Broccoli Sprouts & Sulforaphane

It’s Q&A Day at 10almonds!

Have a question or a request? We love to hear from you!

In cases where we’ve already covered something, we might link to what we wrote before, but will always be happy to revisit any of our topics again in the future too—there’s always more to say!

As ever: if the question/request can be answered briefly, we’ll do it here in our Q&A Thursday edition. If not, we’ll make a main feature of it shortly afterwards!

So, no question/request too big or small 😎

❝How much science is there behind sulforaphane / broccoli spirits and its health claims??❞

So, first of all, what it is: sulforaphane is a compound found in Brassica oleracea, of which species broccoli is a cultivar. It’s found in the other Brassica oleracea cultivars too (e.g. cauliflower, various cabbages, Brussels sprouts, kale, etc), but for whatever reason*, most research has been on broccoli and broccoli sprouts.

*Likely the reason is: research begets research—it’s easier to get funding to expand upon previous research, than it is to break ground on researching a different plant, where for the first third of your paper you have almost no existing scientific literature to cite. So once they got started on broccoli sprouts, everything else has been broccoli sprouts too.

And for clarity on what broccoli sprouts are: this means that when broccoli seeds have been germinated and just begun to sprout, they are harvested and eaten. That’s the one-line explanation, anyway; there’s a little more to it than that, so anyone interested should check out our previous main feature:

Good Things Come In Small Packages: Sprout Your Seeds, Grains, Beans, Etc

…and for more depth than we have room for in a one-page article, check out this book we reviewed:

The Sprout Book: Tap Into The Power Of The Planet’s Most Nutritious Food – by Doug Evans

One thing that the science is clear on: sprouts of a given plant indeed have much higher general nutritional density than their “adult” siblings. And in the case of sulforaphane specifically, it’s about 100x higher in broccoli sprouts than in adult broccoli:

Broccoli or Sulforaphane: Is It the Source or Dose That Matters? ← we suggest skipping down to the section “broccoli-based clinical trials”

So, that prompts the next question: do we care?

In other words: is sulforaphane really particularly important?

Sulforaphane vs cancer

The most well-evidenced health-giving property of sulforaphane is its anticancer activity:

Brassicaceae-Derived Anticancer Agents: Towards a Green Approach to Beat Cancer

A lot of the research there is epidemiological rather than RCTs, and where there are RCTs, they are mostly small ones, like this 10-person broccoli soup study about bioavailability (rather than the effects themselves):

Bioavailability of Glucoraphanin and Sulforaphane from High-Glucoraphanin Broccoli

To get into sulforaphane’s anticancer potential in seriousness, we have to look at a lot of in-vitro studies trialling it to limit carcinogenesis, or to shrink tumors with it, or specifically targetting cancer stem cells with it, which make for quite compelling reading:

Dietary Sulforaphane in Cancer Chemoprevention: The Role of Epigenetic Regulation and HDAC Inhibition

A quick aside: if you’re reading that and thinking “Why is sonic the hedgehog in here?” it’s because after the observation of the influence of certain genes that influence cuticular denticles (the growth of spikes) on fruit fly larvae (bearing in mind the fruit fly Drosophila melanogaster is used for so much first- or second-line genetic research, being either the go-to or the go-to after the nematode C. elegans) caused the whole group of genes to get called “hedgehog genes” and then it became scientific convention to name each newly researched gene in that set after a different kind of hedgehog. One of them, instead of being named after a real-world hedgehog species like the others, got named after the videogame character.

Unfortunately, this now means that because the gene is associated with a certain congenital brain disorder, sometimes a doctor has to explain to a family that the reason their baby has a brain defect is because of a mutated sonic hedgehog.

Ok, back to talking about cancer. Let’s just quickly drop a few more papers so it’s clear that this is well-established:

• Multi-targeted prevention of cancer by sulforaphane ← this shows how it works on the cellular level
• Cruciferous vegetables: dietary phytochemicals for cancer prevention ← this shows how it works on the population level

However, that’s not the only established benefit:

❝SFN has other beneficial effects in addition to cancer protection. SFN exhibits neuroprotective effects and is implemented in treating conditions such as traumatic brain injury, Alzheimer’s disease and Parkinson’s disease.❞

Source: Sulforaphane in broccoli: The green chemoprevention!! Role in cancer prevention and therapy

Now, after the extract we quoted above, the rest of the section “other health benefits of sulforaphane” includes a lot of speculation, weak science, and/or things attributable to other phytochemicals in broccoli, including various polyphenols, vitamins, and minerals.

About those broccoli spirits

Ok, we know it was a typo, but… Actually, there is something worth mentioning here, and that’s that sulforaphane is only activated when glucoraphanin (its inactive form) comes into contact with myrosinase (an enzyme that’s only released when the plant is damaged).

In other words, it’s necessary to injure the broccoli before consuming it, in order to release the spirits myrosinase. Now, while very few people are out there swallowing adult broccoli plants whole, it could well happen that people might wolf down uncut broccoli sprouts, since they are only small, after all.

For this reason, it’s best that broccoli, even if it’s broccoli sprouts, be cut while raw before consumption.

In terms of cooking, heat in excess of 140℃ / 284℉ will destroy the glucoraphanin, and less/no glucoraphanin means less/no sulforaphane.

So, enjoying them raw or lightly steaming them seems to be best for this purpose:

Impact of thermal processing on sulforaphane yield from broccoli (Brassica oleracea L. ssp. italica)

Just want a supplement?

Many studies (including some cited by the research reviews we cited above) deal with sulforaphane in extract form, rather than whole plants, so there’s no shame in taking it that way if you’re not a fan of broccoli.

We don’t sell it, but here for your convenience is an example product on Amazon 😎

Enjoy!