What Vitamins, Foods, and Drinks Should You Avoid with Hypothyroidism?

Health Line

6 hours ago

Certain supplements, foods, and beverages may affect thyroid function or interfere with the absorption of thyroid medication.
Hypothyroidism, or low thyroid hormone, affects an estimated 11.7% of people in the United States. It's treated by using a medication called levothyroxine to replace the missing thyroid hormone.
If you've been diagnosed with hypothyroidism, your doctor may also recommend certain dietary adjustments. These can include reducing your consumption (or the timing of your consumption) of certain vitamins, supplements, and foods.
This article reviews the foods, vitamins, and supplements to be mindful of with hypothyroidism, and how to reduce your risk of potential interactions when taking your thyroid medication.
Vitamins and supplements that may affect thyroid function or interfere with medication absorption
If you're being treated for hypothyroidism, use caution when it comes to the following supplements, as they can interfere with the absorption of your thyroid medication:
calcium
iron
iodine
Calcium and iron supplements
Proper absorption of your thyroid medication (levothyroxine) is needed in order for it to work effectively. When it isn't absorbed well, it is less effective at restoring your thyroid hormone levels.
If you need to take iron or calcium supplements, talk with your doctor about the best time to do so. It's generally recommended to take iron supplements at least 4 hours before or after taking levothyroxine.
Alternatively, you can ask your doctor about switching to liquid levothyroxine. It's primarily absorbed in the small intestine, and this may help decrease the risk of absorption problems caused by these interactions.
Iodine supplements
While iodine is important for making thyroid hormones, most people in the United States already get enough through iodized salt and common foods.
Taking too much iodine, especially without a proven deficiency, can make thyroid problems worse, especially in people with autoimmune conditions like Hashimoto's thyroiditis.
For example, research shows that too much iodine is toxic to thyroid cells. In people who are more prone to thyroid disease, this may trigger or worsen inflammation that may lead to Hashimoto's thyroiditis, a type of hypothyroidism caused by an autoimmune reaction.
Due to this, talk with a healthcare professional before taking iodine supplements if you've been diagnosed with Hashimoto's thyroiditis.
Foods and beverages that may affect thyroid function or interfere with medication absorption
Similar to iron and calcium supplements, some evidence suggests that certain foods and beverages may interfere with the absorption of levothyroxine.
These include:
high-fiber foods
soy products
milk
coffee
certain fruit juices, such as grapefruit juice and orange juice
papaya
It's important to point out that the evidence for some of these is rather limited or conflicting. For example, some studies have found that soy has little clinical impact on levothyroxine absorption, and avoiding it has few proven benefits.
Nevertheless, if you'd like to prevent interactions with these foods, you can do so by putting enough space between when you take your levothyroxine and when you eat.
Doctors typically recommend taking your medication on an empty stomach with water, 30 to 60 minutes before eating, or at bedtime, at least two hours after the last meal. This gives your medication ample opportunity to absorb properly.
Is it ok to drink alcohol with hypothyroidism?
While moderate alcohol use may be OK, it's important to be mindful of the potential effects of alcohol on thyroid function. Alcohol can interfere with the absorption of essential nutrients, such as iodine, which is needed for thyroid function. Alcohol can also damage the liver, which plays a role in hormone regulation.
Goitrogens
A goitrogen is a substance found in certain foods, such as cruciferous vegetables like kale, broccoli, and cabbage. When eaten in moderate amounts, these vegetables are nutritious additions to your diet, especially if cooked.
However, if consumed in excess, goitrogens can interfere with thyroid function by:
Blocking iodine: Goitrogens may prevent iodine from entering the thyroid gland, which is needed to produce thyroid hormones.
Interfering with TPO: The thyroid peroxidase (TPO) enzyme attaches iodine to the amino acid tyrosine, which together form the basis of thyroid hormones.
Reducing TSH: Goitrogens may interfere with thyroid stimulating hormone (TSH), which helps the thyroid gland produce hormones.
Getting enough iodine and selenium in your diet can also help limit the effects of goitrogens on your thyroid function.
In addition, some research has cast doubt on the idea that goitrogen-containing vegetables have a negative effect on the thyroid gland.
Talk with your doctor if you have concerns about your diet and how it may affect your thyroid function.
Foods high in iodine
Similar to the iodine supplements, it's a good rule of thumb to be mindful when consuming foods that are high in iodine, as too much iodine can make thyroid problems worse, especially if you have Hashimoto's thyroiditis.
However, it's worth noting that these foods should not be avoided unless a doctor gives specific instructions. They are part of a healthy diet and are not harmful for most people with hypothyroidism.
Examples of foods that are naturally rich in iodine include:
seaweed
seafood like cod, oysters, and shrimp
dairy products like milk and yogurt
eggs
It's also important to point out that some foods, such as breads and pastas, are iodine-enriched. Many table salts are also iodized. As such, be sure to check food labels while shopping.
How to reduce interactions with your thyroid medication
A 2015 survey of 925 people taking levothyroxine found that high percentages of respondents reported consuming medications, supplements, or foods that could interfere with levothyroxine.
Just over 13% of respondents to the survey also reported difficulty managing their hypothyroidism. This underlines the importance of taking steps to reduce interactions with your thyroid medication.
When to take your thyroid medication
Your doctor will typically suggest taking levothyroxine in the morning before breakfast
To maximize absorption and prevent interactions, it's recommended to take levothyroxine:
on an empty stomach, 30 to 60 minutes before eating breakfast
four hours before or after taking medications or supplements that can affect absorption
Other medications that can affect levothyroxine absorption
Some examples of medications and supplements that can affect levothyroxine absorption include:
antacids
proton pump inhibitors
bile acid sequestrants, a type of cholesterol-lowering medication
sodium polystyrene sulfonate, a potassium-binding medication
sevelamer, a phosphate-lowering medication
orlistat, a weight loss drug
iron and calcium supplements
If you ever have any questions or concerns about how to take levothyroxine, it's always a good rule of thumb to ask your doctor for advice.
Takeaway
If you're being treated for hypothyroidism, there are certain supplements, foods, and beverages that you may want to limit or avoid. Some may interfere with your thyroid medication, while others may affect your thyroid function.
For example, iron and calcium supplements, high fiber foods, and soy products may interfere with your body's absorption of levothyroxine. Meanwhile, consuming excess iodine or foods containing goitrogens could affect your thyroid function.