What vitamins should not be taken with thyroid medication?

This article outlines which vitamins should not be taken with thyroid medication, so that you can maintain a healthy thyroid gland and avoid negative interactions.

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Posted

November 03, 2021

The standard of care for hypothyroidism and Hashimoto’s is to utilize a synthetic thyroid hormone replacement medication identical to the T4 hormone produced by the thyroid gland.

Most medically trained doctors will prescribe levothyroxine to their patients, of which the most well-known brand name in the UK is Synthroid.

While this article focuses on things that can potentially interact with or sabotage the effectiveness of T4 medications, it’s worth noting that some people may never feel their best taking only T4 thyroid medication.  It is also important to look out for some of the non-active ingredients that cause side effects and worsening of symptoms. 

 

Multivitamins

The most popular thyroid supplements include iodine combined with thyroid-relevant nutrients such as B vitamins, zinc, selenium, copper, and molybdenum, and thyroid-stimulating herbs such as ashwagandha and guggul. You may find some of the amino acids such as tyrosine included as well adrenal supporting herbs such Siberian Ginseng and Liquorice. It is important that you choose a thyroid supplement containing ingredients that have been extensively studied for their efficacy and safety in peer reviewed clinical trials.
As a general recommendation, multivitamins need to be taken away from thyroid medication but we always recommend you consult your doctor or practitioner before starting a new supplement regime.

B12

B12 is required for protein synthesis, cell reproduction, and normal growth. Vegans and vegetarians are at greatest risk of deficiency, as B12 is only found in animal foods and cannot be synthesized by the human body. Those with pernicious anaemia, H. pylori, gut hyperpermeability, dysbiosis and SIBO may also be susceptible. Another important consideration is high homocysteine levels (often a sign of B12 and folate deficiency) which is linked with increased risk of cardiovascular disease and high cholesterol [1]. 

Patients with Hashimoto’s and Hypothyroidism have a greater risk of being B12 deficient due to the comorbidities mentioned above. Vitamin B12 is often best taken sublingually, especially if pernicious anaemia (a type of autoimmune condition in which the immune system attacks the intrinsic factor, a protein in our stomach that is required for B12 absorption), and H. pylori are key factors. As always, take your supplements away from medication under medical supervision.

Vitamin D

Vitamin D deficiency has been associated with numerous autoimmune diseases in the scientific literature [2]. Vitamin D plays an important role in balancing the Th1 (cell-mediated) and Th2 (humoral) arms of the immune system. It does this by influencing T-regulatory (Th3) cells, which govern the expression and differentiation of Th1 and Th2 cells [3].

There is significant amount of medically reviewed data in which Vitamin D deficiency is associated with autoimmune thyroid disease (AITD) [4], and has been shown to benefit autoimmune-mediated thyroid dysfunction [5].

Vitamin D has also been shown to regulate insulin secretion and sensitivity and balances blood sugar [6].

Vitamin D is often taken sublingually and is recommended to be taken away from your thyroid medication. If you are taking an immunosuppressant medication, please consult your doctor or practitioner. 

Collagen

Collagen is a protein that is the main component of connective tissue, including cartilage, tendons, bone, skin, and ligaments. A great source of collagen is bone broth which is often recommended for healing the lining of the gut – a key component of our treatment protocol within the functional medicine approach. Find out more here.

As it’s a naturally occurring compound in our body, there is no known contraindication, especially if it comes from food. However, if you are sensitive to foods that are high in histamine, you may want to avoid bone broth while you heal, as collagen is considered a high histamine food.

Zinc

Zinc is important for gut health, immune function, tissue healing, the conversion of T4 to T3, and the production of TSH. It can help tighten the intestinal junctions of those with intestinal permeability as well.

Since zinc is needed to form TSH, those who are constantly producing TSH are more likely to develop deficiencies in zinc. If you have celiac disease or any other malabsorption syndrome that has caused intestinal damage, you may have an impaired ability to absorb zinc [7].

There are no known interactions between levothyroxine and zinc at this time, however we will always recommend consulting your practitioner or doctor.

CoQ10

CoQ10 is a vitamin like substance and has a crucial role in energy production within our cells. It has been shown to be highly effective in treating mitochondrial dysfunction, a commonly found problem in hypothyroidism.  

CoQ10 is generally a safe supplement but it needs to be taken away from your medication.

Guggul

Guggul is utilized by India’s traditional Ayurvedic medicine to help with many conditions. It seems to work by enhancing the activity of enzymes involved in thyroid hormone production. Most notably, isolated guggulsterone (the active compound of guggul) appears to enhance the activity of deiodinase, an enzyme that powers the conversion of inactive thyroid hormone (T4) into its active (T3) form [8].

However, taking guggul along with medications that are metabolized by liver enzymes may decrease the effectiveness of these medications [9] so it should be taken away from thyroid medication and under close medical supervision.

Iodine

Iodine is a trace mineral that is required for the synthesis of thyroid hormones [10].  Iodine is primarily found in sea vegetables such as dulse and wakame and seafood. Individual tolerance of iodine varies from one person to the next, so finding the right level (and form) of dietary and supplemental intake to support your thyroid may necessitate some experimentation. 

It is always best to consult an experienced practitioner when it comes to iodine as the right balance if this nutrient is key when it comes to managing thyroid health. Iodine is usually included in our thyroid function panel, find out more here. 

Acetyl L-carnitine

Carnitine is an amino acid that exists in several forms, including acetyl-L-carnitine, L-carnitine and propionyl-L-carnitine. Research shows that carnitine supplementation supports the reduction in fatigue in hypothyroid patients [11], as well as improves muscle weakness for both hypo- and hyper- thyroid patients by supporting mitochondrial function and energy production [12]. Carnitine deficiencies have been associated with thyroid imbalances and supplementing with carnitine may provide a useful tool in easing debilitating fatigue, a common symptom for hypothyroid patients. 

However, some evidence suggests that acetyl carnitine may inhibit the activity of thyroid drugs, so best taken far apart under careful supervision. 

Alpha lipoic acid

Alpha-lipoic acid is an organic compound with antioxidant properties. It’s made in small amounts by your body but also found in foods and as a supplement. It may benefit skin aging, memory, heart health, and weight loss. There is some data in the scientific literature which suggests it can be helpful for people with hypothyroidism [13].

However, alpha lipoic acid may be contraindicated with the thyroid hormone medication Levothyroxine as it can potentially lower levels of thyroid hormone T3 and increase levels of TSH [14] so it is best to consult your GP or practitioner before supplementing with this compound. 

Grapefruit juice

It is well-known that grapefruit juice can interact with many medications, including certain cholesterol-lowering statin drugs, blood pressure drugs, antihistamines, and thyroid medication. One of the ways grapefruit does this is by inhibiting CYP3A4, an enzyme in the liver and intestine that helps metabolize (break down) approximately 50% of all medications. This can lead to potentially excessive blood levels of these medications, increasing their effects and side effects. So, it is best to avoid grapefruit juice whilst on thyroid (and potentially other) medication.

 

The thyroid gland is vital to the metabolic activity of almost every cell in the body and is extremely sensitive to any change and imbalance, so we must consider a system-wide approach when treating thyroid dysfunction. In order to successfully treat conditions related to the thyroid, we need to understand what triggers the cascade of dysfunction. Only then we can begin to mitigate these triggers to start a path to healing. This is where functional medicine offers a thorough and comprehensive approach and arms us with appropriate tools to fully investigate this multifactorial and global disease. 

At the London clinic of nutrition, we combine industry-leading nutrition and functional medicine expertise, alongside the latest in-house testing, so we can attend to all your health needs in one trip. We have built a reputation for ‘treating the untreatable’ and we are well known for complex chronic illnesses such as Lyme and hypothyroidism.

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