Many people with digestive symptoms like bloating, gas, gut pain, reflux, weight issues, diarrhea, constipation and mood issues have an overgrowth of the bacterial in their small intestine. It is estimated that half or more of the people who are diagnosed with IBS, actually have SIBO or small intestinal bacterial overgrowth.
This overgrowth is caused by low stomach acid and slow motility. Both of these issues can be exacerbated by stress but there is usually a deeper underlying cause.
A common cause of low stomach acid AND slow motility can be a slow thyroid, which down-regulates metabolism. A slow thyroid slows down digestion and all metabolic processes.
The thyroid controls the speed of food passing through the digestive tract. This is called “peristalsis, gut transit time and/or motility”.
As metabolism slows down because of a slow thyroid (hypothyroidism) it can cause digestive symptoms like dyspepsia (indigestion or stomach pain), low stomach acid, poor absorption, constipation, gallstones, anemia and bacterial overgrowth in the small intestine. It can also cause weight gain.
The thyroid is often an overlooked part of the digestive health picture. Additionally, hypothyroidism is often under diagnosed.
Why is this?
Because doctors typically only use one thyroid marker (TSH) to gauge the health of the thyroid. This could read as normal when the rest of the hormones are low.
You can have a sluggish thyroid and it won’t show up on tests until the imbalance becomes severe.
The hair tissue mineral analysis test and the DUTCH hormone test, measure the health of the thyroid, warning of dysfunction (slowing down or speeding up) before it shows up on blood tests.
Symptoms are not a great way to self diagnose but they can provide a clue that the thyroid is struggling. Some of the symptoms of a slow thyroid are:
Fatigue, dry skin, constipation, depression, hair loss, forgetfulness/brain fog, feeling cold, depression, sleep issues, thinning of the eyebrows (esp. outer edge), overwhelm and weight gain.
For a fast thyroid the symptoms are opposite, diarrhea, anxiety, irritability, weight loss, fast heart beat, feeling overheated, difficulty swallowing, vomiting, lactose intolerance, liver problems and flare ups of H. pylori infection.
More than half of people with hypothyroidism have SIBO
A 2014 study showed the link between hypothyroidism and small intestinal bacterial overgrowth and revealed than more than half of people with hypothyroidism also have SIBO. The impaired motility and stomach acid is probably why.
In this case, supporting the thyroid is an important part of getting rid of SIBO for good.
The primary cause of hypothyroidism is Hashimotos, an autoimmune disease that occurs when the immune system attacks the thyroid. An overactive immune system attacks the thyroid ducts, which prevents them from getting enough thyroid hormones into the blood and slowing everything down.
One of the triggers of Hashimotos is an infection like h. pylori. There can be a link between h. pylori, SIBO and the thyroid.
H. pylori is a bacterial overgrows in the stomach which inflames the stomach and lowers acid production.
One of the best ways to test for an h. pylori infection is the GI Map. Many other tests can produce false negatives. H. pylori is hard to test for and can cause the same type of symptoms as SIBO.
In my SIBO guide I list the other root causes of SIBO. A slow thyroid is the most common, but not the only cause. This blog post is about investigating the thyroid as a root cause of SIBO or symptoms of slow metabolism listed above.
It is not always straight forward to get answers about the thyroid so I am going to talk about how you can test properly for it and also mention some root causes of thyroid dysfunction.
If a slow thyroid is lowering stomach acid and compromising motility it will also be causing other unpleasant issues around sleep or mood. These symptoms can raise anxiety which will add a snowball effect.
Proper Thyroid testing
As I mentioned, most doctors only test TSH. I suggest getting a full thyroid panel, including antibodies.
If your doctor refuses to order a full panel, saying your TSH is normal and doesn’t warrant it. You can order your own panel. And if you need help, get in touch and I can send you in the right direction.
A full thyroid panel requires a blood draw. Some kits use blood spots (you prick your finger and put a drop of blood on blotter paper), but blood spot tests are not as accurate as blood draws.
Here are the markers I suggest:
Free T3
Free T4
Reverse T3 (this shows how T4 converts to the active hormone T3 in the liver)
Antibodies tell us if the immune system is attacking the thyroid. A TPO over 35 qualifies as the autoimmune disease Hashimotos.
You can also add total T3 and T4 but they are not as important as the free hormones that are circulating in your blood.
A full thyroid panel is more likely to uncover dysfunction, but to read it correctly you need to refer to the functional ranges below.
For example, TSH is considered elevated by doctors when it is over 4.5 or 5 but some docs won’t suggest medication until it gets higher, closer to 10.
According the functional range, a TSH over 2 signals that the thyroid is slowing down. A TSH of 3.5 may be ignored by a doctor but may be causing a slow down in the body.
The functional (optimal) ranges are below.
The most common treatment for a slow thyroid is hormone replacement in the form of pharmaceuticals levothyroxine or Synthroid. There is also a desiccated thyroid option and a T3 only option.
Thyroid meds can ease symptoms but they won’t heal the thyroid.
Another option is to take a hair mineral analysis or the DUTCH hormones test to check the status of the thyroid, plus adrenals, hormones, etc…
So how do you support your thyroid after you get results?
How to support the thyroid naturally
The thyroid needs minerals enough minerals, like selenium and iodine to function optimally.
A mineral test tell us which minerals are lacking. It can also tell us if metals, like mercury are stressing the thyroid, and preventing iodine from getting into the cells.
Mercury comes from metal dental amalgams, large fish like tuna, or from vaccines. If your body doesn’t detox well, metals and mercury build up and block beneficial minerals from getting into the cells where they are needed.
You can take iodine in the form of kelp, seaweed or supplements. Anything from the sea will supplement iodine.
A blood sugar stabilizing supplement called inositol and vitamin A is also very supportive for thyroid function.
Lifestyle tips for supporting the thyroid
If Hashimotos is responsible for thyroid issues, cutting out gluten is the most helpful intervention. Gluten increases antibodies and the immune on the thyroid.
Chlorine (from drinking water or pools) and fluoride (in toothpaste) can compete with iodine’s absorption into the thyroid.
Red light therapy, saunas (Swedish or infrared saunas) and castor oil packs applied on the thyroid are very supportive for the thyroid. So is healing the gut and clearing out infections like h. pylori.
Metaphysical reasons for thyroid dysfunction is not speaking up or speaking your truth or feeling like there’s never enough time (always feeling rushed).
I hope this blog post can raise awareness about the thyroid’s impact on the gut and digestion. As well as how to properly test thyroid hormones and support a struggling thyroid.
A happier thyroid means a happier metabolism, and happier gut. If you have SIBO, the thyroid may be a key missing piece. But even those who don’t have SIBO can benefit from thyroid testing.
Angela Privin is proof that IBS is NOT an incurable disease, but a cry for help from a gut out of balance. When the body AND mind are complaining, it’s an opportunity to examine what’s not working and change it. After solving her own IBS mystery almost two decades ago, Angela became as a health coach to help others. Angela uses root cause medicine protocols personalized to the individual to solve each IBS mystery. Her tools are lab testing, dietary changes, supplementation, subconscious mind work and nervous system rebalancing . Learn more here.