The Thyroid and Tryptophan

Thyroid Nutrients
Written By Kylie Wolfig

What is Tryptophan?

  • Definition: Tryptophan is an essential amino acid, meaning our body cannot produce it, and we must obtain it through our diet.

  • Function: It plays a crucial role in protein synthesis, the production of neurotransmitters (like serotonin), and hormone regulation.

  • Precursor Role: Tryptophan is a precursor to serotonin (the "feel-good" neurotransmitter) and melatonin (the sleep-regulating hormone).

  • Connection to Thyroid: Tryptophan indirectly influences thyroid health through its role in neurotransmitter balance, stress response, and inflammation control.

What Types of Tryptophan Are There and What Do They Do?

  • L-Tryptophan: The naturally occurring form found in food sources such as turkey, chicken, eggs, and dairy. It is responsible for serotonin production.

  • 5-Hydroxytryptophan (5-HTP): A metabolite of tryptophan that is often used in supplement form to boost serotonin levels directly.

  • Free vs. Bound Tryptophan: Free tryptophan circulates in the blood and is available for uptake into the brain, while bound tryptophan is attached to albumin and not immediately available.

  • Supplemental Tryptophan: Used therapeutically for mood disorders, sleep disturbances, and sometimes thyroid function support indirectly through stress reduction.

Daily Requirements for Tryptophan

  • Infants (0-6 months): 11 mg/kg body weight per day

  • Children (1-3 years): 10 mg/kg per day

  • Teenagers (14-18 years): 6 mg/kg per day

  • Adults: Approximately 4-6 mg/kg per day

  • Pregnant Women: Slightly higher needs due to increased protein synthesis and serotonin requirements

  • Breastfeeding Women: Higher intake is recommended to support milk production and maternal mental health.

Note: Individual needs may vary based on stress levels, sleep quality, and overall health.

What Does Tryptophan Do in Our Body?

  • Serotonin Production: Acts as a precursor for serotonin, which regulates mood, appetite, and sleep.

  • Melatonin Production: Converts into melatonin, aiding in circadian rhythm regulation and sleep quality.

  • Protein Synthesis: Contributes to the formation of proteins essential for cellular repair and function.

  • Immune Function: Supports immune system regulation by reducing inflammation.

  • Stress Adaptation: Helps modulate stress responses and reduces cortisol levels.

Symptoms of Tryptophan Deficiency

  • Mood Disorders: Anxiety, depression, irritability

  • Sleep Disturbances: Insomnia or poor-quality sleep

  • Cognitive Issues: Difficulty concentrating or brain fog

  • Digestive Problems: Poor gut motility or altered gut flora

  • Fatigue: Persistent tiredness or low energy

  • Increased Cravings: Especially for carbohydrates and sugar

  • Poor Stress Tolerance: Increased reactivity to stress

What Does Tryptophan Do for Our Thyroid Pathway?

  • Stress Reduction: Lower stress levels reduce cortisol, which can otherwise suppress thyroid hormone production.

  • Inflammation Control: Helps regulate inflammation, reducing thyroid tissue damage in autoimmune thyroid diseases (e.g., Hashimoto's thyroiditis).

  • Serotonin-Thyroid Link: Adequate serotonin levels support mood and stress resilience, indirectly benefiting thyroid function.

  • Thyroid Hormone Activation: Proper tryptophan metabolism supports liver function, which is crucial for converting T4 to T3 thyroid hormones.

What Does Tryptophan Do for Our Liver?

  • Detoxification Support: Aids liver detoxification pathways, supporting the breakdown of toxins.

  • Prevents Fatty Liver Disease: Adequate tryptophan levels reduce the risk of fat accumulation in the liver.

  • Supports T4 to T3 Conversion: Liver enzymes convert the inactive thyroid hormone T4 into the active T3 form, and tryptophan supports overall liver function.

  • Reduces Inflammation: Modulates inflammatory cytokines that may impair liver health.

What Does Tryptophan Do for Our Gut?

  • Gut-Brain Axis: Tryptophan regulates serotonin production in the gut, which influences digestion and gut motility.

  • Immune Balance: Supports the gut's immune system by regulating inflammatory responses.

  • Gut Microbiome Support: Helps maintain a balanced gut microbiome, reducing dysbiosis risk.

  • Leaky Gut Prevention: Supports gut lining integrity, preventing toxins from entering the bloodstream.

Physical Ailments that Affect Tryptophan Absorption or Utilization

  • Chronic Stress: Increases cortisol, which can interfere with tryptophan metabolism.

  • Inflammation: Chronic inflammation can deplete tryptophan levels.

  • Liver Disease: Impairs conversion of tryptophan into serotonin and melatonin.

  • Poor Gut Health: Dysbiosis or leaky gut can reduce tryptophan absorption.

  • Autoimmune Conditions: Conditions like Hashimoto’s can impair tryptophan metabolism.

Foods That Impact Tryptophan Levels

  • Enhance Tryptophan Uptake: Protein-rich foods (turkey, chicken, fish, eggs), dairy, nuts, and seeds.

  • Inhibit Tryptophan Uptake: Excessive refined sugars, caffeine, and alcohol.

  • Gut Health Impact: Fermented foods can improve gut health and tryptophan absorption.

Medications That Impact Tryptophan Levels

  • SSRIs (e.g., fluoxetine): Can alter tryptophan metabolism.

  • Corticosteroids: Increase tryptophan breakdown.

  • Antibiotics: Disrupt gut flora, reducing tryptophan absorption.

  • Oral Contraceptives: May deplete tryptophan levels over time.

Natural Supplements That Negatively Impact Tryptophan

  • Excessive Vitamin B6: Can disrupt tryptophan metabolism.

  • High-Dose Zinc: May compete with tryptophan for absorption.

  • Excessive Melatonin Supplements: Can downregulate natural tryptophan-to-melatonin conversion.

Heavy Metals That Impact Tryptophan

  • Mercury: Disrupts serotonin production from tryptophan.

  • Lead: Impairs liver detoxification and tryptophan metabolism.

  • Cadmium: Affects gut health, indirectly reducing tryptophan absorption.

Testing for Tryptophan Levels

  • Blood Tests: Measure free and bound tryptophan levels.

  • Serotonin Levels: Indirect indicator of tryptophan status.

  • Urine Organic Acid Test: Assesses tryptophan metabolites.

Nutrients Required for Tryptophan Absorption

  • Vitamin B6: Essential for tryptophan metabolism into serotonin and melatonin.

  • Magnesium: Supports tryptophan conversion pathways.

  • Zinc: Assists in serotonin synthesis.

  • Vitamin C: Reduces oxidative stress during tryptophan metabolism.

Foods High in Tryptophan

  • Turkey

  • Chicken

  • Salmon

  • Eggs

  • Dairy products (yogurt, cheese)

  • Nuts (almonds, cashews)

  • Seeds (pumpkin seeds, sunflower seeds)

A Recipe High in Tryptophan

Turkey Caesar Salad Bowl

Ingredients: Turkey, boiled eggs, camembert, cos lettuce, chives, pinenuts, caesar dressing

Instructions: Combine all in a bowl and season to taste.

Extra: Using Turkey instead of chicken ramps up the tryptophan levels!

Other Random Information About Tryptophan

  • Tryptophan absorption is improved when combined with carbohydrates.

  • Exercise can increase tryptophan transport to the brain.

  • Excess tryptophan supplementation can cause serotonin syndrome, a rare but serious condition.

Disclaimer: The information provided in this article is for educational purposes only and is not intended to diagnose, treat, or cure any medical condition. Always consult with a qualified healthcare professional before making any changes to your diet, lifestyle, or treatment plan. Individual needs may vary, and what works for one person may not be suitable for another.

Kylie Wolfig
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