12 Proven Health Benefits of Kale

The leafy kale has become one of the supreme foods for the health-conscious individual, and why not?

It is packed with nutrients and is a versatile food that can be included with other food items. It is filled with multiple vitamins and minerals that go beyond basic nutritional value.

Kale is also rich in bioactive components that have shown the potential to treat and reduce symptoms of chronic diseases. It’s no wonder that kale has gained popularity as a superfood.

Let’s look at the health benefits with scientific backing that has propelled this leafy vegetable to the top rungs of the food industry.

The 12 Significant Health Benefits of Kale

Kale on the table

Kale comes from a family of plants known to botanists and biologists as Cruciferae. The other name is Brassicaceae. It has 375 genera (biological classification) and 3000 species. These also include Brussels sprouts, broccoli, cabbage, and cauliflower apart from many others.

Kale Juice Improves Coronary Artery Disease Factors

A 2008 investigation was held to evaluate the effects of 3 months of kale supplementation on coronary artery disease condition in men suffering from hypercholesterolemia (high cholesterol present in the blood) (1).

32 men with the condition consumed 150 ml of kale juice every day for 12 weeks. Dietary assessments and anthropometric measurements (measuring of muscle, bone and adipose tissue) were taken. Blood samples of the participants were tested to note biochemical profiles.

It was observed that the concentrations of HDL(high-density lipoprotein) to LDL (low-density lipoprotein) cholesterol increased by 27%. LDL and atherogenic index decreased by 10%. There was no change in body mass index, waist and hip circumference. It was also noted that the smoking status of the subjects had a bearing on the results of this investigation.

Summary: Kale juice positively affects serum lipid profiles reducing the risks of coronary artery disease in male subjects. It influenced an increase in good cholesterol and a decrease in bad cholesterol by a noteworthy percentage.

Reduces The Risk Of Cardiovascular Diseases

The Asian populations consume a variety of cruciferous vegetables. Few studies have been held to determine the potential health provisions of these diets in the control and prevalence of diseases.

The objective of an analysis that took place with the participation of 134,796 Chinese adults in 2 cohort studies was to determine the association of cruciferous vegetables, non-cruciferous vegetables, and fruit intake with mortality (2).

Food-frequency questionnaires were used with home visits to ascertain the causes of death and its links to important statistics. 3442 deaths of women were followed up for 10 years and 2 months. 1951 death of men had a mean follow-up of 4 years and 6 months.

The intake of fruits and vegetables was inversely associated with mortality. A dose-response pattern was discerned in the consumption of cruciferous vegetables. It was also recorded that the main cause of deaths was due to cardiovascular diseases.

Summary: The exhaustive study indicates that consuming cruciferous vegetables like kale, cabbage, broccoli, and Brussels may result in good heart health and a longer life span. The analysis also pointed to the fact that the quantity of cruciferous vegetables in nutrition plays a vital role.

Anti-Oxidative Properties Of Kale

A comparative study was undertaken on the antioxidant properties of Kale and Spinach (3). It was included in the ‘International Journal of Advanced Research In Biological Sciences’ in 2017.

The standard method of analysis of AOAC (Association of Official Analytical Chemists (International) was used with DPPH (diphenylpicrylhydrazyl) to determine the plant properties that scavenge free radicals.

Free radicals are unstable molecules that form because of metabolic processes. The study was on the aqueous extracts of kale and spinach. The content of iron, calcium,  fiber, and protein in kale increased by 8.7%, 37.23%, 41%, and 41.6%.

The free radicals scavenging activity in kale was higher compared to spinach. The study concluded on the suggestion that kale leaves were equally health benefiting as spinach and could also be used as an economical therapeutic remedy for people.

Summary: Kale exhibited higher free-radicals scavenging activity. The characteristic kale with its antioxidative properties is promising and should be further explored to treat metabolic disorders such as diabetes and cardiovascular diseases.

Brain Boosting Benefit of Kale

A research article in ‘frontiers in Aging Neuroscience’ brought into focus the activity of a component found in kale (4). Lutein in kale and other cruciferous plants and fruits like avocado have brain-boosting constituents particularly in those who are middle-aged and old. It concentrates on the tissues of the brain and eyes.

The study reported the brain performance of middle-aged people (with higher levels of lutein)  was on par with the younger generation than with their age peers.

60 adults in the age group of 25 to 45 years tested their eye tissues to measure lutein levels. Neural activity was noted through electrodes as they completed 2 challenging tasks that demanded brain efforts.

 The previous study had indicated a link between the lutein levels and better performance among older people who had cognitive decline experiences. The neuro-electrical signature was similar to that of their younger counterparts. The data recommends the protective role of lutein and its ability for enhanced cognition.

Summary: Lutein found in fruits and plants like kale increases cognition among middle-aged and older people. It has the potential to address cognitive concerns among other age groups.

Kale And Vision Health

Eye disorders are more prevalent among the elderly. The leading cause of blindness among Americans above 55 years of age is age-related macular degeneration (AMD). Damage due to oxidative stress from smoking, sunlight and air pollution can cause this disease. That is why antioxidants are part of the solution to this problem.

Eye health is associated with lifestyle and diet. The risk of eye disorders is high for those who are overweight, consume a high-fat diet, drink excessively, and have a low fruit and vegetable diet.

It is a well-known fact that carrots provide important nutrients for eye health. There’s more evidence that other vegetables like the green and yellow ones are more effective in reducing macular degeneration and cataracts. The colored veggies are filled with lutein and zeaxanthin that protect the retina from oxidative stress. Zinc and beta carotene prevents the onset of age-related macular disease.

Easily absorbable lutein and zeaxanthin are found in kale, spinach, greens, lettuces, corn, and egg yolks. If you eat at least 5 to 8 servings of fruits and veggies a day you will be protecting your eyes to a large extent. If you are from a family that has a history of eye disease, check with your ophthalmologist if you should have a supplemental diet with these vital nutrients.

Summary: Lutein and zeaxanthin found in kale and other food items prevent age-related macular disease and other eye disorders. High amounts of these nutrients are found in vegetables and fruits that have varied hues of color.

Kale And Flavonoids

Flavonoids are a group of phytochemicals found in many fruits and vegetables. They are responsible for the bright colors of these foods. Flavonoids are antioxidants with immune systems and anti-inflammatory health benefits. Flavonoids have properties to decrease the risk of type 2 diabetes mellitus.

Studies conducted on the risk and protective factors of flavonoids were inconsistent. Therefore a meta-analysis of related studies was undertaken in 2018 to study the role of flavonoids in the prevention of type 2 diabetes mellitus (5). A systematic search of PubMed and Embase took place in 2017. A dose-response pattern of total flavonoids and the disease was examined.

8 studies that had 312,015 participants of whom 19,953 had developed type 2 diabetes mellitus were considered. It had a follow-up period of 4 to 28 years. A comparative analysis of low and high intake of total flavonoids was linked to a decreased risk in the disease.

An intake of greater than or equal to 550 mg per day of flavonoids was associated with a risk reduction. A linear pattern showed a decrease of 5% for each 30 mg a day increase in total flavonoids.

Summary: The meta-analysis shows that a high intake of total flavonoids and subclasses are linked with lower risk type 2 diabetes mellitus.

Kale May Help Prevent Progress of Cancer

Kale and other cruciferous plants are rich in glucosinolates. These are natural compounds found to be packed with minerals and vitamins with promising health benefits. Chopping or chewing of kale causes the breakdown of these bioactive glucosinolates that produce isothiocyanates and indole-3-carbinol.

Isothiocyanates neutralize the effects of carcinogens. It stalls the growth of these poisonous organisms and causes apoptosis. It is a process where the elimination of possible cancerous and virus-infected cells takes place.

Indole-3-carbinol is another product formed when glucosinolates are broken down. It also has cancer-preventing characteristics. A 2001 article in ‘Journal of Nutrition and Cancer’ brought the focus onto the protective role of these components found in vegetables like kale (6).

Experimental research conducted in living organisms and outside living organisms has strongly suggested that the chemopreventive agents derived from cruciferous vegetables influence the initial states and also the developmental phases of cancer.

Summary: Isothiocyanates and indole-3-carbinol derived from cruciferous plants have the potential to prevent the growth of cancer. It affects the initial stages as well as the spread of cancerous cells.

Antiproliferative Effects Of Kale

Kale is a rich source of antioxidant and anticancer properties. However, the processing of this vegetable can affect the influence of its components. A 2012 test evaluated its effect on the proliferation of cancer cells (7). Green and red cultivars of curly kale were processed. The processing included blanching, freeze storage, boil-in-bag heat treatment.

There was a noteworthy reduction in the number of phenolics, antioxidant capacity, flavonols, glucosinolates, vitamin C, anthocyanins, hydroxycinnamic acids. The red kale was able to withstand the heating process that caused a loss of phytochemicals.

The extracts of green and red curly kale restricted the growth of 3 human colon cancer cell lines (Caco-2, HT-29 and HCT 116). It was observed that fresh kale leaves had a higher capacity in inhibiting these cancer cells than those that were processed.

Summary: The red and green curly kale inhibited the spread of 3 colon cancers in humans. Kale in its fresh state has greater inhibiting characteristics against colon cancer cells than processed kale.

The Detoxification Effect Of Kale

Kale is a rich source of glucosinolates from which isothiocyanates (ITCs) are made. These isothiocyanates aid in the detoxification of cells. The process involves 2 phases. The ITCs are involved in both phases. Sulfur compounds found in large numbers in kale also support the Phase II detoxification.

Toxins are present in processed foods, in the environment, pesticides and pharmaceuticals. In the body, they are first dealt with by antioxidants and then eliminated by glucosinolates. Kale is rich in both components. ITCs are important in the production of enzymes for phase II of detoxification.

Summary: The high amounts of antioxidants, glucosinolates, and sulfur in kale detoxify cells in the body. Isothiocyanates derived from glucosinolates are involved in both the phases of detoxification.

Kale – Abundant in Vitamin C

One serving size of kale provides more than 40% of the RDI (recommended dietary intake) of vitamin C. Vitamin C has been the subject of several research studies for many decades.

Its administration reduced the number of cold infections to about a half in the population of people who were physically active. Two controlled trials have found a dose-response association (8).  The intake was about 6 to 8 grams of vitamin C every day.

These examinations found that vitamin C prevented pneumonia. The effects of vitamin C to treat infections should be further researched. It has also benefited patients suffering from tetanus.

Summary: Kale has more than 40% RDI of vitamin C. Vitamin C has shown promising results in the trial treatment of infections such as pneumonia and tetanus.

Vitamin K In Kale

Many people are unaware of the benefits of vitamin K, unlike popular vitamins. The body needs this nutrient for normal blood clotting and also for bone health. The rich nutrients in leafy kale have more than 10 times the daily value of vitamin K.

One cup of fresh kale has about 215 grams of vitamin K. Only collard greens have as much of this vital component. Scientific evidence has pointed out that vitamin K slows down bone loss after menopause in women. It also enhances bone strength and reduces or limits the risks of fractures due to osteoporosis.

A study held in the late 90s suggested that women who consume at least 100 micrograms of vitamin K each day are at a 30% lesser risk of a hip fracture than women who take less (9). Inadequate vitamin K delays coagulation. Excess blood flow can lead to death.

People suffering from severe digestive disorders or chronic antibiotic therapy may suffer from the insufficiency of vitamin K. Warfarin is an anticoagulant medication that interferes with the functions of vitamin K in the body. Consuming foods rich in vitamin K will be helpful (10).

Summary: Apart from collard greens no other vegetable has as many quantities of vitamin K as kale. The intake of this nutrient prevents bone loss after menopause in women and reduces the risk of hip fractures caused by osteoporosis.

Kale And The Postprandial Effect

A biomedical report that was published online in 2016 brought out the postprandial effect of kale on glucose levels (11). The word prandial means a meal. Postprandial means after a meal. The investigation was conducted on 42 Japanese participants who were in the age group of 21 to 64 years who had fasting plasma glucose levels of less than or equal to 125 mg/dl (milligrams in one-tenth of a lite)r and at 30 minutes postprandial plasma glucose were at 140 to 187 mg/dl.

They ingested placebo or kale-contained food of 7 grams (low-dose) or 14 grams (high-dose) with a high-carb meal. After 30 to 120 minutes the plasma levels of glucose and insulin were evaluated.

The plasma glucose levels with the high and low intake of kale were appreciably lower than those who had taken the placebo. There were no noteworthy differences in insulin levels among the 3 groups. No serious side effects took place with the dosages of kale.

Summary: The study clearly demonstrated that kale suppresses the postprandial increase in plasma glucose levels with a single dose of 7 grams or 14 grams. The high dose of 14 grams kale was safe for consumption.

Some Tips for Cooking Kale

Firstly you need to decide on the type of kale you are going to use.

Types of Kale

The curly kale is the ideal choice when sauteed or roasted with meats and other vegetables. The dry heat of the oven makes the edges crispy. This method can also be used for red or scarlet kale.

The Tuscan or dinosaur kale has a shorter cooking time and is more adaptable. It can be used in salads and soups. Be careful not to overcook it as it will lose its chewy texture. You also have to choose between using fresh or frozen kale.

Frozen kale has a one-year shelf lie and has a sweet flavor compared to fresh kale. However, as the moisture content will be higher it may not be suitable for certain recipes. 

How to Boil Kale Correctly

  1. Remove the leaves from the woody stems. The stems are not soft and edible even after boiling.
  2. Tear the leaves into pieces and rinse them with normal water.
  3. In a large pot of water add a little salt and over a high flame bring it to a boil.
  4. Add the kale leaves and press them down and cover the pot with a lid. Let it boil again for five minutes.
  5. Check a leaf with the help of a fork. If it is still rough and thick, leave it for a couple of minutes in the boiling water.
  6. Use a colander to drain. Move the leaves around to let loose any trapped moisture.
  7. You can remove the excess moisture by pressing the leaves against the sides of the colander.
  8. A pinch of salt and pepper with a drizzle of lemon juice and it’s ready to be served.

3 Quick and Tasty Kale Recipes

Check out some of the quick and easy ways to include this nutrient-packed leafy vegetable into your daily diet.

Kale Pesto

Add 2 to 3 tablespoons of olive oil to a medium-heated saucepan with 2 cloves of minced garlic. Cook for a couple of minutes until it softens.

Add a half cup of water with coarsely chopped kale leaves. Put a lid to the pan and let it cook for 5 minutes. Season with herbs and favored spices.

Kale Salads

It can be made in two ways. You can add olive oil and mix it well for 1-2 minutes. Blanching the leaves is another method where it is placed in boiling water for one minute and then drained.

It should be quickly transferred to a bowl of ice to stall the cooking. Use a colander to press out the excess water.

Paper towels will help to dry the leaves. Blanching removes some of the bitterness that accompanies fresh kale.

Kale Chips

The popular chips variety made of kale takes approximately 15 minutes to prepare. You would require 6 cups of kale leaves, 2 teaspoons of organic coconut oil or butter, Himalayan salt and 1 or 2 teaspoons of nutritional yeast. You could add one pinch of smoked paprika to enhance the flavor.

The kale leaves should be washed and spin-dried. In a saucepan bring together kale leaves and organic coconut oil. Ensure that every leaf is well-coated with oil. Sprinkle Himalayan salt, yeats and your preferred seasoning ingredients. Toss them for equal distribution.

Use a parchment-lined baking sheet to arrange the leaves without overlapping. Bake it at 300-degree Fahrenheit until it turns crispy and dark green. The baking time would be for 15 minutes. Cooling will make the kale chips crispier.

The Final Note

Kale is not only highly nutritious food but is also loaded with antioxidants that prevent diseases. It is considered a ‘superfood’ and the tag is rightly placed.

The inclusion of this leafy vegetable in your diet is simple. As a part of a salad, smoothie or made into crispy chips, it can become a part of your daily diet.

From improving the health of your eyes to an increase in the strength of your bones, it serves many health benefits. Scientific research should be sustained to exploit all the health provisions of this cruciferous plant.

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