Sulforaphane, Broccoli, & Broccoli Sprouts: What are the Benefits?

Bring on the Broccoli and Broccoli Sprouts!

To think, for all those years we used to throw it under the table and give it to the family dog!  It turns out our parents, and our grandparents were right—broccoli IS good for you.  Especially, broccoli sprouts.  This low calorie, high fiber, and vitamin rich superfood is the perfect pick for a nutrient dense vegetable.

One cup of cooked broccoli contains approximately 5 grams of fiber, 3.7 grams of protein, and only 55 calories—a nutritional bargain.  Low calorie, high fiber foods are great to keep your bowels moving and ideal for maintaining a healthy weight.  Fiber helps to maintain healthy cholesterol levels and protein aids in stabilising your blood sugar levels, keeping you feeling fuller, for longer.

Time to Jump on the Broccoli Bandwagon

There is science to back the broccoli bandwagon our parents wish we had jumped on years ago.  What exactly makes broccoli and other cruciferous vegetables so powerful?  According to Shapiro et al., (2001) broccoli, including broccoli sprouts, are both rich sources of glucosinolates and isothiocyanates, compounds which induce phase 2 detoxification liver enzymes, boost antioxidant status, and protect against chemically induced cancer.

Sound too good to be true?

There is a catch—glucosinolates are inactive as phase 2 enzyme inducers and must be hydrolyzed into active isothiocyanates, and this conversion is mediated by the enzyme myrosinase, found in both plants and bowel microflora.  There’s been a lot of talk about the importance of our resident gut bacteria in the literature, and here is just another reason these bug buddies are proving to be so essential to our existence.

The longer broccoli is chewed, the increased activity of myrosinase therefore, the increased conversion of glucosinolates to isothiocyanates (Shapiro et al., 2001).  Cutting, chewing, or otherwise rupturing the plant cell structure in broccoli and broccoli sprouts causes myrosinase to come into contact with glucosinolates thus, increasing the conversion of protective cellular compounds (Houghton et al., 2016).

What makes broccoli so nutritiously beneficial to the body?

A specific glucosinolate, glucoraphanin, is a precursor of a distinct and powerful isothiocyanate named sulforaphane.  Sulforaphane has been shown to inhibit the growth of abnormal cellular tissue, thus, preventing a number of disease states (Fahey et al., 2015).  Furthermore, Fahey et al., (2015) found that the bioavailability of sulforaphane (the abundance of this compound) was increased by 3-4 fold in the presence of myrosinase.

According to Christine Houghton (2010), a Nutritional Biochemist, broccoli sprouts contain 20-50 times more sulforaphane than the mature vegetable.  This isn’t to say cruciferous vegetables aren’t important in the diet.  Cruciferous vegetables, such as broccoli, cauliflower, cabbage, and leeks possess special protective, anti-carcinogenic effects due to the active isothiocyanates.

Carcinogens are the ‘rebels’ that cause oxidative damage to the cells in our bodies.  Sulforaphane upregulates the phase 2 response, as well as influences the genes which contain an antioxidant responsive element.  In layman terms, sulforaphane can ‘switch on’ the genes that activate enzymes in the phase 2 liver detoxification pathway (Fahey et al., 2015).

A randomised, double-blind, placebo controlled study by Kukuchi et al., (2015) found that male participants with fatty liver disease who received broccoli sprout capsules containing sulforaphane for 2 months significantly decreased serum levels of liver function markers.  Results found that liver function markers of oxidative stress, such as AST and ALT (aspartate and alanine aminotransferases) significantly decreased (p = 0.012), whereas there was no reduction in the placebo group (Kukuchi et al., 2015).

Sulforaphane: The Wonder Non-Nutrient Molecule

It is now being recognised that food-derived non-nutrient molecules, such as sulforaphane, can modulate gene expression to influence intracellular mechanisms thus, giving emergence to the fields of nutrigenomics and nutrigenetics (Houghton et al., 2016).  According to Houghton et al., (2016) sulforaphane activates the Nrf2 pathway which induces the expression of cell protective agents.  Nrf2 in the cell ‘switches on’ the cell’s own defense system (Houghton, 2010).

What is Nrf2?

Nrf2 is known as the ‘Master Regulator’ of cellular defense, countering many harmful environmental toxins and carcinogens, as well as the ability to induce phase 2 detoxification enzymes which play a critical role in the body’s ability to rid itself of harmful substances (Houghton et al., 2016). 

If there’s a switch to send out the helpful troupes, is there a switch that promotes inflammation?  Yes!  The protein NF-kB activates the genes that promote inflammation and fried, fatty, and highly processed foods keep these inflammation genes ‘switched on’, pumping out copious amounts of chemicals, known as pro-inflammatory cytokines (Houghton, 2010).  All the more reason to swap the side of chips for a side of greens!

While other antioxidants from foods are beneficial to health, by virtue of its lipophilic nature and low molecular weight, sulforaphane seems to display significantly higher bioavailability in comparison to other polyphenol-based dietary supplements (Houghton et al., 2016).  This is not to disregard other important polyphenols in the diet, rather, to understand that cruciferous vegetables play a key role in maintaining optimal health and a balanced, nutrient dense diet is the key to longevity.

Looking for some food inspiration?  Not sure how to creatively incorporate broccoli into your diet? Check out these quick tips for some helpful ideas:

  • Broccoli sprouts are a great addition to salads
  • Broccoli, cauliflower, and Brussels sprouts taste fabulous roasted, and served alongside a homemade tomato, date, and raisin chutney sauce
  • Lightly steamed is the ideal way to get these veggies; sprinkle on some salt, herbs and drizzle on a lime, cayenne, honey tahini sauce
  • Add cruciferous vegetables to your soups
  • Add some broccoli and broccoli sprouts to quinoa, sweet potato, and black current dishes

Amanda Harasym

Naturopath, Nutritionist, Herbalist

 

References

Fahey J, Holtzclaw W, Wehage S, Wade K, Stephenson K, Talalay P. Sulforaphane bioavailability from glucorphanin-rich broccoli: control by active endogenous myrosinase. PLoS One. (2015);10(11): e0140963. Published online 2015 Nov 2. Doi: 10.1371/journal.pone.0140963. Retrieved from http:// http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629881/.

Houghton C, Fassett R, Coombes J. Sulforaphane and other nutrigenomic Nrf2 factors: can the clinican’s expectation be matched by the reality? Oxid Med Cell Longev. (2016); 2016: 7857186. Published online 2016 Jan. doi: 10.1155/2016/7857186.  Retrieved from http:// http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4736808/.

Houghton, C. Switched on: harnessing the power of nutrigenomics to optimise your health. (2010). First Edition: INTEGRA Publishing.

Kikuchi M, Ushida Y, Shiozawa H, Umeda R, Tsuruya S, Aoki Y, Suganuma H, Nishizaki Y. Sulforaphane-rich broccoli sprout extract improves hepatic abnormalities in male subjects. (2015); Nov 21; 21(43):12457-12467. Published online 2015 Nov 21. Doi: 10.3748/wjg.v21.i43.12457. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4649129/.

Shapiro T, Fahey J, Wade K, Stephenson K, Talalay P. Chemoprotective glucosinolates and isothiocyanates of broccoli sprouts: metabolism and excretion in humans. Cancer Epidemiology, Biomarkers and Prevention. (May 2001). 10;501. Retrieved online from http:// http://cebp.aacrjournals.org/content/10/5/501.full.

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