Remember the My Buddy doll commercials in the 1980s? “My Buddy, My Buddy. Wherever I go, he goes… My Buddy, My Buddy. My Buddy and me.” Well, that’s how I think of my microbiome. We’re besties. I take care of it, it takes care of me. And since we’re all more bacteria than we are human cells, it’s only fitting that our microbiome plays such a huge role in our health.
One of the emerging areas of research is between our gut microbiome and thyroid function. There is no doubt that thyroid hormones influence the structure and function of our gut, including our gut lining and gut motility (how quickly food moves through us). The same is true for how a healthy gut microbiome benefits thyroid function, including the synthesis and conversion of thyroid hormones. Naturally, researchers wanted to know if certain bacteria were correlated with specific thyroid conditions. They found that individuals with healthy functioning thyroids had more anti-inflammatory bacteria than someone with a thyroid condition, who had more pro-inflammatory bacteria. Furthermore, the type of inflammatory-inducing bacteria differed between individuals with various thyroid conditions including Hashimoto’s disease (higher prevalence of SIBO), Grave’s disease (higher prevalence of h. pylori), hypothyroidism, thyroid nodules, and thyroid cancer.
See what I mean. My Buddy and me!
And since I’m a huge fan of doing less and getting more, let’s look at how focusing on our gut health will also support our thyroid health.
Digestion + Absorption
Many of us are very familiar with the primary function of our gut: digestion and absorption. As I discussed in a previous blog post, certain nutrients like iodine, selenium, zinc, and iron are important nutrients in making and converting thyroid hormones. This is why many individuals with nutrient malabsorption diseases (i.e. Celiac disease, Crohn’s disease, ulcerative colitis, etc.) also tend to have thyroid conditions and vice versa.
However, the availability of these nutrients for our thyroid are also influenced by our gut microbiome. Iodine and iron are important for making thyroid hormones. However, researchers found that certain microbes remove iodine from thyroid hormones, while pathogenic bacteria tend to feed on iron. Not cool. This is why knowing what you’re deficient in and why you’re deficient in it, is so important rather than blindly taking supplements. We definitely don’t want to keep feeding the bad bacteria.
Then there’s selenium and zinc. These two minerals are important in converting non-active T4 thyroid hormone to the active T3 thyroid hormone. Researchers also found that certain bacteria feed on selenium and zinc too, which can pull those needed nutrients away from doing their job to convert thyroid hormones. However, unlike the iron-loving pathogens, the selenium and zinc-loving bacteria were beneficial anti-inflammatory bacteria. Again, it’s always best to check before supplementing, even if it feeds the good microbes.
Short-Chain Fatty Acids
I’m a huge fan of fiber for this reason: beneficial microbes feed on fiber and produce short-chain fatty acids (SCFA). SCFA are the main food source for our gut cells and help strengthen the gut lining along with thyroid hormones. They also activate feel-good neurotransmitters like dopamine, GABA, and serotonin. This is important for thyroid health too, because dopamine can decrease thyroid-stimulating hormone (TSH), which is usually high in individuals with hypothyroidism and Hashimoto’s disease. Butyrate, a specific SCFA, also has anti-inflammatory and anti-tumor properties, which decreases cancer risk and supports our immune system (70% of which is housed in our gut).
Gut Permeability + Immune System Activation
We now know that SCFA and thyroid hormones help strengthen our gut lining, and that the specific SCFA, butyrate, also supports our immune system. So, when our gut is out of balance with “bad” bacteria and/or we’re consuming things that break down our gut lining’s tight junctions, we can get what’s known as intestinal permeability or “leaky gut.” The more permeable our gut is, the more pathogens and other things can enter our blood stream and wreak havoc, creating inflammation and putting our immune system on high alert. Researchers hypothesize that this heightened activation of the immune system is where autoimmune diseases, such as Hashimoto’s and Grave’s diseases, may come into play with the health of the microbiome.
How to Support a Healthy Microbiome for Thyroid Health
While we can’t pick-and-choose all of our gut microbes, there are many things we can do to create a diverse gut microbiome, strengthen our gut lining, and not over-burden our immune system.
Eat a variety of fiber-rich plant foods. Fiber improves detoxification as well as providing food for SCFA. Colorful plants are also high in polyphenols, which are great for a healthy gut lining. Studies show that eating 30 different plant foods (vegetables, fruit, beans/lentils, nuts/seeds, whole grains) a week will provide great microbial diversity.
Eat your probiotics (and you can supplement with them too). Fermented foods like yogurt (dairy and non-dairy), kefir, sauerkraut, and kimchi also add microbiome diversity to your gut.
Get dirty and play. Gardening and playing with our pets are great ways to get exposed to a variety of microbes (most of which are healthy ones).
Rest. I feel it’s safe to say that stress has the biggest impact on our health. Find tools to lessen it’s impact in your life, whether that is deep breathing, watching a comedy, getting adequate sleep, or anything else that brings more ease to your life.
Reduce alcohol. Alcohol is rough on our gut lining and immune system. If you’re working on improving your gut and/or thyroid health, look at ways to reduce alcoholic beverages.
Know your medications. While antibiotics may be helpful in killing "bad" bacteria, they also kill the "good" kind too. If you need to take one, considering taking probiotics and eating lots of fiber-rich foods as well to try to offset its side effects. Our gut lining can also be greatly affected by medications such as those used for reflux and stomach ulcers. If you have problems with reflux and stomach ulcers, get tested for h. pylori, which is a pathogen that lives in your stomach and can cause those issues.
I’d love to hear from you. Please comment below or send me an email with one thing you’ll do today to support your gut and thyroid. Also, if you’d like to improve your gut and thyroid health, send me an email and let’s work together!
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With love, Steph
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