Hypothyroidism

In brief

Hypothyroidism is an underactive thyroid: the body runs on a lower setting
Often there is an autoimmune disease (Hashimoto’s); then anti-TPO antibodies are elevated in the blood
Treatment with levothyroxine usually restores hormone levels and reduces symptoms
Lifestyle and nutrition are an important addition: unprocessed food, sufficient protein, healthy fats
Pay attention to adequate iodine, selenium, and vitamin D, preferably from food

1. What does the thyroid do?

The thyroid is a small organ in the neck, in front of the windpipe. It produces thyroid hormones: T4 and T3.

These hormones play an important role in:

Energy and weight
Body temperature
Heart rate and blood pressure
Mood and concentration
Bowel movements
Muscles, hair, and skin

When the thyroid works too slowly, there is a shortage of these hormones. This is called hypothyroidism.

2. What is hypothyroidism?

With hypothyroidism, the thyroid works too slowly. The body essentially runs on a lower setting.

Important causes are:

An autoimmune disease (Hashimoto’s), where the immune system attacks the thyroid
Surgery or previous treatment of the thyroid
Certain medications
Sometimes deficiencies in iodine, selenium, or vitamin D

With autoimmune hypothyroidism, anti-TPO antibodies are often found in the blood. These are antibodies against a protein in the thyroid (TPO: thyroperoxidase).

Hypothyroidism is usually well treatable, but often a long-term or lifelong condition.

3. Common symptoms

Not everyone has the same symptoms. Symptoms can develop slowly and often go unrecognized for a long time.

Common symptoms are:

Fatigue and less energy
Getting heavier or difficulty losing weight
Feeling cold easily, cold hands and feet
Slow bowel movements or constipation
Dry skin, hair loss, brittle nails
Stiff or painful muscles and joints
Slow heart rate, less endurance
Heavier or irregular menstruation
Low mood, irritability, slow thinking (“cotton wool in the head”)
Higher cholesterol

If several of these symptoms are recognizable, it’s worthwhile to have this investigated with blood tests.

4. Testing and results

When an underactive thyroid is suspected, blood is usually drawn.

Important values

Value	Meaning
TSH	Hormone from the pituitary that controls the thyroid. With an underactive thyroid, TSH is often elevated
Free T4 (FT4)	Thyroid hormone in the blood. With an underactive thyroid, FT4 is often lowered

Additionally can be measured

Anti-TPO antibodies: often elevated with autoimmune thyroid disease (Hashimoto’s)
Vitamin D
Iron/ferritin and vitamin B12
Cholesterol and blood sugar

Target values

TSH is usually adjusted within the reference values of the laboratory
FT4 should also be within the reference values
For vitamin D, a value above approximately 75 nmol/L is often aimed for

Which exact target values are appropriate depends on age, symptoms, and overall health.

5. Treatment with thyroid hormone

The standard treatment is levothyroxine. This is a tablet with thyroid hormone (T4).

Important points of attention

Take the tablet at the same time every day
Preferably on an empty stomach, with a glass of water
Then wait at least 30 minutes to an hour before eating and drinking (except water)
Take iron or calcium supplements at a different time of day

After starting or changing the dose, it usually takes 6 to 8 weeks before it’s meaningful to check blood values again. The dose can then be adjusted if necessary.

Many people notice clear improvement in symptoms over weeks to months once the dose and values are well adjusted.

6. Lifestyle and nutrition with hypothyroidism

Medication is the foundation of treatment. Lifestyle and nutrition can support recovery and help improve energy, weight, and overall health.

6.1 Eating in general

Choose mainly:

Unprocessed products
Sufficient protein: meat, fish, eggs, unsweetened dairy (if well tolerated)
Lots of vegetables, possibly supplemented with some berries
Healthy fats: olive oil, butter, nuts, seeds, avocado

Limit:

Sugar, soft drinks, fruit juice
White bread, white pasta, cookies, pastries
Chips, snacks, and other highly processed products

6.2 Iodine

Iodine is needed for producing thyroid hormone.

Important sources of iodine:

Seafood, shellfish
Eggs
Iodized salt
Bread (if the baker uses iodized salt)

If you eat little or no bread and little fish, it’s important to pay extra attention to other sources of iodine.

Daily requirement: the recommended amount for adults is around 150 micrograms of iodine per day, from food and any supplement together.

Safe guidelines:

Preferably choose an iodine tablet or multivitamin with about 75 to 150 micrograms of iodine per day
Don’t use multiple iodine tablets at once
Avoid high iodine doses from supplements

With this approach, iodine intake stays near the desired amount, without large peaks.

6.3 Selenium

Selenium is important for converting T4 to T3 and for protecting the thyroid.

Important sources:

Meat and organ meats
Fish
Eggs
Nuts (especially Brazil nuts)

Safe approach:

Try to get selenium mainly through food
If a supplement is still used: choose a low dose (for example 50 to 100 micrograms per day)
Avoid long-term use of higher doses

With symptoms such as hair loss, brittle nails, or gastrointestinal complaints in combination with high selenium supplementation, it may be wise to stop.

6.4 Vitamin D

Vitamin D is important for bones, muscles, and the immune system.

Important sources:

Sunlight on the skin
Fatty fish, eggs, liver
Fortified products and vitamin D supplements

Many people have low vitamin D levels, especially in winter and with little outdoor light.

Practical:

A blood value above approximately 75 nmol/L is often aimed for
A commonly used maintenance dose is 800 to 2000 IU vitamin D3 per day
The exact dose depends on baseline value, weight, skin type, and sun exposure

6.5 Weight, exercise, sleep, and stress

Weight:

Hypothyroidism can make you gain weight more easily
Once the thyroid is reasonably adjusted, a calm and sustainable approach helps:
- No crash diets
- Sufficient protein
- Attention to muscle building and daily exercise

Exercise:

Walking every day is a good and safe start (for example 30 minutes, possibly divided over the day)
2 to 3 times per week simple strength training supports muscle mass and metabolism

Sleep:

Aim for 7 to 9 hours of sleep per night
Fixed bed and wake times help hormone balance
Limit bright screen light (phone, tablet, TV) in the last hour before sleep

Stress:

Long-term stress can disrupt hormone balance and recovery
A daily short rest moment helps, for example:
- Calm breathing
- Relaxation exercises
- Walking in nature
- Taking time for things that bring calm

7. When to be extra alert?

It’s wise to be extra alert with:

Clear worsening of fatigue, low mood, or anxiety
Unexplained rapid weight gain or loss
Heart palpitations, trembling, sweating, strong restlessness (may indicate too much thyroid hormone)
Pregnancy or desire to have children
Starting new, strongly dosed supplements (especially iodine and selenium)

8. Summary

Hypothyroidism is an underactive thyroid: the body runs on a lower setting
Often there is an autoimmune disease; then anti-TPO antibodies are elevated in the blood
Treatment with levothyroxine usually restores hormone levels and reduces symptoms
Lifestyle and nutrition are an important addition: unprocessed food, sufficient protein, healthy fats, and limiting sugar and white flour products
Pay attention to adequate iodine, selenium, and vitamin D, preferably from food and if necessary with low, safe doses from supplements (don’t dose high)
Calm weight loss, regular exercise, good sleep, and reducing chronic stress support recovery

Veelgestelde vragen

What is hypothyroidism?

Hypothyroidism is an underactive thyroid where the body produces too little thyroid hormone (T4 and T3). The body essentially runs on a lower setting. The most common cause is the autoimmune disease Hashimoto's.

What are the symptoms of an underactive thyroid?

Common symptoms are: fatigue, weight gain, feeling cold easily, slow bowel movements, dry skin, hair loss, stiff muscles, low mood, slow thinking, and higher cholesterol. Symptoms can develop slowly and often go unrecognized for a long time.

How do I best take levothyroxine?

Take the tablet at the same time every day, preferably on an empty stomach with a glass of water. Then wait at least 30 minutes to an hour before eating and drinking (except water). Take iron or calcium supplements at a different time of day.

Which nutrients are important for hypothyroidism?

Iodine (for thyroid hormone production), selenium (for T4 to T3 conversion), and vitamin D are important. Preferably from food: seafood, eggs, Brazil nuts, fatty fish. Supplements only in low doses and with proven deficiency.

Medische Disclaimer: De informatie van Stichting Je Leefstijl Als Medicijn over leefstijl, ziektes en stoornissen mag niet worden opgevat als medisch advies. In geen geval adviseren wij mensen om hun bestaande behandeling te veranderen. We raden mensen met chronische aandoeningen aan om zich over hun behandeling goed door bevoegde medische professionals te laten adviseren.

Medical Disclaimer: The information provided by Stichting Je Leefstijl Als Medicijn regarding lifestyle, diseases, and disorders should not be construed as medical advice. Under no circumstances do we advise people to alter their existing treatment. We recommend that people with chronic conditions seek advice regarding their treatment from qualified medical professionals.