Intermittent fasting alternates fasting and feeding periods at varying frequencies and durations, enabling your body to take a rest and repair itself in the non-eating intervals. Intermittent fasting has been touted for its many health benefits, including its potential to increase longevity, reduce risks of diabetes, promote heart health, prevent Alzheimer’s disease, and more.
This eating cycle impacts our body in many ways, including our hormones. One common concern is how intermittent fasting affects our thyroid health. The thyroid gland affects metabolism, growth, and development in our body, and regulates many of its functions, as hormones are released into the bloodstream.
This raises questions, such as:
- Can you fast if you have a thyroid condition?
- Can fasting help reverse a thyroid problem?
- Is fasting really safe for your thyroid?
Fasting Helps Improve Thyroid Function
Research has shown that intermittent fasting has positive effects on the function of our thyroid. Intermittent fasting helps in the conversion of T4 to T3. If T4 is not converted, there will be a lack of sufficient T3 that affects how you feel and use fat as energy. T3 is crucial in the body’s use of energy from fat, so if the cells don’t get signaled properly, it impairs their ability to burn fat efficiently.
Another important thyroid hormone is TSH. These levels are dictated by the body’s circadian rhythm. Intermittent fasting is reported to have positive effects on our body’s internal clock, a cycle that also regulates hormones. TSH increases at night and decreases during the day. An increase in TSH is a signaled part of thyroid function, and intermittent fasting helps boost its increase during the fasting window.
Intermittent fasting helps decrease inflammation in cells, and as our body gets accustomed to consistent fasting, it becomes more responsive to hormones. This is why it is believed to be able to help eliminate hormonal problems, including thyroid conditions.
Proceed with Caution
While intermittent fasting is believed to help improve thyroid function, those who have existing thyroid conditions should be extra careful and be guided by a health professional before doing this type of fasting.
For example, those who have hyperthyroidism and Grave’s Disease have difficulty gaining weight. This is why intermittent fasting is probably not a good idea until their thyroid issue has been resolved.
Hypothyroidism is linked to hypoglycemia because it can increase insulin sensitivity. So those who have hypoglycemia are discouraged from doing intermittent fasting because going without food for long periods can cause blood sugar levels to drop to unhealthy and even dangerous levels.
People who have Hashimoto’s thyroiditis mostly are not safe to do intermittent fasting if their blood sugar levels, adrenal function, and circadian balance are not yet stable. Otherwise, they can benefit from short fasting periods.
Pregnant women should also avoid intermittent fasting as the pregnancy-related hormones estrogen and human chorionic gonadotropin (hCG) may increase thyroid levels. They are also at risk of hypothyroidism and hyperthyroidism during pregnancy, and untreated thyroid problems can lead to complications such as premature birth, preeclampsia, low birth weight, and miscarriage.
Intermittent fasting can have great benefits for thyroid function. It has an impact on three important thyroid hormones: T3, T4 and TSH. Those who have existing thyroid conditions are advised to seek guidance from their healthcare providers before engaging in intermittent fasting to ensure that it will not worsen their conditions.
There are also not sufficient scientific studies on humans to support the real benefits of intermittent fasting on thyroid function, but some experts still believe it does have the ability to help reverse thyroid problems. This stems from intermittent fasting’s contribution to the body’s need to take a break from digestive duties and repair itself.
