Could it be Hashimoto’s? Why your thyroid test can look normal

You keep gaining weight even though you eat sensibly, your hair is thinning, you feel cold all the time, and you wake up exhausted with a brain that will not switch on properly until lunchtime. These are textbook signs of an underactive thyroid, and yet so many women are told their thyroid results are completely ‘normal’, and they simply need to learn to live with these symptoms.

If this is you, you might want to dig deeper and test for an autoimmune condition called Hashimoto’s thyroiditis. I live with this condition myself, and I was lucky to have a private blood test which identified it after struggling with symptoms for a while, even though my standard blood tests were normal, despite very obvious symptoms. I then flagged it to my doctor and was told to manage it on my own. It has been quite a lonely journey at times, and I don’t want you to feel like you are in the same boat.

The good news is that nutrition and lifestyle changes have completely turned things around for me, and it is now well managed. No more foggy brain, no more thinning hair, no more wearing two jumpers in the summer! I hope the information below helps you just as much, so you can start to feel like yourself again and get your zing back.

In this first post of a two-part series, you will learn to recognise whether Hashimoto’s might be behind how you feel, and I will explain why it slips through the net so often. In the companion post, I share the practical nutrition, lifestyle and supplement steps that can help to reduce your thyroid antibodies, if this is what you are dealing with.

What is Hashimoto’s thyroiditis?

Your thyroid is a small butterfly-shaped gland at the front of your neck, and it acts a bit like the accelerator pedal for your whole body. It sets the pace for your metabolism, which is how quickly you convert food into energy, and it influences everything from your heart rate and body temperature to your mood, your digestion and your monthly cycle. When it runs slowly, you feel like you are permanently running on empty and your spark plugs are misfiring.

In cases of Hashimoto’s, the problem is not the thyroid itself to begin with, it is the immune system which has developed an autoimmune skew. For reasons we are still piecing together, the immune system starts treating the thyroid as a threat and sends antibodies to attack it. This slow, low-grade attack inflames the thyroid gland and, over months and years, chips away at its ability to make enough thyroid hormone. Because thyroid hormones influence every cell throughout the body and brain, when thyroid hormone output starts to dip, you can feel it almost everywhere, which is why the symptoms can seem so scattered and unconnected.

Hashimoto’s is far more common than most people realise and is estimated to affect roughly 7 to 8 percent of people worldwide, with women 4 to 10 times more likely to develop it than men. It becomes more common in middle age, and it often clusters in families alongside other autoimmune conditions. So, if your mum, your sister or your aunt has a thyroid problem, coeliac disease or type 1 diabetes, your own risk goes up. That is my family’s story with my mum and great uncle with type 1 diabetes and lots of cousins with coeliac disease.

The array of thyroid symptoms

When women describe their symptoms to me, they often apologise for how random their list sounds. It is not random at all and once you know the thyroid is involved, the pattern of signs and symptoms clicks into place. The classic signs of a sluggish, under-supported thyroid include:

What surprises many women is just how far the effects of an autoimmune thyroid spread. Hashimoto’s can drive a whole set of symptoms that nobody thinks to blame on the thyroid, and these are the ones that so often get investigated in isolation, or dismissed altogether:

Energy that crashes an hour or two after eating. One of the reasons Hashimoto’s hides so well is that many women with it look completely well on the outside, even while they feel dreadful on the inside. It tends to be a hidden, low-grade struggle, and it is very easily just dismissed as stress-induced, chronic fatigue or simply getting older. So many women rearrange their whole day around their energy dips and assume this is just how they need to manage their ligfe going forward.

Why your blood test can look normal

This is the part of Hashimoto’s that causes the most heartache and confusion, so let me explain what is going on. When you go to your GP with a handful of thyroid symptoms, the first blood test they carry out is almost always TSH, or thyroid-stimulating hormone. TSH is the message your brain sends to your thyroid telling it to work harder.

When the thyroid is struggling, the brain starts to signal louder, and TSH rises. In the UK a result is usually only flagged as underactive once your TSH climbs above about 4.5 mU/L, at which point you might be offered thyroid hormone replacement such as Levothyroxine.

Here is the issue. Those reference ranges are wider than in many other countries, and many thyroid specialists consider the sweet spot for TSH to be 2.5 mU/L or lower. In fact, for women trying to conceive, many clinics like to see TSH below 2.5 mU/L , because a higher level can affect fertility and early pregnancy. So, you can feel thoroughly unwell with a TSH that sits inside the “normal” band, and be told there is nothing obviously wrong with your thyroid.

In the early years of Hashimoto’s, the immune attack can be well underway, and your antibodies can be sky high, while your TSH still looks normal (mine was always around 2.0 mU/L), because your thyroid is just keeping up. Since there is no medication for the raised antibodies, this is why you are sent away expecting to manage the autoimmunity and symptoms yourself.

Since GPs do not routinely test thyroid antibodies, this early autoimmune phase often goes unseen. It is not unusual for a woman to live with debilitating symptoms for a decade or more before her TSH finally rises enough to earn a diagnosis and treatment with Levothyroxine. That is a very long time to feel unwell and unheard, and it is why I am so passionate about looking at thyroid antibodies earlier, when the symptoms and family history suggest it may be appropriate, and looking deeper into why the thyroid has gone awry.

The two thyroid tests you need to check

If your symptoms point to your thyroid being the culprit, but your TSH looks fine, the missing pieces of the puzzle are usually your thyroid antibodies. There are two antibodies that need checking through a blood test:

• Thyroid peroxidase antibodies, or TPO antibodies, which are raised in the great majority of people with Hashimoto’s
• Thyroglobulin antibodies, or TG antibodies, which are raised in a good proportion of cases and help complete the picture

When these antibodies are elevated, it usually tells us that autoimmune activity is present, driven by inflammation in the body. In the UK, these markers are not part of the standard GP panel, so most women only get them through an endocrinologist, a private GP, or a nutrition professional specialising in thyroid autoimmunity.

A private thyroid antibody test is relatively inexpensive, often well under £100, and it can be the most important and empowering blood test result you ever get. Alongside the two antibodies, it is well worth having other thyroid markers checked such as TSH, free T4 and free T3. Also have your ferritin and iron, your vitamin D, your B12 and folate, and your cholesterol looked at, because these fill in the rest of the story as they are all vital for a healthy thyroid.

Please do always report raised antibodies to your GP or endocrinologist, even if they won’t do much if your TSH is normal. It matters, because they will want to keep an eye on your thyroid over time, check for any structural changes such as nodules with an ultrasound if needed. Further testing may also be needed if your results or symptoms suggest another thyroid condition, such as Graves’ disease.

It is natural to fixate on the antibody number and to want to watch it fall. Bringing it down is a worthwhile aim, and you will feel better once the antibodies are lower. However, how you actually feel matters just as much as any number on a blood test, as they can go up and down easily. So, try to keep your attention on your energy, your digestion, your mood and your overall wellbeing rather than on a single figure on a page of blood tests.

Why thyroid medication alone may not be the whole answer

Once TSH rises high enough in blood tests, the standard and very sensible medical treatment is levothyroxine, a synthetic version of the thyroid hormone T4. For many people, it is truly life-changing and restores a great deal to how they feel, and I would never want anyone to see it as the enemy. If your doctor has prescribed it, please keep taking it and monitor your TSH closely with regular blood tests.

What levothyroxine does not do is switch off the autoimmune attack and the inflammation. It tops up the hormone your thyroid can no longer make, which addresses the underactive side of the illness, and yet it does not lower your antibodies or calm the immune activity behind them. This is why some people feel much better on medication but never quite themselves, and why a proportion continue to have symptoms even when their TSH looks perfect on paper. Research suggests that many people on levothyroxine still notice lingering symptoms.

There are a couple of reasons for that. First, T4 is really a storage form that your body has to convert into the active hormone T3, and some people convert it less efficiently, partly down to their genes and partly down to their nutrient status. For a minority who stay symptomatic on optimised levothyroxine, endocrine guidelines now support a carefully monitored trial of adding some T3, so this is a conversation worth having with your specialist if you are still struggling. T3 is currently offered only privately, and usually not through the NHS in the UK.

Second, and this is the heart of it, if the underlying immune activity and the gut and lifestyle factors driving it are never addressed, the internal attack can rumble on. This is where nutrition and lifestyle earn their place, working hand in hand with medical care rather than instead of it.

What tips the immune system into attacking the thyroid

There is no one single cause for Hashimoto’s. What we have instead is a picture of genetics loading the gun and a mix of everyday triggers pulling the trigger. Understanding these helps enormously, because several of them are things we can actually influence ourselves.

Your genes and your family history

Hashimoto’s Thyroiditis runs in families, and certain genetic variants that affect how the immune system behaves are shared with other autoimmune conditions inlcuding coeliac disease and type 1 diabetes, such as the HLA genetic SNP variants. Genes are not destiny though, but they do set your susceptibility. It is the interaction of your genetic blueprint with your environment that decides whether Hashimoto’s shows up and how much it affects them.

Your hormones

The fact that women are so much more likely to develop Hashimoto’s than men points a clear finger at female sex hormones. Often Hashimoto’s symptoms come on around times of big hormonal change, such as after having a baby, and during the perimenopause. Postpartum thyroiditis, a bout of thyroid inflammation in the year after birth, can mimic post-natal depression and depletion, which is one reason I always want to know a woman’s antibody status if she is planning a pregnancy or has recently had a baby.

Your gut

Researchers are increasingly interested in the relationship between the digestive tract, the gut microbiome and autoimmune disease. When the gut lining becomes more permeable than it should be, sometimes described as leaky gut, and when the balance of gut bacteria is disturbed, the immune system can become confused and more prone to attacking the body’s own tissues. Given that so much of the immune system lives in and around the gut wall, this is one of the most important areas we work on, and I will come back to it in detail in the companion post to this blog.

Infections

Certain viruses appear to act as triggers for autoimmunity. Epstein-Barr, the virus that triggers glandular fever, often shows up in the history of people with autoimmune thyroid disease, and its reactivation may be part of what sets the condition off, which could help explain why fatigue is such a hallmark.

More recently, cases of new autoimmune thyroid activity have been reported following Covid infection, alongside other new autoimmune conditions, so a viral trigger is very much part of the story for some people.

Diet, stress and your environment

Our lifestyle and environment play a bigger role in how well you manage your Hashimoto’s than most people realise, and the good news is that these are often the very things we can work on straight away.

A typical modern diet, heavy in ultra-processed foods and sugar but light on protein and nutrient-rich whole foods, may leave the body short on some of the vitamins and minerals it needs to keep the thyroid and immune system working well. Nutrients such as selenium, zinc, iron, vitamin D and the B vitamins all have a part to play, and when we are running on quick convenience foods and sugary snacks we tend to miss out on the very things that help us feel steady and energised. Building your meals around plenty of vegetables, high-quality protein, and healthy fats gives your body far more to work with, and your thyroid will thank you for it.

Chronic stress and a constantly high cortisol state keep the immune system on edge too. When we are always in fight-or-flight mode, whether from a hectic family life, work pressure, or simply never stopping to rest, the body diverts its energy away from repair and digestion, which can nudge an already sensitive immune system into overdrive. Learning to build in moments of calm, whether that is a proper lunch break, a walk outside or a decent night’s sleep, is not a luxury when you have Hashimoto’s, and these are part of the treatment.

Our soils are increasingly low in key minerals such as selenium, which the thyroid relies on heavily to make its hormones and to keep inflammation in check. This means that even a fairly healthy diet can fall short, and it is one reason selenium comes up so often in the thyroid conversation. A couple of Brazil nuts a day is a simple and delicious way to top up. Also prioritise beans, pulses and eggs.

And a build-up of certain toxins and heavy metals, including mercury, can interfere with thyroid function and add to the toxic load your body is already carrying. Being mindful of the sources you can control, such as choosing lower mercury fish (and avoiding tuna) and supporting your natural detox pathways with plenty of fibre, water and colourful vegetables, which all help to lighten that burden over time.

Round Up

If you have read this far and had some ‘aha’ moments, whether it is recognising your own foggy mornings, your cold hands, the wad of hair in your brush and the excess weight that will not shift, then it is well worth finding out whether Hashimoto’s is part of your picture. The symptoms vary enormously from one woman to the next, and they can be complex to untangle.

The good news is that you do not have to wait years for a rising TSH to be taken seriously. Ask about testing your thyroid antibodies and nutrient buddies that support your thyroid function as the next step, and know that recognising what is going on is the first and most powerful step you can make.

If you would like a proper look under the bonnet, our NatureDoc thyroid specialists can run comprehensive thyroid, nutrient and gut testing, make sense of the results with you, and build a plan around how you feel. Come and work with us, and let us help you find your spark again.

Then head over to the second post in this series, where I walk you through the seven nutrition and lifestyle steps that can make the biggest difference when supporting Hashimoto’s and your overall thyroid health.

This blog was first published on 12th October 2017 and has been updated.

References

• Global prevalence of Hashimoto’s thyroiditis: a systematic review and meta-analysis
• Hashimoto’s thyroiditis: from pathogenesis to clinical management
• Hashimoto’s thyroiditis: an update on pathogenic mechanisms, diagnostic protocols and therapeutic strategies
• The thyroid and the gut
• All disease begins in the (leaky) gut: the role of zonulin-mediated gut permeability in chronic inflammatory diseases
• Zonulin, regulation of tight junctions and autoimmune diseases
• The role of Epstein-Barr virus infection in the development of autoimmune thyroid diseases
• Systematic review of Covid-19 and autoimmune thyroiditis
• Assessment and treatment of thyroid disorders in pregnancy and the postpartum period
• A review of the safety of triiodothyronine in combination with levothyroxine for the management of hypothyroidism
• Levothyroxine and combination therapy for persistent symptoms of hypothyroidism: a systematic review
• A study reporting raised TPO antibody positivity in healthy women following iodine supplementation