Antioxidant-Related Health Benefits
Like most of its fellow cruciferous vegetables, kale has been studied
more extensively in relationship to cancer than any other health
condition. This research focus makes perfect sense. Kale’s nutrient
richness stands out in three particular areas: (1) antioxidant
nutrients, (2) anti-inflammatory nutrients, and (3) anti-cancer
nutrients in the form of glucosinolates. Without sufficient intake of
antioxidants, our oxygen metabolism can become compromised, and we can
experience a metabolic problem called “oxidative stress.” Without
sufficient intake of anti-inflammatory nutrients, regulation of our
inflammatory system can become compromised, and we can experience the
problem of chronic inflammation. Oxidative stress and chronic
inflammation — and the combination of these metabolic problems — are
risk factors for development of cancer. We’ve seen research studies on 5
specific types of cancer — including bladder cancer, breast cancer,
colon cancer, ovarian cancer, and prostate cancer — and intake of
cruciferous vegetables (specifically including kale). As a group, these
studies definitely show cancer preventive benefits from kale intake, and
in some cases, treatment benefits as well.Kale’s cancer preventive benefits have been clearly linked to its unusual concentration of two types of antioxidants, namely, carotenoids and flavonoids. Within the carotenoids, lutein and beta-carotene are standout antioxidants in kale. Researchers have actually followed the passage of these two carotenoids in kale from the human digestive tract up into the blood stream, and they have demonstrated the ability of kale to raise blood levels of these carotenoid nutrients. That finding is important because lutein and beta-carotene are key nutrients in the protection of our body from oxidative stress and health problems related to oxidative stress. Increased risk of cataracts, atherosclerosis, and chronic obstructive pulmonary disease (COPD) are three such problems. Also among these chronic health problems is cancer since our overall risk of cells becoming cancerous is partly related to oxidative stress.
Within the flavonoids, kaempferol is a spotlight antioxidant in kale, followed by a flavonoid called quercitin. But recent research has also made it clear that at least 45 different antioxidant flavonoids are provided in measurable amounts by kale. This broad spectrum of flavonoid antioxidants is likely to be a key to kale’s cancer-preventive benefits and benefits that we expect to be documented for other health problems stemming from oxidative stress.