Shaun Ward MSc ANutr
Kale is a leafy green vegetable belonging to the Brassicaceae family. It is also known as a cruciferous vegetable, similar to cabbage, broccoli, cauliflower, collard greens and brussels sprouts.
This vegetable has become a staple in the diets of health-conscious individuals over recent years as much attention has been placed on kales high content of bioactive compounds.
These include vitamin C, pro-vitamin A, calcium, magnesium, iron, zinc and manganese, phenolic antioxidants, and dietary fiber.
In fact, kale is arguably the most nutritious green leafy vegetable you can eat.
1. Very High In Micronutrients
Eating more kale is a great way to dramatically increase the total micronutrient content of a diet.
100 grams of raw kale contains :
- Vitamin K: 1021% of the daily recommended intake
- Vitamin A precursor (beta-carotene): 308% of the daily recommended intake
- Vitamin C: 200% of the daily recommended intake
- Vitamin B6: 14% of the daily recommended intake
- Manganese: 39% of the daily recommended intake
- Calcium: 14% of the daily recommended intake
- Potassium: 13% of the daily recommended intake
Although this amount of kale is a lot when eaten raw, it is becoming increasingly popular to use kale as part of a ‘health smoothie’, using a blender to liquidize the kale down to a much smaller amount that is easier for people to consume.
For plant-based eaters, kale is especially important as it contains high amounts of vitamin K and calcium which are not as accessible with the removal of animal products. Both these nutrients are critical for bone health and preventing osteoporosis.
Further, a unique advantage of kale in comparison to other green leafy greens is that it does not contain significant amounts of oxalate – an anti-nutrient that can prevent minerals from being efficiently absorbed .
2. High in Antioxidants
Much like other green leafy vegetables, kale is a dense source of antioxidants including beta-carotene, vitamin C, flavonoids, and polyphenols.
Antioxidants are extremely important for preventing or inhibiting the effects of free radicals that often leads to the oxidative damage of cells.
Reduced cell damage from a high antioxidant intake is important for decreasing the risk of many diseases and increasing longevity.
It is important to keep in mind that when kale is heated during cooking processes then this can significantly lower antioxidant activities by 50-90% . Based on this, eating raw kale is advised over other cooking methods.
3. Boosts Immune Function
Kale is a great source of vitamin C, which has consistently shown to help protect the body against infections by encouraging the production of white blood cells that can create antibodies to fight infectious microorganisms .
Vitamin C not only aids the functioning of these white blood cells, but also protects them from damage against harmful substances such as free radicals.
This is a key reason why vitamin C can halve the number of colds in physically active people, and simultaneously shorten the duration of colds when they are apparent .
Amazingly, a single cup of raw kale actually contains more vitamin C than an orange!
4. May Lower Cholesterol Levels
Excess cholesterol levels in the blood are linked with the build-up of plaque on arterial walls, which can cause cardiovascular disease and increase the chances of a heart attack.
Consuming kale juice frequently for 12 weeks has shown to increase the amount of HDL ("good") cholesterol by ~25% and lowering LDL (“bad”) cholesterol by ~10% .
In fact, kale can be ~50% as effective as strong cholesterol-lowering drugs that can be prescribed by a doctor .
5. May Protect Against Cancer
The main compound within kale that can fight cancer is sulforaphane. This substance is only found within cruciferous vegetables and acts at a molecular level to help prevent the initial formation of cancer.
Sulforaphane is a relatively newly studied component of this food group, but has already proved to be an effective chemoprotective agent in cell culture and animal studies by inhibiting cell multiplication, and via being selectively toxic to cancer cells .
Some data also demonstrates sulforaphanes biological activities and health benefits in humans, with some indication that it may be a suitable chemopreventive agent in cancers such as breast, prostate, colon, skin, lung, stomach, and bladder .
6. May Aid Weight Loss
Although there is no study directly testing the effects of kale on weight loss, it is clear that kale would be a smart inclusion for any weight loss diet.
As always, foods low in calories, relative to the volume of food, are going to help weight loss by increasing an individuals feeling of satiety from a meal.
Eating plenty of foods with low energy density has even been highlighted during weight loss trials as a factor which positively influences physiological and psychological changes .
Kale contains just 33 calories in 1 whole cup, along with 2 grams of fiber, so it can definitely be labeled as a low energy density food.
Kale is a leafy green, cruciferous vegetable that has become a staple in the diets of health-conscious individuals over recent years.
It is particularly high in micronutrients such as vitamin C, B6, K, beta-carotene, manganese, calcium, and potassium. Kale is also rich in antioxidants such as flavonoids and polyphenols.
If kale is consumed in significant amounts, it can help to boost immune function, lower cholesterol levels, aid weight loss, and even prevent cancer.
Kale is best consumed in its raw form as heating can significantly lower the activity of antioxidants.