Foods High in Sulforaphane: Broccoli Sprouts, Cooking & Myrosinase

If you are looking for foods high in sulforaphane, the most important fact is that foods usually do not contain one fixed, ready-made sulforaphane dose. They mainly contain the precursor glucoraphanin, and the amount of sulforaphane you generate depends heavily on myrosinase, preparation and individual conversion.

That is why a food ranking based only on glucoraphanin concentration misses the practical question: how much sulforaphane does this preparation actually deliver?

Best food sources at a glance

1. Broccoli sprouts: the standout practical source

Broccoli sprouts dominate sulforaphane research because young sprouts can provide substantial glucoraphanin together with active myrosinase. Human studies have used fresh sprouts, sprout beverages and sprout-derived extracts to study both pharmacokinetics and biological effects.

In a human crossover study, fresh broccoli sprouts produced substantially greater and faster sulforaphane and erucin metabolite exposure than a tested broccoli supplement whose myrosinase had been inactivated.^[1]

A separate feeding study found fresh sprouts produced roughly three times higher sulforaphane-metabolite exposure than the myrosinase-treated extract tested in that experiment.^[2]

Those studies do not mean every sprout serving beats every modern supplement. They show that fresh sprouts are a biologically effective precursor-plus-enzyme system and that finished formulation matters.

2. Raw broccoli can deliver much more sulforaphane than cooked broccoli

One of the clearest human food studies had eight men eat the same 200 g amount of broccoli either raw or cooked. Estimated sulforaphane bioavailability was about 37% after raw broccoli versus 3.4% after cooked broccoli. Peak plasma concentration also occurred much earlier after raw broccoli.^[3]

The lesson is not that cooked broccoli is “bad.” Cooking can preserve useful nutrients and makes broccoli easier to eat for many people. The sulforaphane-specific issue is that heat can deactivate native myrosinase while leaving some glucoraphanin precursor behind.

3. Mustard can restore the conversion step after cooking

Mustard seed is rich in active myrosinase. A randomized crossover study tested 200 g of cooked broccoli with or without 1 g of powdered brown mustard seed in healthy adults. Adding mustard increased urinary sulforaphane-N-acetylcysteine by more than fourfold.^[4]

This provides human proof of the underlying enzyme strategy: when the broccoli's own myrosinase has been inactivated, an external active source can materially increase conversion.

It does not establish a universal household mustard dose or prove that more mustard is always better.

4. Mature broccoli is still a meaningful glucoraphanin food

Mature broccoli is the most familiar dietary source, but sulforaphane yield varies with cultivar, growing conditions, storage and cooking. The ESCAPE trial illustrates how much standardization matters: researchers used broccoli soups specifically bred to deliver different glucoraphanin exposures rather than treating all broccoli as chemically interchangeable.^[5]

That kind of controlled food design is very different from estimating an exact dose from a normal dinner plate.

5. Other cruciferous vegetables

Brussels sprouts, cabbage, kale, cauliflower, bok choy, watercress, arugula and related Brassica vegetables contribute glucosinolates to the diet. Their glucosinolate profiles differ, and not every cruciferous vegetable is especially rich in glucoraphanin.

For sulforaphane specifically, broccoli sprouts and broccoli remain the most directly relevant foods because glucoraphanin is the precursor most consistently tied to sulforaphane production.

Does chopping broccoli increase sulforaphane?

Disrupting plant tissue brings glucoraphanin and myrosinase into contact. Chopping, crushing and chewing therefore support the chemistry required for sulforaphane formation while active enzyme remains available.

What household preparation cannot give you is a precise, reproducible clinical dose. Cultivar, storage, temperature, chopping time and endogenous enzyme activity all introduce variability.

Does cooking destroy sulforaphane?

“Destroy” is too simple. Heating can deactivate myrosinase, which reduces rapid conversion of glucoraphanin into sulforaphane. Some precursor can remain and later be converted by gut microbes or an added enzyme source.

The human raw-vs-cooked study shows the practical consequence: the cooked preparation produced dramatically lower and delayed systemic exposure even though the broccoli amount was the same.^[3]

A practical food-first strategy

1. Use broccoli sprouts if you tolerate and handle them safely. They are the most research-relevant whole-food source.
2. Include ordinary broccoli and other crucifers for overall dietary quality.
3. Avoid assuming heavy cooking preserves myrosinase activity.
4. If eating well-cooked broccoli, an active raw myrosinase source such as mustard is biochemically and clinically plausible.
5. Do not chase an exact milligram number from home-prepared food. Food exposure is variable by nature.

Food vs supplement: what human evidence says

The comparison is not “natural food good, supplements bad” or the reverse. Fresh sprouts outperformed a myrosinase-inactivated supplement in one human crossover study,^[1] while well-designed enzyme-containing formulations can substantially improve precursor conversion.^[6]

Food offers a whole-food matrix and naturally coordinated precursor/enzyme system when handled appropriately. A supplement can offer convenience and standardization. The useful comparison is the delivered sulforaphane exposure.

See our full broccoli sprouts vs supplements guide for that decision.

Bottom line

Broccoli sprouts are the strongest practical whole-food source in the human sulforaphane literature. Raw broccoli can also deliver meaningful exposure, while cooking can sharply reduce conversion by deactivating myrosinase. Human data show that adding an external active myrosinase source such as mustard can restore much of that conversion potential.

So when thinking about foods high in sulforaphane, do not ask only “Which vegetable has the most?” Ask which preparation preserves or restores the glucoraphanin-to-sulforaphane conversion system?