Do you ever feel tired and sluggish, and find yourself putting on a few pounds? Or perhaps you’re anxious, irritable, and no matter how much you eat, you're just not gaining weight? Does Dr Google think your thyroid is to blame for all your woes? Dr Pete Taylor, Professor Annice Mukherjee and Professor Kristien Boelaert are tackling the misinformation online about underactive and overactive thyroid conditions.
Sally: Hello and welcome to Hormones: The Inside Story, the podcast from the Society for Endocrinology. I'm Dr Sally Le Page, an evolutionary biologist and science presenter, and I'll be chatting with a whole bunch of hormones scientists - or endocrinologists - to bring you surprising stories and cutting edge research.
Sally: Today we’re asking: have I got a thyroid problem? Does Dr Google think your thyroid is to blame for all your woes?
Peter: I feel tired, sluggish and I've gained weight. Lots of people the last two, three years have an absolutely miserable time and it does lead to lots of thyroid function testing.
Sally: Should you trust the thyroid tests you buy off the internet?
Annice: They may start you on treatment that you don't need because those thyroid function tests were not abnormal because of a thyroid problem. They were abnormal because of other things going on.
Sally: And what happens if your thyroid goes into overdrive?
Kristien: Often they come in and say, "I'm eating like a horse and losing weight, and don't know why that is." And essentially what you get is speeding up of virtually every physiological system in your body.
Sally: Do you ever feel tired and sluggish, and find yourself putting on a few pounds? Or perhaps you’re anxious, irritable, and no matter how much you eat, you're just not gaining weight?
Sally: It's easy to explain these kinds of symptoms away as just consequences of living in the modern world. But it doesn't mean you should ignore them either.
Sally: So perhaps you've turned to everyone's favourite doctor, Dr Google, and if you type in your symptoms you'll probably end up reading countless articles about your thyroid, suggesting it's the cause of all your concerns.
Sally: Too tired? Must be a thyroid issue. Too much energy? Probably a thyroid issue... Always cold? It's your thyroid. Always hot? It's ... also your thyroid. Gaining weight? Losing weight? Sounds like your thyroid isn't working too well, here's a thyroid function test you should order to find out.
Sally: In fact, you might start to wonder whether the thyroid ever works properly because the internet paints a picture of a small gland that's to blame for more or less every symptom you can think of.
Sally: So what is the thyroid, and how can something so tiny have such an oversized effect?
Peter: Your thyroid is a wee butterfly shaped gland in your neck. I'd say it's about five centimetres, probably I guess about the size of a plum?
Sally: That's Dr Pete Taylor, a physician working for the NHS and a hormones researcher studying thyroid disease.
Sally: Your brain controls your thyroid by making the aptly named thyroid stimulating hormone, or TSH, telling your thyroid to release two hormones, called T3 and T4.
Sally: So when everything is functioning as it should, what does the thyroid actually do?
Peter: Your thyroid is responsible for controlling all your other organ systems. It controls your body's metabolism i.e. how your body processes and utilises energy and how it functions. You need thyroid hormone for your heart functions. Same thing with your guts. And things like in your liver how it turns over cholesterol. But it's also critically important to your mood as well.
Peter: So small gland, lots of effects on everything else.
Sally: You can think of your thyroid as the thermostat for your body's activity; turn it up and your metabolism and other body functions speed up. Turn it down and everything slows down.
Sally: If you're feeling tired all the time and you're putting on weight, there's a chance your thyroid thermostat might be set too low, something we call an underactive thyroid, or hypothyroidism.
Peter: Hypo: below. So you are below activity. So that's basically a slow, sluggish thyroid. So you're tired, you're fatigued. Your heart rate will be going quite slow so you can find your blood pressure goes down as well.
Peter: You can get some change in the quality of your hair, particularly you can get a thinning of your outer eyebrows. You can find that you can get a bit of a dry mouth as well. You can get quite a hoarse voice.
Peter: And your muscles can be quite weak. Even things like your knee reflexes, they aren't as brisk as well. And people can complain about dry skin as well.
Peter: Your other symptoms can include constipation and bizarrely in women, you tend to get very heavy periods when you're hypothyroid.
Sally: Changes in your skin, your heart, your voice, your reflexes even - that's quite the range of symptoms. What's making the thyroid slow down and triggering all these strange effects?
Peter: The most common cause of an underactive thyroid is where your body has taken a dislike to your thyroid and you've got an autoimmune attack from your thyroid. So that's called Hashimoto's disease and it's very common in women. Women get more autoimmune conditions than men so they're more likely to get other conditions like coeliac as well. But thyroid is pretty much the most common autoimmune condition.
Sally: When we say common, we really do mean common. In the UK alone, it's estimated that around 1 in 50 people have Hashimoto's disease at any given time. It disproportionately affects women, being up to 10 times more common in women than men, and it often runs in the family which suggests there's a genetic component too.
Sally: Other than Hashimoto's, are there any other reasons why someone's thyroid might be underactive?
Peter: Historically, iodine deficiency can be a cause of an underactive thyroid, but most of the world is now iodine sufficient. So that's less of a problem.
Sally: We'll be delving more into iodine in next week's episode about diet and hormones. While you can get an underactive thyroid if you don't eat enough iodine, it's pretty rare to be so deficient that you see major symptoms.
Sally: Hashimoto's disease is much more likely to be the cause of an underactive thyroid and it's fairly straightforward to diagnose with just a simple blood test:
Peter: It's mainly done by GPs and the blood test measures usually two things. One is your TSH level and one is T4. We tend to rely more on the TSH level; we feel that TSH is the more sensitive marker of thyroid status.
Peter: It does lead to lots of thyroid function testing and about 20 to 30% of the population may have their thyroid checked in a given year.
Sally: That's a huge number of thyroid tests.
Sally: Thankfully, Hashimoto's disease is very easy to treat. Most patients will be given a drug called levothyroxine, which is a synthetically made body-identical thyroid hormone that replaces the hormones that your own thyroid fails to produce.
Peter: It's something that you need to be on for the rest of your life and it's a tablet usually taken just simply once a day.
Sally: Levothyroxine is a very common drug.
Sally: Around 3 million Brits take it every day, making it the second most commonly prescribed drug in the UK, after statins to reduce cholesterol.
Sally: But do that many people really have something wrong with their thyroid?! Actually, it's not so clear.
Peter: It is used as a scapegoat for lots of symptoms and conditions. It's always good to get checked, but it's probably being overstated how common these things are.
Peter: The real challenge really is because the symptoms are very non-specific. I've talked about your thyroid getting checked if you're feeling tired, if you're feeling sluggish, if you're gaining weight. Lots of people the last two, three years have had an absolutely miserable time. I feel tired, sluggish, and I've gained weight. So all these things are very, very common.
Sally: Because hypothyroidism is such a common health condition, it can be tempting to blame any kind of fatigue or low mood on an underactive thyroid. Ultimately, this can lead to overdiagnosis, and people being given drugs to treat it when they don't actually need them.
Sally: For this reason, it is important that any thyroid tests are overseen by your doctor. If you are feeling slow and sluggish, do talk to your GP as they will be more than happy to get blood tests done for you to check your thyroid function.
Sally: But with long waiting times to see doctors and busy lifestyles, people are increasingly turning to the internet for medical advice.
Annice: People in general now are seeking health information from social media. That's the primary source of health information, particularly since the pandemic when everybody went online.
Sally: This is Professor Annice Mukherjee, a consultant endocrinologist and author.
Sally: If you go online and google 'thyroid testing', you'll be confronted with a multitude of different home testing kits that you can order in a few clicks without even needing to set foot in a GP practice. And they certainly look convincing.
Annice: Glossy brands make websites and social media feeds look excellent.
Annice: And if they get endorsed by social media influencers who have thousands, hundreds of thousands of followers, it can look like the real deal. So people believe they are receiving factual information.
Sally: But we all know you shouldn't trust everything you see on the internet. And so to find out how reliable these direct-to-consumer thyroid function tests really are, Annice looked into the scientific research backing them up.
Sally: She found that, for some of those tests, there is simply no scientific evidence that they actually work. This includes tests like the DUTCH test:
Annice: The DUTCH test, as far as I know, looks at dried urine and it produces a very detailed set of results. They're not validated by any conventional healthcare system, as far as I can see.
Sally: ... or the Reverse T3 test...
Annice: So Reverse T3 is a thing in thyroid autonomy, but it has absolutely no research basis or evidence base for being useful in testing whether or not your thyroid is working properly. And it has no role to help you in working out how to manage your symptoms.
Sally: There are other tests out there that are currently being studied to see how useful they might be for managing thyroid issues. One of these is the Deiodinase 2 - or DIO2 - test for short. It's a genetic test that in the future might be able to predict how well people who have already been diagnosed with a thyroid condition will react to certain treatments.
Annice: That is a really interesting field of research and it really is exciting, particularly if you are somebody who's struggling with thyroid symptoms and you're on treatment.
Sally: But right now, it's not useful at diagnosing whether or not you've got a thyroid problem in the first place.
Annice: It's a possible future development but it's not something that we can apply to current practice.
Sally: And then finally, there are tests called "extended thyroid panels" which you might see offered online. These are very similar to the tests a hormone specialist might order for you.
Annice: Those are things that can be done within standard healthcare settings, and they are frequently used and often very helpful.
Sally: Yes, these are scientifically backed tests, but that doesn't mean it's necessarily a good idea to order one for yourself online without first consulting a doctor
Annice: It can be difficult to interpret those test results. That should be done really by a specialist.
Sally: This is because your thyroid isn't the only thing that can affect your test results
Annice: Thyroid function tests fluctuate in people who have other illnesses. So if you take lots of people who are unwell for any reason, their thyroid tests can be abnormal and then they can normalise spontaneously.
Sally: And if that's the case, you don't need to worry about taking thyroid drugs because once your illness is over, your thyroid will sort itself out on its own.
Sally: The big problem with all of these online tests is that people are exploiting you.
Annice: Those brands are making money out of people and they're free to do so. There's no law against it. Their tests have got lots of testimonials from celebrities and influencers and perhaps even some people who have medical qualifications who are working as brand ambassadors or influencers.
Annice: It doesn't have any proper, validated, peer-reviewed scientific research evidenced on their website as far as I can see. So if you go to practitioners online who aren't actually credible practitioners or perhaps who have conflicts of interest, they're making money out of products and services that they're promoting to you. They may start you on treatment that you don't need because those thyroid function tests were not abnormal because of a thyroid problem, they were abnormal because of other things going on.
Sally: So if you're tired it could be an underactive thyroid, it could be something else. But as we already heard from Pete, there is a good safe available drug out there for hypothyroidism. So if you're feeling rubbish and you suspect your thyroid is underactive, why not just take some pills and see if your wellbeing improves? If the drugs are safe, does it really matter if you take them when you don't need them?
Annice: If you take thyroid medication whether you've got a problem or not, it will speed up your metabolism. So it might give you a little bit of energy, but that won't last. And so what happens then is you then start to feel worse again.
Annice: And you are overtreating something that doesn't need treating. And that can cause heart problems, bone thinning. It can make you feel more anxious. It can make you tremulous. It can cause insomnia. It can cause all sorts of side effects.
Sally: If you are given artificial thyroid hormones when you don't have a thyroid problem, you're not only failing to treat the actual cause that's making you feel unwell, you are also tipping your thyroid hormones off balance:
Annice: You're giving yourself an overactive thyroid by taking a drug you don't need.
Kristien: In an overactive thyroid gland, essentially what you get is speeding up of all the metabolism.
Sally: This is Kristien Boelaert, a professor of endocrinology at the University of Birmingham and consultant at University Hospitals Birmingham.
Sally: So far, we've talked about what happens when your thyroid is underactive; when it isn't producing enough hormones. But on the flip side, you can also have an overactive thyroid; when your body has too much of the thyroid hormones, either because you are taking treatments you don't need or because your thyroid is producing more than it should.
Kristien: About 2-3% of the population have an overactive thyroid gland. It tends to be significantly more common in women than in men, so about five to ten times more common in women than in men.
Sally: An overactive thyroid is also called hyperthyroidism, and yes, it does sound confusingly similar to hypothyroidism, or underactive thyroid. HypO means low, hypER means high. Don't blame me, I didn't come up with these names.
Sally: The most common cause of an overactive thyroid is an autoimmune disease called Graves disease.
Kristien: It's named after Robert Graves who described it, not because people end up in a grave.
Sally: If you're thinking that this sounds familiar - you're right! Both hypo AND hyperthyroidism are most commonly caused by autoimmune conditions where the immune system attacks the thyroid.
Sally: But while Hashimoto's disease leads to the thyroid gland producing less hormone, Graves disease has the opposite effect, and causes it to release way more thyroid hormones than it should. As well as Graves disease, there are a few additional reasons why your thyroid may be overactive, although they are less common:
Kristien: About 10 to 15 percent of causes of hyperthyroidism in the United Kingdom and the United States is called toxic nodular disease, so there is one or more nodules in the thyroid gland that function out of control.
Kristien: And then about 10% of what we see is actually an inflammation of the thyroid gland. And that's often associated with a viral infection and then usually it returns back to normal.
Sally: Regardless of whether your overactive thyroid is caused by an autoimmune disease, inflammation or an infection, what sort of symptoms should people look out for?
Kristien: People lose weight and often they come in and say, "I'm eating like a horse and I'm losing weight and don't know why that is." They may get a tremor or shaking of their hands. They will feel anxious and irritable. They may have concentration difficulties. They may have menstrual irregularities.
Sally: The symptoms of an overactive thyroid can be quite severe - so it's pretty unlikely you will see it advertised as the next weight loss aid.
Kristien: Your bones become weak and that predisposes you to fractures.
Kristien: An untreated overactive thyroid gland is associated with significant risks of cardiovascular disease. So people may present with a fast heart rate and palpitation, sometimes an irregular heart rate, and that may then be associated with an increased risk of stroke. So a number of very unwanted outcomes that are associated with it.
Sally: Thankfully, these outcomes can be avoided with the appropriate treatment:
Kristien: There are medications that we use to block the thyroid gland and many people with an overactive thyroid gland will be started on those either in the short, medium, or longer term. There are other treatments available such as radioactive iodine and surgery.
Sally: If you were listening to last week's episode about diabetes, you'll know that our hormones change a lot during pregnancy, which can sometimes lead to health complications such as gestational diabetes.
Sally: Well, a similar thing happens with your thyroid during pregnancy too.
Kristien: Pregnancy per se affects thyroid function because the hormone that you need to maintain pregnancy is actually very similar to TSH. It's called HCG and it's what makes people sick in pregnancy.
Kristien: And so the high levels of that pregnancy maintaining hormone in early pregnancy may result in abnormal thyroid function tests without there actually being anything wrong with the thyroid gland. So that's not true thyroid disease.
Sally: Because the pregnancy maintaining hormone, called HCG, looks so similar to the thyroid stimulating hormone, the thyroid gland can get confused and misinterpret the high levels of pregnancy hormone as a signal to produce more thyroid hormones.
Sally: Luckily it's not too much to worry about: in the vast majority of cases, your thyroid hormone levels will fall back to normal as soon as the pregnancy is over.
Sally: But in a small number of cases, an overactive thyroid during pregnancy doesn't have anything to do with HCG at all. Instead, it's overactive because of an underlying thyroid condition such as Graves disease that just happened to coincide with when the person became pregnant.
Kristien: It's very important to distinguish between the two because pregnancy hormone-caused overactivity of the thyroid gland often does not need treatment whereas Graves Disease needs to be very carefully managed in pregnancy.
Sally: If Graves disease isn't properly treated during pregnancy, the foetus will be exposed to high levels of thyroid hormones throughout its development. And what's more, the mother's immune system might start attacking the foetus's thyroid as well as her own, making matters even worse.
Sally: All this puts the pregnancy at a much higher risk of ending in a miscarriage or a still-birth, and if the mother does carry to term, the baby is more likely to be born underweight.
Sally: Thankfully, this is very rare and treatable.
Sally: Pregnancy or no pregnancy, testing for an overactive thyroid is pretty straightforward. It usually consists of a simple blood test that measures thyroid hormone levels as well as immune system activity. Occasionally, doctors might also request a thyroid scan to look for any tell-tale signs of inflammation around the thyroid gland; all basic stuff. So if you notice you've started losing weight for no apparent reason, you can't concentrate and you're anxious all the time, there's no reason not to chat to your GP about it.
Sally: Balanced thyroid levels are essential for a healthy life. If your thyroid is underactive, you could feel tired, depressed and rubbish. If it's overactive you could feel anxious, twitchy and... well, also rubbish.
Sally: So if you've not been feeling like yourself recently, whether you're lethargic or stressed out, you don't need to grin and bear it and carry on with your life as normal. Instead, you should maybe ask yourself - have I got a thyroid problem?
Sally: As with any medical concern, your first port of call should be to talk to a GP because thyroid function is easy to test.
Kristien: We've all been scared of COVID. Life has changed, things have been difficult. There's the cost of living, there's a lot of worries. But if people think actually, no, there is more to this than me just being a bit anxious then I think it's not an expensive test to do a thyroid function test and see your doctor. If someone really has two or more symptoms and there is irritability and weight loss for no obvious reason then a thyroid function test should be very high on the list of priorities of a test to be done.
Sally: Now, with GP practices often being busy, you might feel a bit silly walking into your doctor's office just because you're feeling tired or anxious. And it may be tempting to just stay at home and order a thyroid function test online instead. But you should remember that many online tests have little to no scientific backing. It is always better to talk to a medical specialist than rely on claims you see on Google or social media.
Annice: The wonderful world of hormones are quite difficult to interpret by the public and that makes it easy for scammers to manipulate people.
Annice: The sort of health misinformation epidemic is rising rapidly at the moment and people haven't had time to assimilate and understand how to be discerning regarding misinformation. We have a duty of care to understand what is going on on social media as experts, and when we can understand what's going on, we can try to counteract it.
Sally: If you do see a doctor and they diagnose you with a thyroid condition, there are plenty of treatments to help you feel normal again. In fact treating a thyroid condition is so straightforward that it can be tempting to blame all your symptoms on your thyroid. If your thyroid tests come back normal, you might even feel a bit disappointed and disheartened that you're still left feeling rubbish without the option of a seemingly easy treatment.
Peter: If you get labelled with hypothyroidism, that becomes an excuse for quite lot of symptoms. So we may miss the actual thing that's making you poorly. Or dare I say, for some people, the actual reason is quality of life because the modern world is pretty robustly harsh at the moment. Yes it may be poor diet, poor sleep, poor exercise; any of those may be causing a lot of those symptoms.
Peter: Is this all medical or is there an element of the consequences of the modern lifestyle being quite so tough? And I think that's one thing I think we've not been quite so good at.
Sally: Regardless of whether your thyroid is to blame for how you're feeling, your doctors should still be able to help you. Even if your thyroid tests come back normal, that doesn't mean how you're feeling is your new normality.
Sally: A thyroid test, no matter its results, is not the end of your journey towards feeling better, but the start.
Annice: If the doctor says, "Don't worry, your thyroids are normal," I think that's the wrong answer. I don't think we should be saying that as doctors.
Annice: I think we should be saying, "Look, your thyroid tests are normal, so this isn't your thyroid, but clearly there's something very major causing your symptoms because they're having a big impact on your quality of life. Let's see what they are due to and resolve that."
Sally: That's all for now. Thanks to all our guests; Dr Pete Taylor, Professor Annice Mukherjee and Professor Kristien Boelaert.
Sally: Next week, you'll be hearing more about the thyroid as I ask whether my coffee order of choice messes with my thyroid hormones...
Sarah: A soya latte, if it's not fortified, would not replace the iodine as if it was a latte made with cow's milk, and we know that iodine is essential for thyroid hormone production.
Sally: ... whether drinking soya milk does anything to oestrogen levels...
Tim: If a woman was producing a certain amount of oestrogen on her own and then she consumed large amounts of soya, you'd have both the natural hormone and the plant oestrogen in the blood as well.
Sally: ...and whether I need to worry about the hormones found in cow's milk...
Tim: Cows will secrete IGF1 in their milk, but it's not a simple story. Frustratingly in many areas of science, the truth is quite hard to get to and may be complicated.
Sally: Hormones: The Inside Story is a podcast from the Society for Endocrinology. Explore more about the world of hormones at yourhormones.info and follow them on Twitter @your_hormones.
Sally: The show is a First Create the Media production. It was researched, written and produced by me, Sally Le Page and Emma Werner. Our executive producer is Kat Arney. Thank you for listening and we'll see you again soon.