The green smoothie craze has taken the world by storm, with everyone from die-hard vegans to paleo people jumping on the cabbage and spinach-laden drinks bandwagon. Read on to learn about the health issues associated with overzealous consumption of green smoothies and why drinking these beverages regularly may not be as conducive to optimal health.
While green smoothies have earned a reputation for being extremely healthy, these drinks have a dark side that few people are aware of. This does not mean that you should leave them, but you should be aware of what this side implies that everything consumable (without balance) has.
Are green smoothies healthy?
In the health community, the green smoothie has become the poster child for healthy eating. If you’re a fan of green smoothies, your typical recipe probably looks like this:
- 1 apple, peeled, cored and chopped.
- 1 cup unsweetened almond milk.
- 2 cups destemmed and chopped spinach or kale.
- 1 cup of broccoli.
This green smoothie is packed with veggies – spinach, kale, and broccoli, so it must be healthy, right? Well, not necessarily. While cruciferous vegetables and leafy greens certainly have health benefits, consuming large amounts of them in green smoothies may not be healthy in the long run, for several significant reasons.
Heavy metals in crucifers
Cruciferous vegetables, such as kale, broccoli, cauliflower, and cabbage, have been found to contain high levels of a toxic heavy metal, thallium.
Cruciferous vegetables contain goitrogens, which are naturally occurring plant chemicals that inhibit the absorption of iodine by the thyroid gland and reduce thyroid hormone production, thereby decreasing thyroid function.
Too much oxalate is not good
Many green leafy vegetables, like spinach and kale, are rich in oxalates. Oxalates are plant-based compounds that can promote kidney stone formation and inflammation when consumed in large amounts.
As you can see, it may be time to reconsider whether regularly drinking green smoothies is a good choice for our health.
Cruciferous vegetables and leafy greens undoubtedly have many health benefits, but consuming large amounts of them in green smoothies may not be healthy in the long run.
Are there heavy metals in your kale?
The soil in which vegetables grow has a significant impact on their micronutrient content. However, just as beneficial minerals are transferred from the soil to plants, so are toxic metals?
Unfortunately, research shows that toxic heavy metal thallium, which occurs in the soil as a byproduct of smelting and burning coal, preferentially accumulates in cruciferous vegetables such as kale, broccoli, cauliflower, cabbage, etc. Brussels sprouts and Chinese cabbage.
Thallium, toxic metal in green smoothies
This means that people who eat a lot of cruciferous vegetables, as green smoothie aficionados often do, can be exposed to high levels of thallium.
After much research, he was finally able to trace his symptoms back to thallium toxicity as a result of his cruciferous green smoothie habits with lots of greens.
Unfortunately, when it comes to thallium, even low-level exposures can cause symptoms like nausea, diarrhea, stomach pain, hair loss, and peripheral neuropathy.
While some medical authorities have argued that toxic metals are present in our environment and that we shouldn’t be concerned about trace levels in otherwise healthy vegetables, the problem remains that heavy metal exposures are additive. And synergistic.
Many heavy metals have similar adverse effects on the body, so continued consumption of thallium in vegetables, plus daily exposure to other sources of heavy metals, exponentially increases the body’s toxic load.
Based on this evidence, if you regularly drink green smoothies and experience unusual health issues, it may be time to research your thallium level and rethink your green smoothie habit.
Organic is the solution
If you’re not ready to ditch your green smoothies yet, at least consider using only organic cruciferous vegetables in your drink. Soils that are rich in carbon-based matter, such as soil on organic farms, have been found to prevent the transfer of thallium to plants.
This effect is less likely to occur on carbon depleted soils used on conventional farms. This means that organic products may contain lower levels of heavy metals, such as thallium, compared to conventionally raised products, which could result in a healthier green smoothie.
Green smoothies and the thyroid gland
Regarding green smoothies, they can also have adverse effects on the thyroid gland. The thyroid gland requires the mineral iodine to make thyroid hormones.
Cruciferous vegetables, common ingredients in green smoothies, contain compounds called glucosinolates, which inhibit the absorption of iodine by the thyroid. This can result in a reduced ability of the thyroid gland to produce hormones, leading to reduced function and potentially a thyroid disorder.
In addition, the risk of a high consumption of cruciferous vegetables that deteriorates thyroid function is higher in people with iodine deficiency. Iodine deficiency is not uncommon in people following a Paleo diet, as the main dietary sources of available iodine are sea vegetables, iodized salt, dairy, and fortified foods, which are often excluded from a Paleo diet. Or raw.
While large amounts of raw cruciferous vegetables pose a problem for the thyroid gland, cooked cruciferous vegetables appear to be much safer. Cooking cruciferous vegetables stimulates the production of an enzyme called myrosinase that helps deactivate iatrogenic glucosinolates.
Choosing to eat cruciferous vegetables in their whole food form (unground) is another way to reap the health benefits of these vegetables without taking a heavy hit from goitrogens; it is much more difficult to overeat vegetables when they are in their full form compared to juiced or mixed in a green smoothie.
Oxalates in green smoothies
Another major problem with green smoothies is that they are often high in oxalate, a type of natural plant compound that promotes kidney stone formation and inflammation in certain people when eaten in excess.
Oxalate occurs in large amounts in spinach, chard, dandelion greens, beets, kale, berries, broccoli, cabbage, and carrots. In some people, oxalates build up in body tissues and cause inflammation.
In fact, oxalate accumulation has been associated with chronic pain, nephrolithiasis (also known as kidney stones), neurological symptoms, vulvar pain, and fibromyalgia pain.
Currently, a high oxalate intake is defined as consuming 250 mg of oxalate per day. For reference, a cup of raw spinach contains about 656 mg of oxalate.
As you can see, it would be quite easy to go overboard on oxalates if you regularly have green smoothies, which often contain a cup or more of spinach.
Research has confirmed that green juices made from common vegetables contain high levels of soluble oxalates and that consumption of these beverages can precipitate the formation of oxalate kidney stones.
Including varied vegetables is part of the solution
Some green smoothie advocates recommend that “spinning” vegetables include low-oxalate options like mustard greens, watercress, and lettuce; this can help prevent the oxalate overload induced by the green smoothie.
Certain genetic variants, such as the SLC26A1 variant, and pre-existing intestinal problems, such as Crohn’s disease and symbiosis, can increase an individual’s susceptibility to the harmful effects of oxalates in the diet. For these people, reducing dietary oxalate intake can significantly relieve symptoms.
Replenishing the gut with beneficial bacteria from probiotics and fermented foods can also aid in oxalate breakdown, as several probiotic species, including Lactobacillus rhamnosus, Bifidobacterium animalis subsp. Lactis BI07 and Oxalobacter formigenes have been found to degrade oxalate in the diet.
Final notes on green smoothies
Unfortunately, green smoothies are not as healthy as we have been led to believe, due to their thallium, goiter, and oxalate content. Instead of relying on green smoothies as the main source of vegetables, it is recommended to eat vegetables in their whole food form and cook cruciferous vegetables to reduce their goitrogen content.
If you’re not ready to give up green smoothies entirely, choose organic veggies, which may be lower in heavy metals; rotate your veggies to regularly include low-oxalate options like mustard greens and watercress; and consider supplementation with oxalate-degrading probiotics like Lactobacilli and Bifidobacteria.