The Healthspan Map · Endocrine & Metabolic
Thyroid dysfunction
Named for Thyroid dysfunction
| Nutrient or lever | Direction | Strength | Evidence type | What was found | Source |
|---|---|---|---|---|---|
| Iodine | Eat enough of | Strong | Established clinical | Iodine is the substrate for T3/T4; deficiency causes goiter, nodular disease and hypothyroidism. | Thyroid nutrition review (J Endocrinol Invest 2026) (opens in a new tab) |
| Iodine | Don't overdo | Strong | Established clinical | Excess iodine (kelp/supplements) can precipitate hyperthyroidism or trigger autoimmune thyroiditis/hypothyroidism via thyrocyte ROS — the high end of the U-curve. | Thyroid nutrition review (J Endocrinol Invest 2026) (opens in a new tab) |
| Selenium | Eat enough of | Strong | RCT / meta-analysis | Selenium powers deiodinases (T4→T3) and glutathione peroxidase; supplementation lowers TPO antibodies in Hashimoto’s. | Micronutrients & autoimmune thyroid review (PMC12372124) (opens in a new tab) |
| Anchor foods | Watch this | Moderate | Review / narrative | A Mediterranean-style pattern is associated with lower thyroid antibodies and inflammation in Hashimoto’s, supporting autoimmune thyroid function. | Micronutrients & autoimmune thyroid review (PMC12372124) (opens in a new tab) |
| Colours a day | Watch this | Moderate | Review / narrative | Dietary antioxidants help preserve thyrocyte oxidative status; oxidative stress and apoptosis are early triggers of autoimmune thyroid damage. | Minerals & autoimmune hypothyroidism review (PMC7574993) (opens in a new tab) |
| Iron | Eat enough of | Moderate | Review / narrative | Thyroid peroxidase is heme-dependent; iron deficiency is strongly associated with hypothyroid status and impairs hormone synthesis. | Minerals & autoimmune hypothyroidism review (PMC7574993) (opens in a new tab) |
| Sleep duration | Watch this | Moderate | Systematic review | Sleep normally inhibits TSH; sleep deprivation nearly doubles nocturnal TSH, and poor sleep is associated with subclinical hypothyroidism. | Thyroid & sleep patterns systematic review (PMC11285688) (opens in a new tab) |
| Sleep regularity | Watch this | Moderate | Systematic review | Night-shift/circadian disruption is associated with elevated TSH and higher rates of subclinical hypothyroidism — the clearest sleep-timing link to thyroid. | Shift-work & thyroid systematic review (PMC7084223) (opens in a new tab) |
| Supplement discipline | Do this | Moderate | Review / narrative | Iodine and selenium both follow a U-shape: repletion within the optimal window helps, but over-supplementation (especially iodine) can precipitate dysfunction — disciplined dosing matters. | Nutrition & thyroid myths/facts review (J Endocrinol Invest 2026) (opens in a new tab) |
| Tobacco / vaping — quit | Do this | Moderate | Review / narrative | Smoking interferes with iodide trapping at the Na⁺/I⁻ symporter and is linked to Graves’ disease and thyroid eye disease. | Diet in thyroid disorders review (PMC11451952) (opens in a new tab) |
| Vitamin D | Eat enough of | Moderate | Review / narrative | Vitamin D deficiency is far more common in Hashimoto’s/Graves’ patients and acts as an immunoregulatory factor in autoimmune thyroid disease. | Minerals & autoimmune thyroid review (PMC7574993) (opens in a new tab) |
| Zinc | Eat enough of | Moderate | Review / narrative | Zinc is required for thyroid hormone production and T3-receptor function; deficiency impairs thyroid metabolism. | Minerals & thyroid review (PMC7574993) (opens in a new tab) |
| BMI | Watch this | Emerging | Cohort / observational | In ~5,000 adults with obesity, higher body weight (via visceral fat/leptin) predicted higher TSH within the normal range — excess weight nudges thyroid signalling upward. | Fontana et al., obesity–TSH cohort (PMC9606412) (opens in a new tab) |
| Breath/mind (slow breathing) | Do this | Emerging | Review / narrative | Chronic stress activates the HPA axis and cortisol, which can disturb thyroid signalling; stress-reduction is a plausible support for autoimmune thyroid. | Thyroid & HPA/cortisol review (PMC11144793) (opens in a new tab) |
| Cardio (moderate + intervals) | Do this | Emerging | Review / narrative | Moderate exercise favourably shifts immune balance (more T-regulatory cells) in autoimmune thyroid disease; excessive training can be counterproductive (J-curve). | Autoimmune thyroid & physical activity review (PMC12561809) (opens in a new tab) |
| Copper | Eat enough of | Emerging | Review / narrative | Copper is among the trace minerals influencing thyroid hormone synthesis and regulation. | Nutrition & thyroid review (PMC11314468) (opens in a new tab) |
| Daily movement baseline | Do this | Emerging | Review / narrative | Regular non-excessive activity beats sedentariness for autoimmune-thyroid outcomes and helps manage the weight/metabolic burden of hypothyroidism. | Autoimmune thyroid & physical activity review (PMC12561809) (opens in a new tab) |
| Magnesium | Eat enough of | Emerging | Mechanistic | Magnesium supports the sodium-iodide symporter that maintains iodine supply for hormone synthesis. | Minerals & thyroid review (PMC7574993) (opens in a new tab) |
| Protein | Eat enough of | Emerging | Mechanistic | Tyrosine, from dietary protein, is the amino-acid backbone of thyroid hormones. | Nutrition & thyroid review (PMC11314468) (opens in a new tab) |
| Selenium | Don't overdo | Emerging | Review / narrative | Very high selenium risks selenosis and may adversely affect thyroid/metabolic markers — the top of selenium’s own U-shape. | Minerals & thyroid review (PMC7574993) (opens in a new tab) |
| Sleep quality (refreshed) | Watch this | Emerging | Review / narrative | Poor sleep quality correlates with elevated TSH/T4 and, via HPA-axis/cortisol activation, can disturb the hypothalamic–pituitary–thyroid axis. | Thyroid dysfunction & sleep quality study (PMC11144793) (opens in a new tab) |
| Ultra-processed food — cut back | Do this | Emerging | Review / narrative | Diet quality shapes the diet–gut–thyroid axis; poor patterns drive dysbiosis and micronutrient gaps that alter thyroid function. | Nutrition & thyroid narrative review (PMC11314468) (opens in a new tab) |
| Vitamin A (RAE) | Eat enough of | Emerging | Review / narrative | Vitamin A participates in thyroid hormone metabolism and TSH regulation; low status is one micronutrient contributor to dysfunction. | Nutrition & thyroid review (PMC11314468) (opens in a new tab) |
| Vitamin B12 | Eat enough of | Emerging | Review / narrative | B12 is commonly low in autoimmune thyroid disease (pernicious-anemia overlap); repletion supports Hashimoto’s patients. | Micronutrients & autoimmune thyroid review (PMC12372124) (opens in a new tab) |
| Vitamin E | Eat enough of | Emerging | Review / narrative | Vitamin E’s antioxidant action is among the nutrient factors examined for protecting thyrocytes in hypothyroidism/Hashimoto’s. | Micronutrients & autoimmune thyroid review (PMC12372124) (opens in a new tab) |
Held for the whole Endocrine & Metabolic system
These rows name no single condition. The Map records them against the whole body system, so they are shown separately rather than folded in.
| Nutrient or lever | Direction | Strength | Evidence type | What was found | Source |
|---|---|---|---|---|---|
| BMI | Watch this | Strong | Established clinical | High BMI drives the metabolic-endocrine cluster: insulin resistance, T2D, dyslipidemia, PCOS. | Obesity clinical review (opens in a new tab) |
| BMI | Watch this | Strong | RCT / meta-analysis | BMI discriminates the cardiometabolic-risk cluster across >300,000 adults. | Ashwell et al., Obesity Reviews 2012 (opens in a new tab) |
| Movement (breaking up sitting) | Do this | Strong | RCT / meta-analysis | Sedentary behaviour independently worsens glucose and lipid metabolism and raises type 2 diabetes risk. | Patterson et al., Eur J Epidemiol 2018 (meta-analysis) (opens in a new tab) |
| Movement (breaking up sitting) | Do this | Strong | RCT / meta-analysis | Regular movement breaks improve glycemic and metabolic regulation. | Breaking-up-sitting experimental studies (opens in a new tab) |
| Sleep duration | Watch this | Strong | RCT / meta-analysis | Sleep duration has a U-shaped link with type 2 diabetes; risk is lowest at 7-8 h and rises for both short and long sleep. | Shan et al., Diabetes Care 2015 (meta-analysis) (opens in a new tab) |
| Sleep duration | Watch this | Strong | Cohort / observational | Sleeping <6 h vs 7 h raised incident type 2 diabetes risk by ~30%, independent of baseline health. | 45 and Up Study + meta-analysis (n=447,124) (opens in a new tab) |
| Vitamin D | Don't overdo | Strong | Established clinical | Toxicity (almost always from supplements, UL 100 mcg/4,000 IU) causes hypercalcemia and hypercalciuria. | NIH ODS / MedlinePlus (Hypervitaminosis D) (opens in a new tab) |
| Vitamin D | Don't overdo | Strong | Established clinical | Toxicity (almost always from supplements, UL 100 mcg/4,000 IU) causes hypercalcemia and hypercalciuria. | NIH Office of Dietary Supplements — Vitamin D (opens in a new tab) |
| Waist-to-height ratio | Watch this | Strong | RCT / meta-analysis | WHtR had the greatest discriminatory power for the cardiometabolic-risk cluster. | Ashwell et al., Obesity Reviews 2012 (>300,000 adults) (opens in a new tab) |
| Body Roundness Index | Watch this | Moderate | Cohort / observational | Higher BRI reflects visceral adiposity and cardiometabolic risk. | "Body Roundness Index Associated With Cardiometabolic Multimorbidity and Mortality: A Multistate Analysis", Obesity 2025 (opens in a new tab) |
| Cardio / VO2max | Watch this | Moderate | RCT / meta-analysis | Low CRF predicts incident type 2 diabetes and metabolic disease. | Lang et al., BJSM 2024 (opens in a new tab) |
| Chloride | Eat enough of | Moderate | Established clinical | Chloride depletion (from vomiting, diuretics, NG suction) causes metabolic alkalosis and, secondarily, hypokalemia; low dietary intake is uncommon. | NIH Clinical Methods – Serum Chloride (opens in a new tab) |
| Chloride | Don't overdo | Moderate | Established clinical | Hyperchloremia (from dehydration, excess saline, renal dysfunction) causes hyperchloremic metabolic acidosis. | Critical-care chloride review (PMC10995984) (opens in a new tab) |
| Consistency (the weekly dose) | Do this | Moderate | RCT / meta-analysis | Strengthening activity improves insulin sensitivity and lowers diabetes/metabolic risk. | Momma et al., BJSM 2022 (opens in a new tab) |
| Phosphorus | Don't overdo | Moderate | Mechanistic | Excess phosphate alters the hormones regulating calcium (PTH, FGF-23, vitamin D), causing secondary hyperparathyroidism and hypocalcemia. | NIH ODS – Phosphorus (opens in a new tab) |
| Sleep regularity | Watch this | Moderate | Cohort / observational | Irregular sleep-wake timing is associated with metabolic abnormalities and glycemic dysregulation. | Sleep-regularity and metabolic literature (MESA; UK Biobank) (opens in a new tab) |
| Waist-to-hip ratio | Watch this | Moderate | Cohort / observational | High waist-to-hip ratio reflects visceral fat and cardiometabolic risk. | Central-adiposity literature (opens in a new tab) |
| Vitamin A (RAE) | Don't overdo | Emerging | Established clinical | Prolonged high-dose vitamin A can cause hypercalcemia. | Case series (PMC10185110) (opens in a new tab) |