Everyone knows kale is good for you, but in this article we provide 10 reasons why we think kale is Superfood No. 1. The health benefits of kale go well beyond providing a truckload of vitamins and minerals; this superfood is packed with phytonutrients such as glucosinolates and flavonoids as well. Thanks to its broad nutritional profile, kale is thought to help fight cardiovascular disease, asthma, and rheumatoid arthritis; to prevent several types of cancer and pre-mature aging of the skin; and to promote the health of the urinary tract. For details on these and other proven health benefits of eating kale, keep reading.
Kale – An Antioxidant Superstar
Curly kale is a nutritional powerhouse packed with antioxidants such as vitamin C, beta-carotene, kaempferol and quercetin. As a result of its high antioxidant content, kale is one of the vegetables with the highest ORAC rating. Only a handful of vegetables – including raw garlic, red cabbage, sweet potatoes, savoy cabbage, beet greens and arugula – have been reported to have a higher ORAC rating than kale.
ORAC, which stands for Oxygen Radical Absorbance Capacity, measures foods' ability to scavenge free radicals. Free radicals are unstable molecules that can cause damage to your body at the cellular level. The cellular damage caused by free radicals has been implicated in the pathogenesis of several diseases and disorders, including macular degeneration of the eye, cardiovascular diseases, thrombosis, asthma, an impaired immune system, atherosclerosis, Alzheimer's disease, diabetes, and rheumatoid arthritis.
In addition to providing pure health benefits, kale's antioxidants can also provide beauty benefits. The free radical neutralizing effects of the antioxidants in kale can help keep your skin looking great by preventing loss of skin elasticity triggered by excessive ultraviolet radiation. When your skin is exposed to ultraviolet radiation from the sun, it forms metalloproteinases. Metalloproteinases are enzymes that help repair sun-injured connective tissue. However, not all metalloproteinases are beneficial: some metalloproteinases destroy collagen, which can lead to wrinkles and fine lines on the skin. Free radicals seem to support the production of these collagen-damaging metalloproteinases.
Impressive Anti-Cancer Effects
In addition to providing a truckload of vitamins and flavonoids, kale contains several glucosinolates including glucobrassicin, glucoraphanin and sinigrin. When you eat kale, these compounds are converted into isothiocyanates in your digestive tract. A large body of evidence suggests that isothiocyanates may help prevent cancer and, in some cases, even suppress the growth of cancerous tumors. Isothiocyanates work their anti-cancer magic by eliminating potential carcinogens from the body, by conferring protection against DNA damage, and by stimulating apoptosis (self-destruction) of cancerous cells.
Most of the research related to isothiocyanates, kale and cancer has focused on colon cancer and breast cancer, but there's also evidence that kale and other foods that contain glucosinolates may also provide protection against prostate cancer, ovarian cancer, and bladder cancer.
Kale Promotes Urinary Health
If all the above-listed positive effects associated with eating kale are enough to convince you to eat more of this superfood, consider this: the potential health benefits of kale also include enhanced urinary health, which may extend well beyond protection against bladder cancer. Kale is listed as one of the best foods to fight UTIs due to its extraordinary nutritional profile. Kale is chock-full of pro-vitamin A (kale contains almost as much pro-vitamin A as carrots), and pro-vitamin A is known to promote healthy surface linings of the urinary tracts.
A 2007 study published in Pediatrics International, a renowned scientific journal, investigated the effect of vitamin A on recurrent UTIs (urinary tract infections). The researchers gave 12 volunteers with recurrent UTIs vitamin A supplementation, in addition to antimicrobial treatment. The control group, also consisting of 12 volunteers, were given a placebo. During the first 6 months of the study, the infection rate of the group who took the vitamin A supplement dropped from 3.6 to 0.8, while the infection rate stayed at 2.8 in the control group.
Furthermore, kale is low in oxalates, which offers additional health benefits for people who suffer from certain types of hyperoxaluria (excessive urinary excretion of oxalate) and to people who are prone to developing calcium-oxalate kidney stones. Oxalates are naturally-occurring substances present in significant amounts in many green leafy vegetables such as spinach, purslane and parsley. The link between foods rich in oxalates and kidney stones has caused quite some debate over the purported health benefits of green smoothies, and if you have reason to be concerned about oxalates in your diet, using kale (instead of spinach) in your green smoothies may be the way to go.
Tips for Maximizing Kale's Health BenefitsHopefully you're convinced of the nutritional value of kale by now, and the next step is to add more kale to your diet. Here are a few interesting facts about kale and tips on how you can maximize the health benefits of kale in your dishes:
- Kale is also known as borecole and cow cabbage, so if you cannot find kale in your local supermarket right away, you may want to check if borecole or cow cabbage is available. In the scientific community, kale is known as Brassica oleracea L. var. acephala.
- Different varieties of kale are available. These include dinosaur kale (also called black cabbage and cavolo nero), curly kale (Scots kale), and Red Russian kale.
- Kale has an ORAC rating of 1,770. The ORAC rating of a food gives an indication of the food's antioxidant capacity. For the sake of comparison, raw spinach has an ORAC rating of 1,515, cauliflower has an ORAC of 839 and celery has an ORAC of 497.
- Good substitutes for kale in recipes include: rapini, collard greens, Swiss chard, mustard greens, napa cabbage, kohlrabi leaves and spinach.
- Young leaves of this green leafy vegetable can be eaten raw, for example in salads.
- An easy recipe to transform kale into a healthy warm dish: Sauté kale on a pan and mix it with chopped onions, crushed garlic and a drizzle of extra virgin olive oil.
- When kale is cooked, it loses a significant proportion of its vitamin C and polyphenol content. However, cooking does not have a significant impact on the beta-carotene content of kale.