Hypothyroidism or underactive thyroid, is a condition in which the thyroid gland does not produce enough hormones, leading to a slowdown in metabolism and various bodily functions. The thyroid plays a crucial role in regulating energy production, metabolism, temperature control and hormonal balance, making its function essential for overall health and longevity.
If left untreated, hypothyroidism can contribute to fatigue, weight gain, cognitive decline, cardiovascular issues and metabolic disorders. Early detection, proper management and lifestyle adjustments can help maintain thyroid health and improve longevity.
Causes of hypothyroidism
Hypothyroidism can develop due to various factors, including autoimmune conditions, nutrient deficiencies and hormonal imbalances. Common causes include:
- Autoimmune disorders (Hashimoto’s Thyroiditis): the most common cause of hypothyroidism is Hashimoto’s thyroiditis, an autoimmune condition where the immune system mistakenly attacks the thyroid gland, reducing hormone production;
- Iodine deficiency or excess: iodine is crucial for thyroid hormone production and both deficiency and excess iodine intake can disrupt thyroid function. Iodine deficiency is common in regions with low iodine in soil and food;
- Hormonal imbalances (Pituitary or Hypothalamic Dysfunction): the thyroid is regulated by thyroid stimulating hormone (TSH), produced by the pituitary gland. If the pituitary gland is not functioning properly, thyroid hormone levels may drop;
- Genetic factors and family history: a family history of thyroid disorders increases the risk of developing hypothyroidism;
- Medications and medical treatments: certain medications, such as lithium, beta blockers and corticosteroids, can suppress thyroid function. Thyroid surgery or radiation therapy (for cancer or hyperthyroidism) can also lead to hypothyroidism;
- Aging and lifestyle factors: aging naturally slows thyroid function, making older adults more susceptible. Chronic stress, poor diet and exposure to environmental toxins (such as heavy metals and endocrine disruptors) can also contribute to thyroid dysfunction.
Common symptoms of hypothyroidism
Hypothyroidism affects multiple body systems, leading to a range of symptoms:
Metabolic slowdown
- Fatigue and low energy levels;
- Unexplained weight gain despite normal diet and activity;
- Cold intolerance (feeling cold even in warm environments).
Cognitive and mood changes
- Brain fog and difficulty concentrating;
- Memory issues;
- Depression, mood swings and irritability.
Digestive issues
- Constipation and bloating due to slowed digestion;
- Low stomach acid leading to poor nutrient absorption.
Skin, hair and nail health
- Dry, rough skin;
- Hair thinning or hair loss;
- Brittle nails.
Cardiovascular effects
- Slow heart rate (bradycardia);
- High cholesterol levels;
- Fluctuations in blood pressure.
Since hypothyroidism symptoms can overlap with other conditions, proper testing and diagnosis are essential for accurate treatment.
Diagnosis and testing
Doctors diagnose hypothyroidism through blood tests that measure thyroid hormone levels:
- TSH (Thyroid Stimulating Hormone): elevated levels indicate an underactive thyroid;
- Free T3 and free T4 (thyroid hormones): low levels confirm reduced thyroid activity;
- Thyroid antibodies: tests for Hashimoto’s thyroiditis;
- Reverse T3 (rT3): assesses how the body is utilizing thyroid hormones;
- Iodine, selenium and iron levels: important for thyroid hormone production.
Regular thyroid function tests are recommended, especially for those with a family history or symptoms of hypothyroidism.
Treatment and management
Managing hypothyroidism requires a combination of medication, nutrition and lifestyle changes to support optimal thyroid function.
Thyroid hormone replacement therapy
The most common treatment is levothyroxine (T4 hormone replacement), which restores normal hormone levels. Some individuals benefit from combination therapy (T4 + T3 medications) or natural desiccated thyroid (NDT).
Nutritional strategies for thyroid health
Certain nutrients play a crucial role in thyroid function:
- Iodine: found in seaweed, iodized salt, dairy and eggs;
- Selenium: supports thyroid hormone production (Brazil nuts, sunflower seeds);
- Zinc: essential for hormone activation (beef, pumpkin seeds, chickpeas);
- Iron: necessary for T4 to T3 conversion (red meat, spinach, lentils);
- Omega 3 fatty acids: reduce inflammation (salmon, flaxseeds, walnuts).
Foods to avoid
- Goitrogens (interfere with iodine absorption): found in raw cruciferous vegetables (broccoli, kale, cabbage);
- Ultra-processed foods and refined sugar: increase inflammation and metabolic stress;
- Excess caffeine and alcohol: can interfere with hormone balance.
Lifestyle changes
- Stress management: chronic stress elevates cortisol, which can suppress thyroid function. Meditation, deep breathing and yoga are beneficial;
- Adequate sleep: sleep deprivation can worsen hormone imbalances;
- Regular exercise: improves metabolism and mood but should be balanced to avoid overexertion.
Hypothyroidism is a common but manageable condition that affects metabolism, energy and overall well being. Early diagnosis, thyroid hormone therapy, proper nutrition and lifestyle modifications can help individuals restore thyroid function and maintain long term health.
By optimizing thyroid health, individuals can improve energy levels, metabolic function, brain health and cardiovascular well being, all of which contribute to longevity and quality of life.
