Are you getting enough greens in your diet? Here's a couple reasons why everyone would benefit more of them.
Mustard greens, also known as Brassica juncea, are a cruciferous dark leafy green that grows in all parts of the world. Nutritionally, they are a good source of fiber, vitamin C, vitamin A, vitamin K and glucosinolates (GSLs). The U.S Department of Agriculture (USDA) posts on their website that mustard greens per 100g provide 3.5g of fiber, 94mg of calcium, 70.6mg of vitamin C, and 10,588 IU of vitamin A (USDA Mustard Greens). Spinach is also a leafy green, but has a different nutrient profile providing slightly less fiber, more iron, magnesium, and potassium (USDA Spinach). One benefit of mustard greens compared to spinach is the higher amounts of GSLs that are becoming popular in nutritional science for their anti-cancer properties (Soundararajan 2020).
GSLs are naturally occurring compounds in Brassicaceae vegetables such as mustard greens. After they are ingested or injured, they become hydrolyzed by the enzyme myrosinase into isothiocyanates (ITCs). Unlike their precursor GSLs which are stable, ITCs are highly reactive compounds, especially against cancerous cells. ITCs have been seen to stimulate programmed cell death, autophagy and arrest tumor cell proliferation (Soundararajan 2020).
Mustard green GSLs and their metabolite ITCs have other possible benefits in areas like horticulture. GSLs have been seen to have an antimicrobial effect on Phytophthora capsici (Phytophthora blight), a common soil-bourne disease. GSL containing plants have been proposed as a potential natural alternative to the use of toxic and harmful pesticides in our food supply. Antonious et al. conducted a study measuring concentrations of GSLs in arugula and mustard greens grown in various crops. The crops compared were (1) no-mulch untreated soil as the control, (2) sewage sludge treated soil, (3) horse manure treated soil, (4) chicken manure treated soil. Results showed that mustard greens contained between 900-1400 micrograms of GSLs, chicken manure containing lowest concentrations and highest concentrations of GSLs in sewage sludge. Keep in mind this study was not designed to promote the addition of toxic sewage sludge to farming practices, but to analyze the generation of GSLs in different situations (Antonious 2017).
Another benefit of mustard greens and other members of the Brassica family is the fiber content. Fiber aids in healthy digestion by binding to unfavorable digestive metabolites and is excreted from the body. Fiber also has been seen to bind with bile acids which helps to clean the gallbladder, reduce cholesterol and promote good cardiovascular health and healthy weight loss. Kahlon et al. describe in their study how steamed mustard greens compare in bile acid binding capacity with other vegetables, such as broccoli, kale, spinach and cabbage. Results showed that mustard greens had significantly more acid binding capacity than most other vegetables in their experiments (Kahlon 2008).
U.S Department of Agriculture, Food Date Central Search Results: Mustard Greens. Accessed July 13th, 2020
U.S Department of Agriculture, Food Date Central Search Results: Spinach. Accessed July 13th, 2020
Soundararajan, P., & Kim, J. S. (2018). Anti-Carcinogenic Glucosinolates in Cruciferous Vegetables and Their Antagonistic Effects on Prevention of Cancers. Molecules (Basel, Switzerland), 23(11).
Antonious, G. F., Turley, E., Antonious, A., & Trivette, T. (2017). Emerging technology for increasing glucosinolates in arugula and mustard greens. Journal of Environmental Science and Health. Part. B, Pesticides, Food Contaminants, and Agricultural Wastes, 52(7), 466–469
Kahlon, T. S., Chiu, M.-C. M., & Chapman, M. H. (2008). Steam cooking significantly improves in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage. Nutrition Research, 28(6), 351–357.