Hypothyroidism and Thyroid Replacements


thyroid-supplementsFood and Supplement Considerations for Thyroid Disease

If you’re diagnosed with hypothyroidism, you’re likely to be prescribed the medication Synthroid, which replaces the thyroid hormone T4 which your body is no longer making enough of on its own.

As Jill described in her post last week, inadequate levels of thyroid hormones can cause a host of problems, not the least of which is a sluggish metabolism that may interfere with achieving and maintaining a healthy weight.

I find many people taking Synthroid, however, are unaware of how much this medication can affect how you eat.  The reason: Food and supplements can interfere with its absorption. That makes it important to take the med on an empty stomach. Some foods may also interfere with its action.

Synthroid for Hypothyroidism: 4 Food & Supplement Issues

1 Take Synthroid on an empty stomach.

Most people do this upon waking.  I have met a few people who take it before bedtime, but it can be challenging to consistently ensure that your stomach is empty at bed time.  Food can remain in the stomach for at least 4 hours and often longer if a meal was large and high in fat.

2 Wait one hour before eating.

Giving yourself a full hour with only that medication in the stomach will ensure the best rate of absorption.  Personally I find it VERY challenging to wait that one hour for coffee, so I used to take my Synthroid in the very early morning (3 or 4 am, since my puppy had me up then anyway) and then go back to sleep.

3 Foods & Supplements to Avoid for 4 hours after taking Synthroid.

Certain foods and minerals, if consumed within a few hours of taking this medication, will decrease absorption as well.  Avoid these foods and supplements at breakfast to ensure a 4-hour window between taking the med and consuming any of the following foods.

  • Soy Products – such as soy milk, tofu, soy yogurt, etc.
  • Walnuts
  • Calcium, Iron, or Magnesium Supplements – For this reason I avoid multi vitamin-mineral supplements in the morning, which are likely to contain some of these minerals.  Taking a multi at lunch time is usually far enough away from the Synthroid, but also far enough away from bed time.  Multis (since they usually have high levels of B vitamins) can sometimes interfere with sleep if taken in the evening.
  • High Fiber Foods – To me, this means anything that has more than 5 grams of fiber per serving.  I wouldn’t worry about a bowl of oatmeal or whole grain toast. However, I might avoid cereals known for their fiber content like Kashi, Fiber One, Uncle Sam, or bran cereals.  I would also avoid taking a fiber supplement within 4 hours of taking Synthroid.

4 Grapefruit is Questionable.

This fruit might have a minor effect on Synthroid.  For the ultra cautious, you may decide to avoid eating grapefruit often when taking Synthroid.

If you are taking Synthroid or levothyroxine (generic form), consider these tips for making sure the medication is most effective.

Hopefully that didn’t make your head spin if you take thyroid meds.  If you do, were you aware of all these interaction?

4 responses to “Hypothyroidism and Thyroid Replacements”

  1. BJ says:


    Hi Robyn,

    All are great suggestions. My Naturopathic Doctor also suggested taking thyroid meds just before bed (and at least 2 hours after eating). Her colleague -an MD from Harvard- said they have all theit thyroid patients do this and it seems to be more effective after sitting in the body all night- and you don’t have to worry about when to eat in the morning. 🙂

  2. robyn563 says:

    Good to know, BJ! Luckily I’m off my thyroid meds right now, but if I ever start up again, I would consider this, if it makes a difference in utilization. It certainly would help with eliminating night time snacking for many.

  3. Lisa H. says:

    Thanks for this blog Robyn! It was eye-opening for me to learn all of this from you during my recent stay at GM. Pleased that you are spreading the word. I’m also staying away from those cruciferous vegetables I loved. Who knew? The doctor certainly never told me.

  4. Robyn Priebe says:

    Hi Lisa, please don’t “stay away” from cruciferous vegetables, that’s not what I’m suggesting. Just make sure that you are selecting a variety of veggies and not primarily focusing on that plant family.

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