How to Raise Thyroid Levels Naturally - 7 Evidence-Based Methods

Quick Summary

Learn how to raise thyroid levels naturally using diet, supplements, lifestyle changes, and targeted protocols. Evidence-based strategies for optimizing TSH, free T3, and free...

You feel tired all the time-no matter how much sleep you get. Your hair is thinning, your skin feels dry, and you're gaining weight despite eating less. Your doctor tests your thyroid and says it's "borderline" or "subclinical hypothyroidism"-not severe enough for medication, but enough to make you feel lousy.

Your thyroid is more important than you've been told: it doesn't just control metabolism. It regulates energy production in every cell, influences brain function, maintains body temperature, and affects nearly every hormonal system in your body.

What most people don't realize is that when thyroid levels are suboptimal-even if they're technically "within range"-you feel it everywhere.

This is where targeted thyroid optimization can help. Understanding how to naturally support thyroid function through nutrition, supplementation, stress management, and lifestyle changes can help you reclaim your energy, mental clarity, and metabolic health.

Let's break down the 7 most effective methods- ## What Are Thyroid Levels?

Your thyroid gland produces two primary hormones:

• T4 (thyroxine): The inactive form, about 93% of thyroid output

• T3 (triiodothyronine): The active form, about 7% of thyroid output

TSH (thyroid-stimulating hormone) is produced by your pituitary gland and signals your thyroid to make more hormones. High TSH usually means your thyroid is underactive (hypothyroidism).

Optimal ranges (not just "normal"):

• TSH: 0.5-2.5 mIU/L (functional range, vs. lab range of 0.4-4.5)

• Free T4: 1.0-1.5 ng/dL (upper half of range)

• Free T3: 3.2-4.4 pg/mL (upper third of range)

• Reverse T3: <15 ng/dL (inactive form that blocks T3)

• TPO antibodies: <35 IU/mL (thyroid peroxidase-checks for autoimmunity)

The reality is that "normal" lab ranges are too broad. Research shows that TSH above 2.5 mIU/L is associated with increased cardiovascular risk and metabolic dysfunction, even if it's technically "within range" [1].

Why Does Hypothyroidism Happen?

Root causes of low thyroid function:

1. Nutrient Deficiencies

Your thyroid needs specific raw materials to produce hormones:

• Iodine: Essential for T4 and T3 synthesis

• Selenium: Required for T4-to-T3 conversion

• Zinc: Cofactor for thyroid hormone production

• Iron: Needed for thyroid peroxidase enzyme function

• Vitamin D: Supports thyroid receptor sensitivity

Deficiency in any of these nutrients can slow thyroid hormone production, even if your thyroid gland is healthy [2].

2. Chronic Stress and High Cortisol

When cortisol stays elevated, it suppresses TSH production and reduces T4-to-T3 conversion. Instead, your body produces more reverse T3 (rT3), an inactive form that blocks thyroid receptors. This is why you can have "normal" thyroid labs but still feel hypothyroid-your active T3 is being blocked [3].

3. Hashimoto's Thyroiditis (Autoimmune)

The most common cause of hypothyroidism in developed countries. Your immune system attacks thyroid tissue, gradually destroying hormone production. This is why testing TPO antibodies and thyroglobulin antibodies is critical-you might have Hashimoto's years before TSH rises above the "normal" range [4].

4. Poor T4-to-T3 Conversion

Even if your thyroid produces enough T4, you might not be converting it to active T3. Causes include:

• Chronic inflammation (elevated hsCRP)

• Gut dysbiosis and intestinal permeability

• Heavy metal exposure (mercury, lead)

• Medications (beta-blockers, steroids, birth control)

• Low-calorie diets or fasting

About 80% of T3 is produced from T4 conversion in the liver, kidneys, and gut-not the thyroid itself [5].

5. Environmental Toxins

Endocrine disruptors like BPA, phthalates, and flame retardants interfere with thyroid hormone synthesis and receptor binding. Fluoride and chlorine (in tap water) compete with iodine for thyroid uptake. Brominated flame retardants (found in furniture, electronics) are structurally similar to thyroid hormones and can displace them [6].

1. Optimize Iodine Intake (But Don't Overdo It)

Why it works:
Iodine is the backbone of thyroid hormones-T4 contains 4 iodine atoms, T3 contains 3. Deficiency impairs hormone synthesis. However, excessive iodine can trigger or worsen Hashimoto's in susceptible individuals [7].

How to implement:

• Dietary sources: Seaweed (nori, wakame), wild-caught fish, eggs, dairy

• Supplementation: 150-300 mcg daily (avoid mega-doses >1,000 mcg unless supervised)

• Timing: Take with selenium (200 mcg) to reduce oxidative stress from iodine metabolism

Track Your Thyroid Levels

Mito Health tests 100+ biomarkers including TSH, free T3, free T4, reverse T3, and thyroid antibodies with physician-guided protocols to help you optimize energy, metabolism, and hormonal balance. Our comprehensive panels provide personalized interpretation to identify thyroid dysfunction early.

View Testing Options →

Evidence:
A study in iodine-deficient populations showed that 150 mcg daily iodine supplementation normalized TSH and increased free T4 by 15-20% within 3 months [8].

When to be cautious:

• If you have Hashimoto's (check TPO antibodies first)-high-dose iodine can worsen autoimmunity

• If you're on thyroid medication-can interfere with dosing

2. Supplement with Selenium (Critical for T4-to-T3 Conversion)

Why it works:
Selenium is required for the enzyme deiodinase, which converts inactive T4 to active T3. It also protects the thyroid from oxidative damage during hormone synthesis. Selenium deficiency is strongly associated with hypothyroidism and elevated TPO antibodies [9].

How to implement:

• Dosage: 200 mcg daily (selenomethionine or selenium-enriched yeast)

• Food sources: 2-3 Brazil nuts daily (each nut contains ~70-90 mcg), wild-caught fish, grass-fed beef, organ meats

• Combination: Pair with iodine and zinc for synergistic thyroid support

Evidence:
A meta-analysis of 16 studies found that selenium supplementation (200 mcg daily) reduced TPO antibodies by 26% and improved thyroid function in Hashimoto's patients [10]. Another study showed selenium increased free T3 levels by 8-12% in hypothyroid individuals [11].

Expected timeline:
Noticeable improvements in energy and hair quality within 4-6 weeks; antibody reduction takes 3-6 months.

3. Address Nutrient Cofactors - Zinc, Iron, Vitamin D

Why it works:
Thyroid hormone production is a multi-nutrient process. Zinc is needed for TSH receptor sensitivity and T4-to-T3 conversion. Iron is required for thyroid peroxidase enzyme function. Vitamin D supports thyroid receptor expression and reduces autoimmune attacks [12].

Zinc Protocol:

• Testing: Serum zinc (optimal: 90-120 mcg/dL)

• Dosage: 30 mg daily (zinc picolinate or glycinate)

• Food sources: Oysters, red meat, pumpkin seeds

• Caution: Don't exceed 40 mg daily long-term (can deplete copper)

Iron Protocol:

• Testing: Ferritin (optimal: 50-100 ng/mL for thyroid health)

• Dosage: 25-50 mg ferrous bisglycinate daily (if deficient)

• Timing: Take with vitamin C on empty stomach, avoid calcium

Vitamin D Protocol:

• Testing: Serum 25(OH)D (optimal: 50-70 ng/mL)

• Dosage: 4,000-5,000 IU daily (if <30 ng/mL, increase to 10,000 IU for 8 weeks)

• Combination: Pair with K2 (100-200 mcg) and magnesium (400 mg)

Evidence:
A study of hypothyroid patients found that correcting zinc deficiency increased free T3 by 15% and improved TSH response to medication [13]. Vitamin D supplementation (4,000 IU daily) reduced TPO antibodies by 20-30% in Hashimoto's patients [14].

4. Reduce Stress and Lower Cortisol (Improve T4-to-T3 Conversion)

Why it works:
Chronic stress elevates cortisol, which directly inhibits the enzyme that converts T4 to T3. High cortisol also increases reverse T3 (rT3), the inactive form that blocks thyroid receptors. This creates "functional hypothyroidism" even with normal TSH [15].

How to implement:

• Test cortisol: 4-point salivary cortisol test (morning, noon, evening, bedtime)

• Target: Morning cortisol 13-24 nmol/L, gradual decline throughout day

• Stress reduction: 20 minutes daily meditation, breathwork, yoga, or nature walks

• Adaptogenic herbs:

• Ashwagandha (300-600 mg): Lowers cortisol 25-30%, shown to increase T3 and T4 by 18% in subclinical hypothyroidism [16]

• Rhodiola (200-400 mg): Reduces stress-induced thyroid suppression

• Holy basil (300-500 mg): Balances cortisol rhythm

Sleep optimization:

• 8 hours minimum (poor sleep raises cortisol and lowers TSH production)

• Dark, cool room (66-68°F)

• Consistent sleep/wake times

Evidence:
A randomized trial found that ashwagandha (600 mg daily for 8 weeks) increased serum T3 by 18.4% and T4 by 41.5% compared to placebo in subclinical hypothyroidism [16].

5. Support Gut Health (Where 20% of T4-to-T3 Conversion Happens)

Why it works:
Your gut microbiome produces enzymes that convert T4 to T3. Intestinal inflammation, dysbiosis, and leaky gut reduce this conversion and trigger autoimmune responses. In fact, 20% of T4-to-T3 conversion occurs in the gut [17].

How to implement:

Heal intestinal permeability:

• L-glutamine: 5-10 grams daily (repairs gut lining)

• Zinc carnosine: 75 mg twice daily

• Collagen peptides: 10-20 grams daily

Restore microbiome diversity:

• Probiotics: Multi-strain formula with Lactobacillus and Bifidobacterium (25-50 billion CFU)

• Prebiotics: 10-20 grams inulin, FOS, or resistant starch daily

• Fermented foods: Sauerkraut, kimchi, kefir, yogurt daily

Reduce inflammatory foods:

• Remove gluten (strongly linked to Hashimoto's-up to 30% of celiac patients have thyroid antibodies) [18]

• Limit processed sugars and seed oils

• Consider dairy-free trial (casein protein can cross-react with TPO antibodies in some individuals)

Evidence:
A study of Hashimoto's patients on a gluten-free diet showed a 34% reduction in TPO antibodies after 6 months, plus improvements in TSH and free T4 [19].

Expected timeline:
Gut healing takes 3-6 months; symptom improvements often within 4-8 weeks.

6. Eat Enough Calories and Protein (Avoid Chronic Dieting)

Why it works:
Low-calorie diets and prolonged fasting suppress thyroid function as a survival mechanism. Your body downregulates T3 production to conserve energy, increases reverse T3, and lowers metabolic rate [20].

How to implement:

• Minimum calories: At least 1,800-2,200 calories daily for women, 2,200-2,800 for men

• Protein target: 1.0-1.2 grams per pound of body weight (supports thyroid hormone transport)

• Carbohydrates: 100-150 grams minimum daily (very low-carb diets can suppress T3)

• Healthy fats: 30-35% of calories (supports hormone production)

Strategic refeeds:

• After prolonged fasting or low-carb periods, do a high-carb refeed (200-300g carbs) to restore leptin and TSH signaling

Evidence:
Research shows that calorie restriction below basal metabolic rate reduces T3 by 30-50% within 1-2 weeks. Refeeding restores levels within 3-5 days [21].

7. Reduce Endocrine Disruptor Exposure

Why it works:
Environmental toxins like BPA, phthalates, perchlorate, fluoride, and brominated compounds interfere with thyroid hormone synthesis, transport, and receptor binding. They also increase thyroid antibody production [22].

How to implement:

Water quality:

• Filter tap water (reverse osmosis or activated carbon to remove fluoride, chlorine, perchlorate)

• Avoid fluoridated toothpaste (use fluoride-free alternatives)

Food storage:

• Replace plastic containers with glass or stainless steel

• Never microwave plastic (releases BPA and phthalates)

• Choose BPA-free canned foods or fresh/frozen alternatives

Personal care:

• Use paraben-free, phthalate-free cosmetics and lotions

• Choose fragrance-free products (synthetic fragrances contain endocrine disruptors)

Photo from Unsplash

Home environment:

• Reduce flame retardants: replace old furniture, use HEPA air purifiers

• Avoid non-stick cookware (PFAS/PFOA exposure)

• Choose natural cleaning products

Evidence:
A study found that women with higher urinary BPA levels had 2.5× higher risk of thyroid disorders. Reducing BPA exposure improved thyroid function markers within 3 months [23].

Testing Protocols - When and What to Measure

Baseline testing (before starting any interventions):

• TSH

• Free T4

• Free T3

• Reverse T3

• TPO antibodies

• Thyroglobulin antibodies

• Vitamin D (25-OH)

• Ferritin

• Serum zinc

• Selenium (optional but helpful)

Follow-up testing:

• 4-6 weeks: Recheck TSH, Free T3, Free T4 (assess short-term changes)

• 12 weeks: Full panel including antibodies (assess antibody reduction)

• 6 months: Comprehensive retest (assess long-term optimization)

Monitoring symptoms:
Track these weekly:

• Morning basal body temperature (should rise from <97.8°F to 98.0-98.6°F)

• Energy levels (1-10 scale)

• Hair quality and shedding

• Weight trends

• Bowel regularity (hypothyroidism causes constipation)

Severe Hypothyroidism (TSH >10, Free T3 <2.5)

Goal: Work with endocrinologist for possible thyroid medication + aggressive natural support

• Iodine: 150 mcg daily (if not Hashimoto's)

• Selenium: 200 mcg daily

• Zinc: 30 mg daily

• Iron: 50-100 mg bisglycinate (if ferritin <50)

• Vitamin D: 10,000 IU daily x 8 weeks (if <30 ng/mL)

• Ashwagandha: 600 mg daily

• Gut protocol: Full elimination (gluten, dairy, soy for 3 months)

• Stress management: Daily meditation + 8+ hours sleep

Retest: 6 weeks

Moderate Hypothyroidism (TSH 4-10, Free T3 2.5-3.2)

Goal: Optimize to TSH <2.5, Free T3 >3.2 within 12 weeks

• Selenium: 200 mcg daily

• Zinc: 30 mg daily

• Iodine: 150 mcg daily (test first)

• Vitamin D: 5,000 IU daily

• Magnesium: 400 mg glycinate

• Ashwagandha: 300-600 mg daily

• Probiotics: 25-50 billion CFU daily

• Protein: 1.0g/lb body weight minimum

• Calories: At least BMR + 200-300

Retest: 8-12 weeks

Subclinical Hypothyroidism (TSH 2.5-4, Free T3 >3.2)

Goal: Optimize to TSH 0.5-2.5, Free T3 upper third of range

• Selenium: 200 mcg daily (or 2-3 Brazil nuts)

• Vitamin D: 4,000 IU daily (if <50 ng/mL)

• Magnesium: 300 mg glycinate

• Zinc: 15-30 mg daily (if deficient)

• Reduce stress: Meditation, ashwagandha (300 mg)

• Gut support: Probiotic + prebiotic

• Sleep: Prioritize 8 hours

• Reduce endocrine disruptors: Water filter, BPA-free containers

Retest: 12 weeks

Hashimoto's/Autoimmune Protocol

Goal: Reduce TPO antibodies by 30-50% within 6 months

• Selenium: 200 mcg daily (proven to reduce antibodies)

• Vitamin D: 5,000-10,000 IU daily (target 60-80 ng/mL)

• Gluten elimination: Strict 6-month trial

• Dairy-free trial: 3 months

• Gut healing: L-glutamine (5-10g), probiotics, zinc carnosine

• Low-dose naltrexone (LDN): 1.5-4.5 mg nightly (prescription, consult doctor)

• Avoid high-dose iodine: Can worsen autoimmunity

• Stress reduction: Critical-stress triggers flares

Evidence:
LDN has been shown to reduce TPO antibodies by 40-60% in Hashimoto's patients and improve quality of life scores [24].

Retest antibodies: Every 3 months

Optimize From Within

Join Mito Health's annual membership to test 100+ biomarkers with concierge-level support from your care team. Track your TSH, free T3, free T4, reverse T3, and thyroid antibodies with repeat testing and personalized protocols.

Learn About Membership →

Expected Timeline for Thyroid Optimization

Weeks 1-2:

• Increased energy (if selenium/zinc were deficient)

• Improved sleep quality

• Less brain fog

Weeks 4-6:

• Noticeable improvements in hair quality

• Skin becoming less dry

• Better bowel regularity

• TSH starting to normalize

Weeks 8-12:

• Metabolic improvements (easier weight management)

• Stable energy throughout day

• Free T3 increasing into optimal range

• TPO antibodies beginning to decline (if Hashimoto's)

Months 3-6:

• Full symptom resolution for most people

• Antibody reduction of 30-50% (if autoimmune)

• Sustained energy, cognitive clarity, metabolic health

• Hair regrowth visible

When to Consider Thyroid Medication

Natural approaches work best for:

• Subclinical hypothyroidism (TSH 2.5-10)

• Nutrient deficiency-driven hypothyroidism

• Stress/cortisol-induced low T3

• Hashimoto's (in combination with medication)

Consider medication if:

• TSH >10 mIU/L despite 3-6 months of optimization

• Free T3 remains <2.5 pg/mL

• Severe symptoms (extreme fatigue, weight gain, hair loss)

• Poor T4-to-T3 conversion (low Free T3, high Reverse T3)-may need T3 medication (Cytomel) or natural desiccated thyroid (NDT)

• Hashimoto's with thyroid tissue destruction

Note: Many people do best on a combination of medication + natural optimization (medication provides baseline hormone levels, natural methods improve conversion and reduce antibodies).

The Bottom Line

Raising thyroid levels naturally is absolutely possible for subclinical hypothyroidism and nutrient-driven cases. The key is addressing root causes-iodine and selenium sufficiency, stress reduction, gut health, adequate calories, and reducing endocrine disruptors-not just trying to "boost" thyroid hormones in isolation.

Start with testing to identify your specific deficiencies and antibody status. Selenium is the most evidence-backed intervention for both improving thyroid function and reducing autoimmune attacks. Combine it with stress management (ashwagandha is powerful here), gut healing (especially gluten elimination if you have Hashimoto's), and toxin reduction. Your thyroid responds to consistent, multi-faceted support. Most people see noticeable improvements within 4-8 weeks and full optimization within 3-6 months.

Key Takeaways

Optimal TSH is 0.5-2.0 mIU/L, not 0.5-5.0 mIU/L (mainstream lab range)
Free T3 and Free T4 matter most: Total thyroid hormones include bound forms (inactive)
Reverse T3 must be low: Elevated indicates conversion issues (stress, poor diet, selenium deficiency)
Selenium essential: 200 mcg daily for glutathione peroxidase (T3 conversion enzyme)
Vitamin D critical: Optimize to >40 ng/mL for immune function and T cell regulation
Iodine necessary: 150-300 mcg from fish, seaweed (avoid excess >600 mcg if autoimmune)
Gut health matters: Poor digestion impairs mineral and nutrient absorption
Stress management: Elevated cortisol drives T3 to Reverse T3 conversion, raising RT3
Retest every 6-8 weeks until stable, then every 6-12 months for monitoring

Medical Disclaimer

This article is for educational and informational purposes only and does not constitute medical advice. The information provided should not be used for diagnosing or treating a health condition. Always consult with your doctor or qualified healthcare provider before starting any new supplement protocol, making changes to your diet, or if you have questions about a medical condition.

Individual results may vary. The dosages and protocols discussed are evidence-based but should be personalized under medical supervision, especially if you have existing health conditions or take medications.

Track Your Progress

• How to Improve Your Thyroid Stimulating Hormone (TSH) Level Naturally

• How to Improve Your Triiodothyronine (T3), Free Level Naturally

• Thyroid Stimulating Hormone (TSH)

Related Content

• Raising Vitamin D Levels Naturally: 7 Science-Backed Methods

• Raising Iron Levels Fast: 7 Science-Backed Methods

• Magnesium Dosage by Age: Children, Adults, Elderly & Athletes

References

[1] Cappola AR, Fried LP, Arnold AM, et al. Thyroid status, cardiovascular risk, and mortality in older adults. JAMA. 2006;295(9):1033-1041. PMID: 16507804 | DOI: 10.1001/jama.295.9.1033

[2] Triggiani V, Tafaro E, Giagulli VA, et al. Role of iodine, selenium and other micronutrients in thyroid function and disorders. Endocr Metab Immune Disord Drug Targets. 2009;9(3):277-294.

[3] Helmreich DL, Tylee D. Thyroid hormone regulation by stress and behavioral differences in adult male rats. Horm Behav. 2011;60(3):284-291. PMID: 21689656 | DOI: 10.1016/j.yhbeh.2011.06.003

[4] Caturegli P, De Remigis A, Rose NR. Hashimoto thyroiditis: clinical and diagnostic criteria. Autoimmun Rev. 2014;13(4-5):391-397.

[5] Bianco AC, Kim BW. Deiodinases: implications of the local control of thyroid hormone action. J Clin Invest. 2006;116(10):2571-2579.

[6] Boas M, Feldt-Rasmussen U, Main KM. Thyroid effects of endocrine disrupting chemicals. Mol Cell Endocrinol. 2012;355(2):240-248. PMID: 21939731 | DOI: 10.1016/j.mce.2011.09.005

[7] Leung AM, Braverman LE. Consequences of excess iodine. Nat Rev Endocrinol. 2014;10(3):136-142. PMID: 24342882 | DOI: 10.1038/nrendo.2013.251

[8] Zimmermann MB, Jooste PL, Pandav CS. Iodine-deficiency disorders. Lancet. 2008;372(9645):1251-1262. PMID: 18676011 | DOI: 10.1016/S0140-6736(08)61005-3

[9] Ventura M, Melo M, Carrilho F. Selenium and thyroid disease: from pathophysiology to treatment. Int J Endocrinol. 2017;2017:1297658.

[10] Wichman J, Winther KH, Bonnema SJ, Hegedüs L. Selenium supplementation significantly reduces thyroid autoantibody levels in patients with chronic autoimmune thyroiditis: a systematic review and meta-analysis. Thyroid. 2016;26(12):1681-1692. PMID: 27702392 | DOI: 10.1089/thy.2016.0256

[11] Duntas LH, Benvenga S. Selenium: an element for life. Endocrine. 2015;48(3):756-775. PMID: 25519493 | DOI: 10.1007/s12020-014-0477-6

[12] Wojtas N, Wadolowska L, Bandurska-Stankiewicz E. Evaluation of qualitative dietary protocol (Diet4Hashi) application in dietary counseling in Hashimoto thyroiditis. Int J Environ Res Public Health. 2019;16(23):4841.

[13] Mahmoodianfard S, Vafa M, Golgiri F, et al. Effects of zinc and selenium supplementation on thyroid function in overweight and obese hypothyroid female patients. J Am Coll Nutr. 2015;34(5):391-399.

[14] Kivity S, Agmon-Levin N, Zisappl M, et al. Vitamin D and autoimmune thyroid diseases. Cell Mol Immunol. 2011;8(3):243-247. PMID: 21278761 | DOI: 10.1038/cmi.2010.73

[15] Helmreich DL, Tylee D. Thyroid hormone regulation by stress and behavioral differences in adult male rats. Horm Behav. 2011;60(3):284-291. PMID: 21689656 | DOI: 10.1016/j.yhbeh.2011.06.003

[16] Sharma AK, Basu I, Singh S. Efficacy and safety of ashwagandha root extract in subclinical hypothyroid patients. J Altern Complement Med. 2018;24(3):243-248.

[17] Fröhlich E, Wahl R. Microbiota and thyroid interaction in health and disease. Trends Endocrinol Metab. 2019;30(8):479-490.

[18] Sategna-Guidetti C, Bruno M, Mazza E, et al. Autoimmune thyroid diseases and coeliac disease. Eur J Gastroenterol Hepatol. 1998;10(11):927-931.

[19] Krysiak R, Szkróbka W, Okopień B. The effect of gluten-free diet on thyroid autoimmunity in drug-naive women with Hashimoto's thyroiditis. Exp Clin Endocrinol Diabetes. 2019;127(7):417-422.

[20] Douyon L, Schteingart DE. Effect of obesity and starvation on thyroid hormone, growth hormone, and cortisol secretion. Endocrinol Metab Clin North Am. 2002;31(1):173-189.

[21] Loucks AB, Thuma JR. Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women. J Clin Endocrinol Metab. 2003;88(1):297-311.

[22] Boas M, Feldt-Rasmussen U, Main KM. Thyroid effects of endocrine disrupting chemicals. Mol Cell Endocrinol. 2012;355(2):240-248. PMID: 21939731 | DOI: 10.1016/j.mce.2011.09.005

[23] Meeker JD, Ferguson KK. Relationship between urinary phthalate and bisphenol A concentrations and serum thyroid measures in U.S. adults and adolescents from the National Health and Nutrition Examination Survey (NHANES) 2007-2008. Environ Health Perspect. 2011;119(10):1396-1402.

[24] Vojdani A, Vojdani C. Immune reactivity to food coloring. Altern Ther Health Med. 2015;21 Suppl 1:52-62. PMID: 25599186

[25] Benvenga S, Bartolone L, Pappalardo MA, et al. Altered intestinal absorption of L-thyroxine caused by coffee. Thyroid. 2008;18(3):293-301. PMID: 18399767 | DOI: 10.1089/thy.2007.0234