A study on green smoothies: not all greens are CREATED equal
Freshly prepared green smoothies are full of goods, including vitamins, dietary fiber, minerals and antioxidants. They are (sometimes) delicious and (always) make us feel good about ourselves. They make us “healthy”. As good as they can be though, there are some things we should know when preparing those babies. Below, I list the major guidelines to follow when making green smoothies. I extracted all these data from a recent peer-reviewed research that you can find here. Let’s dive in!
High sugar levels in smoothies: I know, we’re trying to be healthy kings and queens here, but the truth is out. A green smoothie with 200g spinach, 1 banana and 1/2 apple contains 30g of sugars and 200 calories. That’s home-made. In retail, green smoothies can contain between 5 to 11g of free sugars per 100ml, a level at which we enter the domain of soft drinks which usually contain 10g of sugar per 100ml.
The solution: make the smoothies yourself VS buying them in stores to keep an eye on your ingredients. Keep the fruits in your green smoothies low in sugar, such as less-ripe bananas or berries. Click here to look at the difference in sugar levels in different fruits.
Oxalic Acid or oxalates: those are present in great quantities in spinach, quinoa, amaranth and rhubarb. When these foods are consumed raw and occasionally, no major health risk appears associated. However, chronic consumption of these foods either raw or in large quantities (like 200g of spinach daily) can have negative effects on our digestive system. What happens is that oxalates reduce the solubility of the other minerals present in the food. What does that mean? In simple words, a large consumption of oxalic acid will prevent the absorption of good nutrients like calcium. This low absorption can in turn have an impact on bladder and kidney health, where unabsorbed minerals can form bladder stones.
The solution: soaking or cooking those vegetables decrease oxalic acid content by 30 to 85%, so cooking your spinach before adding it to your smoothie can actually make it healthier. Cook, cool under cold water and add to your smoothie.
Nitrate and Nitrite: these compounds are usually present in leafy greens like spinach (again!), rocket and chard. Nitrates convert to nitrites in our body and reduce the ability of our red blood cells to transport oxygen. As a result, our tissues receive less oxygen than they should, and we don’t want that. Now, you must know that nitrate levels in foods depend greatly on their farming processes. For example, leafy greens cultivated in green houses and/or in winter will have up to 37% more nitrate than when farmed outdoors, in the summertime. Nitrate levels are also highly affected by nitrogen fertilizers; in organic farming, these types of fertilizers are not allowed and therefore, yield vegetables lower in nitrates.
The solution: choose your leafy greens when they are in season, not when farmed in greenhouses. Additionally, organic leafy greens may be a better choice to decrease nitrate and nitrite levels. If you have a garden, why not try and grow them!
Raw cabbage, kale and their undigestible fibers: it is pretty common to present symptoms of flatulence, abdominal distension (bloating) and a sense of discomfort after consuming raw cabbage or kale. This is due to the fermentation of the fibers present in these ingredients and their processing by the bacteria in our digestive tract. Flatulence and bloating, not cool.
The solution: Traditionally, these foods are cooked and seasoned with herbs such as dill, fennel or caraway to ease the effect of gas and bloating. Soaking them before-hand is also recommended to reduce the amount of undigestible fibers.
Anthranoids in aloe vera leaves: aloe vera has gained a lot of popularity in the recent years as a digestive-tract soothing ingredient. If you grow your own aloe vera and consume the gel inside, keep in mind that the leaves contain anthranoids, which have laxative effects and are potentially carcinogenic. The gel inside the leaf does not contain this compound and is safe to consume, but it is easy to transfer the leaf juice into the gel when preparing the leaves by ourselves.
The solution: Keep this in mind as you prepare your concoction or purchase your aloe from a trusted manufacturer.
On that note, these precautions do not mean that smoothies are bad, but simply that there are better ways to prepare them. There is a myriad of foods and ingredients that you can incorporate into your healthy beverage, such as berries, celery, cucumber, lemon and lime, goji berries etc… Now that you know a bit more about your ingredients particularities, play around and happy smoothly-ing !
