Does your gut need a reset?

Yes, I'm Ready

Do you want to start feeling better?

Yes, Where Do I Start?

Do you want to start feeling better?

Yes, Where Do I Start?

Why Your Thyroid Diagnosis Might Be a Misdiagnosis

Thyroid Symptoms Like Brain Fog and Fatigue May Actually Be Coming From Your Gut

Key Takeaways:
  • An underactive thyroid diagnosis can cover anything from the autoimmune disorder Hashimoto’s thyroiditis, through subclinical hypothyroidism and clinical hypothyroidism without autoimmunity.
  • Hypothyroid conditions are often diagnosed and medicated too early.
  • In many cases, a wait-and-see approach is more appropriate as thyroid hormone levels can correct themselves without medication.
  • Gut health and thyroid health are closely related; sometimes symptoms that seem like thyroid symptoms might actually be due to gut issues.
  • Improving your gut health with a healthy diet, probiotics, and limiting foods you might be intolerant or sensitive to may improve your thyroid gland function.
  • Gut therapy may even mean you don’t need to use thyroid hormones or can reduce the dosage.

Were you given an underactive thyroid diagnosis, or are you experiencing symptoms that you suspect are from low levels of thyroid hormones? If so, you’re not alone. In fact, around one in twenty Americans have some degree of hypothyroidism [1]. Symptoms, when you get them, can include fatigue and brain fog, dry skin, weight gain, and feeling cold.

When hypothyroidism is a clear clinical diagnosis, treatment with thyroid hormones can be a life-changer. You can expect your energy levels to lift, your mood to improve, and your thoughts to be clearer. 

However, in this article, I want to cover the less clear-cut cases of hypothyroid diagnosis, which we see many of in the clinic. 

For example, you may have started taking thyroid hormones based on lab test results, not symptoms. Or maybe you can’t get the dose right or are still having symptoms despite your hormone levels returning to normal. 

The reality is that there are a lot of well-meaning but off-target treatments out there for thyroid disorders. 

More specifically, within the functional medicine space, there’s a tendency to overdiagnose and overtreat hypothyroidism. This laser focus on “treating the numbers” can be a distraction from investigating other potential problems, like gut imbalances,  which may actually underlie hypothyroid symptoms.

These issues make diagnosing hypothyroidism a lot more complicated than it needs to be, which has created a lot of confusion for both patients and providers. But the good news is that hypothyroidism is frequently easier to diagnose than most think, as I’ll explain below.

Let’s dig into your underactive thyroid diagnosis to find out what may actually be going on under the surface. Before getting started, it’s helpful to clarify some of the terminology around hypothyroidism.

Defining Hypothyroid

You’re probably familiar with terms such as hypothyroid, sluggish thyroid, and underactive thyroid. Though these all roughly describe the situation that your thyroid likely isn’t working as well as it should, it’s helpful to understand the descriptions around hypothyroidism a little better.

This way, you and your healthcare provider will be working from the same page, and you’ll also be able to understand when the terminology is a little off.

Here’s a quick explainer:

Clinical Hypothyroidism 

Clinical hypothyroidism (also known as overt hypothyroidism, frank hypothyroidism, or just hypothyroidism) is a clear-cut diagnosis when a blood test shows that you have:

  • Low levels of the thyroid hormone thyroxine (T4) released by the thyroid gland (free T4 below 0.82 mg/dL) [2].
  • AND high levels of thyroid stimulating hormone (TSH), released by the pituitary gland (above 4.5 IU/mL) [3]. 

The correct course of action for clinical hypothyroidism is to treat with thyroid hormone, usually the medication levothyroxine.

Subclinical Hypothyroidism 

Subclinical hypothyroidism is when levels of thyroxine T4 hormone are normal, but levels of TSH are high. 

However, in some situations, like being in an older age group, it’s perfectly normal for TSH levels to be somewhat above the “normal” range without any symptoms.

It may not be accurate to label everyone with marginally high TSH levels as having medicable hypothyroidism.

In any case, mild symptoms of subclinical hypothyroidism can often be treated with appropriate diet and lifestyle steps, and may not need hormone therapy.

Hashimoto’s Disease or Hashimoto’s Thyroiditis 

Hashiomoto’s is the autoimmune disorder that is the most common cause of subclinical and hypothyroidism in the USA (in some other parts of the world low iodine consumption is a more common cause) [1]. 

It may or may not present with hypothyroid symptoms (depending on your TSH and T4 levels), but if you have a Hashimoto’s diagnosis, you’ll want to monitor your labs and any symptoms to see if they progress. 

A sign of having Hashimoto’s is if your levels of thyroid peroxidase (TPO) antibodies are high. Research suggests the presence of these antibodies is 90% sensitive in detecting thyroiditis [4].

It’s important to note that having Hashimoto’s doesn’t mean you will definitely go on to develop full-blown hypothyroidism, though it’s more likely if you have very high TPO antibodies above 500 IU/mL [5].

In fact, the Tehran Thyroid Study, which followed the course of thyroid disease in a large cohort of people over nine years, found those with elevated TPO antibodies (indicative of Hashiomoto’s) only had a 9–19% chance of becoming hypothyroid after 6 years of follow up [6, 7]. 

TG (thyroglobulin) antibodies may also be included in antibody testing, but they do not accurately predict autoimmunity [8].

One of the most effective ways to help autoimmune conditions (and thereby prevent Hashimoto’s progressing into hypothyroidism) is to improve your gut health. I’ll develop this idea in more detail below.

Underactive or Sluggish Thyroid

These two terms don’t have any specific medical meaning. They can encompass anything on the hypothyroid spectrum — from subclinical hypothyroidism with no symptoms, to being symptomatic with non-specific symptoms (fatigue, constipation, hair loss, etc.) but with all thyroid labs within normal limits.

Many well-intentioned functional medicine providers will often prescribe thyroid medication to people who fall along this spectrum. However, I frequently see that “sluggish thyroid” patients won’t respond to thyroid hormone — instead, a gut–healing protocol often leads to greater symptom improvement. 

Thyroid Conditions are Over-Diagnosed and Over-Medicated

Both conventional and natural medicine practitioners are prone to over-diagnosing hypothyroidism. 

If it feels like your doctor rushed to diagnose you and get you started on medication, I’d advise that you get a second opinion.

More specifically, if the labs used to diagnose you did NOT show abnormally high TSH paired with abnormally low T4, then you likely are not clinically hypothyroid and may not need medication. 

One interesting study involved a group of nearly 300 patients who had been taking thyroid hormone replacement therapy for years, despite not having strong diagnostic indicators of hypothyroidism. 

During the trial, these patients stopped taking their thyroid hormone medication (levothyroxine) for 6–8 weeks while being monitored by researchers [9]. After going without thyroid hormone replacement for several weeks:

  • 61% of patients returned normal thyroid function test results 
  • These patients were able to stay off their thyroid medication longer term 

Another study validated these findings and showed that subclinical hypothyroidism will often correct itself without any intervention. The study followed 225 people diagnosed with subclinical hypothyroidism through a population screening program. This group was followed for 6 months with no treatment. After this time, the vast majority (73.8%) had moved back out of the hypothyroid range and had normal TSH levels again [10]. 

This suggests hypothyroidism can be transient, and a watch-and-see is often best. There is no need to rush to hormone treatment unless you fall into the overt hypothyroidism category.

That said, your thyroid could always use some attention, especially if you are having symptoms. In my experience, the best way to look after your thyroid and stave off hypothyroidism is to address gut health problems. 

Gut Health is Key to Thyroid Health

Some patients with subclinical hypothyroidism find their TSH levels and symptoms normalize once issues with their gut health (such as gut infections, leaky gut, and microbiome imbalances) have been addressed. As a result, people can sometimes prevent having to take thyroid medication or can come off medication they were already prescribed. 

Other patients will need to continue with thyroid hormone replacement therapy. However, I’ve seen several cases where, after a gut-healing program, the patient’s digestive system absorbs the hormone medication better and the patient can reduce their dose. 

Why does poor gut health impact the thyroid gland so much? Well, when our gut microbiome is imbalanced, it can create inflammation and immune system abnormalities that also affect thyroid function and thyroid hormone production. More specifically, [11, 12]:

  • Altered immune responses in the gut can contribute to or aggravate autoimmune conditions, including Hashimoto’s thyroiditis.
  • Poor gut health can alter the activity of enzymes that impact thyroid hormone levels and reduce the absorption of minerals important to thyroid health.
  • Gut inflammation can trigger brain fog, depression, and other cognitive issues that are similar to hypothyroid symptoms. 

Thyroid Symptoms or Gut Symptoms?

The final bullet point above is important because thyroid symptoms can sometimes be confused with gut symptoms. This can explain why some patients who have received treatment for a hypothyroid diagnosis continue to have symptoms despite now having entirely normal thyroid hormone levels. 

In fact, we saw so many patients in the clinic for whom this was the case, that we published a case series and literature review to alert other functional and integrative practitioners to this observation.

Symptoms that can masquerade as thyroid problems, but are actually gut-related include fatigue, anxiety, brain fog, and depression [13, 14, 15, 16, 17, 18].

These residual problems won’t go away with continued hypothyroid treatment because it is not the thyroid that is at issue, but the gut.

Diet and Probiotics Are Key Strategies in Gut Healing

To improve your gut health in a way that will underpin good thyroid health, a diet that is anti-inflammatory, nutrient-rich, and takes account of foods you may be intolerant or sensitive to is a good base.

Finding a Diet that Fits

Many of my patients do well using a Paleo diet framework, as it checks the above boxes without being overly restrictive.

A Paleo diet usually minimizes gluten and lactose, which research suggests are two of the commonest food sensitivities in people with hypothyroid issues.

For example, two studies showed lactose restriction and a gluten-free diet were associated with significant decreases in TSH levels for Hashimoto’s patients on thyroid medication [19, 20]. That said, you should monitor your reactions using a food and symptoms diary. If you seem to tolerate wheat and dairy well, i.e. you don’t react with gas, bloating, abdominal cramps, or other symptoms after you eat them, there’s no need to remove them.

Some people find their thyroid and gut symptoms worsen when they eat too many of certain carbohydrates known as FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols). This can feel counterintuitive if you are affected because FODMAPs are found mainly in healthy high-fiber plant foods like garlic, onions, apples, and mangos, for example. The reason FODMAPs are an issue if you have a particularly sensitive gut, is that gut bacteria like to ferment them, producing a lot of gas.

If your tolerance to a healthy plant-based, high-fiber diet seems low, particularly if you have pre-existing irritable bowel syndrome, a low FODMAP diet may best suit your needs [21].

As your gut heals, you’ll be able to tolerate more foods and get back to a more varied diet, which is ultimately good for your gut microbiome health. You can find much more detail about elimination diets and how to do them safely for thyroid conditions if you sign up for my Thyroid Self Help Guide.

Probiotics Can Be a Game-Changer 

Probiotics can be super helpful in getting your gut back in shape. Here are some of the ways that they can promote better gut health.

  • Increase the bacterial diversity, or health, of your bacterial community [22, 23, 24]
  • Fight pathogens (harmful bugs) and their toxins [22, 23, 25, 26, 27)
  • Promote a more rapid recovery from imbalanced gut organisms [22, 23]
  • Promote a healthy immune response in your gut [22, 23, 28, 29, 30]
  • Reduce gut inflammation [22, 23, 24]
  • Encourage the growth of healthier microbes in your gut [22, 23, 28]
  • Reduce leaky gut, which is damage to your gut lining [22, 23, 31, 32, 33]

Remember, probiotics create a healthy gut, which means a healthier thyroid. One study found that when thyroid patients improved their gut health by using probiotics, they were able to use less of the thyroid medication levothyroxine (Synthroid) [34]

If you’re a little confused about which probiotics to take, it helps to know that nearly every probiotic product can be classified into one of these three categories [35].

  • Lactobacillus and Bifidobacterium
  • Saccharomyces boulardii (a healthy fungus)
  • Soil-based bacillus species

Some patients do well with taking just one product from one category — usually a Lactobacillus and Bifidobacterium blend. However, studies suggest mixtures of probiotics taken together tend to be more effective [36, 37]. The feedback we get from patients at the clinic suggests that a triple therapy approach, which means taking one probiotic from each of these three categories, often achieves better results. 

Regardless, it’s fair to give probiotics a trial period of 2–3 months to make sure you give your body a chance to reap the full benefits. 

Other Supplements That Might Help

Probiotics are the only supplement that I would routinely recommend for everyone with thyroid disease. But there are some other supplements that I want to draw your attention to that might be of use depending on your individual circumstances. This table breaks down these and gives you an idea of if or when you might benefit

Vitamin D

Thyroid Health Connection Practical Advice
  • Low vitamin D levels are associated with hypothyroidism [38, 39]. 
  • Research suggests that vitamin D supplements can improve autoimmune hypothyroidism measured through a reduction in TPO antibodies [40, 41, 42, 43]
Overall, vitamin D is worth taking, as deficiency is common, especially if you have cold, dark winters or get minimal sun exposure. You can have your levels tested easily and inexpensively if you want a definitive answer about your vitamin D status. Take Vitamin D for at least 3 months to see if there is a notable effect on hypothyroid symptoms [42]. 


Thyroid Health Connection Practical Advice
  • Selenium can improve thyroid antibodies, postpartum Hashimoto’s, and thyroid gland structure as measured by an ultrasound thyroid scan (an imaging test) [44] [45].
  • Hypothyroidism patients also tend to have lower thyroid antibodies than those who didn’t take selenium [46].
Not all studies show the benefits of selenium in helping a thyroid diagnosis [47, 48]. There appears to be no downside though, and because selenium is neither expensive nor invasive, it seems reasonable to try selenium supplements and see how you respond. 

Betaine Hydrochloride (HCL)

Thyroid Health Connection Practical Advice
  • Research shows that up to 40% of hypothyroid patients also have stomach autoimmunity, resulting in low stomach acid [49, 50]. Betaine HCl is a supplement that can increase stomach acid levels.
Reasons to consider betaine HCL for hypothyroid issues are if you have a history of autoimmune diseases (other than Hashiomoto’s) are over 65, or have a history of anemia.


Thyroid Health Connection Practical Advice
  • A small study showed that low iron (measured as serum ferritin) was correlated with lab markers for hypothyroidism [51]. 
  • Another study showed that iron deficiency was related to thyroid hormone status [52]. 
It’s best to be tested for low iron stores before supplementing, as too much iron can increase oxidation in the body [53]. Being a woman with heavy periods, and eating only a plant-based diet are risk factors for iron deficiency. 


Thyroid Health Connection Practical Advice
  • A systematic review found a correlation between the severity of hypothyroidism and low zinc and selenium levels [54]. 
  • In a clinical trial, 6 months of zinc supplementation improved serum thyroid markers [55]
The data on zinc and hypothyroid isn’t definitive. Therefore, supplemental zinc may be worth a 1-month trial, and if no improvements, discontinue.

What About Iodine?

Though iodine deficiency is a key cause of hypothyroidism (goiter) in some parts of the world, too much can also be a problem. Supplementation is not recommended in the USA, where iodine intakes are generally sufficient. That’s because too much iodine can actually increase the incidence of thyroid autoimmunity [56] and is a risk factor for hypothyroidism [57].

This means you should only take supplemental iodine if you know you’re definitely deficient.

If You Need Medication, You Need Medication

Though I’ve made the case that many patients are given thyroid hormone replacement therapy too readily, medication can be important. If your T4 and TSH tests indicate it is necessary (see above in the Defining Hypothyroid section), you should definitely go ahead with it.

The conventional medicine choice is usually to give the T4 thyroxine hormone in its synthetic form (levothyroxine).

However, there is another, more active, thyroid hormone known as triiodothyronine or T3 used in the body. We naturally make it by converting T4 to T3 in the body, but T3 can also be taken as a medication.

Many functional health practitioners prefer using a combination of T4 and T3 (from desiccated pig thyroid). They do this on the basis that the body might have a hard time converting T4 to T3. 

However, the evidence for combination T3 and T4 therapy isn’t impressive. One meta-analysis (the highest quality type of research) and a review have shown that there is no reliable evidence that combination T4 and T3 is better than T4 monotherapy for treating symptoms [58, 59]. 

That said, a review paper found that patients preferred T3/T4 combination therapy over T4 alone 50–70% of the time [59].

Overall, I prefer to use synthetic T4 as we know it works and is a more consistent and regulated product without significant side effects. The American Thyroid Association also does not recommend combining T4 and T3 [60].

If T4 monotherapy doesn’t resolve my patient’s symptoms, or if they feel unhappy with their results, then I’ll consider moving on to a combination of T3 and T4.

Thyroid Diagnosis: It’s Nuanced

If you’ve been uncertain or confused about your hypothyroid symptoms or thyroid hormone levels, I hope you now understand more of the complexity around this topic. 

The bottom line is that hypothyroidism is a wide spectrum and, depending where you are on that spectrum, you may or may not need hormone therapy.

Whether you require medication or not, it pays to look after your underlying gut health, which can help reduce symptoms such as brain fog and fatigue that are typical of both gut problems and hypothyroidism.

If you’d like to work through your thyroid issues in more depth, you should check out my thyroid course, which will show you how to self-manage thyroid conditions. Or, if you prefer, reach out for a virtual one-to-one consultation with one of our highly experienced practitioners.

The Ruscio Institute has also developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.

➕ References

  1. Hypothyroidism (Underactive Thyroid) – NIDDK [Internet]. [cited 2023 Jul 23]. Available from:
  2. Lee J, Ha J, Jo K, Lim D-J, Lee J-M, Chang S-A, et al. High Normal Range of Free Thyroxine is Associated with Decreased Triglycerides and with Increased High-Density Lipoprotein Cholesterol Based on Population Representative Data. J Clin Med. 2019 May 28;8(6). DOI: 10.3390/jcm8060758. PMID: 31142048. PMCID: PMC6616420.
  3. Thayakaran R, Adderley NJ, Sainsbury C, Torlinska B, Boelaert K, Šumilo D, et al. Thyroid replacement therapy, thyroid stimulating hormone concentrations, and long term health outcomes in patients with hypothyroidism: longitudinal study. BMJ. 2019 Sep 3;366:l4892. DOI: 10.1136/bmj.l4892. PMID: 31481394. PMCID: PMC6719286.
  4. Ragusa F, Fallahi P, Elia G, Gonnella D, Paparo SR, Giusti C, et al. Hashimotos’ thyroiditis: Epidemiology, pathogenesis, clinic and therapy. Best Pract Res Clin Endocrinol Metab. 2019 Dec;33(6):101367. DOI: 10.1016/j.beem.2019.101367. PMID: 31812326.
  5. Ehlers M, Jordan AL, Feldkamp J, Fritzen R, Quadbeck B, Haase M, et al. Anti-Thyroperoxidase Antibody Levels >500 IU/ml Indicate a Moderately Increased Risk for Developing Hypothyroidism in Autoimmune Thyroiditis. Horm Metab Res. 2016 Sep 8;48(10):623–9. DOI: 10.1055/s-0042-112815. PMID: 27607246.
  6. Amouzegar A, Gharibzadeh S, Kazemian E, Mehran L, Tohidi M, Azizi F. The Prevalence, Incidence and Natural Course of Positive Antithyroperoxidase Antibodies in a Population-Based Study: Tehran Thyroid Study. PLoS ONE. 2017 Jan 4;12(1):e0169283. DOI: 10.1371/journal.pone.0169283. PMID: 28052092. PMCID: PMC5215694.
  7. Amouzegar A, Ghaemmaghami Z, Beigy M, Gharibzadeh S, Mehran L, Tohidi M, et al. Natural course of euthyroidism and clues for early diagnosis of thyroid dysfunction: tehran thyroid study. Thyroid. 2017 May;27(5):616–25. DOI: 10.1089/thy.2016.0409. PMID: 28071990.
  8. Fröhlich E, Wahl R. Thyroid Autoimmunity: Role of Anti-thyroid Antibodies in Thyroid and Extra-Thyroidal Diseases. Front Immunol. 2017 May 9;8:521. DOI: 10.3389/fimmu.2017.00521. PMID: 28536577. PMCID: PMC5422478.
  9. Livadas S, Bothou C, Androulakis I, Boniakos A, Angelopoulos N, Duntas L. Levothyroxine replacement therapy and overuse: A timely diagnostic approach. Thyroid. 2018 Nov 30; DOI: 10.1089/thy.2018.0014. PMID: 30351232.
  10. Abu-Helalah M, Alshraideh HA, Al-Sarayreh SA, Al-Hader A. Transient high thyroid stimulating hormone and hypothyroidism incidence during follow up of subclinical hypothyroidism. Endocr Regul. 2021 Dec 7;55(4):204–14. DOI: 10.2478/enr-2021-0022. PMID: 34879182.
  11. Fröhlich E, Wahl R. Microbiota and thyroid interaction in health and disease. Trends Endocrinol Metab. 2019 Aug;30(8):479–90. DOI: 10.1016/j.tem.2019.05.008. PMID: 31257166.
  12. Bravo JA, Julio-Pieper M, Forsythe P, Kunze W, Dinan TG, Bienenstock J, et al. Communication between gastrointestinal bacteria and the nervous system. Curr Opin Pharmacol. 2012 Dec;12(6):667–72. DOI: 10.1016/j.coph.2012.09.010. PMID: 23041079.
  13. Frändemark Å, Jakobsson Ung E, Törnblom H, Simrén M, Jakobsson S. Fatigue: a distressing symptom for patients with irritable bowel syndrome. Neurogastroenterol Motil. 2017 Jan;29(1). DOI: 10.1111/nmo.12898. PMID: 27401139.
  14. Airaksinen J, Komulainen K, García-Velázquez R, Määttänen I, Gluschkoff K, Savelieva K, et al. Subclinical hypothyroidism and symptoms of depression: Evidence from the National Health and Nutrition Examination Surveys (NHANES). Compr Psychiatry. 2021 Aug;109:152253. DOI: 10.1016/j.comppsych.2021.152253. PMID: 34147730.
  15. Han CJ, Yang GS. Fatigue in Irritable Bowel Syndrome: A Systematic Review and Meta-analysis of Pooled Frequency and Severity of Fatigue. Asian Nurs Res (Korean Soc Nurs Sci). 2016 Mar;10(1):1–10. DOI: 10.1016/j.anr.2016.01.003. PMID: 27021828.
  16. Ng QX, Peters C, Ho CYX, Lim DY, Yeo W-S. A meta-analysis of the use of probiotics to alleviate depressive symptoms. J Affect Disord. 2018 Mar 1;228:13–9. DOI: 10.1016/j.jad.2017.11.063. PMID: 29197739.
  17. Altobelli E, Del Negro V, Angeletti PM, Latella G. Low-FODMAP Diet Improves Irritable Bowel Syndrome Symptoms: A Meta-Analysis. Nutrients. 2017 Aug 26;9(9). DOI: 10.3390/nu9090940. PMID: 28846594. PMCID: PMC5622700.
  18. Marum AP, Moreira C, Saraiva F, Tomas-Carus P, Sousa-Guerreiro C. A low fermentable oligo-di-mono saccharides and polyols (FODMAP) diet reduced pain and improved daily life in fibromyalgia patients. Scand J Pain. 2016 Aug 22;13:166–72. DOI: 10.1016/j.sjpain.2016.07.004. PMID: 28850525.
  19. Asik M, Gunes F, Binnetoglu E, Eroglu M, Bozkurt N, Sen H, et al. Decrease in TSH levels after lactose restriction in Hashimoto’s thyroiditis patients with lactose intolerance. Endocrine. 2014 Jun;46(2):279–84. DOI: 10.1007/s12020-013-0065-1. PMID: 24078411.
  20. Virili C, Bassotti G, Santaguida MG, Iuorio R, Del Duca SC, Mercuri V, et al. Atypical celiac disease as cause of increased need for thyroxine: a systematic study. J Clin Endocrinol Metab. 2012 Mar;97(3):E419-22. DOI: 10.1210/jc.2011-1851. PMID: 22238404.
  21. Magge S, Lembo A. Low-FODMAP Diet for Treatment of Irritable Bowel Syndrome. Gastroenterol Hepatol (N Y). 2012 Nov;8(11):739–45. PMID: 24672410. PMCID: PMC3966170.
  22. Sanders ME. Impact of probiotics on colonizing microbiota of the gut. J Clin Gastroenterol. 2011 Nov;45 Suppl:S115-9. DOI: 10.1097/MCG.0b013e318227414a. PMID: 21992949.
  23. Derrien M, van Hylckama Vlieg JET. Fate, activity, and impact of ingested bacteria within the human gut microbiota. Trends Microbiol. 2015 Jun;23(6):354–66. DOI: 10.1016/j.tim.2015.03.002. PMID: 25840765.
  24. Leblhuber F, Steiner K, Schuetz B, Fuchs D, Gostner JM. Probiotic Supplementation in Patients with Alzheimer’s Dementia – An Explorative Intervention Study. Curr Alzheimer Res. 2018;15(12):1106–13. DOI: 10.2174/1389200219666180813144834. PMID: 30101706. PMCID: PMC6340155.
  25. Wang F, Feng J, Chen P, Liu X, Ma M, Zhou R, et al. Probiotics in Helicobacter pylori eradication therapy: Systematic review and network meta-analysis. Clin Res Hepatol Gastroenterol. 2017 Sep;41(4):466–75. DOI: 10.1016/j.clinre.2017.04.004. PMID: 28552432.
  26. García-Collinot G, Madrigal-Santillán EO, Martínez-Bencomo MA, Carranza-Muleiro RA, Jara LJ, Vera-Lastra O, et al. Effectiveness of Saccharomyces boulardii and Metronidazole for Small Intestinal Bacterial Overgrowth in Systemic Sclerosis. Dig Dis Sci. 2020 Apr;65(4):1134–43. DOI: 10.1007/s10620-019-05830-0. PMID: 31549334.
  27. Greco A, Caviglia GP, Brignolo P, Ribaldone DG, Reggiani S, Sguazzini C, et al. Glucose breath test and Crohn’s disease: Diagnosis of small intestinal bacterial overgrowth and evaluation of therapeutic response. Scand J Gastroenterol. 2015 May 19;50(11):1376–81. DOI: 10.3109/00365521.2015.1050691. PMID: 25990116.
  28. Toribio-Mateas M. Harnessing the power of microbiome assessment tools as part of neuroprotective nutrition and lifestyle medicine interventions. Microorganisms. 2018 Apr 25;6(2). DOI: 10.3390/microorganisms6020035. PMID: 29693607. PMCID: PMC6027349.
  29. Stenman LK, Lehtinen MJ, Meland N, Christensen JE, Yeung N, Saarinen MT, et al. Probiotic With or Without Fiber Controls Body Fat Mass, Associated With Serum Zonulin, in Overweight and Obese Adults-Randomized Controlled Trial. EBioMedicine. 2016 Nov;13:190–200. DOI: 10.1016/j.ebiom.2016.10.036. PMID: 27810310. PMCID: PMC5264483.
  30. Frei R, Akdis M, O’Mahony L. Prebiotics, probiotics, synbiotics, and the immune system: experimental data and clinical evidence. Curr Opin Gastroenterol. 2015 Mar;31(2):153–8. DOI: 10.1097/MOG.0000000000000151. PMID: 25594887.
  31. Mujagic Z, de Vos P, Boekschoten MV, Govers C, Pieters H-JHM, de Wit NJW, et al. The effects of Lactobacillus plantarum on small intestinal barrier function and mucosal gene transcription; a randomized double-blind placebo controlled trial. Sci Rep. 2017 Jan 3;7:40128. DOI: 10.1038/srep40128. PMID: 28045137. PMCID: PMC5206730.
  32. Sindhu KNC, Sowmyanarayanan TV, Paul A, Babji S, Ajjampur SSR, Priyadarshini S, et al. Immune response and intestinal permeability in children with acute gastroenteritis treated with Lactobacillus rhamnosus GG: a randomized, double-blind, placebo-controlled trial. Clin Infect Dis. 2014 Apr;58(8):1107–15. DOI: 10.1093/cid/ciu065. PMID: 24501384. PMCID: PMC3967829.
  33. Lamprecht M, Bogner S, Schippinger G, Steinbauer K, Fankhauser F, Hallstroem S, et al. Probiotic supplementation affects markers of intestinal barrier, oxidation, and inflammation in trained men; a randomized, double-blinded, placebo-controlled trial. J Int Soc Sports Nutr. 2012 Sep 20;9(1):45. DOI: 10.1186/1550-2783-9-45. PMID: 22992437. PMCID: PMC3465223.
  34. Talebi S, Karimifar M, Heidari Z, Mohammadi H, Askari G. The effects of synbiotic supplementation on thyroid function and inflammation in hypothyroid patients: A randomized, double‑blind, placebo‑controlled trial. Complement Ther Med. 2020 Jan;48:102234. DOI: 10.1016/j.ctim.2019.102234. PMID: 31987229.
  35. Fleishman MS RDN C. IPA guidelines to qualify a microorganism as probiotic [Internet]. International Probiotics Association. [cited 2021 Jun 1]. Available from:
  36. American College of Gastroenterology Task Force on Irritable Bowel Syndrome, Brandt LJ, Chey WD, Foxx-Orenstein AE, Schiller LR, Schoenfeld PS, et al. An evidence-based position statement on the management of irritable bowel syndrome. Am J Gastroenterol. 2009 Jan;104 Suppl 1:S1-35. DOI: 10.1038/ajg.2008.122. PMID: 19521341.
  37. Ford AC, Quigley EMM, Lacy BE, Lembo AJ, Saito YA, Schiller LR, et al. Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome and chronic idiopathic constipation: systematic review and meta-analysis. Am J Gastroenterol. 2014 Oct;109(10):1547–61; quiz 1546, 1562. DOI: 10.1038/ajg.2014.202. PMID: 25070051.
  38. Appunni S, Rubens M, Ramamoorthy V, Saxena A, Tonse R, Veledar E, et al. Association between vitamin D deficiency and hypothyroidism: results from the National Health and Nutrition Examination Survey (NHANES) 2007-2012. BMC Endocr Disord. 2021 Nov 12;21(1):224. DOI: 10.1186/s12902-021-00897-1. PMID: 34772378. PMCID: PMC8590325.
  39. Mackawy AMH, Al-Ayed BM, Al-Rashidi BM. Vitamin d deficiency and its association with thyroid disease. Int J Health Sci (Qassim). 2013 Nov;7(3):267–75. PMID: 24533019. PMCID: PMC3921055.
  40. Wang S, Wu Y, Zuo Z, Zhao Y, Wang K. The effect of vitamin D supplementation on thyroid autoantibody levels in the treatment of autoimmune thyroiditis: a systematic review and a meta-analysis. Endocrine. 2018 Mar;59(3):499–505. DOI: 10.1007/s12020-018-1532-5. PMID: 29388046.
  41. Krysiak R, Kowalcze K, Okopień B. Selenomethionine potentiates the impact of vitamin D on thyroid autoimmunity in euthyroid women with Hashimoto’s thyroiditis and low vitamin D status. Pharmacol Rep. 2019 Apr;71(2):367–73. DOI: 10.1016/j.pharep.2018.12.006. PMID: 30844687.
  42. Zhang J, Chen Y, Li H, Li H. Effects of vitamin D on thyroid autoimmunity markers in Hashimoto’s thyroiditis: systematic review and meta-analysis. J Int Med Res. 2021 Dec;49(12):3000605211060675. DOI: 10.1177/03000605211060675. PMID: 34871506. PMCID: PMC8711703.
  43. Jiang H, Chen X, Qian X, Shao S. Effects of vitamin D treatment on thyroid function and autoimmunity markers in patients with Hashimoto’s thyroiditis-A meta-analysis of randomized controlled trials. J Clin Pharm Ther. 2022 Jan 3; DOI: 10.1111/jcpt.13605. PMID: 34981556. PMCID: PMC9302126.
  44. Drutel A, Archambeaud F, Caron P. Selenium and the thyroid gland: more good news for clinicians. Clin Endocrinol (Oxf). 2013 Feb;78(2):155–64. DOI: 10.1111/cen.12066. PMID: 23046013.
  45. Köhrle J. Selenium and the thyroid. Curr Opin Endocrinol Diabetes Obes. 2015 Oct;22(5):392–401. DOI: 10.1097/MED.0000000000000190. PMID: 26313901.
  46. Wichman J, Winther KH, Bonnema SJ, Hegedüs L. Selenium Supplementation Significantly Reduces Thyroid Autoantibody Levels in Patients with Chronic Autoimmune Thyroiditis: A Systematic Review and Meta-Analysis. Thyroid. 2016 Dec;26(12):1681–92. DOI: 10.1089/thy.2016.0256. PMID: 27702392.
  47. Winther KH, Wichman JEM, Bonnema SJ, Hegedüs L. Insufficient documentation for clinical efficacy of selenium supplementation in chronic autoimmune thyroiditis, based on a systematic review and meta-analysis. Endocrine. 2017 Feb;55(2):376–85. DOI: 10.1007/s12020-016-1098-z. PMID: 27683225. PMCID: PMC5272877.
  48. Zheng H, Wei J, Wang L, Wang Q, Zhao J, Chen S, et al. Effects of Selenium Supplementation on Graves’ Disease: A Systematic Review and Meta-Analysis. Evid Based Complement Alternat Med. 2018 Sep 26;2018:3763565. DOI: 10.1155/2018/3763565. PMID: 30356415. PMCID: PMC6178160.
  49. Lahner E, Annibale B. Pernicious anemia: new insights from a gastroenterological point of view. World J Gastroenterol. 2009 Nov 7;15(41):5121–8. DOI: 10.3748/wjg.15.5121. PMID: 19891010. PMCID: PMC2773890.
  50. Sterzl I, Hrdá P, Matucha P, Čeřovská J, Zamrazil V. Anti-Helicobacter Pylori, anti-thyroid peroxidase, anti-thyroglobulin and anti-gastric parietal cells antibodies in Czech population. Physiol Res. 2008 Feb 13;57 Suppl 1:S135–41. DOI: 10.33549/physiolres.931498. PMID: 18271683.
  51. Association between serum ferritin and thyroid hormone profile in hypothyroidism – – Deposit for Medical Articles [Internet]. [cited 2021 Jul 1]. Available from:
  52. Soliman AT, De Sanctis V, Yassin M, Wagdy M, Soliman N. Chronic anemia and thyroid function. Acta Biomed. 2017 Apr 28;88(1):119–27. DOI: 10.23750/abm.v88i1.6048. PMID: 28467346. PMCID: PMC6166193.
  53. Puntarulo S. Iron, oxidative stress and human health. Mol Aspects Med. 2005 Oct;26(4–5):299–312. DOI: 10.1016/j.mam.2005.07.001. PMID: 16102805.
  54. Talebi S, Ghaedi E, Sadeghi E, Mohammadi H, Hadi A, Clark CCT, et al. Trace Element Status and Hypothyroidism: A Systematic Review and Meta-analysis. Biol Trace Elem Res. 2020 Sep;197(1):1–14. DOI: 10.1007/s12011-019-01963-5. PMID: 31820354.
  55. Kandhro GA, Kazi TG, Afridi HI, Kazi N, Baig JA, Arain MB, et al. Effect of zinc supplementation on the zinc level in serum and urine and their relation to thyroid hormone profile in male and female goitrous patients. Clin Nutr. 2009 Apr;28(2):162–8. DOI: 10.1016/j.clnu.2009.01.015. PMID: 19250719.
  56. Foley TP. The relationship between autoimmune thyroid disease and iodine intake: a review. Endokrynol Pol. 1992;43 Suppl 1:53–69. PMID: 1345585.
  57. Katagiri R, Yuan X, Kobayashi S, Sasaki S. Effect of excess iodine intake on thyroid diseases in different populations: A systematic review and meta-analyses including observational studies. PLoS ONE. 2017 Mar 10;12(3):e0173722. DOI: 10.1371/journal.pone.0173722. PMID: 28282437. PMCID: PMC5345857.
  58. Wiersinga WM. L-T4 and L-T3 combined treatment vs L-T4 alone. Ann Endocrinol (Paris). 2007 Sep;68(4):216–9. DOI: 10.1016/j.ando.2007.06.008. PMID: 17689474.
  59. Borson-Chazot F, Terra J-L, Goichot B, Caron P. What Is the Quality of Life in Patients Treated with Levothyroxine for Hypothyroidism and How Are We Measuring It? A Critical, Narrative Review. J Clin Med. 2021 Mar 30;10(7). DOI: 10.3390/jcm10071386. PMID: 33808358. PMCID: PMC8037475.
  60. Jonklaas J, Bianco AC, Bauer AJ, Burman KD, Cappola AR, Celi FS, et al. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid. 2014 Dec;24(12):1670–751. DOI: 10.1089/thy.2014.0028. PMID: 25266247. PMCID: PMC4267409.

Getting Started

Book your first visit


I care about answering your questions and sharing my knowledge with you. Leave a comment or connect with me on social media asking any health question you may have and I just might incorporate it into our next listener questions podcast episode just for you!