Vitamins, dietary nutrients and minerals play a surprisingly big role in how healthy our thyroid is. We are still learning how many of these nutrients work but so far we know that the top 10 nutrients for hypothyroidism (low thyroid hormone) are:
1. Vitamin A – Supplementation with Vitamin A for 4 months has been shown to significantly reduce TSH levels and increase T3 levels in premenopausal women(1). Vitamin A deficiency creates hypothyroidism and particularly seems to affect T3 levels which may not be picked up in a standard blood test(2). The recommended daily amount of Vitamin A is 900-3000μg per day but it is much safer as beta carotene, the inactive form of vitamin A (which has no upper threshold). It is also worth noting that Vitamin A is a fat-soluble vitamin and therefore cannot be absorbed without fat.
Top 5 sources of Vitamin A in order are:
- Goji berries – dried (8128μg per 100g)
- Liver – beef, panfried (5454μg per 100g)
- Sweet potatoes (4490μg per 100g) most as beta-carotene
- Spinach – raw (852μg per 100g) most as beta-carotene
- Carrots – raw (627μg per 100g) most as beta-carotene
2. B vitamins including B2, B6 & B12
- B2 (riboflavin) deficiency causes low thyroid hormone levels(3) – the pathways for B2 and thyroid hormone production involve methylation and therefore may be affected by MTHFR gene mutations. Patients with B2 deficiency are also significantly more prone to depression (3). T4 also helps B2 be converted to its more active form so it can be used by the body(4). B2 deficiency can also lead to B6 deficiency(5). The recommended daily amount of Vitamin B2 is 1.3-40mg per day. B2 can be destroyed by sunlight.
Top 5 sources of Vitamin B2 in order are:
- Liver – beef, panfried (3mg per 100g)
- Eggs – whole, boiled (0.4mg per 100g)
- Portabello mushrooms – grilled (0.4mg per 100g)
- Yoghurt or kefir – full fat (0.3mg per 100g)
- Beef steak – cooked (0.3mg per 100g)
- B6 (pyroxidine) – Animal studies show low B6 (pyroxidine) levels can cause a reduction in TSH and therefore low T3 and T4. its action seems to be on the hypothalamus(6). Low B6 causes poor immune function important in the main cause of thyroid disease. The recommended daily amount of Vitamin B6 is 1.4-200mg per day. Women taking oral contraceptives can be low in B6 as can those with inflammatory diseases like rheumatoid arthritis.
Top 5 sources of Vitamin B6 in order are:
- Pistachios – roasted (1.7mg per 100g)
- Tuna – yellowfin, cooked (0.9mg per 100g)
- Salmon – wild altlantic (0.8mg)
- Liver – beef, panfried (0.7mg per 100g)
- Chicken or turkey breast – roasted (0.6mg per 100g)
- B12 – Approximately 40% of hypothyroid patients are B12 deficient and many don’t have any symptoms of B12 deficiency and even those with ‘normal’ B12 levels had an improvement in symptoms with B12 supplements. (7). The recommended daily amount of Vitamin B12 is 1.5μg-2000μg per day. Vegans very often become Vitamin B12 deficient unless taking a supplement as it is from animal based foods.
Top 5 sources of Vitamin B12 in order are:
- Clams (98.9μg per 100g)
- Liver – beef, panfried (26μg per 100g)
- Sardines – tinned in oil (8.9μg per 100g)
- Tuna – tinned in water (4.2μg per 100g)
- Beef steak – grass-fed, minced, cooked (2.6μg per 100g)
3. Vitamin C – Can protect the thyroid from damage by chemical toxins and heavy metals which are a risk to the thyroid (8) (9). The recommended daily amount of Vitamin C is 60mg-1000mg per day. However, Vitamin C is very safe even at very large doses of up to 10,000mg and it’s only side effect is diarrhoea (which can make it useful to aid constipation). Vitamin C cannot be stored in the body so must be consumed regularly.
Top 5 sources of Vitamin C in order are:
- Red pepper – sweet, raw (128mg per 100g)
- Kiwi fruit (92.7mg per 100g)
- Broccoli – cooked (64.9mg per 100g)
- Strawberries (58.8mg per 100g)
- Oranges (53.2mg per 100g)
4. Vitamin D – Vitamin D helps maintain a healthy immune system. When Vitamin D levels are low you are more likely to have autoimmune thyroid disease (10), such as hypothyroidism (Hashimoto’s). In the UK the low light levels make Vitamin D deficiency common. After taking a Vitamin D supplement patients saw a decrease in the levels of antibodies attacking the thyroid gland(11). The recommended daily amount of Vitamin D is 10-100μg per day (400-4000IU). Our diet rarely gives us enough Vitamin D, it is mainly made from sunlight outdoors. Through 6 months of the year the UK does not have high enough light levels for us to produce adequate Vitamin D. It is important to take a supplement* if you are pregnant, spend a lot of time indoors or have a darker skin colour. *If over 30 take Vitamin K2 alongside your Vitamin D supplement to avoid calcification of blood vessels.
Top 5 sources of Vitamin D in order are:
- Sunlight – Our main source
- Swordfish – cooked (16.5μg per 100g)
- Salmon – sockeye, cooked (13.2μg per 100g)
- Tuna – yellowfin, cooked (1.7μg per 100g)
- Egg – large, boiled (2.2μg per 100g)
5. Iodine – An essential mineral for the thyroid found in seafood and seaweed. Thyroid hormones are made using iodine and therefore it is essential for their production. The RDA of iodine is 140-500μg per day. Seaweeds are a great addition to your food or taken as a supplement to support your thyroid. We have a ground, dried seaweed shaker next to our salt and pepper and add it to food regularly.
Top 5 sources of Iodine in order are:
- Seaweed (3000-200,000μg per 100g)
- Haddock (323.7μg per 100g)
- Cod (191.6μg per 100g)
- Kefir (50μg per 100g)
- Eggs (50μg per 100g)
6. L-Tyrosine – Is an important amino acid (component of protein) needed to make thyroid hormone. Without enough iodine or tyrosine we cannot make thyroid hormone. L-Tyrosine is found in dairy, meats, fish, eggs, nuts, beans and wheat. L-Tyrosine supplements are also shown to help brain function when stressed (12) and can help us to multitask (13). The RDA of Tyrosine is 33mg per kg per day e.g. 2310mg for a 70kg man per day and the upper limit is unknown but up to 300mg/kg (21000mg for a 70kg man) have been used safely.
Top 5 sources of Tyrosine in order are:
- Parmesan (1995mg per 100g)
- Meat – beef or lamb, roasted (1386mg per 100g)
- Salmon – cooked (1157mg per 100g)
- Chicken – breast, cooked (1155mg per 100g)
- Pumpkin seeds (1093mg per 100g)
7. Magnesium – Low levels of magnesium seem to cause a decrease in T4 (thyroid hormone) levels (15) and magnesium supplements can help raise T4 levels (15). The RDA is 270-400mg per day. Magnesium deficiency occurs more commonly in those with bowel diseases and type 2 diabetes.
Top 5 sources of Magnesium in order are:
- Almonds – dry roasted (281mg per 100g)
- Cashews – roasted (292mg per 100g)
- Pumpkin seeds (262mg per 100g)
- Peanuts – dry roasted (176mg per 100g)
- Spinach – boiled (79mg per 100g)
8. Omega 3 fats – Can protect brain function against the negative effects of hypothyroidism improving memory (14) and can improve the effectiveness of thyroid hormone in the body (16) (so may improve symptom of hypothyroidism). There are several different types of omega 3 fat including ALA (alpha-linolenic acid) which is present in plant oils, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) which are present in fish oils. Raising our levels of EPA and DHA from fish oils helps us reduce inflammation and improves health.
*Krill oil is the most bioavailable (easily used by the body) form of omega 3 (17). The recommended daily amount of omega 3 (mainly from DHA & EPA) is 500mg per day if you are not eating fish then you need up to 4 times as much ALA to get the balance of omega 3’s. Up to 4000mg of omega 3 daily can be taken safely and is recommended in some health conditions.
Top 5 sources of Omega 3 are:
- Krill oil (42000mg per 100g as EPA & DHA)*
- Mackerel (1294mg per 100g s EHA & DPA)
- Salmon (1071mg per 100g as EPA & DHA)
- Flax seed (24200mg per 100g as ALA)
- Chia seed (17830mg per 100g as ALA)
- Walnuts (7992mg per 100g)
9. Selenium – One of the most important minerals for the thyroid, selenium is essential for a healthy thyroid throughout life and improves the symptoms of hypothyroidism in Hashimoto’s disease (18) and taking selenium as a supplement improves levels of anti-thyroid antibodies and can improve thyroid function especially in pregnancy (19). The RDA is 60μg-75μg and up to 350μg daily can be taken safely.
Top 5 sources of Selenium in order are:
- Brazil nuts (1820μg per 100g)
- Halibut – cooked (55.4μg per 100g)
- Sunflower seeds(53μg per 100g)
- Sardines (52.7μg per 100g)
- Shitake mushrooms – cooked (24.8μg per 100g)
10. Zinc – Another critical mineral for the thyroid gland. Zinc supplements can improve T3 levels and decrease TSH levels and improve conversion from T4 (inactive form of thyroid hormone) to T3 (active form) (20). Zinc needs to be taken in daily as the body has no ability to store it. Vegetarians and those with digestive problems are more likely to be low in zinc. The RDA is 7-11mg daily and up to 25mg daily is safe to take.
Top 5 sources of Zinc in order are:
- Oysters (90.5mg per 100g)
- Pumpkin seeds (7.6mg per 100g)
- Crab (7.6mg per 100g)
- Cashew nuts – raw (5.8mg per 100g)
- Beef – mince, cooked (4.8mg per 100g)
- Chickpeas – tinned (1.5mg per 100g)