Posts Tagged ‘goitrogens’

Green Smoothie Health Benefits

October 16th, 2011




Green smoothies are becoming increasingly popular amongst the health conscious and for good reason too. You may have even noticed that your local smoothie bar has started stocking them. Green smoothies to put it simply are just your average fruit smoothie with raw green vegetables added to them, most commonly the leafy greens.

Green smoothies can be a great way to increase the amount of dark green vegetables you and your child gets in there diet. Even adding a small serving of green vegetables to your smoothies can substantially increase the nutrient content and health benefits. The dark green colour can be off putting to many children, so find some ways to disguise the smoothie by using smoothie cups or colored/stained glasses. You can also decrease the richness of the green colour by adding more fruit such as berries or bananas to your smoothie, this will also decrease any strong green taste.

Green Smoothie Nutrition

Leafy greens are a good source of protein whilst also being typically low in fat, they are a good source of the vitamins A(beta-carotene), K, C and folic acid. Dark greens are also a small source of the essential fatty acid Omega-3 which plays an important role in cardiovascular and overall health.

Green vegetables are also a great source of the minerals iron and calcium, this can be important for those who exclusively follow plant based diets such as vegans. You can increase the bio-availability of plant iron(non-heme) by including Vitamin C rich foods at the same time, this goes hand in hand with green smoothies as fruit is often used as a base. Green leafy vegetables are also a rich source of other minerals such as magnesium, manganese, potassium, copper and zinc.

Dark leafy green vegetables such as Spinach and Kale are rich in the carotenoids Lutein and Zeaxanthin which act as antioxidants to protect you from the damaging effects of free radicals. Both phyto-chemicals also play a role in maintaining eye health and protect the eyes from developing age-related macular degeneration and cataracts.

We briefly mentioned Lutein and Zeaxanthin above, but green vegetables also contain other phyto-chemicals. Phyto-chemicals are plant chemicals that have protective or disease preventive properties. An example of a well known phyto-chemical would be lycopene which is naturally found in tomatoes. Each green has its own unique phyto-nutrients and each thus has different health benefits to be had. So try to constantly rotate which green vegetables you are using in your smoothie, then same applys to fruits also so you can expose yourself to a variety of different nutrients and phyto-chemicals.

Green Smoothie Benefits

Adding a daily green smoothie to my diet was one of the best things i have done for my health overall. I have noticed a big increase in energy(this is coming from someone who used to have chronic fatigue syndrome), better skin, increased mood, clearer eyesight and much more. Many people start the day with caffeine for there energy fix, coffee like other stimulants can weaken adrenal gland function and thus rob the body of energy. So replace the morning coffee for a green smoothie packed with nutrients to keep you buzzing naturally without the detrimental effects of caffeine.

I actually prefer green smoothies over juices as they still have the fiber intact and thus don’t mess with blood sugar levels in the way juice does. Fiber is very important for health and has a number of functions such as feeding the gut flora(good bacteria), binding to toxins, plays a role in the formation of bile and much more.

The anecdotal list of benefits attributed to green smoothies is endless, but what we do know scientifically from research studies is that green vegetables have a big role to play in reducing the risk of many diseases such as certain cancers, heart disease, diabetes, stroke and many other degenerative health problems. Not only that but green vegetables, the leafy type in particular are some of the most nutrient and phyto-chemical dense foods we have access too, so it is little wonder that they provide a powerful punch when it comes to improving health.

It would take a book in itself to list the numerous studies on each of the green vegetables researched benefits, so have a little search and see what you can find. Some studies have found even increasing as little as one portion of green vegetables a week can significantly lower your risk of heart disease and risk of certain cancers such as those of the stomach.

What Green Vegetables To Use?

The most commonly used green vegetables in smoothies are spinach, kale, romaine and other types of lettuce, collards, swiss chard, arugula, broccoli, celery and watercress.

See the goitrogen/precaution section below for those who have suspected or confirmed thyroid disease. Care must be taken with what green vegetables you select for your smoothies as many contain goitrogens which interfere with thyroid function.


Some like to add green herbs such as Parsley, Coriander(Cilantro), Basil, Mint, Aloe Leaf and so on to their smoothies. These herbs should be used in small amounts compared to the other greens you add. Not only are they a very potent source of nutrition and other beneficial alkaloids, most of them are not meant to be used in large amounts and nor do you need to, to get the wonderful benefits each possesses. Parsley for instance is rich in coumarins which thin the blood, so should be avoided by those taking blood thinner medication.

Now although the above fresh green herbs are fine to add to your smoothie, i will say that adding powdered tonic herbs for example is a bit of a waste of time. You might see many guides or recommendations to add these medicinal herbs to your smoothie but in my opinion these are better consumed on an empty stomach. Many of the active compounds and nutrients that give these herbs there benefits would be blocked by other nutrients in smoothie. As with pretty much all medicinal herbs, they are best taken on an empty stomach at least 25 minutes before meals to get the full benefits.

Sea Vegetables

Id like to emphasize the point of adding sea vegetables to your green smoothies. Lets face it most don’t find seaweeds particularly appealing when it comes to taste, but sea vegetables pack an amazing punch when it comes to nutrition and achieving optimal health. Adding a small serving can substantially increase the protein(amino acid), vitamin and especially the mineral content of your green smoothie, not only that but sea vegetables have many documented health benefits such as reducing the risk of certain types of cancer, protecting against cardiovascular disease and so on. Sea vegetables are our best source of minerals and trace elements we have access to. Another bonus is that seaweeds are a rich source of the mineral iodine so they can offset the potential problem of “goitrogenic” green vegetables in your smoothie.

Research is showing that iodine deficiency is still a big problem in the UK as well as many other countries. Vegans are at an increased risk of iodine deficiency being that dairy(milk/cheese) and eggs are the main dietary sources. So start including some sea vegetables in your smoothies to make sure you are getting sufficient levels of iodine.


If money permits you can enhance your smoothie further by adding nutrient and health promoting superfoods to your green smoothies. Some examples of “superfoods” commonly added to smoothies include Chlorella, Spirulina, Wheatgrass, Barleygrass, Hemp Seeds/Protein Powder and Pollens.

You might see videos of people dumping 15-20 different superfoods and powders into their smoothies, not only is this very costly but it really isn’t necessary either. There are only so many nutrients the body can absorb at the one time, so the best idea is to rotate the superfoods you do add to your smoothie so that you are exposing yourself to different nutrients and phyto-chemicals. I am not really fond of the buzzword superfoods but it has become industry accepted now and looks to be here to stay. The foods above are in my opinion superfoods but so are fruits, vegetables, nuts, seeds and sprouts for example.

Whilst we are on the subject of sprouts these are also great to add to your smoothies. Sprouts are an amazing source of nutrition and are relatively cheap so stick a little in your smoothie to give it a boost.

Goitrogens, Oxalates & Precautions

Those with existing thyroid disease should be careful with what raw green vegetables they select for their smoothies. Many of the dark green vegetables are considered goitrogenic which means they interfere with the thyroids ability to uptake the mineral iodine. Cooking for as little as 10 minutes can largely inactivate the goitrogenic compounds, but because we are using the raw green vegetables in the smoothies care must be taking for those who suffer from thyroid disorders. A diet low in the mineral iodine can exacerbate the effects of goitrogenic foods taken in excess.

The good news is that there are still many great nutrient dense green vegetables that you can use in your smoothies which are not considered goitrogenic, some examples include romaine lettuce, watercress, red/green/swiss chard, dandelion greens, nettle leaf, parsley, cilantro, sea vegetables, arugula, wheatgrass and other types of lettuce such as iceberg and red lettuce. If you wish to increase the nutrient content of your smoothie further you can add a small amount of green superfoods such as chlorella, spirulina, barley grass and wheatgrass. Many greens such as nettle leaf, watercress and sea vegetables also support thyroid gland health and the latter two are good sources of the mineral iodine which as said can offset the effects of goitrogens.

There is another precaution for some individuals when it comes to consuming green smoothies and that is the oxalate issue. Some green vegetables such as spinach and kale contain measurable amounts of naturally occurring substances known as oxalates. High levels of oxalate in the body can produce various health problems. Individuals with existing or suspected kidney or gallbladder problems may want to avoid foods with high oxalate content.

There is some thought that oxalates can bind to minerals such as calcium and iron thus lowering them, but most studies have shown that the effect of oxalates on calcium absorption is relatively minimal and is likely of no concern in healthy individuals. It is still not clear from research whether reducing dietary consumption of oxalates helps prevent the formation of calcium oxalate stones. Those who have been at past risk of calcium oxalate stones should take care in consuming high amounts of oxalates until further research proves otherwise.

We will be adding some delicious and nutritious green smoothie recipes to the site shortly, so keep an eye out.

Here is a link to our first green smoothie recipe – Berry Green Smoothie Recipe

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