Can Green Smoothies Worsen Thyroid Health?

I think it’s safe to say that we’re in a “smoothie era”, as millions of people consume smoothies on a daily basis.  There are a number of positive benefits of consuming green smoothies.  I personally have a green smoothie every morning for breakfast, and many of my patients do the same.  But while there are some great health benefits of drinking green smoothies on a daily basis, there are also some potential downsides of drinking these.

Before I discuss some of the potential “risks” of drinking green smoothies on a daily basis, I’d like to briefly mention a few of the primary benefits of green smoothies:

Benefit #1: Green smoothies can make it easier to start the day with a few servings of vegetables.  I look at the food diaries of patients all of the time, and to no surprise, most people don’t eat enough vegetables on a daily basis.  And most people who eat a few servings of vegetables per day don’t eat any during breakfast, but instead eat them during lunch and/or dinner.  Obviously this doesn’t apply to everyone, but it does apply to most people. It definitely applied to me growing up, as for the first few decades of my life I usually had a bowl of sugary cereal with cow’s milk for breakfast.

Benefit #2: Smoothies offer “instant hydration”, as they allow you to start the day off with a couple of cups of water.   To be fair, many people don’t add water to their smoothies, but instead add something else such as cow’s milk, almond milk, coconut milk, etc.  But many people don’t drink enough water, and so I would encourage you to at least add one cup of water to your smoothie.  For example, if you currently add two cups of coconut milk to your smoothies, try adding only one cup of coconut milk and one cup of purified water.  On most days I personally add 1/4 cup of organic almond milk to my smoothies, and 1 3/4 cups of purified water.

Benefit #3: You of course can include other healthy ingredients to your smoothies.  In addition to green leafy vegetables you can add carrots, avocados, and berries.  Many people can also add raw egg yolks and/or coconut oil to their smoothies.  Some people add a type of protein powder to their smoothie, which usually is fine, but just remember that these powders shouldn’t take the place of whole healthy foods.  I know some people have smoothies which consist of almond or coconut milk, strawberries and bananas, some type of protein powder, and nothing else.  While this is healthier than the bowl of sugary cereal I mentioned earlier, you should also add some vegetables and a healthy type of fat such as an avocado or coconut oil.  I can understand not wanting to add a raw egg yolk, although when combined with the other ingredients I mentioned, most people won’t even taste the raw eggs.  But besides the fact that some people find adding a raw egg to be disgusting, if someone is following a strict autoimmune paleo diet then they probably won’t be adding eggs to their smoothies.

So these are some of the health benefits of drinking smoothies.  But there are also some potential risks of drinking smoothies:

Risk #1: Green smoothies are typically goitrogenic. This of course depends on which green vegetables are added to the smoothie, but two of the most common green leafy vegetables added to smoothies are kale and spinach.  And while both of these have healthy nutrients, eating large amounts of raw kale and spinach can potentially inhibit thyroid activity.  Although there might be some risks with those people who have a hypothyroid condition with regards to eating large amounts of raw goitrogenic vegetables, adding 1/2 cup to one cup of these vegetables to a daily smoothie usually won’t cause a problem with most people, even those with hypothyroidism and Hashimoto’s Thyroiditis.  On the other hand, adding a few cups of raw goitrogenic vegetables to your smoothies and having one or two of these on a daily basis might cause problems in some people with hypothyroid conditions.  I spoke about goitrogens in greater detail in an article I wrote entitled “An Update On Goitrogenic Foods and Their Impact on Thyroid Health“.

Risk #2: Green smoothies can be high in oxalates. Oxalates are substances which bind to calcium, and this interferes with its absorption.  Eating foods high in oxalates can therefore lead to a decrease in bone density.  Another risk is that large amounts of oxalates can cause kidney stone formation.  I actually spoke about this in a post entitled “Should Spinach Be Avoided In Those With Thyroid Conditions?“, as I discussed the risk of loading smoothies with foods high in oxalates, such as spinach and swiss chard.  But it’s not just green leafy vegetables which are high in oxalates, as blackberries, blueberries, and raspberries are also high in oxalates, and of course many people add berries to their smoothies.  Once again, I’m not suggesting that people shouldn’t add berries to their smoothies, or other foods high in oxalates.  But it might be a good idea to minimize the amount of these foods you add to your smoothies.

Risk #3: Smoothies prepared the wrong way can spike up your blood sugar levels. Although I do think it’s fine to add some fruit to your smoothies, some people add too much fruit.  Bananas are one of the most commonly added fruits to smoothies, and while many people do fine adding a small banana to their smoothie, some people will add a few bananas, along with a few servings of other fruits to their smoothies.  This can especially be problematic for someone who has blood sugar imbalances, or an underlying yeast infection.  It’s not uncommon for people to prefer fruit over vegetables, and this definitely describes me.  When I first began making smoothies I probably added too much fruit, but I currently add 1/4 cup of organic berries to my smoothies and in my opinion it tastes fine.  Adding a healthy source of protein or fat will minimize the impact that the fructose will have on your blood sugar levels.  I would recommend adding an avocado, one tablespoon of coconut oil, and/or one or two raw egg yolks.

Risk #4: Some people include unhealthy ingredients in their smoothies. Although I’m fine with most people adding some type of “healthier” protein powder to their smoothie, doing so isn’t required.  And even if you do add a small amount of protein powder, you want your smoothie to consist primarily of whole foods.  Add a small amount of fruit, a few servings of vegetables, a healthy type of fat, etc.  But if you do add a protein powder you want to make sure it’s of good quality, and you also want to carefully read the ingredients and make sure it doesn’t include any artificial colorings or flavorings, as well as other unhealthy ingredients.

So What’s The Final Verdict?

I think most people with thyroid and autoimmune thyroid conditions can have green smoothies without a problem.  Just like anything else, the key is having a “balanced” smoothie.  Some people add too much fruit, while others add excessive amounts of green leafy vegetables.  But most people will do fine adding a small amount of fruit, while adding a few servings of vegetables, making sure to add a variety of different vegetables (i.e. 1/2 cup of arugula, 1/2 cup carrots, 1/2 cup broccoli, etc.).

Some healthcare professionals are opposed to smoothies because they feel it’s better to eat your food rather than drink your food.  In other words, rather than consume some or all of these ingredients in the form of a smoothie, they would recommend to simply have one or two eggs for breakfast, a few servings of vegetables, a serving of berries, a healthy type of fat, some meat, etc.  I can’t argue with this, as I admit that it’s better to sit down and eat a meal rather than drink a smoothie.  However, we live in an “era of convenience”, and whereas most people aren’t going to take the time to individually prepare all of these foods, many people are willing to add them to a smoothie.  Of course it can also be time consuming to make a smoothie, as I know it takes me awhile to make my morning smoothie.  In any case, for those people who are preparing a healthy breakfast I’m not suggesting to replace it with a smoothie.  On the other hand, for those people who aren’t eating a healthy breakfast and/or aren’t consuming a sufficient amount of vegetables each day, then having a daily green smoothie might be a good idea.

Something else to keep in mind is that even if you have a morning smoothie, you obviously still want to eat vegetables throughout the day.  I recommend eating a combination of raw and cooked vegetables.  Some healthcare professionals don’t recommend any raw veggies, but I think having a few servings of these are fine, along with having a few servings of cooked vegetables.  But there are some people who will overdo it with the raw vegetables, as they might have a green smoothie for breakfast, a big salad for lunch, another smoothie as an afternoon snack, and another salad for dinner.  I’m not opposed to people having salads, but they also should try adding in a few servings of steamed veggies each day.

In summary, millions of people consume green smoothies on a daily basis, and there are both benefits and risks of drinking these.  Some of the primary benefits of green smoothies are that they allow you to add some extra vegetables, along with some purified water, and other healthy ingredients, such as healthy fats and protein.  However, green smoothies are usually goitrogenic, can be high in oxalates, and might spike up the blood sugar levels.  You of course want to make sure not to add unhealthy ingredients, which can easily be avoided by sticking with whole foods, and organic foods whenever possible.  Overall I think green smoothies are fine for most people with thyroid and autoimmune thyroid conditions to drink on a daily basis, but you want to make sure not to load it up with too much of a single ingredient, such as green leafy vegetables, fruit, protein powder, etc.