Kale’s health benefits are primarily linked to the high concentration and excellent source of antioxidant vitamins A, C, and K — and sulphur-containing phytonutrients.

Carotenoids and flavonoids are the specific types of antioxidants associated with many of the anti-cancer health benefits. Kale is also rich in the eye-health promoting lutein and zeaxanthin compounds.

Beyond antioxidants, the fiber content of cruciferous kale binds bile acids and helps lower blood cholesterol levels and reduce the risk of heart disease, especially when kale is cooked instead of raw.

Super-Rich in Vitamin K

Eating a diet rich in the powerful antioxidant vitamin K can reduce the overall risk of developing or dying from cancer, according to a study in the American Journal of Clinical Nutrition. Vitamin K is abundant in kale but also found in parsley, spinach, collard greens, and animal products such as cheese.

Vitamin K is necessary for a wide variety of bodily functions, including normal blood clotting, antioxidant activity, and bone health.

But too much vitamin K can pose problems for some people. Anyone taking anticoagulants such as warfarin should avoid kale because the high level of vitamin K may interfere with the drugs. Consult your doctor before adding kale to your diet.

Kale might be a powerhouse of nutrients but is also contains oxalates, naturally occurring substances that can interfere with the absorption of calcium. Avoid eating calcium-rich foods like dairy at the same time as kale to prevent any problems.

Eat More Kale

In summer, vegetable choices abound. But during the cooler months, there are fewer in-season choices — with the exception of kale and other dark, leafy greens that thrive in cooler weather.

To find the freshest kale, look for firm, deeply colored leaves with hardy stems. Smaller leaves will be more tender and milder in flavor. Leaves range from dark green to purple to deep red in color.

Store kale, unwashed, in an air-tight zipped plastic bag for up to five days in the refrigerator.