Thyroid health and Down syndrome


Thyroid health is complicated and opinions regarding assessment and treatment differ considerably.

One thing that is well recognised however, is that thyroid dysfunction, in particular clinical hypothyroidism, is a significant problem within the Down syndrome community.

It’s been estimated that the chance of hypothyroidism for a person with Down syndrome is 28 times higher than in the general population.

Studies have also detected higher than normal levels of thyroid stimulating hormone (TSH) in 85% of infants under 12 months old and autoimmune thyroid disease increasing in children over the age of eight.

If left untreated, hypothyroidism limits both intellectual and physical development and can result in a plateauing of intellectual functioning, or in some instances regression.

The article will discuss possible reasons for the high rates of thyroid hormone imbalance within the community and ways in which they can be addressed through natural medicines and diet.

This article will also attempt to explain why so many infants and children within the Down syndrome community still exhibit signs and symptoms of hypothyroidism despite taking conventional medication and showing lab results within standard range.

Thyroid hormones are required for every cell in the body to function. They are crucial for the promotion of brain development and skeletal growth in the first two to three years of life.

Incomplete assessment and treatment of hypothyroidism can result in an irreversible stunting of optimal brain development, and studies have shown a link between childhood hypothyroidism and symptoms of autism, due to central nervous system damage.

Hypothyroidism is also linked to low stomach acid production, which leads to a decrease in the metabolism of foods and the absorption of nutrients. Low stomach acid also contributes to gut issues such as bloating, constipation, leaky gut, SIBO (small intestinal bacterial overgrowth) and food intolerance. 

To follow is a list of common signs and symptoms associated with hypothyroidism and Down syndrome, you will notice that they correlate significantly.

This comparison chart has been kindly shared by Dr Erica Peirson, from the Peirson Centre for Children. you can view the original PowerPoint presentation here.

Additional symptoms of hypothyroidism include:

  • Puffy face
  • Dull looking skin
  • Choking
  • Constipation
  • Dry, brittle hair
  • Jaundice
  • Low muscle tone (floppy infant)
  • Low hairline
  • Poor feeding
  • Short stature
  • Sleepiness
  • Sluggishness
  • Hoarse-sounding cry or voice
  • Short arms and legs
  • Wide hands with short fingers

If a child still exhibits some or many of these symptoms despite being tested and medicated for a thyroid dysfunction, parents are often told by conventional practitioners, that these signs and symptoms are simply a part of having Down syndrome. This is not necessarily the case and the child may still be in a state of hypothyroidism.

To explain how such misdiagnosis occurs, it requires us to look at the thyroid hormones and functions themselves.

To understand the purpose of thyroid health, we need to focus on the end goal, which is to have enough of the correct thyroid hormone available to switch on each and every cell in the body.

Too little thyroid hormone in the cell leads to hypothyroidism, too much hyperthyroidism.

To understand the journey towards this goal, it helps to envisage the path of thyroid hormones as a relay race, where each participant is working as part of a team.

TSH – The race begins in the hypothalamus, which senses when the levels of thyroid hormone in the body are low and responds by releasing a hormone, which kick starts the pituitary gland into producing thyroid-stimulating hormone (TSH).

Thyroid stimulating hormone, as the name suggests, stimulates the thyroid gland, which is found in the neck area, into producing thyroid hormones T3 and T4, until levels in the blood return to normal.

T4 & T3 – T4 is the main hormone produced by the thyroid gland. This hormone is totally inactive biologically. It’s only after an iodine atom is removed, making it into T3, that it has an effect on the body. Without enough T3 people experience Hypothyroid symptoms.

T3 is the essential active thyroid hormone that the body needs in order to function, it’s like a key that fits into the lock of the cells and switches them on.

Thyroid gland – The function of the thyroid gland is to take iodine, found in many foods, and convert it into T4 and T3 thyroid hormone. This is often why iodine supplementation in the form of kelp, or seaweed is recommended for thyroid health.

Many people think that hypothyroidism is due to a faulty thyroid gland but this usually isn’t the case.

Radiology reports identify that many individuals with Down syndrome have smaller than average thyroid glands.

Reverse T3 – This often overlooked thyroid hormone is essentially the wrong form of active T3, created when the wrong iodine is taken off the T4 hormone. Reverse T3 is high in all babies until around day 11 after birth, then it normally switches off. Growing anecdotal evidence suggests that this may not be the case for individuals with Down syndrome and the reverse T3 production may continue well into childhood.

Reverse T3 blocks the cells receptor sites for active T3 hormone. It’s like having the wrong key for the lock, stopping active T3 from switching on the cell.
Thyroid hormone metabolism
Blood tests may indicate that T4 and T3 levels are in range, however if there is undetected high Reverse T3 in the system, then a child can still be clinically hypothyroid. This situation is known as Euthyroid Sick Syndrome or Non-thyroidal Illness Syndrome, conditions that are familiar to general practitioners and pediatricians.

A Naturopath in the US, Dr Erica Pierson, discovered that in 400 of her infant and child patients with Down syndrome, the majority exhibited high levels of RT3. This pattern was observed primarily in children from birth until four years of age.

The issue with undetected high levels of Reverse T3, is that blood test results may show that free T3 and TSH are in range and your doctor will put your child’s symptoms down to having Down syndrome, however in reality the hormone being produced isn’t the right one to switch on the cells, therefore your child may still have hypothyroidism.

The major cause of high Reverse T3 is any sort of stress on the body. During stress, the body attempts to conserve energy by converting T3 thyroid hormone into Reverse T3, which blocks thyroid function. This can be a normal healthy response in the short term but can be problematic if prolonged.

The following are the major causes of stress and high RT3 for children and adults with Down syndrome.

  • Oxidative stress as it up-regulates diodinase 3 enzyme
  • Low iron / ferritin
  • High cortisol levels (High cortisol levels increase TSH making thyroid function worse)
  • Inflammation (auto-immune diseases such as coeliac)
  • High levels of Leptin and Insulin
  • Gut infections and imbalances (up to 20% of T4 is converted to T3 in the gut)

The conventional approach to testing thyroid health is to evaluate TSH levels and occasionally T4.

A doctor or paediatrician may view TSH levels as being within the standard reference range which is 0.7 – 6.00 mU/L and consider thyroid function to be fine. The optimal reference range from a functional medicine perspective is between 0.5 – 2.00 mU/L.

If TSH levels are significantly elevated then synthetic T4 hormone replacement, Thyroxine, will be prescribed. Giving T4 only medication, doesn’t guarantee that it will be converted into the active T3 hormone the body needs, which is why a child’s symptoms may not diminish despite medication.

Thyroxine treatment does not support the improved functioning of the thyroid gland or indeed contribute to thyroid hormone conversion, therefore your child may need to be on the treatment for the rest of their life, as the underlying causes of their hypothyroidism are not being addressed.

There is some research to suggest that long term use of this medication can negatively affect the heart and contribute to bone loss, and unless medication levels are closely monitored, long term use may lead to idiopathic hyperthyroximia, or hyperthyroidism caused by the medication.

There are several issues with thyroid hormone evaluation using only TSH as a guide:

-Studies have shown that that tighter reference ranges regarding TSH are required.

– Evaluating TSH is not the most accurate way to assess true thyroid function.

-Patients who are treated with T4 medication often still have low free T3 (active thyroid hormone).

– Lab results should not replace the physical examination of symptoms.

One study that looked at thyroxine treatment in children with congenital hypothyroidism, observed that the high-dose group performed better on indexes of intelligence, verbal ability, and memory but had more behavior problems reflecting increased anxiety, social withdrawal, and poorer concentration, so this may be something to consider if your child fits this profile.

A naturopath or functional medical professional will view thyroid hormone imbalance from a root cause perspective and treat accordingly using specific nutrients, dietary modifications and treatment of any underlying issues, such as gut infections, inflammation, oxidative stress and adrenal insufficiency, all of which can contribute to thyroid hormone disruption.

This is certainly not the quick fix approach and does require more investigation and commitment; however the results create a positive effect not only on thyroid hormones but for the body as a whole.

It is entirely possible for children with Down syndrome to avoid thyroxine treatment and enjoy the health and cognitive benefits of optimal thyroid function, such as sustainable energy, alertness, endurance and an ability to concentrate, grow and develop consistently.

Accurate testing for hypothyroidism includes these baseline blood tests:

  • TSH and antibody levels
  • FT3 (Free T3)
  • FT4 (Free T4)
  • RT3 (Reverse T3)

Thyroid antibodies should be checked when assessing thyroid status to rule out autoimmune induced hypothyroidism, more commonly known as Hashimoto’s thyroiditis.

The Endocrine Society has determined the reference range for thyroid antibodies to be:

  • TPO TgAb (Throglobulin antibodies) < 4.0 IU/mL
  • TgAb (Thyroperoxidase) < 2.00 IU/mL

Additional blood tests for a comprehensive assessment include:

  • Iron studies – ferritin is very important for the conversion of T4 to T3.
  • Zinc
  • Copper
  • Vitamin D
  • CBC with differential and platelets – platelets in hypothyroidism tend to be high in numbers and small in size.
  • Cortisol – pediatric four point saliva kit Oxidative stress
  • Lipid panel – high triglycerides can show calories are not being burned because metabolism is slow.

These tests need to be individually written up by your GP, they cannot simply write TFT Thyroid Function Test which is the standard test and does not include the FT4, FT3 and RT3 required for proper thyroid assessment.

All these labs are available through medicare (Australia only), except RT3 which will cost approximately $70-$80.

Many parents report that they have trouble accessing these blood tests, especially Reverse T3. If that is the case for you, then continuing symptoms and observation should alert you to the possibility that this reading would be high.

An experienced functional medical practitioner, or naturopath will take these observations into account and treat your child holistically with a view to addressing the root cause and not merely the symptoms.

The following reference ranges have been compiled by Dr Erica Pierson from the Peirson Center for Children.


Thyroxine is a synthetic T4 only medication and the most common medication offered to children with elevated TSH. Whilst TSH levels may drop whilst taking this medication, Reverse T3, if an existing issue, will most likely increase and will continue to block T3 hormone from making it into the cells.

This situation is known as thyroid hormone resistance which Dr’s and pediatricians consider rare but may not be the case in infants and children with Down syndrome.

Liothyronine is a synthetic form of T3 medication which can be used to reduce high levels of Reverse T3. When T3 medication is given, Free T3 levels will increase and the TSH, T4 and RT3 hormone levels will drop.

It’s advised that this medicine is not given to those with heart or adrenal gland conditions and can only be prescribed and monitored by a qualified and experienced medical professional.

Natural desiccated thyroid is a T3 and T4 medication, as opposed to thyroxine which is T4 only. This product can be freely purchased on the internet, however it’s highly recommend that you seek the guidance of an experienced practitioner to oversee dosage and usage.

It’s important to understand that these medications do not address any the underlying issues that will be contributing to the thyroid imbalance, therefore these will need to be addressed if full function is to be restored.

that support thyroid function such as zinc, iron, tyrosine, vitamin e, selenium and iodine should be prescribed based on test results. Many of these vitamins and minerals are found in multi-nutrient formulas that are tailored to meet the needs of individuals with Down syndrome, you can read more about these here.

The primary areas that a Naturopath or functional medicine practitioner will address in order to balance thyroid function and hormones are as follows:

1.Adrenal Function.
2. Inflammation.
3. Intestinal and Gut Health.

If adrenal function is compromised, herbs such as Ashwaganda have been shown to support the adrenal glands and lower cortisol levels, which results in a natural lowering of TSH.

Inflammation can unfortunately be a problem for individuals with Down syndrome, caused by a number of things such as food intolerance, coeliac disease, poor diet, gut dysbiosis and insulin resistance.

These issues can however all be handled with the correct dietary advice and supplements such as curcumin (turmeric) and essential fatty acids.

A comprehensive stool analysis is an extremely worthwhile investment for a child or adult with thyroid imbalance. Identifying and treating infections, leaky gut and unbalanced gut flora will not only assist in improving thyroid hormone conversion but treatment will decrease inflammation, oxidative stress and adrenal dysfunction, as well as improving nutrient absorption.

Despite mainstream testing and treatment many children are still experiencing symptoms of hypothyroidism, which many practitioners mistake for normal and expected symptoms of Down syndrome.

This may not be the case and many of the health issues associated with hypothyroidism can and are being alleviated by assessing and treating the underlying causes in a holistic and natural way.

Helen Goodwin


Hypothyroidism in Down syndrome

Thyroid dysfunction in Down syndrome: Relation to age and thyroid autoimmunity

Euthyroid Sick Syndrome

Thyroid hormone and brain developement

Thyroid dysfunction and Down syndrome

Catherine C. Thompson and Gregory B. Potter. Thyroid Hormone Action in Neural Development. Oxford Journals Volume 10, Issue 10 Pp. 939-945

Reverse T3 in human newborn

Baxter, R.G., Martin, F.I.R., Larkins, R.G., Heyma, P., Myles, K. & Ryan, L. (1975). Down syndrome and thyroid function in adults. Lancet ii, 794-796.

Licastro, F., Mocchegiani, E., Zannotti, M., Arena, G., Masi, M. & Fabris, N. (1992). Zinc affects the metabolism of thyroid hormones in children with Down’s syndrome:

Coleman M. Thyroid dysfunction in Down syndrome: A review. Down Syndrome Research and Practice. 1994;2(3);112-115.

Desouza LALadiwala UDaniel SMAgashe SVaidya RAVaidya VA. Thyroid hormone regulates hippocampal neurogenesis in the adult rat brain. Mol Cell Neurosci. 2005 Jul;29(3):414-26.

Andi Durkin:

Prasher VP. Down Syndrome and Thyroid Disorders: A Review. Down Syndrome Research and Practice. 1999;6(1);25-42.

Mayo Clinic:

Stop The Thyroid Madness:

Effects of levothyroxine replacement or suppressive therapy on energy expenditure and body composition.

Is a normal TSH synonymous with “Euthyroidism” in levothyroxine Monotherapy.

Nonthyroidal illness syndrome and euthyroid sick syndrome in intensive care patients.

Effect of obesity and starvation on thyroid hormone, growth hormone, and cortisol secretion.

Elevated thyroid stimulating hormone is associated with elevated cortisol in healthy men and women

Profile of Hypothyroidism in Down’s syndrome

Levothyroxine treatment and occurrence of fracture of the hip.

Long term effects of L-thyroixine therapy for congenital hypothyroidism.

Excessive thyroid hormone replacement therapy

Long term cardiovascular effects if levothyroxine therapy in young adults with congenital hypothyroidism



0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *