Nutrition & Lifestyle Thyroid Support

Womens HealthDigestion
Written By Keris Marsden

Why your thyroid deserves a closer look

Your thyroid is a small gland at the front of your neck, but its impact on health is huge. Thyroid hormones set the pace for almost every system in the body: how efficiently you turn food into energy, how warm you feel, how quickly you digest food, how clearly you think and how well your immune system responds.

That is why, when something is off with the thyroid, the symptoms rarely stay in one place.

In my clinic, I often find a thyroid issue sitting upstream of fertility struggles, sluggish digestion (slow transit time, and even gastroparesis, where the stomach empties too slowly), brain fog and a run of infections that never fully clear.

One interesting observation is that I often see thyroid issues in busy, highly active individuals who are spinning many plates. They are often working long hours and do a lot of caring for others, personally and professionally.

I've also seen a lot of thyroid issues in clients who do a lot of exercise, especially if rest, recovery and nutrition aren't dialled in to support their body.

If you're experiencing chronic, hard-to-pin-down symptoms, I encourage you to get your thyroid checked as a minimum.

Below, I walk through the signs to look out for, how to get tested, the nutrients your thyroid needs, the treatment options available, and the food and gut support I use with clients.

Signs your thyroid may need a closer look

Thyroid symptoms tend to creep in slowly and overlap with lots of other conditions, including perimenopause, so they are easy to dismiss. Look out for a cluster of these rather than any one on its own:

  • Fatigue that sleep does not fix

  • Hair loss or thinning, including the outer edges of the eyebrows

  • Dry, rough skin and brittle nails

  • Poor wound healing

  • Constipation or a slow, sluggish gut

  • Feeling cold when others are comfortable

  • Weight gain, or finding weight very hard to shift

  • Brain fog, slowed thinking or poor memory

  • Low mood or depression

  • Muscle aches, weakness or cramps

  • Tingling or numbness in the hands and fingers (carpal tunnel symptoms)

  • Irregular or heavy periods, or difficulty conceiving

  • Low libido

  • Poor immunity and a higher risk of infections

  • Later signs: a hoarse voice, a puffy face, a slow heart rate or anaemia

Your risk is higher if you have a strong family history of thyroid problems, or another autoimmune condition such as coeliac disease, type 1 diabetes, pernicious anaemia, vitiligo or rheumatoid arthritis.

The most common cause of an underactive thyroid in the UK is autoimmune, where the immune system attacks the thyroid gland. This is known as Hashimoto's thyroiditis.

Getting tested

If your symptoms warrant it, a thyroid function test is usually straightforward to get on the NHS. Ask your GP for TSH (thyroid stimulating hormone) and free T4 as a minimum.

Be aware that some labs only run free T4 if TSH comes back outside the range, and thyroid antibodies are not routinely checked.

If you would like a fuller picture, or want to track your levels over time, these private providers use UKAS-accredited laboratories (the same accreditation standard as NHS labs):

A useful private panel includes TSH, free T4, free T3, and TPO and thyroglobulin antibodies.

Most offer a home finger-prick kit, with the option to upgrade to a venous blood draw at a partner clinic. I advise clients to have a blood draw as it tends to be more reliable. Prices change often, so it is worth comparing before you book.

Your thyroid requires multiple nutrients

Making thyroid hormones is a nutrient-intensive process. Most people know that iodine is a building block of thyroid hormones. Fewer people realise how much the thyroid also depends on selenium and other vitamins and minerals.

Selenium is essential for the enzymes that convert T4 (the storage hormone) into T3 (the active hormone).

It helps protect the thyroid from oxidative stress. In people with Hashimoto's, randomised trials show selenium supplementation can lower thyroid antibodies, and in those not yet on medication, TSH too.

In the UK, selenium intake has fallen from around 60 mcg a day in the 1970s to roughly 30 to 40 mcg today, below the recommended 60 mcg for women and 75 mcg for men. The main reason is a shift from selenium-rich North American wheat to UK and European wheat grown on low-selenium soils, and climate modelling suggests soil selenium in many parts of the UK may fall by more than 10% this century.

Brazil nuts are often suggested as a fix, but they are not a reliable source. Their selenium content varies hugely depending on where they were grown, and drought in the Amazon has hit supply hard, with the 2025/26 crop forecast at around a third below the previous year and prices rising sharply.

Beyond iodine and selenium, your thyroid also relies on:

  • Iron: the enzyme that makes thyroid hormone needs iron, and low ferritin is common, especially in women with heavy periods

  • Vitamin B12: often low in people with Hashimoto's, which shares an autoimmune link with pernicious anaemia

  • Vitamin A: supports thyroid hormone signalling

  • Zinc: involved in making TSH and in T3 binding to its receptors

  • Vitamin D: low levels are common in autoimmune thyroid disease

  • Protein: provides tyrosine, the amino acid backbone of thyroid hormones

Some of these, such as iron and B12, can be picked up on an NHS full blood count and iron panel. Others, like zinc and vitamin A, are rarely tested on a regular basis.

Where to start

Eat for nutrient density. Build meals around protein, colourful vegetables, healthy fats and slow-release carbohydrates. Eggs, seafood, oily fish, meat, dairy (if you tolerate it), pulses, nuts and seeds all bring thyroid-friendly nutrients to the table.

Consider a good-quality multivitamin. Look for a high-grade formula that provides at least 100 mcg of selenium. If you take levothyroxine, choose one without iodine, such as Metagenics Multi Essentials One A Day, which is free from iodine, iron and copper. Check the selenium on the label and top up if needed, but avoid stacking several selenium products, as too much can be harmful.

If you take levothyroxine, take it on an empty stomach and keep your multivitamin, and anything containing iron, calcium or magnesium, at least four hours apart from it, as these can reduce absorption.

Add vitamin D, especially in winter. Most people in the UK need at least 2,000 IU a day through the autumn and winter months, and some need up to 4,000 IU. Testing your level first helps you get the dose right. I usually suggest a vitamin D3 with added K2. If you take warfarin or another blood thinner, check with your GP before taking K2.

Get moving and get outside. Regular movement and daylight support energy, mood, circulation and metabolism, which is exactly where thyroid hormones do their work. If you are tired, start simply: a daily 30-minute walk, ideally in morning light.

Other useful tests

  • Thyroid antibodies (TPO and thyroglobulin): show whether an autoimmune process is behind your symptoms

  • Coeliac screen: coeliac disease is more common in people with autoimmune thyroid disease. You need to be eating gluten regularly for the test to be accurate, so test before you cut it out

  • Full blood count, ferritin, B12, folate and vitamin D: to check the nutrients your thyroid relies on

Before any thyroid test, stop your vitamins and minerals for a few days beforehand, particularly anything containing biotin. Biotin is common in multivitamins and hair, skin and nail supplements, and it can distort thyroid results. If you are unsure, ask whoever is running the test how long to pause.

Treatment options

Levothyroxine

The standard treatment for an underactive thyroid is levothyroxine, a synthetic form of T4. Your dose is personalised to you and adjusted using blood tests until your levels are stable. For many people it works well. For others, symptoms persist even when their blood results look "normal", which is where the conversation about other options begins.

Adding T3 (liothyronine)

There is growing campaigning in the UK for better access to T3 alongside levothyroxine. NICE does not currently recommend it routinely. However, a 2023 joint consensus statement from the British Thyroid Association and the Society for Endocrinology says a trial of combined T4 and T3 may be warranted for some people with confirmed hypothyroidism and persistent symptoms, once levothyroxine has been optimised and other causes ruled out. On the NHS, this has to be started by an endocrinologist rather than your GP, and access varies a lot by area.

Combination therapy is available in many other European countries, although levothyroxine is still the first choice there too. In a survey of French doctors, for example, almost all used levothyroxine as their main treatment, and around 14% would consider a T4 and T3 combination for persistent symptoms.

If you want to explore this privately, two well-reviewed UK specialists with an interest in thyroid care and T3 are:

  • Dr Hisham Maksoud, consultant endocrinologist with clinics in Derby, Lincoln, Nottingham and London

  • Dr Paul Jenkins, consultant endocrinologist at The London Endocrine Centre

Desiccated thyroid (Armour, NP Thyroid, Nature-Throid)

Desiccated thyroid is made from pig thyroid glands and contains both T4 and T3. In the UK it is unlicensed and not prescribed on the NHS, so it is only available privately.

The research is genuinely interesting. In a 2013 double-blind crossover trial (Hoang et al.), 70 people took desiccated thyroid and levothyroxine for 16 weeks each without knowing which was which. Overall quality of life scores were similar, but 49% preferred desiccated thyroid, compared with 19% who preferred levothyroxine, and they lost a few pounds on it. A 2021 follow-up trial found similar preferences: 45% preferred desiccated thyroid, 32% a T4 and T3 combination, and 23% levothyroxine alone. Because hormone content can vary between batches, this is one to explore with a specialist, never by buying online.

Low dose naltrexone (LDN)

LDN is naltrexone at a fraction of its usual dose, thought to calm and rebalance the immune system. Many people with Hashimoto's report feeling better on it, but the evidence so far is largely anecdotal. A proper trial, ThyroLDN, is now under way in Australia. It is a double-blind, placebo-controlled study testing whether LDN improves thyroid-related quality of life in people with Hashimoto's who still have symptoms despite optimal levothyroxine. Results are not yet published. In the UK, LDN is only available on private prescription.

Whichever route you explore, please never stop or change thyroid medication without speaking to your prescriber.

Nutrition adaptations

I always start with the basics before anything more specific:

  • Balance your blood sugar. Eat a nutrient-dense diet with regular meals at consistent times. I am not a huge fan of fasting when a system is out of balance, because I want to make sure the body is getting adequate nutrition first.

  • Keep alcohol within healthy limits. I often suggest no more than 2 units in any one day, with several alcohol-free days each week.

  • Keep processed foods to a minimum. They make up a small proportion of what you eat, with room left for the foods you enjoy purely for pleasure.

Trying gluten and dairy free

Once the basics are in place, this next part is more anecdotal, drawn from what I see in clinic. Many of my clients feel better removing gluten and dairy as a minimum, and some also choose to remove nightshades (tomatoes, potatoes, peppers and aubergines). If you would like to see whether it helps you:

  • Get a coeliac screen first. You need to be eating gluten regularly for the test to be accurate, so test before you cut it out.

  • Try 30 days without gluten and dairy. Notice how you feel, including your energy, digestion, skin and mood, then reintroduce them one at a time to see whether anything changes.

A few things could be going on here. There can be a strong placebo effect when we change our diet and start paying closer attention to how we feel. And interestingly, some clients tell me they can enjoy these foods on holiday without the same symptoms.

That is why one of my key pieces of advice is to match your food to your nervous system. When you are stressed, busier than usual or feeling more sensitive, stick with the foods your system digests easily and that leave you feeling good. When you are more relaxed, sleeping well and getting more sunlight, perhaps on holiday, you may find you can vary your diet a little more.

It is also worth knowing that the culprit is not always the gluten or dairy itself. Many of the foods that contain them are also high in FODMAPs, which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. These are short-chain carbohydrates that naturally draw water into the gut and are fermented by gut bacteria, creating bloating, discomfort and pain that is easily mistaken for a food intolerance. Wheat, for example, is high in fructans, and milk contains lactose. With some clients, we simply reduce the overall FODMAP load a little rather than cutting out whole food groups.

Supporting gut transit time

When the thyroid slows down, the gut often slows with it. Supporting transit time can make a real difference to bloating and comfort, and it does not have to mean removing food groups.

Here is what I often use with clients:

  • Eat slowly and chew well. Sit down to eat, put your fork down between mouthfuls and chew each one thoroughly. Leaving gaps between meals rather than grazing also gives the gut time to do its natural housekeeping.

  • Support stomach acidity at mealtimes. Bitter leaves such as rocket and chicory, or a little apple cider vinegar or lemon in water before meals, can help prime digestion. Skip this if you have reflux or ulcers, or take acid-lowering medication, unless your practitioner advises otherwise.

  • Magnesium. Somewhere between 350 and 600 mg a day can support bowel motility. Start low and build up gradually, as loose stools mean you have gone too far. Take it at least four hours away from levothyroxine, and check with your GP first if you have kidney problems.

  • Ginger, and lots of it. Include fresh root ginger across the day: ginger tea, grated into porridge, and added to soups and stews.

  • A motility supplement. My favourites are:

  • A digestive enzyme complex. This can help some people with a heavy, slow feeling after meals. Read my blog on digestive enzymes for more.

Nervous System and Emotional Support

This may arguably be the most important point of all. If we can begin to support the nervous system, adapt an individual's stress load and life load, and help them process the emotions they are experiencing, the whole body may be able to find its way back towards balance a little more easily. This doesn't happen overnight, but the education I provide to clients about their nervous system, and how to use embodied practices to begin gently resetting their stress response, is an important starting point.

We often begin with non-sleep deep rest (NSDR) practices, often referred to as yoga nidra, or body scans, as a way to set aside time for stillness, become a little more connected to the body and start to feel embodied. In my opinion this is a very important part of addressing chronic symptoms, because we are often trying to escape the symptoms and sensations within our body, which only creates more fear and anxiety. Together, we begin to explore the concept of safety and self-care.

One of the most challenging aspects of this for my clients is putting boundaries in place and understanding their need to be doing all the time, which often serves as a coping mechanism to settle and regulate themselves.

I remind my clients that there are strong links between their perception of a situation, the threats and anxieties they hold, and how their biology responds. Simply becoming aware of this, and learning to reframe situations, can sometimes be more impactful than selenium.

A final note

Thyroid health is rarely about one single fix. Get tested, build the nutritional foundations, look after your gut and your nervous system, and work alongside your GP or specialist on the medical side. This blog is for information only and is not a substitute for personalised medical advice. If you would like support putting this into practice, you can book a consultation with me.

Resources

Keris Marsden
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