Section
Broccoli sprouts
Three-day-old broccoli seedlings carry far more glucoraphanin than mature broccoli. Everything on growing them, eating them, and what a portion actually delivers.
Quick answer
Broccoli sprouts are broccoli seeds germinated for roughly three to five days and eaten whole. They are the most concentrated common food source of glucoraphanin, the precursor that becomes sulforaphane when the tissue is damaged. They are also cheap to grow at home in a jar.
Young broccoli seedlings concentrate glucoraphanin far more densely than the mature vegetable. The 1997 paper that established this reported three-day-old sprouts carrying on the order of twenty to fifty times the glucoraphanin found in mature broccoli by weight, though the range across cultivars and growing conditions is wide, and later work has found considerable variation between seed lots.
That matters because glucoraphanin is the precursor. Sulforaphane itself is not present until the sprout is chewed, chopped or blended, at which point myrosinase converts one into the other. A sprout you swallow whole delivers less than the same sprout chewed thoroughly.
This section covers growing them, storing them, how much to eat, and how sprouts compare with mature broccoli and with supplements.
This page describes published research. It is general information, not medical advice, and it is not a recommendation to take anything. Sulforaphane and cruciferous-vegetable supplements can interact with medication. Talk to a doctor or pharmacist before starting a supplement, particularly if you are pregnant, breastfeeding, on anticoagulants, or being treated for thyroid disease.