While many people are familiar with turnip roots, most people may not regularly eat turnip greens (also called turnip tops or turnip leaves). Turnips belong to the cruciferous Brassicaceae family and share many of same health benefits as other brassicas, like improved detoxification and reduced cancer risk. These biennial plants take two years to grow and reproduce, and when they do, they pack a nutritional punch. Turnip greens may not have been the direct focus of many research studies, but they are often included in studies on cruciferous vegetables and dark leafy greens as a whole. Considering the plant is much higher in many nutrients than more popular crucifers, like broccoli and cauliflower, turnip greens deserve some attention.
Key Nutrients in Turnip Greens
Turnip greens offer a wide range of nutrients with important health benefits. These include:
- Vitamin K: Turnip greens and other leafy green vegetables are rich sources of vitamin K. This vitamin plays a crucial role in bone metabolism, vascular health, and normal blood coagulation.1 Since these greens also contain calcium, turnip greens can be considered to have significant bone-mineralizing potential.
- Vitamin A and Carotenoids: Turnip greens are particularly high in carotenoids, including beta-carotene, in both the upper and lower leaves. Beta-carotene is the easiest form of carotenoid for the body to convert into vitamin A. In addition to supporting eye health, carotenoids may also support cognitive and cardiovascular health and may reduce the risk for certain cancers.2
- Folate: One cup of cooked turnip greens contains almost half of the daily recommended intake for folate, an important methylation nutrient.3 Folate is an essential nutrient necessary to DNA and RNA synthesis, amino acid metabolism, and the prevention of neural tube defects.
- Other nutrients: Turnip greens are also a good source of vitamin C, manganese, calcium, and copper.
Phytoactive Nutrients in Turnip Greens
Turnip greens have an impressive list of biologically active phytonutrients that promote health in a number of ways. Glucosinolates – unique to cruciferous vegetables – flavonoids, and the carotenoid lutein are just a few of the plant compounds that make turnip greens so beneficial:
- Glucosinolates and Myrosinase: Glucosinolates are biologically active, sulfur-containing glucosides abundant in cruciferous plants, including turnip greens. Cutting, chopping, or even the act of chewing glucosinolate-rich foods releases myrosinase enzymes, which hydrolyze glucosinolate into its metabolites. Glucosinolate metabolites include indole-3-carbinols, isothiocyanates, and sulforaphane: phytonutrients shown to increase the production of detoxification enzymes and linked with lower rates of certain cancers.4
- Flavonoids: Kaempferol, quercitin and myricetin are just three of the 35 flavonoids identified in turnips. Because flavonoids provide UV protection to plants, they are highly concentrated in turnip greens.5 Flavonoids are potent free radical scavengers that help the body balance inflammation, prevent oxidative stress and may protect against chronic diseases, including cancer and heart disease.6
- Lutein: Turnip greens are also a rich source of lutein, an eyesight-supporting carotenoid shown to reduce the risk for macular degeneration.7 Lutein and its isomer zeaxanthin are the only two carotenoids that can cross the blood-retina barrier to support healthy eyesight and eye health. These carotenoids are thought to prevent age-related macular degeneration, age-related cataracts, visual impairment, as well as other types of eye disorders.8 Lutein appears to help filter damaging blue light and combat free radicals in the eye itself.9
Health Benefits Associated with Turnip Greens
Since turnip greens are dark, leafy, and cruciferous vegetables, they offer a wide range of potential health benefits attributed to the vegetables in those categories.
Prospective studies on aging have found that diets that included higher amounts of dark leafy greens – the equivalent of about one serving per day – were associated with slower rates of cognitive decline, comparable to participants who were 11 years younger.10 The carotenoid lutein, found abundantly in turnip greens and other dark leafy greens, preferentially accumulates in the human brain at different points in the life cycle, which suggests it plays an important role.11
Lutein, a carotenoid found in turnip greens and other dark leafy greens, is instrumental in healthy eyesight and believed to prevent age-related macular degeneration, age-related cataracts, visual impairment, as well as other types of eye disorders.12 This carotenoid crosses the blood-retina barrier to form macular pigment in human eyes.13 Macular pigments are supportive to many aspects of vision and visual performance, making lutein critical to eye health.14
Eating dark leafy greens regularly has been associated with improved cardiovascular outcomes, including reduced risk for cardiovascular disease, coronary heart disease, and ischemic stroke. Many of these benefits were found in those eating just over one serving per day.15
Not all dietary nitrates are harmful. Naturally occurring nitrates found in turnip greens, other dark leafy greens, and beetroot may support blood vessel function and healthy blood flow. The nitrate content in dark leafy greens has been found to promote healthy endothelial function and blood pressure in adults.16
Diets high in dark leafy greens like turnip greens are associated with improved bone mineral density, stronger bones, and a reduced risk for osteoporosis. This is likely related to the vitamin K found in these vegetables. Vitamin K has been found to modulate bone metabolism, and human trials have demonstrated that vitamin K can increase bone mineral density and reduce fracture rates in people with osteoporosis.17
Health Benefits Associated with Cruciferous Vegetables
In addition to being a dark leafy green, turnip greens are also a cruciferous vegetable, which means that eating turnip greens confers even more potential benefits. For example, the phytonutrients in brassicas have been found to modulate inflammation, possibly by regulating epigenetic mechanisms related to the inflammatory cascade.18
Cruciferous vegetables are known to contain phytonutrient compounds that upregulate detoxification enzymes. These glucosinolates compounds support glutathione synthesis and up-regulate phase II detoxification enzymes in the body.19
People who eat cruciferous vegetables regularly have been found to have a lower risk for chronic illness, including heart disease, cardiovascular disease, and stroke.20 Eating a diet rich in cruciferous vegetables is also linked with lower risk for certain cancers, including colorectal, breast, bladder, lung, prostate, and ovarian cancers.21
Some interesting facts about turnip greens:
- Likely first domesticated in ancient Greece
- Important crop because they last through the winter and help to maintain soil health
- Staple crop in Nordic countries prior to 18th century when they were replaced by potatoes
- Rutabagas are a cross between turnip and cabbage and were first produced in Scandinavia
Turnip greens have a peppery flavor, similar to mustard greens and arugula. Because they tend to be fibrous, they are best eaten cooked. Whether sautéed, braised, or added to soups, turnip greens are one of the healthiest and nutrient-dense vegetables around.
Download the turnip greens pamphlet from the Color of Food series.