think—and far too often misunderstood by conventional care.

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💥 What’s Going On When Thyroid & A1C Are Both Off?

You're doing everything "right"—eating well, exercising regularly, staying consistent. Then your blood work comes back and it knocks the wind out of you:

• TSH is high

• TPO antibodies are present

• And your A1C is suddenly 5.9, 6.1… maybe even 6.4

This suggests you’re pre-diabetic—or worse—diabetic, even though your fasting blood glucose looks perfectly normal.

What gives?

Let’s break it down.

🧠 Why Low Thyroid Can Raise A1C 1️⃣ Slowed Glucose Clearance

Thyroid hormones—especially T3—help your body move glucose out of your blood and into your cells. When your thyroid is sluggish, glucose lingers longer in the bloodstream, raising your A1C.

2️⃣ False-High A1C from Red Blood Cell Turnover

• A1C is your 3-month blood sugar average, based on how much sugar sticks to your red blood cells.

• Hypothyroidism slows red blood cell turnover, so they live longer and pick up more sugar.

• This creates a falsely elevated A1C even if your actual blood sugar is low.

🔎 Example: One woman had a blood glucose of 85 but an A1C of 6.1%. Her thyroid was sluggish, which explained the mismatch.

3️⃣ Increased Insulin Resistance

Low thyroid can impair insulin sensitivity in muscle and fat cells, meaning glucose doesn’t get cleared as easily, and more stays in circulation. Result? A higher A1C.

4️⃣ Impaired Liver Metabolism

Your liver converts T4 to T3. A sluggish thyroid impairs this conversion and slows liver glucose regulation. The result is even more chaos in your blood sugar balance.

🧪 Key Thyroid Labs to Watch Lab What It Means Ideal Range TSH Stimulates thyroid hormone 1.0–2.0 mIU/L Free T3 Active hormone for metabolism, mood, energy Higher end of normal Free T4 Storage form of thyroid hormone Should be adequate for T3 conversion Reverse T3 Blocks Free T3 activity Should be low TPO Antibodies Signals Hashimoto’s Should be undetectable  

👉 High TPO antibodies = Hashimoto’s risk 👉 TSH high + Free T3 low = classic underactive thyroid

📉 How Hashimoto’s Plays Into It

Hashimoto’s is an autoimmune thyroid condition, common in midlife women. Your body attacks its own thyroid tissue, often triggered by:

• Gluten sensitivity

• Gut permeability (leaky gut)

• Stress and nutrient deficiencies

💡 Tip: Gluten-free is often essential for Hashimoto’s. Your immune system may attack gluten—and mistakenly attack your thyroid because the tissue looks similar.

🍬 What About A1C? A1C % What It Means < 5.7% Normal 5.7–6.4% Pre-diabetic 6.5%+ Diabetic  

🛑 BUT: If your glucose is normal (85–95) and your A1C is elevated, don’t panic yet. Check your thyroid—it may be giving you a false high A1C.

🧬 What To Do If This Is You

1. Ask for these labs in your next blood panel:

   • Free T3

   • Free T4

   • TSH

   • TPO antibodies

   • A1C

   • Fasting insulin (not typically included—ask for it!)

2. Track your blood sugar using a CGM or monitor like Stelo This will confirm your real-time glucose levels.

3. Support your thyroid and metabolism through:

   • Adequate protein intake

   • Smart resistance training

   • Healing your gut (especially if Hashimoto’s is present)

   • Key nutrients: Selenium, zinc, iodine, magnesium, vitamin D

4. Consider a functional medicine doctor or endocrinologist if your primary provider doesn’t address the thyroid–A1C connection.

🧘‍♀️ You’re Not Broken. You’re Just Not Being Told the Full Story.

I see this every single month—fit, responsible women being told they’re pre-diabetic without an accurate explanation.

This podcast—and my programs—are here to help educate, clarify, and empower. If this resonated with you, visit www.JLCstrong.com to:

✅ Explore my self-study programs ✅ Sign up for updates on my next live coaching round of Mastering Midlife ✅ Learn how to read your own labs and reclaim your body confidence

 

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