Thyroid | SH2B3 (rs3184504)

SH2B3 and Thyroid Health: What Your Genotype May Mean

The thyroid gland plays a central role in regulating metabolism, energy, mood, and reproductive function by producing hormones that influence many body systems. Variations in the SH2B3 gene can alter immune system regulation and inflammatory responses. Certain SH2B3 variants have been linked to an increased tendency toward autoimmune conditions such as Hashimoto’s thyroiditis. This article explains how differences at the rs3184504 site may affect thyroid risk, describes common symptoms to watch for, and provides practical, evidence-informed diet, supplement, lifestyle, and monitoring suggestions to support thyroid health and fertility.

How SH2B3 influences thyroid autoimmunity

SH2B3 helps regulate immune signaling pathways that keep inflammatory responses in balance. When genetic differences change how this regulation works, the immune system can be more likely to target the thyroid gland. In Hashimoto’s thyroiditis the immune attack damages thyroid tissue and often leads to lower thyroid hormone production, or hypothyroidism. Symptoms can develop gradually and include fatigue, weight gain, cold sensitivity, hair thinning, constipation, mood changes, irregular or heavy menstrual cycles, and difficulties with fertility.

Common signs to monitor

• Persistent fatigue or low energy
• Unexplained weight gain or difficulty losing weight
• Feeling colder than others
• Hair loss or thinning
• Dry skin and brittle nails
• Changes in menstrual cycle or fertility challenges
• Constipation, brain fog, or low mood

Genetic interpretations

Diet and nutrient strategies to support thyroid and immune health

Nutrition cannot change your DNA, but it can support normal thyroid function and healthy immune balance. Focus on a varied, nutrient dense eating pattern.

• Iodine: Necessary for thyroid hormone production. Aim to get iodine from iodized salt, seafood, dairy, or fortified foods. Avoid excessive intake from high dose supplements unless directed by your provider.
• Selenium: Supports thyroid hormone metabolism and may help modulate autoimmune activity. Food sources include Brazil nuts, seafood, eggs, and organ meats. Typical dietary intake is preferred; supplements can be considered under clinical guidance.
• Vitamin A: Important for thyroid hormone signaling. Get vitamin A from colorful vegetables, liver in moderation, eggs, and dairy or from provitamin A carotenoids in carrots and leafy greens.
• Zinc and iron: Both are needed for thyroid hormone production and conversion. Include lean meats, legumes, nuts, seeds, whole grains, and leafy greens. If you suspect deficiency, check labs before supplementing.
• Moderate goitrogenic foods: Raw cruciferous vegetables and high soy intakes can interfere with thyroid function when consumed in very large amounts and when iodine intake is low. Light cooking reduces goitrogenic potential. Most people can eat these foods in moderation.
• Gluten sensitivity: Some people with autoimmune thyroid disease notice improvement when gluten is reduced or removed. Test for celiac disease if symptoms suggest it before starting restrictive diets.
• Consistent eating patterns: Regular balanced meals with adequate protein, healthy fats, and fiber support metabolic stability and reproductive hormone balance.

Supplement considerations

• Selenium: May be helpful to support thyroid health in people with autoimmune thyroiditis. Typical supplemental doses are modest and should be discussed with your clinician.
• Myo-inositol: Emerging evidence suggests myo-inositol may support immune function and thyroid autoimmunity in some people. Discuss appropriateness and dosing with your provider.
• Vitamin D: Low vitamin D is common and has been associated with increased autoimmune risk. Check levels and supplement if deficient under medical supervision.
• Avoid high dose iodine or iron supplements unless deficiency is documented and you are following a clinician recommended plan.

Lifestyle and monitoring tips

• Regular testing: If you have symptoms or family history, ask your clinician about testing TSH, free T4, free T3, and thyroid antibodies at intervals appropriate for your situation.
• Track reproductive health: Monitor menstrual cycles, fertility signs, and discuss reproductive plans with your provider, since thyroid dysfunction can affect fertility and pregnancy outcomes.
• Reduce exposure to endocrine disruptors: Minimize unnecessary plastics, limit pesticide exposure, avoid unregulated supplements, and choose safer personal care products when possible.
• Prioritize stress management: Chronic stress can affect immune and thyroid function. Incorporate sleep, movement, mindfulness, and social support.
• Coordinate care: If you have other autoimmune diseases, talk with your clinician about integrated monitoring and management strategies.

When to see your healthcare provider

• If you notice persistent symptoms such as fatigue, unexplained weight gain, hair loss, menstrual changes, or temperature intolerance
• If you have a family history of autoimmune thyroid disease or other autoimmune conditions
• If you are planning pregnancy or experiencing difficulties with fertility
• Before starting any new supplement, especially iodine, selenium, iron, or high dose vitamin D

PlexusDx provides genetic information to help you understand potential risks and to support conversations with your healthcare team. PlexusDx does not provide medical advice. Always consult your healthcare provider before making medical or supplement changes based on genetic results.