Kale as a Superfood


Kale is a leafy vegetable from the cabbage (Brassica oleracea) family, that is related to other vegetables such as broccoli, cauliflower, and brussels sprouts.


It can come in many different colours and varieties, with one of the most common being curly kale, or Scots kale, which is distinguished by green, curly leaves, and a hard, fibrous stem. Kale grows best in cooler climates, especially Mediterranean regions, but is also found in many other areas of the world. Kale leaves can be flat or curly, and grow up to 6 feet in height, with colours including green, purple, white, and lavender.


It is an extremely nutrient dense food, full of important vitamins and minerals that the body requires to function on a cellular level. It also contains very low amounts of calories and fats, with a large portion of the fat amount being the healthy omega-3 fatty acid known as alpha linoleic acid.


When it comes to buying kale, it is beneficial to get the organic variety as it is more likely to have been planted in safe, healthy soil, and would not have been treated with harmful chemicals, therefore reducing means the likelihood of being contaminated with toxins. Kale is one of the most heavily pesticide sprayed crops so it is important to buy organic sourced kale for this reason.



kale - health benefits

  • Kale is low in calories, has low amounts of fat, and is high in fibre: A single cup of kale contains approximately 36 calories, 0.5 grams of fibre, 3 grams of protein, and 4 grams of fat, most of which is from healthy omega-3 fatty acid content. Due to its high fibre content, it is great for digestion and elimination.
  • It is high in iron: Per calorie, kale has more iron content than beef. Iron is essential for oxygen transport throughout the body through haemoglobin formation, cell growth, brain function, proper liver function, healthy hair, skin, and nails, and keeping the immune system healthy enough to fight infection. Many enzymes throughout the body contain and require iron for a variety of functions, including those involved in energy production. Iron is also an essential component of myoglobin which is a protein that helps to store oxygen in muscle cells.
  • It contains antioxidants: Kale contains high amounts of antioxidants such as beta-carotene, Vitamin C, quercetin, kaempferol, and various other flavonoids and polyphenols which aid to protect the body against free radicals and the damage they can cause to cells, DNA, and proteins. As a result, they help to protect the body against cancer and many other diseases including Alzheimer’s, Parkinson’s, cardiovascular disease, and autoimmune and inflammatory disorders to name a few.
  • It aids with inflammation: One cup of kale contains approximately 10% of the recommended daily allowance of omega-3 fatty acids, which are beneficial in reducing inflammation and treating inflammatory disorders such as arthritis, asthma, and autoimmune diseases.
  • Lowers cholesterol: When we eat a fatty meal, the liver turns cholesterol into bile acids, which are then released into the digestive system. When all of the fats have been absorbed, and the bile acids have served their purpose, they are reabsorbed into the blood stream to be used again. Kale contains substances called bile acid sequestrants which bind bile acids in the digestive system and prevent them from being reabsorbed. This reduces the total levels of cholesterol in the body. The consumption of kale has been shown to increase the levels of “good” HDL cholesterol in the system by up to 27% while reducing the levels of “bad” LDL cholesterol by 10%.
  • High in vitamin K: One cup of kale provides 684% of the RDA of vitamin K. Vitamin K is essential for healthy blood clotting by activating certain proteins and allowing them the ability to bind to calcium. It is also important for bone health as it helps in the transportation of calcium throughout the body.
  • High in vitamin A: One cup of kale contains approximately 206% of the RDA of vitamin A from its beta-carotene content. Vitamin A is essential for healthy vision, healthy immune and reproductive systems, and healthy and properly functioning organs. It also plays an important role in the development of bones and teeth, and aids in the protection against infections of the skin, lungs, and mouth by providing a kind of barrier. It is possible to overdose on vitamin A, particularly in supplement form, but the vitamin A found in kale originates as the antioxidant beta-carotene, which is then converted into a version of vitamin A which is far less toxic.
  • High in vitamin C: Per cup, kale contains 134% of the RDA of vitamin C. Vitamin C is essential for the formation and maintenance of body tissue including that of the skin, bones, and blood vessels. It helps to repair and regenerate tissues, protect against heart disease, improve the absorption of iron, decrease total levels of “bad” LDL cholesterol, and help to improve immune function. Vitamin C can also help to prevent IMA-induced DNA damage. kale-vitamin-c
  • High in calcium: Per calorie, kale has more calcium content than milk, which helps to prevent bone loss, maintain a healthy metabolism, and prevent osteoporosis.
  • High in potassium: Per cup, kale contains 9% of the RDA of potassium. Potassium is essential for the regulation of blood pressure, to help the heart muscle beat properly, regulate fluids, send nerve signals, and to regulate muscle contractions.
  • Fights cancer: Not only is kale high in antioxidants, it also contains certain compounds such as sulforaphane, which prevents the formation of cancer at a cellular level, and indole-3-carbinol which is another cancer preventing substance. Kale also contains chlorophyll, and while the body cannot absorb this substance, it acts to bind to the heterocyclic amine carcinogens produced from grilling animal-based foods at high temperatures and prevents the body from absorbing them.
  • Protects the eyes: Kale contains two important nutrients called lutein and zeaxanthin which actively help to protect against damage caused by aging, including cataracts and macular degeneration.
  • Improves mental health and prevents depression: Kale is high in levels of omega-3 fatty acids which have been shown to be effective at treating the symptoms of depression. Most medications for this condition have negative side effects for both the short and the long-term, while omega-3 fatty acids are well tolerated and have a range of positive health benefits. Kale also contains carotenoids which studies show there may be a link between carotenoids and an improved mood. Kale is high in many vitamins and minerals which are effective in elevating moods and treating depression. For example, folate is helpful in regulating serotonin levels, and has been shown to be successful in treating depression, especially when paired with vitamin B-12, and can also boost the efficiency of antidepressant medication. Magnesium is also beneficial for the development of serotonin and therefore the balancing of moods.
  • Aids with diabetes: The fibre in kale is helpful for lowering blood glucose levels in people with type-1 diabetes, and improving blood sugar, lipids, and insulin levels in people with type-2 diabetes. The presence of an antioxidant called alpha-lipoic acid is also beneficial because it has been shown to lower glucose levels, increase insulin sensitivity, and prevent oxidative stress-induced changes in people with diabetes.
  • Improves bone health: Due to the high calcium content of kale, it is effective at increasing bone mass and preventing conditions such as weak bones, fractures, and osteoporosis. The high vitamin K content is also beneficial as it works to improve the body’s absorption of calcium while reducing the urinary excretion of it.
  • Promotes healthy skin, nails, and hair: Kale is high in beta-carotene which is a carotenoid which is converted into vitamin A as required. This nutrient is essential for enabling all bodily tissue growth, including the skin and hair, and also for the production of sebum which is the oil that keeps the skin and hair moisturized.
  • Improves heart health: Kale is high in magnesium and potassium, which have both been associated with a reduced risk of heart disease. Potassium is effective in reducing hypertension as it acts to dilate the blood vessels. Due to its high calcium content as well, kale is beneficial for the heart due to its ability to lower cholesterol. Studies suggest that consuming too much calcium, especially in supplement form, can actually increase the risk of heart disease, and concluded that sufficient calcium intake via foods rather than supplements was the safer, more beneficial way.
  • Prevents stomach ulcers: Kale can help to prevent the occurrence of H-pylori related stomach ulcers (a type of bacteria which can cause ulceration of the stomach walls), due to kale’s glucosinolate content, which prevents the adherence of the bacteria to the stomach’s mucous lining.
  • Prevents anaemia: Not only is kale high in levels of iron, it also contains high amounts of vitamin C which is helpful in improving iron absorption.
  • Helps to detoxify the body: Kale contains specific compounds made from glucosinolates, called isothiocyanates (ITC’s), which are highly effective at helping to cleanse the body from the toxins we are exposed to every day through our environment and the things we consume. The antioxidants present in kale first act to destroy the toxins in the body, and then the ITC’s work to flush them out.
  • Has powerful anti-inflammatory properties: Kale has an ideal ratio of omega-3 and omega-6 fatty acids. Omega-6 fatty acids tend to worsen inflammation, while omega-3 fatty acids reduce and prevent inflammation. Most western diets contain high levels of omega-6 fatty acids, and not enough omega-3 acids, resulting in an inflammatory diet.
  • Rich in folate: Kale contains high amounts of folate, with 1 cup providing 5% of the RDA. Folate is required by the body to make DNA and other genetic material and an increased intake is often recommended during pregnancy so as to reduce the likelihood of birth defects and to promote proper brain development in infants. Synthetic folate supplements have been potentially linked to detrimental health conditions such as epilepsy, insomnia, mood swings, lack of concentration, vitamin B-12 deficiency, and zinc absorption difficulty while there are hardly any detrimental effects of dietary consumption of folate.
  • Rich in manganese: The amount of manganese present in kale per 1 cup equates to 26% of the RDA. Manganese is required for the formation of connective tissue, bones, sex hormones, and blood clotting factors. It also aids to regulate the metabolism, calcium absorption, and blood sugar levels and also plays a role in brain and nerve function.



Serving size: 1cup = 67g

  Amounts per serving %RDA
Vitamin A 10302IU 206%
Vitamin C 80.4mg 134%
Vitamin K 547mcg 684%
Vitamin B1 (thiamine) 0.1mg 5%
Vitamin B2 (riboflavin) 0.1mg 5%
Vitamin B3 (niacin) 0.7mg 3%
Vitamin B6 0.2mg 9%
Vitamin B9 (folate) 19.4mcg 5%
Vitamin B5 (Pantothenic acid) 0.1mg 1%
Total fat 0.5g 1%
Total carbohydrates 6.7g 2%
Dietary fibre 1.3g 5%
Total calories 33.5 (140kJ) 2%
Protein 2.2g 4%
Calcium 90.5mg 9%
Iron 1.1mg 6%
Magnesium 22.8mg 6%
Phosphorous 37.5mg 4%
Potassium 299mg 9%
Sodium 28.8mg 1%
Zinc 0.3mg 2%
Copper 0.2mg 10%
Manganese 0.5mg 26%
Selenium 0.6mcg 1%



Commonly prescribed heart disease medications known as beta-blockers can cause an increase in potassium levels in the blood. High potassium foods such as bananas and cooked kale should be consumed in moderation when taking this medication as too high levels of potassium can be detrimental to health, particularly in those whose kidneys are not fully functional.

Due to its high levels of vitamin K, kale could also potentially interact with blood-thinning drugs such as warfarin or Coumadin.

Vitamin K can also increase the risk of blood clots in people who are at risk of developing them.

Kale, along with the other cruciferous vegetables, is considered a goitrogenic food, which means that it contains goitrogens that may contribute to compromised thyroid function and an enlarged thyroid. However, in usual amounts, kale consumption is generally considered healthy and does not need to be avoided. There are no steadfast studies that show that kale has any negative effects on thyroid function.

Eating large amounts of any leafy green vegetable, including kale, can lead to gas, bloating, and constipation.

Kale also contains oxalates which are substances linked to kidney stones and gallstones.