Hashimoto

Hashimoto’s Thyroiditis: A Complete Guide

Hashimoto’s thyroiditis is an autoimmune condition that affects the thyroid gland, often causing hypothyroidism (an underactive thyroid). It is the most common cause of hypothyroidism in the U.S., particularly affecting women.

What Is Hashimoto’s? Hashimoto’s is an autoimmune disorder where your immune system attacks the thyroid gland, leading to chronic inflammation and gradual destruction of thyroid tissue. Over time, this reduces your thyroid's ability to produce hormones.

Signs & Symptoms Symptoms often develop slowly and may be subtle at first:

  • Fatigue
  • Weight gain
  • Depression or anxiety
  • Cold intolerance
  • Hair thinning or hair loss
  • Dry skin
  • Constipation
  • Puffy face
  • Brain fog or memory issues
  • Irregular or heavy menstrual periods
  • Fertility issues
  • Slow heart rate
  • Swelling in the neck (goiter)

How Is It Diagnosed? Diagnosis involves a combination of lab tests and clinical symptoms:

  • TSH: Often elevated; most sensitive marker of thyroid status
  • Free T4: May be low in overt hypothyroidism
  • Free T3: Can be low or normal; reflects active hormone status
  • TPO Antibodies (TPOAb): Elevated in Hashimoto’s; confirms autoimmune cause
  • TG Antibodies (TgAb): Often elevated alongside TPOAb
  • Thyroid Ultrasound: May show irregular texture or shrinkage of the thyroid

Why TSH, Free T3, and Free T4 Can All Be High This may occur temporarily in early or fluctuating phases, known as Hashitoxicosis. The immune attack releases stored hormones into the bloodstream. Eventually, hormone levels drop and hypothyroidism becomes dominant.

What Causes Hashimoto’s?

  • Genetics
  • Environmental triggers (viruses, toxins, stress)
  • Hormonal changes (pregnancy, menopause)
  • Nutrient deficiencies (selenium, zinc, iodine imbalance)
  • Gut permeability ("leaky gut")
  • High estrogen with low progesterone ("estrogen dominance")

Diet & Lifestyle: What to Eat and Avoid Best Foods:

  • Anti-inflammatory foods (berries, leafy greens, olive oil)
  • Selenium-rich foods (Brazil nuts, sunflower seeds)
  • Zinc-rich foods (oysters, pumpkin seeds)
  • Lean protein, fish, bone broth
  • Gluten-free diet (may reduce antibodies in some)
  • Fermented foods for gut health

Foods to Limit/Avoid:

  • Gluten (especially if antibodies are high)
  • Dairy (linked to inflammation in some)
  • Soy (can interfere with thyroid absorption)
  • Ultra-processed foods
  • Excess iodine or seaweed

Supplements That Help

  • Selenium: 200 mcg/day to reduce TPO antibodies
  • Zinc: 15–30 mg/day to support T3 production
  • Vitamin D: Aim for 50–80 ng/mL levels
  • Magnesium: Supports hormone metabolism and sleep
  • Ashwagandha: May help regulate stress response
  • Probiotics: For gut health and immune balance
  • Iron (if low ferritin): Optimal >50 ng/mL for hair and energy

Exercise & Lifestyle Tips

  • Moderate-intensity exercise (walking, swimming, yoga)
  • Manage stress (cortisol dysregulation worsens autoimmunity)
  • Prioritize sleep (7–9 hours per night)
  • Avoid endocrine-disrupting chemicals: BPA, phthalates, parabens

Hormones Affected By Hashimoto’s

  • Low T3/T4: Primary hormones affected by the thyroid
  • High TSH: Pituitary tries to compensate for low thyroid hormone
  • Cortisol: Often elevated due to stress
  • Progesterone: May be low, contributing to estrogen dominance
  • Insulin resistance: Can occur with chronic hypothyroidism

What Happens if Untreated?

  • Goiter
  • Infertility or miscarriage
  • Heart problems (high LDL, bradycardia)
  • Myxedema (life-threatening low thyroid state)
  • Mental health disorders
  • Accelerated cognitive decline

Fun Facts

  • Hashimoto’s was first described by Japanese doctor Hakaru Hashimoto in 1912.
  • Hashimoto’s and celiac disease often overlap.
  • Many patients feel better on combination therapy (T4 + T3) vs. levothyroxine alone.

Final Thoughts Hashimoto’s is complex but manageable with the right support. Comprehensive testing, nutritional therapy, lifestyle changes, and when appropriate, hormone replacement can all dramatically improve quality of life.

If you have signs of Hashimoto’s or hypothyroidism, don’t wait—early diagnosis and treatment can make a world of difference.

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