Cruciferous Veg

Cruciferous vegetables (broccoli, cabbage, kale, etc) seem to be far more beneficial than non-cruciferous vegetables. Those consuming the highest amounts age slower and live longer than counterparts eating similarly high amounts of non-cruciferous vegetables when studied. [R1] [R2]

Why is this? Well, it may be because cruciferous vegetables, particularly those of the Brassica oleracea genus (broccoli, cabbage, brussels sprouts) contain very high amounts of  a molecule called glucoraphanin, which is a precursor to the compound sulforaphane. [R]

Sulforaphane’s Effects

Sulforaphane is a highly beneficial compound that is particularly notable for its anti-cancer effects. It brings about most of its bioefficacy via its ability to activate a nuclear transcription factor called NRF2. [R1] [R2]

NRF2 is a pathway activated to counteract environmental stresses. It upregulates what can broadly be defined as an array cytoprotective (cancer-protective) proteins. These include antioxidants enzymes, heat shock proteins, drug-metabolising enzymes, growth factors and various nuclear receptors, including PPAR delta, which aids in fat and glucose metabolism (see more here). [R]

Further to this, it upregulates enzymes involved in the detoxification of toxic and/or carcinogenic (cancer-causing) compounds. The way in which it does this is particularly effective for promoting safe and efficient detoxification without a build-up of toxic metabolites at any stage of the detoxification process.  [R1] [R2]

Moreover, although it has now emerged that antioxidant supplementation is not only unlikely to make you live longer but potentially harmful (read more here), increased expression of antioxidant enzymes via activation of NRF2 could be very helpful in treating conditions known to be underpinned by oxidative stress and could provide some of those anti-ageing effects we were all originally looking for. [R1] [R2] [R3] [R4]

Also unlike orally consumed antioxidants, such as Vitamin C, the antioxidant enzymes and natural antioxidant defences, such as CoQ10, that are upregulated by NRF2 are not consumed in a linear fashion but have a long-lasting life of many days within the body. [R]

Just as a testament to NRF2’s, and therefore sulforaphane’s, power is the fact that exercise provides some of its anti-inflammatory, antioxidant and detoxification effects via NRF2 by giving a weak prooxidant signal and theoretically we could be getting far, far high levels of NRF2 activation from sulforaphane than with exercise alone. [R]

How to Get More Sulforaphane

In terms of getting the maximum amount of sulforaphane in your diet from now on, broccoli sprouts are your best bet. They contain around 10-100x higher amounts of glucoraphanin in comparison to the mature broccoli plant hence why the majority of studies upon sulforaphane have with broccoli sprout consumption. [R]

In order to maximise the yield of sulforaphane you get out of your broccoli sprouts or mature broccoli plant, heat them to around 60 degrees Celsius for 10 minutes. Do not heat the plant to temperatures any higher than 60 degrees however as this will denature the myrosinase enzyme that allows sulforaphane formation to occur once chewed. [R] After this, you can feel safe in the idea that you’ll be getting lots of beneficial sulforaphane as it has a very high bioavailability, certainly in comparison to other beneficial phytochemicals. [R1] [R2]