Cruciferous vegetables are a robust source of a class of sulfur-rich compounds referred to as isothiocyanates. Isothiocyanates from natural sources are initially biologically inactive and are referred to as glucosinolates. During chewing, crushing, or cutting, glucosinolates are exposed to the enzyme myrosinase, also found within cruciferous vegetables. Glucosinolates are then hydrolyzed and activated to isothiocyanates. Isothiocyanates are a unique and powerful class of chemicals that exhibit anti-cancer, antioxidant, and anti-inflammatory properties. Some frequently researched isothiocyanates include sulforaphane, allyl isothiocyanate, benzyl isothiocyanate, and phenethyl isothiocyanate.
Musculoskeletal Health Benefits of Isothiocyanates
Chronic disease of bone, muscle, tendon, and joint, at least in part, share a common destructive pathway governed by excessive inflammation and oxidative stress. While the exact manner in which organosulfur substances promote musculoskeletal well-being is not precisely known, the likely mechanism is its reduction of chronic oxidative stress and chronic inflammation.
Antioxidant Properties
Isothiocyanates exhibit formidable antioxidant attributes. Isothiocyanates limit the generation of high-energy tissue-destroying oxygen substances called reactive oxygen species. These toxins are commonly formed in the power generator of the cell referred to as the mitochondria. These substances leak out and cause severe damage to healthy DNA, good fats, and essential proteins. Isothiocyanates have been shown to protect against all major oxygen free radicals:
- Hydroxyl radical
- Hydrogen peroxide
- Superoxide radical
Anti-Inflammatory Properties
Isothiocyanates are potent anti-inflammatories. They have been shown to:
- Block NF-κB pathway activation, one of the primary biologic pathways that activates and magnifies inflammation.
- Suppress tumor necrosis factor-alpha (TNF-α), a master signaling molecule that directs and intensifies chronic inflammation.
- Inhibit the expression of local inflammation-promoting enzymes, such as iNOS and COX-2, which cause pain, stiffness, weakness, and swelling.
- Block the synthesis of tissue-destroying enzymes, including ADAMTS-5 and MMP, that attack normal bone, muscle, tendon, and joint tissue.
Selected Evidence
1. Isothiocyanates Support Joint Health:
Chinese researchers injected sulforaphane, a specific type of isothiocyanate, near human osteoarthritic cartilage cells. The sulforaphane was encapsulated in an absorbable plastic coating to aid delivery of the compound. The treatment resulted in less cartilage cell death and less hypertrophy. Both cartilage cell death and hypertrophy are hallmarks of osteoarthritis (Ko et al., 2013).
2. Isothiocyanates Support Bone Health:
Researchers in Austria exposed mouse bone cells to sulforaphane, an isothiocyanate. The researchers found that sulforaphane stimulated bone-building cells called osteoblasts and diminished the activity of osteoclasts, bone-resorbing cells. Inadequate new bone formation coupled with excessive bone resorption is the cardinal cause of osteoporosis (Thaler et al., 2016).
3. Isothiocyanates Support Muscle Health:
Chinese investigators administered sulforaphane to mice and assessed its effect on muscle inflammation. The researchers found that sulforaphane reduced muscle inflammation by reducing the influx of immune cells into muscle tissue and decreasing the production of inflammation-promoting cytokines (Cheng-Cao Sun et al., 2015).
Proper Preparation of Cruciferous Vegetables for Maximum Protection
These methods should be followed in order to get the maximum health boost:
- Vegetables should not be cooked at very high temperatures. Cooking vegetables at high temperatures decreases isothiocyanate availability by up to 300%.
- Avoid microwaving, boiling, or steaming vegetables, as it usually reduces the bioavailability of health-promoting compounds.
- Consuming raw vegetables is the most potent way to promote well-being.
- When eating, vegetables should be chopped and chewed well to maximize benefits.
- Fresh and organic cruciferous vegetables provide the maximum health benefit.
Precautions
Isothiocyanate consumption is generally recognized as safe when consumed in usual culinary and herbal doses. As with any form of supplementation, consult your healthcare provider prior to use if you are pregnant, nursing, taking any medications, or have any medical conditions. Discontinue use and consult your doctor if any adverse reactions occur.
References
- Berenbaum, F. (2014). Does broccoli protect from osteoarthritis? Joint Bone Spine, 81(4), 2846. https://doi.org/10.1016/j.jbspin.2014.04.001
- Davidson, R. K., Jupp, O., De Ferrars, R., Kay, K. D., Culley, K. L., Clark, I. M., & Norton, R. (2013). Sulforaphane represses matrix-degrading proteases and protects cartilage from destruction in vitro and in vivo. Arthritis & Rheumatism, 65(12), 3130-3140. https://doi.org/10.1002/art.38133
- Facchini, A., Stanic, I., Cetrullo, S., Borzì, R. M., Filardo, G., & Flamigni, F. (2011). Sulforaphane protects human chondrocytes against cell death induced by various stimuli. Journal of Cellular Physiology, 226(7), 1771-1779. https://doi.org/10.1002/jcp.22506
- Guerrero-Beltrán, C. E., Calderón-Oliver, M., Pedraza-Chaverri, J., & Chirino, Y. I. (2012). Protective effect of sulforaphane against oxidative stress: Recent advances. Experimental and Toxicologic Pathology, 64(5), 5038. https://doi.org/10.1016/j.etp.2010.11.005
- Higdon, J. V., Delage, B., Williams, D. E., & Dashwood, R. H. (2007). Cruciferous vegetables and human cancer risk: Epidemiologic evidence and mechanistic basis. Pharmacological Research, 55(3), 224–236. https://doi.org/10.1016/j.phrs.2007.01.009
- Isothiocyanates. (2017). Micronutrient Information Center. Retrieved from http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/isothiocyanates
- Ko, J. Y., Choi, Y. J., Jeong, G. J., & Im, G. (2013). Sulforaphane-PLGA microspheres for the intra-articular treatment of osteoarthritis. Biomaterials, 34(21), 5359–5368. https://doi.org/10.1016/j.biomaterials.2013.03.066
- Kong, J. S., Yoo, S. A., Kim, H. S., Kim, H. A., Yea, K., Kim, W. U., & Ryu, S. H. (2010). Inhibition of synovial hyperplasia, rheumatoid T cell activation, and experimental arthritis in mice by sulforaphane, a naturally occurring isothiocyanate. Arthritis & Rheumatism, 62(1), 159–170. https://doi.org/10.1002/art.25017
- Sun, C.-C., et al. (2015). “Sulforaphane Attenuates Muscle Inflammation in Dystrophin-deficient mdx Mice via NF-E2-related Factor 2 (Nrf2)-mediated Inhibition of NF-κB Signaling Pathway.” Journal of Biological Chemistry, 290(29), 17784-17795.
- Thaler, R., et al. (2016). “Anabolic and Antiresorptive Modulation of Bone Homeostasis by the Epigenetic Modulator Sulforaphane, a Naturally Occurring Isothiocyanate.” Journal of Biological Chemistry, 291(13), 6754-6771.
- Tarozzi, A., Angeloni, C., Malaguti, M., Morroni, F., Hrelia, S., & Hrelia, P. (2013). Sulforaphane as a potential protective phytochemical against neurodegenerative diseases. Oxidative Medicine and Cellular Longevity, 2013, 1-10. https://doi.org/10.1155/2013/415078
- Totušek, J., Tříska, J., Lefnerová, D., Strohalm, J., Vrchotová, N., Zendulka, O., & Houška, M. (2011). Contents of sulforaphane and total isothiocyanates, antimutagenic activity, and inhibition of clastogenicity in pulp juices from cruciferous plants. Czech Journal of Food Science, 29(5), 548–556.
- Williams, F. K., Skinner, J., Spector, T. D., Cassidy, A., Clark, I. M., Davidson, R. M., & MacGregor, A. J. (2010). Dietary garlic and hip osteoarthritis: Evidence of a protective effect and putative mechanism of action. BMC Musculoskeletal Disorders, 11, 280-287. https://doi.org/10.1186/1471-2474-11-280
- World’s Healthiest Foods. (2017). Feeling great with cruciferous vegetables. Retrieved from http://www.whfoods.com/genpage.php?tname=btnews&dbid=125
