One of the main priorities in my practice is to stay on top of the latest cutting-edge research in Hashimoto’s disease and thyroid disorders. My latest round of research reviews involved six clinical studies that examined inositol and selenium and how they conferred major benefits in those with Hashimoto’s disease and subclinical hypothyroidism. The highlights of each study are summarized in a table at the end of this article for ease of reference.
What are Inositol and Selenium?
Before we get started, let’s do a quick review on the supplements inositol and selenium.
Inositol is referred to as Vitamin B8 but is not actually a vitamin but a sugar. It naturally occurs in foods such as fruits (especially citrus), beans, grains and nuts. It helps provide structure to your cells and also affects the hormone insulin and how chemical messengers work in your brain.
Some of you may wonder if myo-inositol and inositol are the same thing and the answer is yes. So if you buy a product that is just called “inositol”, this is the myo-inositol form.
D-chiro-inositol is another form that works equally as well as myo-inositol, but the d-chiro-inositol has a slight edge in reducing excessive androgen levels in PCOS whereas the myo form is better with insulin resistance.
I have mainly used inositol over the years with excellent results for the following:
Polycystic ovarian syndrome (PCOS)
Insomnia
Anxiety
Insulin resistance
PMS
Depression
Fibrocystic breast disease
Uterine fibroids
Selenium is a trace element that is essential to well-being. It plays a role in the immune response, cell growth and viral defense as discussed in previous research including the studies of Huang et al. and Brownand and Arthur. Selenium also plays a huge part in the synthesis and function of thyroid hormones. It has antioxidant and anti-inflammatory properties and has been shown in previous investigations including those headed by Gartner et al., Landucci et al. and van Zuuren et al. to reduce an inflammatory condition in patients with Hashimoto’s thyroiditis.
The first study I’d like to cover on inositol, selenium, and Hashimoto's disease came out of Italy in 2017 by Nordio and Basciani.
That study was published in the European Review for Medical and Pharmacological Sciences entitled “Myo-inositol plus selenium supplementation restores euthyroid state in Hashimoto's patients with subclinical hypothyroidism.”
In that study, 168 patients ages 22 to 62 years had a TSH level between 3-6 mIU/L, elevated thyroid peroxidase antibody (TPO) and/or thyroglobulin antibodies (TgAb) and normal free T4 and T3 levels. They were randomized into two groups and were given either 83 mcg of selenium or a combination of 600 mg of myo-inositol and 83 mcg of selenium for six months.
After six months of taking these supplements, all participants taking myo-inositol and selenium showed improvements in their TSH, free T4, thyroid peroxidase antibody (TPO) and thyroglobulin antibody (TgAb). The group taking only selenium had a decrease in TPO levels which we have known for a while now based on previous research. Thyroglobulin levels, however, decreased only in the inositol+selenium group.
Additionally, subjects filled out a symptom questionnaire before and after which showed significant improvement in their thyroid-related symptoms.
In 2013, the research team of Nordio and Pajalich examined the effects of supplementation with myo-inositol and selenomethionine on patients with subclinical hypothyroidism. Their article was published in Journal of Thyroid Research and was entitled, “Combined Treatment with Myo-Inositol and Selenium Ensures Euthyroidism in Subclinical Hypothyroidism Patients with Autoimmune Thyroiditis.”
This study recruited 48 women with autoimmune thyroiditis with blood levels of thyroglobulin (Tg) and thyroid peroxidase (TPO) antibodies above 350 IU/L and TSH levels that were elevated between 4.01 mIU/L and 9.99 mIU/L. They had normal free T4 and free T3 levels.
Two subjects subsequently had to drop out so the group of 46 was split so that 22 patients (Group A) received 83 micrograms of selenomethionine/day for six months. The other group of 24 subjects (Group B) received a combined treatment of 600 mg of myo-inositol with 83 micrograms of selenomethionine supplement for six months.
The patients took the soft-gel supplement with water either 2 hours before or after a meal.
What did the researchers find?
TSH levels decreased only in the subjects that took the combined inositol and selenomethionine (Group B). There was actually no change in TSH levels in the group that took only the selenomethionine (Group A).
What does this mean?
Inositol made the difference when it came to positively impacting TSH levels.
In both groups A and B, thyroid antibodies (TPO and Tg) “significantly decreased”. What is notable is that almost half the patients in Group B that took the combined inositol and selenomethionine supplement demonstrated a drop in the level of thyroglobulin (Tg) antibody that fell below the original criterion for the Tg antibody level to qualify to be in the study. That means that these subjects wouldn’t even have been part of the clinical trial with the levels of thyroglobulin antibody that they ended up with after the six months of supplementation! That’s how much this particular thyroid antibody was reduced!
In 2017, Ferrari and colleagues published a study that appeared in European Review for Medical and Pharmacological Sciences entitled, “Myo-inositol and selenium reduce the risk of developing overt hypothyroidism in patients with autoimmune thyroiditis”. The authors recruited 21 patients with subclinical hypothyroidism and autoimmune thyroiditis along with ultrasound readings that demonstrated “hypoechogenicity” or basically, some structural abnormality in their thyroid which is an indicator of autoimmunity in the thyroid. All patients were treated with 600 mg of myo-inositol and 83 mcg of selenomethionine twice a day for 6 months.
What were the findings?
TSH was significantly reduced in these patients. Thyroid peroxidase (TPO) antibody and thyroglobulin (Tg) antibody levels were also lowered with Tg antibody levels dropping more significantly than TPO levels.
No change in free T4 or free T3 was observed but a marker of inflammation (called CXCL10) was reduced!
To summarize, the combination of myo-inositol and selenium taken by the patients over a 6-month period improved thyroid function by lowering TSH and also reduced autoimmunity and inflammation.
In another study, Benvenga and his team of researchers conducted a clinical trial that was published in 2017 entitled, “Favorable effects of myo-inositol, selenomethionine or their combination on the hydrogen peroxide-induced oxidative stress of peripheral mononuclear cells from patients with Hashimoto’s thyroiditis: preliminary in vitro studies”.
They examined lymphocyte activity (involved in the inflammatory response in Hashimoto’s thyroiditis) and tried to determine if cells would be protected in any way from oxidative stress by supplementing with myo-inositol and selenium in the form of selenomethionine.
The researchers collected blood samples of lymphocytes from 8 female subjects with Hashimoto’s thyroiditis with no other autoimmune disease but with measurable levels of thyroid antibodies (TPO and Tg) along with signs of inflammation detected by a sonogram. Three healthy female subjects were recruited as controls. Please note that this study involved the use of cell samples (in vitro) and how the supplements impacted the cells collected from the subjects.
Tissue samples of lymphocytes were exposed to hydrogen peroxide (H2O2) as the source of oxidative stress. There were measurements taken before the use of the supplements and again after supplementation with myo-inositol alone, selenomethionine alone or a combination of myo-inositol and selenomethionine.
What were the findings of this particular study?
When both inositol and selenium were introduced to the blood samples, the levels of cell toxicity from the stress were reduced “with myo-inositol+selenomethionine being the most potent addition”, or having the greatest therapeutic effect compared to just myo-inositol alone or selenomethionine alone.
When the researchers examined the activity of the cells that are triggered to fight infection (chemokines), with the addition of selenomethionine or the combination of myo-inositol and selenomethionine, there was a drop in the response of these special infection-fighting cells which went below what was measured with exposure to stress that even fell below the baseline condition! It’s not that these infection-fighting cells became less effective. These cells were able to lower their level of activity because they weren’t needed as greatly by the body. Inositol and selenium were at work in protecting the cell samples!
Specifically, the higher the concentration of selenomethionine or the combination of myo-inositol and selenomethionine, the more protective the effect on the cells. What is truly remarkable is that in the Hashimoto’s thyroiditis group, the infection-fighting cells responded even more significantly to the supplementation of myo-inositol and selenomethionine (combined) compared to the control group.
As you may have been able to glean, this study did have a clear weakness: only eight subjects were treated. To add more weight to the findings of these researchers, a larger group of subjects would have been meaningful not only in seeing what would have happened to blood levels of TSH and thyroid antibodies but in the reporting of the subjects’ “quality of life”.
In the fifth article,
