Renowned as a super-food, kale is a leafy green that is highly nutritious and is packed with high levels of vitamins, minerals, and brain-boosting phytonutrients.
In this article, we will look back at the origins of kale, learn why this leafy green is known as a superfood, and find out the top health benefits kale provides, as well as some side effects kale can cause. Then of course, we will share with you some of the best nutrient-packed juice and smoothie recipes containing kale.
In This Article:
A Short History of Kale
Historians say that kale originated in the Mediterranean and Western Asia. This leafy vegetable's origins date back to over 2,000 years ago, and it was one of the most widely eaten vegetables in the Middle Ages. Kale is not just popular in America; it is also a favorite throughout Europe.
In the 19th century, United States Department of Agriculture (USDA) botanist David Fairchild brought home kale from Croatia and introduced it to Americans. At that time, kale was a popular crop among Croatians because it was easy to grow and inexpensive. Shortly after Fairchild introduced kale, Americans mostly kept it as a decorative plant. However, it became a popular choice among edible vegetables in the 1990s for its nutritional value.
During World War II, the Dig for Victory campaign encouraged people in the United Kingdom to grow kale in their gardens. Aside from being easy to grow, kale also provided vital nutrients that the rations did not contain.
Additionally, the English word “kale” was derived from the Latin word caulis, meaning “cabbage”. This leafy vegetable is known as kale around the world, but some countries have their own term for the vegetable. For example, Indians know it as “karam saag,” while Italians call it “cavolo nero”.
Varieties of Kale
Kale is a cruciferous vegetable that belongs to the Brassica oleracea family with other collard greens. For thousands of years, farmers have cultivated kale in many different locations. As such, many varieties and unique types have come up throughout the years. Each kale type may vary in the color of the leaves as well as the vegetable’s height, with different stem lengths.
Curly kale is one of the most common types of kale, and it is the one you see most often in the produce section of the grocery store. It has a pale to deep green color, with large, ruffled, curly-edged leaves and long stems. Curly kale is typically sold as several loose leaves bound together. Additionally, health enthusiasts often recommend this kale variety for salads, soups, and smoothies.
While curly kale may be known as the most common type, it is not the only type of kale with curly leaves. Redbor kale, which has purple leaves, and Scotch kale, which has a blue-green tinge, are just two other types of curly-leaf kale.
Compared to curly-leaf kale, flat-leaf kale is much easier to chop. Because of this, many soups, salads, and stew recipes include various types of flat-leaf kale as ingredients instead of curly-leaf kale. As plain-leaf kales grow, they typically grow upright and tall, as opposed to the curly-leaf kales which tend to sprawl. Hence, flat-leaf kales often grow taller than the curly varieties.
Among the many different types of plain-leaf kale, Lacinato kale and Siberian kale are two of the most popular kinds. Lacinato kale goes by many names, including dinosaur kale, Tuscan kale, and black kale. The leaves grow a bit scaly, hence the name. Meanwhile, gardeners know Siberian kale for its enormous leaves. This type of kale is also sweeter and more tender than the common curly kale.
Also known as salad savoy, ornamental kale is a type of kale often used for decoration. It has a flower-like center, which comes in a variety of colors—from white, a light shade of pink, and purple to magenta. Although many use it for decoration, ornamental kale is also edible. Those who love the veggie use ornamental kale to add color to a dish, and sometimes as a garnish.
Walking Stick Kale
Interestingly, this variation of kale can grow up to ten feet tall. Gardeners who have grown this kale type say that the leaves are edible and delicious, but the long, sturdy stem is not. The name walking stick kale came about because the stem of the plant is often dried out, varnished, and used as a cane or walking stick. Additionally, walking stick kale is one of the lesser-known varieties of kale.
How and where is kale grown?
Kale is a nutrient-packed vegetable that is extremely tolerant to the cold. In fact, gardeners say that cold weather is the best time to harvest kale as it brings out the sweet, nutty flavor exclusive to this leafy green. This cold-hardiness contributed to the vegetable’s popularity throughout the cold-climate regions in Europe. Also, because the cold gives a sweeter taste to kale, the leafy green is more often seen in colder regions.
Farmers consider the kale vegetable as a generally inexpensive crop that is easy to grow. According to the National Kale Day website, kale thrives in small plots of land and personal gardens. Aside from being easy to grow, kale can also desalinate soil.
Furthermore, kale grows best in full sun; those that receive at least 6 hours of sun daily will grow to be stocky and leafy. However, gardeners say that kale can also grow in partial shade, albeit less leafy and stocky than those that get ample sun. Additionally, experts say that kale should be spaced 18 to 24 inches apart. If given enough space, the vegetable’s leaves will grow as big as they can. However, keep in mind that smaller leaves and baby kale tend to be more tender than the bigger ones.
After planting kale, one should keep them regularly watered. Patience also plays an important part in the process of growing kale. Depending on when it was planted, kale can either grow quickly or slowly. Those planted in late summer or early fall may suffer through the hot weather before quickly thriving once the cold starts setting in. Furthermore, gardeners who have grown the vegetable say that kale leaves touched by light frost will taste sweetest when harvested in the fall.
Why is kale considered a superfood?
Health enthusiasts who have tasted kale say that it is not only a powerhouse of nutrients but also delicious. Of course, people have different tastes, but those who grow kale say that there is bound to be a variety that you will love. In recent years, kale has grown increasingly popular in the health world. Not only does it provide a unique flavor, but it also contains many vitamins, minerals, and essential nutrients that we all need every day.
While the many varieties of kale may vary in color, taste, and height, all of them are nutrient-dense. Kale is renowned in the health world as a superfood as it is a great source of vitamin A, vitamin C, calcium, iron, omega 3 fatty acid, and vitamin B6, among other nutrients.
According to the United States Department of Agriculture (USDA), 100g (3.5 oz) of raw kale contains the following nutrients:
- Energy: 35 kcal
- Water: 89.6g
- Carbohydrates: 4.42g
- Total fat: 1.49g
- Protein: 2.92g
- Fiber: 4.1g
- Sugar: 0.8g
- (Retinol) Vitamin A: 30% of the recommended daily value
- Vitamin C: 145% of the recommended daily value
- Vitamin B6: 21% of the recommended daily value
- Calcium: 15% of the recommended daily value
- Iron: 12% of the recommended daily value
- Potassium: 10% of the recommended daily value
Of course, not everyone likes eating vegetables raw. As such, here are the nutrients that 100g (3.5 oz) of frozen, cooked, boiled, and drained kale without salt contains:
- Energy: 44 kcal
- Water: 89.8g
- Carbohydrates: 5.3g
- Total fat: 1.21g
- Protein: 2.94g
- Fiber: 7g
- Sugar: 1.12g
- Vitamin A: 98% of the recommended daily value
- (Ascorbic acid) Vitamin C: 71% of the recommended daily value
- Vitamin B6: 11% of the recommended daily value
- Calcium: 9% of the recommended daily value
- Iron: 7% of the recommended daily value
- Potassium: 6% of the recommended daily value
Aside from being nutritionally dense, kale also offers many health benefits. It contains fiber, antioxidants, vitamins, minerals, and a wide range of essential nutrients that help prevent various health problems. Many health enthusiasts believe that kale helps contributes to keeping the whole body healthy, as well as aids in cancer and diabetes prevention.
Lowers Cholesterol Level
A 2016 Cochrane review found that a diet rich in fiber helped lower blood lipid (fat) levels and blood pressure. This, in turn, led to lower cholesterol levels in the body. Having lower cholesterol levels plays a huge part in reducing one’s risk of heart disease. Kale contains nutrients that help prevent bile acid from being absorbed by the body, which eventually leads to a lower amount of total cholesterol in the body. Additionally, kale also contains loads of fiber, which aids in digestion.
Boosts Eye Health
Experts say that those who suffer from weak eyesight or poor vision will benefit from including kale in their diets. Kale contains two of the most important carotenoids, a type of antioxidant, that are essential for good eye health. These are lutein and zeaxanthin, which also reduce the risk of age-related macular degeneration and cataracts. Kale also provides vitamin C, vitamin E, zinc, and beta-carotene, which all play a role in good eye health.
Reduces Risk of Cancer
All cruciferous vegetables, including kale, contain natural compounds that help fight off cancer. These compounds found in kale help protect our bodies from cell mutation and DNA damage. The may antioxidants present in kale also help prevent inflammation which can lead to certain types of cancer. Additionally, a 2015 study found that a diet rich in fiber can help lower the risk of developing colorectal cancer.
Helps Prevent Diabetes
The American Diabetes Association (ADA) recommends kale in its list of superfoods that are good for overall health and help prevent disease. According to the ADA, kale is rich in vitamins, minerals, fiber, antioxidants, and other essential nutrients that can help prevent or manage diabetes. Furthermore, a 2018 study found that people who consume a high amount of dietary fiber have a lower risk of developing type 2 diabetes. The authors of the study also noted that consuming dietary fiber may lower blood glucose levels.
Keeps Skin and Hair Healthy
Kale doesn’t just help reduce the risk of developing certain illnesses, it also helps keep your hair and skin healthy. This leafy veggie contains loads of vitamin A (retinol), which is vital for healthy cell growth. Furthermore, a vitamin A deficiency often leads to dry skin and the development of acne. Kale also contains beta-carotene, which is a carotenoid that the body stores and converts into vitamin A whenever it needs it.
Helps with Weight Loss
Fitness enthusiasts have also favored kale more and more in recent years. Because it contains few calories and lots of water, kale has become one of the popular food choices for weight loss. Kale also provides fiber, which can aid weight loss by making one feel full longer and thus preventing overeating. Additionally, because kale has high water content, it may also increase urination, hence helping the body flush out any excess water weight.
Can you consume too much kale?
The quick answer to this is yes. Although kale is undoubtedly good for our health, too much of anything is never good for anyone. Of course, incorporating kale into one’s diet can offer many health benefits, but as with anything, moderation is key. As such, always consult your doctor before making any serious changes to your diet.
Almost all plants contain oxalate. Some may have a high amount of it, while others have barely any. High oxalate levels can lead to an increase of calcium or oxalate in the urine, causing kidney stones to form. Beets and dark, leafy greens such as spinach have high oxalate levels. However, although kale contains oxalate, it only has 17mg, compared to spinach that contains 100mg of oxalate. As such, one would have to consume so much kale to cause kidney stones to form.
While health enthusiasts claim that kale is great for boosting one’s health, they also admit that eating a huge amount of this veggie comes with a price. A high intake of kale can be pretty hard on our digestive tract, and it can cause bloating, gas, and constipation. Kale and other cruciferous vegetables contain raffinose, which is a sugar that the body does not digest until gut bacteria ferments it. This indigestible sugar can cause excessive gas, leading to bloating or abdominal discomfort. To avoid this, health enthusiasts recommend eating cooked kale over raw kale.
Lastly, eating kale in large amounts can affect one’s thyroid function. Aside from all the healthy nutrients, kale also contains a glucosinolate called progoitrin. This compound is hydrolyzed into goitrin, which reduces the production of certain thyroid hormones. Essentially, it blocks the iodine that our thyroids need to function.
This can result in blood sugar levels spiking as well as weight gain. Additionally, consuming a large amount of kale may lead to an enlarged thyroid, a condition known as a goiter, which can be brought about by hypothyroidism. However, the good news is that for average, healthy adults, this is not something to worry about. After all, one would need to eat an excessive amount of raw kale for it to have such a huge effect.
How is kale consumed?
As the vegetable became increasingly popular, more and more health enthusiasts found ways to include kale in their diets. Today, many recipes include kale in a variety of ways. Some use chopped kale as a part of their sandwich, salad, vegetable soup, stew, garnish, side dish, juice, or smoothie. Some people eat kale raw, while others cook it in different ways. Kale can be steamed, braised, boiled, sautéed, added to soups or stews, juiced, or blended. In fact, some people even eat kale chips fried in olive oil as a healthier alternative to potato chips.
If you find the taste of common curly kale not to your liking, gardeners say that one of the vast varieties is bound to suit your tastes. Whether you plan to eat kale raw or in cooking, make sure to thoroughly wash the leaves, especially if you bought them from the supermarket. A few months ago, Environmental Working Group (EWG) released their most recent “Dirty Dozen” list, and kale came out third. These vegetables on the list contain the most pesticide out of all of those bought in the supermarket. Thus, health enthusiasts recommend buying organic kale if you cannot grow your own.
Although all kale types vary, most of their stems can be eaten. Of course, you can also choose to discard the stems. Kale can be stored in a loose plastic bag in the fridge for several days. Finally, experts recommend a combination of raw and cooked kale in your diet. Many cancer studies show that raw kale is more beneficial in preventing the disease, while cholesterol studies show that steamed kale is more beneficial.
Adding Kale To Your Juice
Health experts generally recommend drinking eight 8-ounce glasses of water per day. This amount equals about 2 liters or half a gallon a day. Although it is easy to remember, not everyone drinks the recommended amount, much less go over it. To avoid dehydration, some fitness experts have resorted to drinking fresh fruit juice or vegetable juice. Aside from providing their bodies with liquid, drinking fresh juice also contains most of the vitamins, minerals, and essential nutrients that the ingredients contain.
Juicing does not only keep one hydrated, but it also provides many benefits. It aids digestion, helps in weight loss, boosts the immune system, lowers the risk of some chronic diseases, and also offers convenience. After all, not all fruits and vegetables are easy to eat, such as beets. However, in juice form, fruits and vegetables can be brought on the go and easily consumed.
Of course, juicing offers many health benefits, but there are also some disadvantages to it. One of these is that most of the fiber in fruits and veggies is lost during the juicing process. And, since fruit juice concentrates fructose, drinking 100% fruit juice can increase one’s sugar intake. Lastly, juicing can be expensive. If you decide to drink homemade juice, you will need several fruits and veggies to extract enough. Alternatively, you can drink store-bought juice, but those cost more.
Now, we know how adding kale to your juices can be beneficial for your health. If you have consulted your doctor, here are a few kale recipes we recommend to help you get started:
- Easy Green Juice Recipe
- Green Juice in a Blender Recipe
- Kale-aid Recipe
- Green Juice Recipe
- Apple, Carrot, Celery, and Kale Juice Recipe
Make sure to consult your doctor before you decide to start adding any kind of juice to your diet.
Adding Kale to Your Smoothies
Alternatively, drinking smoothies is another great way to keep yourself hydrated. Adding smoothies made from fruits and vegetables to your diet can also provide many health benefits. In fact, health enthusiasts claim that drinking a glass of green smoothie every day greatly benefits their health.
Similar to juicing, blending also provides many health benefits. It boosts digestion, keeps bones healthy, supports the immune system, lowers cholesterol, and reduces the risk of developing some chronic diseases. Just like juicing, blending also provides convenience. Busy health enthusiasts find smoothies a good source of nutrition because they retain all of the essential nutrients—including fiber—found in fruits and vegetables even after blending.
However, while blending may provide many health benefits, there are some downsides to it, as well. Of course, you can avoid some of these by blending responsibly and consulting your doctor before making any changes to your diet. Drinking smoothies can cause digestive issues and kidney issues. Another downside is that smoothies can contain a lot of calories or carbs, depending on what ingredients you add to your blender. Additionally, smoothies may interfere with some medications, so remember to consult your doctor before adding smoothies to your diet.
Now that we have learned how adding kale to your smoothies can be good for your health, as well as some side effects, here are a few smoothie recipes we recommend to help you get started:
- Kale Smoothie Recipe
- Kale Pineapple Smoothie Recipe
- High Protein Blueberry Kale Smoothie
- Pineapple Banana Kale Smoothie Recipe
- Kale, Apple, and Banana Smoothie Recipe