Caffeine and Your Thyroid

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Originally published on 10th October 2016
Last updated on 22nd May 2019

If you have thyroid issues (especially Hashimoto’s), adrenal fatigue, insomnia or trouble sleeping, anxiety etc. it’s important to be aware of the impact of coffee on your thyroid and thyroid medications. 

Affects How Much of Your Thyroid Medication You Absorb

It’s well reported, that coffee impacts the absorption of T4-only thyroid medication such as Levothyroxine, which is why thyroid patients need to wait at least an hour after taking their T4 medication before drinking any tea or coffee.

Another option may be to take T4 medication at night. Some studies have shown that taking levothyroxine at bedtime may improve absorption. It also allows for you to have your morning cup of coffee without worrying about it affecting your thyroid medication.

Increases Blood Sugar

According to this study, caffeine heavily increases our blood sugar levels when consumed.  Blood sugar spikes cause cortisol to shoot up, which can tire out the adrenals and exacerbate hypoglycemia, Hashimoto’s and adrenal fatigue. Not good!

I have covered in another post why so many of us with thyroid problems are likely to suffer from blood sugar imbalances, so this is a serious thing to consider and explore. If you get ‘hangry’ (hungry and angry), dizzy, faint and irritable when hungry, you could well have blood sugar imbalances.

Tires Out The Adrenals

As touched on above, caffeine makes our blood sugar spike, which causes the adrenals to pump out more cortisol. Also, when your blood sugar levels drop below normal, sometimes after a spike, your adrenal glands respond by secreting more cortisol. This cortisol then tells the liver to produce more glucose, which brings blood sugar levels back to normal. Doing this repeatedly can cause abnormal cortisol output and can suppress pituitary function.

Drinking coffee whilst also having adrenal fatigue (note: it is more accurately referred to as hypothalamic-pituitary axis dysfunction) is only adding fuel to the fire.

Damages The Gut Lining and Encourages Acid Reflux

Coffee can irritate the oesophagus or weaken the lower oesophageal sphincter, which prevents the backward flow of stomach contents that causes acid reflux.

Coffee is highly acidic, so it stimulates the release of gastrin and bile. For people with autoimmune conditions, compromised digestion (such as IBS or leaky gut), this can cause further digestive damage to the intestinal lining. This isn’t great for your gut health which is so intertwined with thyroid health and function.

Causes Migraines

Caffeine can trigger migraines and headaches.

Since caffeine narrows the blood vessels that surround your brain, when you stop consuming it, they expand again, and this can cause pain. It’s easy for your body to get used to caffeine, and when you don’t have it in your system, you can have a withdrawal headache or migraine. You may have one cup a day at work, then on the weekends don’t drink it, and experience caffeine withdrawal headaches or migraines. This is a sign of dependency.

If you get migraines or headaches, you should avoid caffeine to avoid it making matters worse.

As explained above, the spike in blood sugar caused by caffeine, could also cause headaches. So caffeine can lead to headaches and migraines in more ways than one.

Some women experience migraines around the time of their period, possibly because of changes in the level of oestrogen and progesterone around this time, and as the below explains, caffeine affects oestrogen levels too…

Can Cause Too Much Oestrogen

Studies have shown that women who consumed at least 500 milligrams of caffeine daily, the equivalent of four or five cups of coffee, had nearly 70% more oestrogen than women who consumed no more than 100 mg of caffeine daily (less than one cup of coffee). Tea is not much better as it contains about half the amount of caffeine compared to coffee.

Migraines, heavy periods, PMT, lumpy breasts, cellulite and even breast cancer can be symptoms of oestrogen dominance.

Oestrogen dominance inhibits T4 to T3 conversion, which can be a reason why your thyroid medication isn’t working or helping you to feel better.

Affects  The Conversion of T4 to T3

Coffee contributes to oestrogen dominance, and, as explained above, oestrogen dominance inhibits T4 to T3 conversion. Conversion issues with thyroid medication seem very common and can be the reason why your meds don’t seem to be helping with energy, removing hypothyroidism symptoms and more.

Contributes to Insomnia and Poor Sleep

This study showed that 400mg of “caffeine taken 6 hours before bedtime has important disruptive [sleep] effects” though this can be dependent on the individual and their ability to metabolise caffeine. It’s well reported to avoid caffeine after lunch time.

As explained above, caffeine exhausts the adrenals, and a key sign of adrenal dysfunction includes trouble getting to sleep and/or staying asleep.

All thyroid patients can benefit from going caffeine-free to see if/how it affects them.

People who give up caffeine tend to report better sleep, less headaches, fewer hot flashes, less anxiety, and less hypothyroid and digestive issues/symptoms.

I realised that caffeine was contributing to my migraines, so I cut it out, and haven’t looked back since.

You can click on the hyperlinks in the above post to learn more and see references to information given.

If you found this article beneficial, please take a moment to share it so we can help others get better with hypothyroidism and Hashimoto's, whilst also raising awareness. "Be Your Own Thyroid Advocate."

Written by Rachel, The Invisible Hypothyroidism

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7 thoughts on “Caffeine and Your Thyroid

  1. Very good written information. It will be valuable to anybody who employess it, as well as yours truly :). Keep up the good work – for sure i will check out more posts.

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