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Originally published on 10th July 2018 Last updated on 31st January 2019
Below are the most common vitamin and mineral deficiencies that I suggest you check out if you’re still feeling unwell.
You can also find a list of recommended supplements here, but please do not supplement unless you’ve confirmed low/deficient levels.
They are either water soluble (not stored in the body and excess is lost immediately through urine) or fat soluble (can be stored in the body). For fat soluble vitamins, you need to consume fat in order to absorb them and reap the benefits.
Iron and Ferritin
Perhaps the most common are low levels in iron or ferritin (stored iron), which can lead to dry skin, heavy fatigue, poor stamina, depression and even pale skin and dark bags under the eyes. I’ve been anaemic a few times myself and it presented with all of these signs. Iron deficiency also impairs thyroid hormone synthesis.
It is worth bearing in mind that as hypothyroidism mainly affects women, many thyroid patients will have low levels of iron/ferritin due to period issues such as heavy or long periods. Iron is central to the production of both red blood cells and thyroid stimulating hormone (TSH). Iron is also important for your thyroid health as it makes the hormone T4, and converts T4 to T3. , 
Always have your levels of this mineral tested before taking a supplement as taking extra iron can be dangerous.
However, Bisglycinate is a popular type of iron as it doesn’t cause stomach issues or constipation. You can find it here: Solgar Gentle Iron – Iron Bisglycinate – 180x20mg Vegicaps.
Taking Vitamin C with iron triples the absorption rate.
Selenium is not naturally occurring in the body, but is a trace mineral found in food and soil. It is vital for the immune system, reproduction and thyroid function, including conversion of thyroid hormone T4 to T3, making it essential for good metabolic function. It is also an antioxidant.
With low selenium levels, you could have symptoms such as brain fog and decreased cognitive functions, as well as a lack of energy and blood results that look ‘OK’, even if you feel unwell. You could also have low Free T3 as a sign that selenium is low or deficient, causing not enough T4 to T3 conversion.
Selenium is also reported to lower thyroid antibodies, helping to manage Hashimoto’s more effectively. 
Being low in B12 can cause tiredness, fatigue, a sluggish metabolism and poor adrenal health. Vitamin B-12 and folic acid are both important for energy and heart protection. B12 is also needed in order to make TSH, a hormone secreted by the pituitary gland that instructs the thyroid on how much thyroid hormone to make. People with hypothyroidism often seem to struggle to absorb B12 and low levels in it can cause mental illness, various neurological disorders, neuralgia, neuritis and bursitis. A leaky gut and poor gut health could well be behind why so many of us have low levels. Vegan and vegetarian diets also pose more risk and taking excessive amounts of Vitamin C can also decrease the availability of B12.
You can find this supplement online rather easily, but I’ve linked to an Amazon one, here: Solgar 500 mcg Vitamin B12 Vegetable Capsules – 50 Capsules.
Low Vitamin D levels seem to be increasingly common, not just among thyroid patients but the general population as a whole. Low levels in this vitamin can cause depression, back pain, joint pain and stiffness, fatigue and poor immune system function. A Vitamin D deficiency can also stop T3 from activating your cell to increase metabolic rate (cold intolerance, low energy and weight gain). Vitamin D has also been shown to lower thyroid antibodies. 
A popular vitamin D supplement can be seen here – Solgar, Natural Vitamin D3, 1000 IU, 180 Tablets. It should always be taken with Vitamin K2.
Vitamin A is fat soluble. A Vitamin A deficiency can stop T3 from activating your cell to increase metabolic rate and energy levels but it is also important for good immune system function. It keeps mucous and skin membranes healthy and aids ageing prevention. Vitamin A must be accompanied by protein to make it available to the body, so if you are on a low protein diet, you may be deficient in this. If you are low on Vitamin A, your ability to produce TSH is limited. This vitamin is also required by the body to convert T4 to T3.
However, it is toxic in large amounts and pregnant women are even advised again consuming liver pate due to high amounts of Vitamin A contained in it and its links with birth defects.
An antioxidant, vitamin E is a fat-soluble vitamin important for many processes in the body, including producing TSH. It is also important for the skin and is good for high blood sugar levels (blood sugar imbalances are common with autoimmune hypothyroidism).
One example: Vitamin E Capsules.
The mineral Zinc is needed for making TSH, a hormone produced by the pituitary to instruct the thyroid gland in making thyroid hormone. It also plays a role in the functioning of the immune system and the conversion of T4 to T3. Solgar 50 mg Zinc Tablets – Pack of 100
The mineral Magnesium is needed in order to make TSH and for the conversion of T4 into T3.
It seems that a diet high in refined food and caffeine can encourage magnesium loss.
Supplementing magnesium can also help cramps, constipation, energy and aches and pains, which are all common symptoms of hypothyroidism.
Magnesium Malate and Chelate seem to be the most popular among thyroid patients, so I’ve provided a link to Magnesium Chelate here: Doctor’s Best High Absorption 100% Chelated Magnesium (120 Tablets)
Without question, iodine is the most controversial mineral when it comes to thyroid health. Some say to supplement, others say not to. It is required by the thyroid gland in order to make the thyroid hormone T4, though, and not enough Iodine can actually cause hypothyroidism. Iodine is required for the normal process of metabolisation of cells and is needed for a normally functioning thyroid – the production mechanisms of thyroid hormones. You can present with a goitre if you’re lacking in iodine due to thyroid cells enlarging.
As recommended by Natural Endocrine Solutions here, for anyone who wants to try supplementing iodine, it is first recommended getting your levels tested, and then if it shows you’re iodine deficient, to start with a small dosage, along with taking antioxidants such as selenium and vitamin C, and magnesium.
If you are looking to try iodine, you can find it on Amazon here: Lugols Iodine – a 12% Solution 30ml.
You can also find a list of recommended supplements to think about here, but please do not supplement unless you’ve confirmed low/deficient levels. Doing so can do more harm than good and you should always consult your doctor first.
Is there one really good multivitamin that incorporate all that’s needed in effective doses?
We’re often advised against multivitamins, as the amount of each vitamin contained in them is usually so small, that it doesn’t do an awful lot. Or we’re told to avoid them because different vitamins can cancel each other out when taken together (or affect each other’s absorption).
However, my functional medicine practitioner had me take a pregnancy multivitamin which she said were the best kind to take if you have to (i.e. due to finances).
Have you had these vitamin and mineral levels tested?
Still feeling tired?
There is also the online thyroid course ‘Freedom From Thyroid Fatigue’, which walks you through how to overcome thyroid fatigue with a personalised approach. Vitamin levels, diet, exercise and more are all covered.
Rachel Hill is the highly ranked and award-winning thyroid patient advocate, writer, blogger, speaker and author behind The Invisible Hypothyroidism. She has two books: ‘Be Your Own Thyroid Advocate‘ and ‘You, Me and Hypothyroidism‘. Her thyroid advocacy work includes authoring books, writing articles, blogging and speaking on podcasts. Rachel has worked with The National Academy of Hypothyroidism, BBC, The Mighty, Yahoo, MSN, ThyroidChange and more. She is well-recognised as a useful contributor to the thyroid community and has received eight 2020 WEGO Health Award Nominations.