A healthy gut is essential for good digestive and immune functions. Our digestive tract or gut
is a host to trillions of microorganisms including bacteria, fungi, and viruses. This is called
the gut microbiota, gut microbiome, or gut flora. This gut flora helps in the defense
mechanism of the body. It helps in the digestion of dietary fiber that the human body is not
able to digest.

When dietary fiber is digested, it produces short-chain fatty acids which are extremely useful
in various body functions including the thyroid. Gut flora helps in the absorption of dietary
minerals like magnesium, calcium, and iron. It synthesizes some important vitamins like
vitamin K and folate and other B vitamins and certain amino acids required for protein
synthesis. Gut flora also impacts neurotransmitters and sends signal to our brain, affecting
moods and mental health.
Gut flora imbalance can adversely impact many functions of our body. Thyroid and gut
health are so interconnected that it is termed the gut-thyroid axis.
Iodine, selenium, zinc, and iron are micronutrients essential for thyroid health and the gut
flora impacts the uptake of all these nutrients. Poor gut health means poor absorption of
micronutrients from the food that we eat. Deficiency of Iodine is directly linked to Goitre
disease. Short-chain fatty acids produced in the digestion of dietary fiber in the gut help in
immune regulation and have anti-inflammatory effects. This helps in preventing autoimmune
thyroid disorders and supports thyroid health.
Alternatively, thyroid hormones interact with the gastrointestinal tract in many ways. Thyroid
hormones indirectly impact digestive motility which means the movement of food from the
mouth through the throat, stomach, small and large intestines, and out of the body. Reduced
motility has been observed in hypothyroidism and increased motility in hyperthyroidism.
This change in motility can cause constipation in hypothyroidism as the time taken by food to
exit is long. This may be due to intestinal edema or swelling.
Increased motility causes diarrhea and malabsorption in hyperthyroidism as it decreases
bowel transit time. These people have fat malabsorption as well, which may lead to excess fat
in the stool.
Autoimmune Thyroid Disease (AITD) has also been linked to gut flora imbalance. People
with autoimmune diseases are found to have altered gut flora. An imbalance in gut flora
increases the prevalence of Hashimoto’s thyroiditis (HT) and Graves’ disease (GD), both
autoimmune disorders. Celiac Disease is also an autoimmune intestinal disease where the
protein in gluten triggers an immune reaction which leads to severe inflammation of the
intestine and leaky gut syndrome. Leaky gut syndrome is increased permeability of the
intestine which can lead to bacteria and toxins in the bloodstream.
Digestive symptoms of an underactive thyroid i.e. hypothyroidism can include low stomach
acid, poor absorption, bloating, constipation, gallstones, chest pain, anemia, and bacterial
overgrowth in the small intestine.

Additionally, it has been observed that thyroid dysfunction is prevalently found in patients
with irritable bowel syndrome (IBS).

Looking at this connection, the thyroid affects your health and the gut affects your thyroid. If
you are suffering from thyroid disorders, then taking only thyroid medication is not
sufficient. Discuss with your doctor if you are having digestive system problems too. You
may be required to get some lab tests to know the root cause so that you can have a more
specific treatment. There is no one-size-fits-all approach to healing and managing illness.
In general, maintaining good gut health goes a long way. Some of the tips for better gut
health are :
 Eat whole foods instead of refined/processed foods. Whole foods contain fibers that
act as probiotics essential for good digestion. Refining and processing remove fibers
from foods which is not good for health.
 Include a variety of fruits and vegetables in your diet for micronutrients and fiber.
People with hypothyroidism may want to avoid cruciferous vegetables like turnips
and cabbage as they may affect thyroid hormone production.
 Include probiotics and fermented foods in your diet like dahi, yogurt, buttermilk,
pickles, kanji, kefir, kimchi, pickles, and idli. Probiotic food is rich in good bacteria
which can become part of your gut flora when consumed in the diet.
 Spices, condiments, and herbs like Ginger, cumin, fennel, garlic, basil, turmeric, and
mint support the digestive system. Including them in your daily diet is a good idea.
Asafoetida (hing) and ajwain (carom seed) can be used in cooking or as ‘kadha’ or tea
to prevent bloating and support digestion.
 Try to eat seasonal and fresh foods as much as possible. Foods with preservatives
have a negative impact on gut health.
 Have a healthy body weight. Include moderate exercise in your daily routine.
Moderate activity is good for both thyroid function and gut health.
 Manage your stress. Stress is more likely to cause a thyroid imbalance in people.
Yoga, meditation, mindfulness, and other relaxation techniques can help individuals
regulate stress in their lives.
 Have a good night's sleep. Sleep helps repair, relax, and regulates stress hormones and
hence supports thyroid function.
 Take care of your teeth. Bacteria from the mouth can enter your digestive tract and
affect your gut flora. So, maintaining good dental hygiene is a must for a good gut.
 Antibiotics indiscriminately kill gut flora. The use of antibiotics must be restricted.
Many illnesses do not need antibiotics as these are self-limiting in nature. Never self-
medicate as medicines may impact your gut and thyroid health.

 Intermittent fasting may also help in maintaining good gut health
Conclusion
Balancing thyroid hormone may be possible through good gut health. Diseases mostly do not
occur in isolation. Once, we identify the root cause, it’s easier to treat and manage the illness.