Thyroid Health: What You Need to Know

Your thyroid is a small, butterfly-shaped gland at the base of your neck with an outsized influence on virtually every system in your body. It controls your metabolism, energy levels, body temperature, weight, and even your mood. Despite its importance, most people know surprisingly little about this gland — until something goes wrong. Here's what you need to know about how your thyroid works, what can go awry, and what you can actively do to support it.

What Your Thyroid Does and Why It Matters

The thyroid produces two primary hormones: T4 (thyroxine) and T3 (triiodothyronine). These hormones affect virtually every cell in your body. They regulate:

• Metabolic rate: How fast your body burns calories and produces energy
• Heart rate and blood pressure: Thyroid hormones directly influence cardiovascular function
• Body temperature: Why some people are always cold often traces back to thyroid function
• Digestion: The speed at which food moves through your digestive tract
• Muscle and nerve function: Reflexes, muscle strength, and cognitive performance
• Skin, hair, and nails: Thyroid hormones influence skin and hair growth cycles
• Mood and mental health: Hormone levels have a direct impact on neurotransmitter activity

The thyroid is controlled by the hypothalamus and pituitary gland in the brain through a feedback loop. When thyroid hormone levels drop, the pituitary releases TSH (thyroid-stimulating hormone), which prompts the thyroid to produce more hormones. This system normally works with precision — until it falls out of balance.

Hypothyroidism: When the Thyroid Underperforms

An underactive thyroid is the most common thyroid condition. It affects an estimated 5 percent of the population, with women affected significantly more often than men.

Common symptoms of hypothyroidism:

• Persistent fatigue and exhaustion
• Unexplained weight gain or difficulty losing weight
• Feeling cold all the time
• Dry skin and brittle hair
• Constipation
• Concentration and memory problems ("brain fog")
• Low mood or depression
• Muscle weakness and joint pain
• Elevated cholesterol levels

The most common cause in developed countries is Hashimoto's thyroiditis — an autoimmune condition where the immune system attacks thyroid tissue. Other causes include iodine deficiency, certain medications, and previous thyroid surgery.

Hyperthyroidism: When the Thyroid Overproduces

In hyperthyroidism, the thyroid produces too many hormones, which accelerates metabolism across the entire body.

Common symptoms of hyperthyroidism:

• Unexplained weight loss despite normal appetite
• Rapid heartbeat and heart palpitations
• Nervousness, irritability, and restlessness
• Trembling hands
• Excessive sweating and heat intolerance
• Sleep disturbances
• Diarrhea or frequent bowel movements
• Muscle weakness

The most common cause is Graves' disease — also an autoimmune condition. Benign thyroid nodules can also lead to hormone overproduction.

Nutrition for a Healthy Thyroid

The right nutrition can support thyroid function. Several nutrients are particularly important:

Iodine: The essential building block for thyroid hormones. Iodine deficiency remains common in many regions. Good sources include iodized salt, ocean fish, seafood, and seaweed. Caution: excessive iodine can be harmful for people with existing thyroid conditions.

Selenium: Essential for converting T4 into T3 (the more active hormone). The thyroid has the highest selenium concentration of any organ. Best sources: Brazil nuts (just 1–2 per day cover your needs), fish, eggs, and whole grains.

Zinc: Important for hormone production and the T4-to-T3 conversion. Sources: meat, seafood, pumpkin seeds, lentils, and cashews.

Iron: Iron deficiency can impair thyroid function. This is especially relevant for women with heavy menstrual periods. Sources: red meat, legumes, spinach, and fortified cereals.

Vitamin D: Research links vitamin D deficiency to autoimmune thyroid conditions. Adequate levels — through sunlight exposure and winter supplementation — are advisable.

Lifestyle Factors That Affect Your Thyroid

Beyond nutrition, several lifestyle factors play a role:

Stress: Chronic stress can disrupt the hypothalamic-pituitary-thyroid axis. Cortisol, the stress hormone, inhibits the conversion of T4 to T3. Stress management is therefore directly relevant to thyroid health.

Sleep: Sleep deprivation affects hormonal regulation, including thyroid hormones. Consistent, adequate sleep supports overall hormonal balance.

Environmental factors: Certain environmental chemicals — known as endocrine disruptors — can interfere with thyroid function. These include BPA (found in some plastic containers), pesticides, and heavy metals. Minimize unnecessary exposure where possible.

Exercise: Moderate, regular exercise supports metabolism and hormone regulation. For those with hypothyroidism, exercise can be especially helpful in countering fatigue and weight gain.

When to See a Doctor

Many thyroid problems go undetected for years because symptoms are nonspecific and develop gradually. A simple blood test (TSH, free T3, free T4) can provide clarity.

Seek medical advice if:

• You notice several of the symptoms described above
• You experience unexplained weight changes
• You feel a lump or swelling in your neck
• You have a family history of thyroid disease
• You feel persistently exhausted or unwell despite a healthy lifestyle

Regular screening is especially important for women over 35, people with family histories of autoimmune conditions, and those who are pregnant or planning pregnancy.

Tracking your well-being, energy levels, and weight over time can provide valuable clues and help you notice changes early.

getNudge helps you monitor your well-being and vital signs over time. The app shows you connections between nutrition, exercise, sleep, and how you feel — so you can spot patterns that might signal changes worth investigating. Download getNudge today and take a proactive approach to your health.