Highlights:
- Sulforaphane, found in cruciferous vegetables, has potent anti-cancer properties
- Active sulforaphane is unstable so it must be taken as a precursor called glucoraphanin together with a natural activator enzyme found in all of these vegetables
- Broccoli sprouts contain the highest amounts of glucoraphanin but other vegetables like watercress, kale, cabbage, collard greens, brussels sprouts, bok choy, mustard greens, and cauliflower are also sources
Another supplement in our stack is Sulforaphane, a molecule found in cruciferous vegetables like broccoli, brussels sprouts, cabbage and cauliflower. Sulforaphane itself is chemically unstable and has a relatively short shelf life. When we eat these vegetables, Sulforaphane is generated in our gut from a stable precursor called glucoraphanin by the action of the enzyme myrosinase, both of which are found in these cruciferous vegetables. As we chew these vegetables, the plant cell walls break down, releasing the enzyme which converts glucoraphanin into sulforaphane. Since the reaction takes place in our GI tract, the freshly made sulforaphane is readily absorbed by the body.
The biology:
A major effect of sulforaphane at a cellular level is the activation of a transcription factor called NRF-2 whose activity declines with age. NRF-2 in turn activates cellular antioxidant and detoxification enzymes and the production of our body’s natural antioxidant, glutathione (https://www.hindawi.com/journals/omcl/2019/2716870/). It also reduces overall inflammation. Multiple lines of evidence point to a neuroprotective effect of sulforaphane by blocking amyloid beta and tau formation (https://www.mdpi.com/1422-0067/22/6/2929/htm).
Clinical evidence:
A recent clinical study demonstrated the effect of Sulforaphane in reducing overall inflammation. Forty healthy overweight adults incorporated 30g of fresh broccoli sprouts into their daily diet for 70 days. The sprouts contained approximately 51 mg of glucoraphanin. During the 70-days the levels of two inflammatory markers IL-6 and CRP decreased steadily in the subjects (https://www.hindawi.com/journals/omcl/2019/2716870/).
Supplementation:
The best source of Sulforaphane is broccoli sprouts. But raw or slightly cooked cruciferous vegetables are also good sources. Here is a longer list of these: broccoli, watercress, kale, cabbage, collard greens, brussels sprouts, bok choy, mustard greens, and cauliflower. But broccoli sprouts contain by far the most sulforaphane. Scientist and youtuber Rhonda Patrick is a big sulforaphane enthusiast. She has some great videos on how to grow sulforaphane (https://www.youtube.com/watch?v=U9iL8Kvugks). She also has a couple of videos on the how to maximize the sulforaphane content in your sprouts (https://www.youtube.com/watch?v=Z7buU-PK7_I, https://www.youtube.com/watch?v=19QFaV9Lj5I). As with everything else, one can also buy the sulforaphane precursor glucoraphanin plus the activating enzymes in capsule form.
Safety:
There are a few things to keep in mind with sulforaphane, if you are taking certain medications. Sulforaphane inhibits the drug metabolizing liver enzyme CYP1A2. So if you are taking any medications that are metabolized by this enzyme, you need to be careful and consider avoiding sulforaphane or not taking it at the same time as the medication. We would suggest talking to your doctor. WebMD has a partial list of these medications (https://www.webmd.com/vitamins/ai/ingredientmono-1070/sulforaphane).
There are also two cases of seizure in autism patients with a history of seizure after taking sulforaphane. it is not clear whether the events are causally linked to sulforaphane.
Paul Talalay and Jed Fahey from Johns Hopkins School of medicine have studied sulforaphane for the past two decades. Here is a good review of sulforaphane from Rhonda Patrick (https://www.youtube.com/watch?v=zz4YVJ4aRfg). She also has a nice interview with Jed Fahey talking about sulforaphane dose (https://www.youtube.com/watch?v=NNmjfTQRK2g).
What I take:
I have personally chosen the supplement option for the ease of taking capsules vs sprouting broccoli regularly. But I enjoy eating broccoli too!