Kale is a leafy green vegetable that belongs to the brassica family (also known as cruciferous vegetables), along with cabbage, broccoli, sprouts and cauliflower. These vegetables are widely hailed for their health-giving properties and recently have been crowned as “superfoods” by marketeers because they are particularly rich in a compound called glucosinolates. Kale has become the new trendy vegetable!
Key facts:
- Only 28kcal per 100g
- Good source of dietary fibre
- Rich source of vitamin A, vitamin C, vitamin K, calcium and iron
- Good source of a wide range of other vitamin and minerals
- High in protein quality (91%)
As kale does not have a tight leaf configuration, it is able to absorb more sunlight than many other brassicas and this reflects in its vitamin content.
Eating
Kale is versatile and can be chopped into stews and soups, added to stir fries, or served in lieu of cabbage for Sunday lunch. Baby leaves are sweeter and work really well in salads.
4 heaped tablespoons kale = 1 of your 5-a-day
What are glucosinolates?
Plants produce compounds that are widely believed to be their own natural defences against insects and other pests, and give the plant its bitter flavour. Scientists are researching these compounds for their health-giving properties, which in nutrition we call “phytochemicals”. Along with brassicas’ high level of vitamin C and A, glucosinolates are considered to have strong antioxidant properties that may be cancer-protecting, but their metabolites can be poisonous to many animals and have adverse effects to people with a goitre if consumed in high concentrated amounts (such as juicing).
Glucosinolates are composed of sulphur and nitrogen, and convert to sulphurophane during digestion. Sulphur has a distinctive smell, not unlike bad eggs, and sulphurophane is responsible for sprouts and other brassicas having their distinct room-clearing reputation. Many people avoid brassicas, beans, lentils and other “offensive” foods for fear of social embarrassment, but this shouldn’t be a problem if consumed in moderate amounts.
Seb is a writer and blogger of food and nutrition. He holds a bachelors and a masters degree in nutrition science, and has studied sports and exercise nutrition at postgraduate level. He specialises in plant-based nutrition and believes passionately that we can all live with a little less meat.
