NATURTREU Brokkoliblüte in the check: High-dose sulforaphane from broccoli extract

The hard data

Which parts concern blood sugar

Sulforaphane

Sulforaphane is the ingredient that makes me sit up most. In 2017, a widely noted paper appeared in Science Translational Medicine (Axelsson et al.) in which a high-dose broccoli sprout extract lowered fasting glucose and HbA1c in people with type 2 diabetes and obesity – via inhibition of hepatic glucose production.

Why I remain cautious nonetheless: this is one study with a limited number of participants; the dose used was very high and came from a standardised sprout extract. Whether a commercially available preparation delivers comparable bioavailable amounts of sulforaphane is the decisive open question .

The bioavailability point: sulforaphane is only formed from its precursor glucoraphanin by the enzyme myrosinase. Many extracts contain glucoraphanin without active myrosinase, which greatly reduces the actually available amount of sulforaphane. With every sulforaphane product it is worth checking whether and how this problem is solved.

Where care is needed

Well tolerated; occasionally gastrointestinal discomfort. With thyroid disease, restraint is sensible at very high cruciferous doses.

My approach

Four weeks focusing on fasting values – that is the parameter the research suggests, not meal peaks.

All of my own measurements are labelled as a single-case observation (n=1) and cannot be transferred to other people.

Sources

1. Product information NATURTREU Brokkoliblüte: composition and dosage per manufacturer (as of July 2026).
2. EU Register of authorised health claims, Regulation (EC) No 1924/2006.
3. Specialist literature and meta-analyses on the ingredients mentioned; classification by assessment in the text.
4. Lean MEJ et al.: DiRECT trial on remission in type 2 diabetes through weight management, The Lancet.