Underactive Thyroid( Hypothyroidism): Foods to eat and avoid

Jul 9
8 min read

I studied diet and nutrition many years ago, but once I recieved my qualification, I decided to put it on the back burner to focus on my role as a Complementary Therapist! So what inspired me to write an article about underactive thyroid( hypothyroidism) and the foods to avoid and eat. It's personal beacuse I have hypothyroidism too and even though I take (Levothyroxine) thyroid medication daily, I still suffered from achy joints, excessive weight gain, dry itchy skin and brittle hair, and whenever I exercised, I was always fatigued and absolutely exhausted, even though my diet was extremely healthy( adhering to the recommended daily amount of the five a day ). No matter what I did, the weight never shifted, at times I felt as if I was constantly carrying around dead weight, I also suffered from low mood and experienced palpitations too. However, while on my Diet & Nutritions course, I discovered the link between diet and disease and through further research discovered, foods to avoid and to eat with an underactive thyroid( Hypothyroidism) However, once I eradicated certain food groups from my diet, mainly spinach/kale and soya, my weight miraculously dropped off, I gained more energy. my hair and skin improved plus I am in a much better frame of mind.

According to McIntosh, J.(2025), hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormones, which can result in a slower metabolism causing symptoms like fatigue, weight gain, and sensitivity to the cold.The most common cause of hypothyroidism is Hashimoto’s thyroiditis, is an autoimmune disorder where the immune system attacks the thyroid gland.While there is currently no cure, people can manage hypothyroidism with synthetic thyroid hormone medication, like levothyroxine( a medication that liturally saved my life) , to help restore hormone levels and alleviate the symptoms. When a person has hypothyroidism, consuming foods with iodine, selenium, and zinc can help the thyroid to work properly.

Certain foods such as soya, gluten, and processed foods may interfere with thyroid function or medication, so limiting those foods may help manage the condition, says Morales-Brown, P

( 2025 ). To help the body fully absorb thyroid medication, it is recommended to take it on an empty stomach, at least 30 to 60 minutes before breakfast, or 3 to 4 hours after dinner.

One should also avoid taking it within 4 hours of eating foods that contain iron or calcium.

The thyroid is a small, butterfly-shaped gland in the throat. Having hypothyroidism, or an underactive thyroid, means that this gland produces less of its hormones than the body needs. This can slow down the body’s metabolism and cause weight gain, tiredness, sensitivity to cold, constipation, dry skin, puffy face.hoarse voice, coarse hair and skin, muscle weakness, menstrual cycles that are heavier than usual or irregular, thinning hair, slowed heart rate, depression and memory problems. Mayo Clinic(2026)

How does the diet affect( Hypothyroidism) underactive thyroid

Having hypothyroidism means that the body does not have enough thyroid hormones.

While changing the diet cannot cure this, it can help manage the condition.

Foods that contain certain nutrients, such as iodine, selenium, and zinc, can help maintain a healthy thyroid function.Some foods may have a negative effect on the thyroid function and worsen symptoms of hypothyroidism.Some foods and supplements can interfere with how well the body absorbs thyroid replacement medicine, so limiting these can also help.

Foods containing Iodine

The body needs iodine to produce thyroid hormones. But because the body cannot make iodine, people need to get it from their diets.

Foods rich in iodine include, cheese, milk, iodized table salt, saltwater fish, seaweed and whole eggs A deficiency in iodine can cause an enlarged thyroid gland, known as a goiter, according to MacGill, M(2023) However, it's crucial to avoid consuming too much iodine, which can actually worsen hypothyroidism, For this reason, a person should only add more iodine to their diet unless recommended by your general practitioner or health provider.

Foods containing selenium

Selenium is a micronutrient that plays a role in the production of thyroid hormones and has antioxidant activity that thyroid tissue naturally contains.According to research,Calissendorff et al.(2017) conducted a randomized clinical trial in which selenium was shown to provide positive effect in the control of hypothyroidism and found that maintaining selenium levels in the body helps prevent thyroid disease and promotes overall health and wellbeing.

Foods rich in selenium include, Brazil nuts, tuna, shrimp, beef, turkey, chicken, ham, eggs, oatmeal and brown rice

Foods containing zinc

Zinc is another nutrient that is good for people with low levels of thyroid hormones, a study by Vafa et al. (2015) found that zinc supplementation, either alone or in combination with selenium, improved thyroid function in overweight or obese female hypothyroid patients.

Foods rich in zinc include, oysters, beef, crab, fortified cereals, pork, chicken, legumes, pumpkin seeds and yogurt

Foods to avoid and why

Certain nutrients can interfere with thyroid health. While foods rich in these nutrients are not off-limits, restricting the intake of these foods may help a person manage their hypothyroidism and weight.

Goitrogens

Three types of goitrogens found in foods like cruciferous vegetables are goitrins, thiocyanates, and flavonoids.Goitrogens are compounds that can interfere with thyroid function, primarily found in certain foods such as cruciferous vegetables like broccoli, cauliflower, and kale.

These compounds, particularly glucosinolates, can inhibit the thyroid's ability to absorb iodine and disrupt hormone synthesis.Petre, A.(2023). While goitrogens can affect thyroid health, moderate consumption of goitrogenic foods is generally safe for healthy individuals with adequate iodine intake. Cooking these foods can deactivate most goitrogens, making them safer to consume. However, individuals with thyroid conditions, especially hypothyroidism, should be cautious and consult healthcare providers regarding their dietary choices

Soya

According to research, Soya might interfere with how the body produces thyroid hormones, Nakamura, Y.(2017), However Otun , E( 2019) argues and says soya has no significant effect on thyroid levels and says identifying the effects of soya on thyroid function may require more research.

Foods that contain soya include- soy milk, soy sauce, edamame and tofu.

Gluten

People with Hashimoto’s disease( a chronic autoimmune disorder in which the immune system attacks the thyroid gland, gradually damaging it and often causing hypothyroidism (low thyroid hormone levels). are more likely to have celiac disease than people without either of those conditions, because hashimoto’s and celiac are both types of autoimmune disorder, and a person with either of these disorders are more likely to develop one or the other. Mayo Clinic(2025) Removing gluten from the diet improves thyroid function in people with hashimoto’s who do not have celiac disease

Celiac disease causes chronic inflammation and damage to the small intestine due to the ingestion of gluten, a protein in wheat and other grains, including barley, oats, and rye.

Treating celiac disease involves switching to a gluten-free diet. People with autoimmune-related hypothyroidism might try going gluten-free to see whether their symptoms will improve says Szkróbka, W, Okopie, N ( 2018)

Processed foods

Reducing the intake of ultra-processed foods and added sugars may help improve symptoms, manage weight, and boost overall well-being.Examples of ultra-processed foods and drinks that also contain high amounts of added sugar include- fast food,hot dogs, doughnuts,, cakes, biscuits and fizzy drinks

Other dietary tips

Most people absorb levothyroxine best when they swallow the tablet on an empty stomach between 30 to 60 minutes before breakfast and any coffee. If morning dosing is impossible, you can take it at bedtime as long as it is at least 3 hours after the last meal. Choose a time and stick to it daily, remember to have your (TSH) blood test re-checked up on your General Practitioners recommendations to ensure your dose is still conducive to your needs.Hartung,S (2025).

The following medications and supplements can interfere with the body’s absorption of thyroid medication, such as acid reflux( medication) , milk, calcium supplements,iron supplements. High-fibre foods, such as bran flakes, fibre bars, and drinks, foods high in iodine and soya-based.

Hypothyroidism meal plan: 7 days

In general, the best diet for a person with hypothyroidism contains plenty of fruits, vegetables, filling proteins, healthy fats, and moderate amounts of healthy carbohydrates.

Still, it is important for each person to experiment and develop a diet that helps them feel their best.

Here’s a 1-week meal plan for an omnivorous person with hypothyroidism:

Monday

Breakfast: Scrambled eggs with salmon
Lunch: A salad with grilled shrimp
Dinner: A black bean and vegetable stir-fry with brown rice

Tuesday

Breakfast: A fruit salad with yogurt and sliced almonds
Lunch: A grilled chicken salad topped with pumpkin seeds
Dinner: Baked salmon with roasted vegetables

Wednesday

Breakfast: An omelet with mushrooms and zucchini
Lunch: Bean soup with a whole wheat or gluten-free roll.
Dinner: Shrimp fajitas with corn tortillas, peppers, and onions

Thursday

Breakfast: A protein smoothie with berries and nut butter
Lunch: A cauliflower rice bowl with ground turkey, black beans, salsa, guacamole, cheese, and veggies
Dinner: Roasted chicken with quinoa and broccoli

Friday

Breakfast: Poached or boiled eggs with avocados and berries
Lunch: Tuna salad lettuce cups with whole wheat or gluten-free crackers
Dinner: A grilled steak with baked sweet potato and a side salad

Saturday

Breakfast: Coconut yogurt with berries and almond butter
Lunch: A turkey burger on a green salad with sweet potato fries
Dinner: Pan-fried crab cakes with brown rice and vegetables

Sunday

Breakfast: A frittata with vegetables
Lunch: A quinoa bowl with vegetables and chickpeas
Dinner: Grilled shrimp skewers with bell peppers and pineapple

Tips for weight loss with hypothyroidism

People with hypothyroidism may gain weight more easily than people without the condition. This is because hypothyroidism can slow metabolism.

Having a healthy diet rich in fruits, vegetables, filling proteins, and healthy fats can help manage weight and boost well-being. These foods are also rich in fibre , which may help people feel fuller for longer.In addition, regular moderate- to high-intensity aerobic exercise and strength training can help boost metabolism and promote weight loss. Staying active can also improve levels of energy and the quality of sleep.

In addition, a person may notice a small weight reduction typically under 10% when they take medication to treat hypothyroidism.

Summary

Hypothyroidism refers to the thyroid gland not producing enough of certain hormones to meet the body’s needs.Untreated, it can reduce metabolism and cause fatigue, among other symptoms. Treatment usually involves taking a synthetic version of thyroid hormones.

Some nutrients and foods can help or hinder the thyroid’s function. Overall, it is important to aim for a healthy diet that supports the absorption of thyroid medication and helps with maintaining a healthy weight.

Reference

Selenium and Thyroid Disease: From Pathophysiology to Treatment

Ventura, M, Melo, M Carrilho, F(2017) cited in Selenium and Thyroid Disease: From Pathophysiology to Treatment - Ventura - 2017 - International Journal of Endocrinology - Wiley Online Library

Hypothyroidism: Foods to eat and avoid. Morales-Brown, P(2025) cited in

Best diet for hypothyroidism: Good foods, what to avoid, and meal plan .

Hypothyroidism (underactive thyroid).The Mayo Clinic(2025) cited in Hypothyroidism (underactive thyroid) - Symptoms and causes - Mayo Clinic

Effects of Zinc and Selenium Supplementation on Thyroid Function in Overweight and Obese Hypothyroid Female Patients: A Randomized Double-Blind Controlled Trial. Mahmoodianfard, S,et al(2015) cited in Overweight and Obese Hypothyroid Female Patients: A Randomized Double-Blind Controlled Trial - PubMed

Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism. Felker, P ,Bunch ,R, M Leung A( 2016)