There is a vegetable that has been studied for over thirty years in the laboratories of the world's most renowned research institutes. Johns Hopkins University in Baltimore isolated its main active ingredient in 1992 and described it as an extraordinary secondary plant compound. Research groups in Germany, the USA, Japan, and Sweden are working intensively on it.
This vegetable costs about two euros at the farmer's market.
It's called broccoli. And the substance that makes it so special is called sulforaphane.
But — and this is the crucial point — only broccoli that is correctly grown, correctly harvested, and correctly prepared contains enough sulforaphane to unleash its full effect. And unfortunately, that is not the broccoli most of us buy and cook.
What Sulforaphane Is — and How It's Formed
Sulforaphane is a secondary plant compound belonging to the family of glucosinolates. It is found in cruciferous vegetables — broccoli, Brussels sprouts, cauliflower, kohlrabi, cress, arugula — but nowhere in as high a concentration as in broccoli, and especially in broccoli sprouts.
However, sulforaphane is not present in the plant in its final form. It is only formed through a chemical reaction.
Broccoli contains glucoraphanin — an inactive precursor — and the enzyme myrosinase. These two are kept neatly separate in the intact plant cell. Only when the cells are damaged by cutting, chewing, or crushing do glucoraphanin and myrosinase come into contact — and react with each other to form sulforaphane.
This sounds familiar — because it's the same principle as with garlic. There, too, the main active ingredient, allicin, is only formed when the cells are damaged.
And the same applies to broccoli: the enzyme myrosinase is destroyed by heat. Anyone who throws broccoli directly into boiling water destroys myrosinase — and thus the ability of glucoraphanin to convert into sulforaphane.
This is the greatest cooking secret of broccoli.
The Cooking Secret — What You Can Do Wrong
Step 1: First cut, then wait.
Cut the broccoli into florets. Lay it out. Wait 40 minutes before heating it.
Why 40 minutes? Because myrosinase and glucoraphanin need time to form sulforaphane after cutting. What has already formed tolerates heat better. Waiting before cooking significantly increases the sulforaphane content in the finished dish.
Step 2: Don't boil — steam or blanch briefly.
Boiling water at 100 degrees immediately destroys myrosinase. Steaming below 70 degrees largely preserves it. Or brief blanching for a maximum of 3 to 4 minutes — then immediately transfer to ice-cold water to stop the cooking process.
Step 3: Add mustard.
Mustard also contains myrosinase. Anyone who adds a teaspoon of mustard to steamed broccoli — or serves arugula or cress with it — adds myrosinase from the outside, which enables the conversion even after cooking.
This is the simplest upgrade you can make in your kitchen.
Step 4: Raw is strongest.
Raw broccoli contains the most sulforaphane. Finely chopped in a salad, as raw vegetables with dip, finely grated over finished dishes — this is the most powerful form.
The special case of broccoli sprouts:
Broccoli sprouts contain up to one hundred times more sulforaphane than mature broccoli. Anyone who adds a small handful of fresh broccoli sprouts to their salad daily receives an exceptionally high dose of this secondary plant compound. Simply sprout them yourself — ready in three to five days.
What Sulforaphane Does in the Body — What Research Shows
Sulforaphane has been intensively researched since its discovery in 1992. It has antioxidant, anti-inflammatory, and antimicrobial effects. Scientists are particularly interested in its cell-protective properties and its influence on the body's detoxification processes.
Population studies show a correlation between regular consumption of cruciferous vegetables and various positive health effects. The exact mechanisms are still being researched — what is clear is that sulforaphane activates the body's own protective mechanisms and stimulates detoxification enzymes.
In a placebo-controlled study with 97 overweight people with Type 2 diabetes, daily intake of broccoli sprout extract for 12 weeks lowered fasting blood sugar by 6.5 percent and improved long-term blood sugar. This is a concrete, measured effect.
Sulforaphane also appears to be effective against Helicobacter pylori — the type of bacteria that can cause gastritis and stomach ulcers. And studies show that it suppresses the formation of early pathological changes in the colon lining and promotes protective gut bacteria.
The German Cancer Information Service summarizes it as follows: There is evidence that sulforaphane could be beneficial for health. It is certain that a balanced plant-based diet with plenty of broccoli and other cruciferous vegetables benefits health.
This is not a promise of a cure — but it is a very good reason to eat regular and well-prepared broccoli.
What Else Is in Broccoli — The Complete Nutrient Profile
Sulforaphane is the star — but it appears in a strong team.
Vitamin C. 100 grams of raw broccoli provide about 90 to 110 milligrams of Vitamin C — significantly more than an orange. Thus, one serving of broccoli covers the entire daily requirement. Vitamin C is heat-sensitive — another reason for gentle cooking.
Vitamin K. Broccoli is one of the best plant-based sources of Vitamin K — essential for blood clotting and bone health.
Folic acid. Important for cell division and DNA synthesis — especially indispensable during pregnancy.
Calcium. Broccoli contains surprisingly much calcium — and the calcium from broccoli is particularly well absorbed by the body. For people who avoid dairy products, broccoli is a valuable source of calcium.
Iron, potassium, manganese, phosphorus — a wide spectrum of minerals that can be further enhanced by healthy, mineral-rich soil.
Dietary fiber for gut health and satiety.
Lutein and zeaxanthin — carotenoids that protect eye health.
Color as a Quality Feature
Deep dark green broccoli with tightly closed florets is the visible sign of a vital plant with high nutrient content. Yellowish broccoli with slightly opened florets indicates that the plant is already beginning to flower — the sulforaphane content then drops significantly.
Freshly harvested broccoli is the most nutrient-rich. Studies show that broccoli loses significant amounts of its secondary plant compounds within three days of harvest — especially when stored warm.
This argues for regional, seasonal purchase — and even more for growing your own.
The Brix Value in Broccoli
According to the Reams Reference Table:
Poor: 6 °Brix — typical supermarket broccoli
Average: 8 °Brix
Good: 10 °Brix
Excellent: 12 °Brix
Broccoli with 12 °Brix has more of everything. More sulforaphane because the plant has carried out more photosynthesis and formed more secondary protective compounds. More Vitamin C. More Calcium. And it tastes more intense — nuttier, less bitter. This is the most direct sensory signal for nutrient density in broccoli.
The Connection That Binds Everything
Sulforaphane is a protective substance. The plant forms it to protect itself from predators, UV radiation, and pathogens. The more vital the plant, the more intense its photosynthesis, the better its mineral supply — the more sulforaphane it forms.
This is the same principle as with all other secondary plant compounds in our superfood series. Quercetin in red onion. Lycopene in tomato. Betacarotene in carrot. Allicin in garlic. Anthocyanins in strawberry. Sulforaphane in broccoli.
They all arise as protective reactions of a vital plant. And they all benefit us when we eat them.
The soil that makes a plant vital makes us healthy.
How to grow broccoli that develops its full sulforaphane potential — with zeolite, paramagnetic basalt, AM+PLUS microorganisms and Greenpower Calcium — we show in the next blog post.
What connects all our superfood articles — why soil health and human health are inseparable — in the article on minerals and damaged soils.
Measure the Brix value yourself — instructions and Reams table — Brix article.
Sources: DKFZ Krebsinformationsdienst, Sulforaphane and Broccoli | PhytoDoc, Sulforaphane Effect and Application | Zentrum der Gesundheit, Sulforaphane | Talalay et al., Johns Hopkins University, Isolation of Sulforaphane 1992 | University of Gothenburg, Broccoli Sprouts and Type 2 Diabetes Study | frag-die-apotheke.de, Broccoli as a Superfood 2025 | lebenskraftpur.de, Sulforaphane Effect and Application
