Are sulforaphane supplements better than microwaved broccoli sprouts?

Armando asked a good question in Upgrade your brain’s switchboard with broccoli sprouts:

“Is there any way to consume sulphorafane in a supplement form? Rather than have to jump so many hops to consume it from broccoli.”

That blog post referenced a 2017 study, whose sulforaphane amount was:

“100 µmol [17.3 mg] sulforaphane as standardized broccoli sprout extract in the form of 2 gel capsules.”

One answer in A pair of broccoli sprout studies was No:

  • “Plasma and urinary levels of total SFN [sulforaphane] metabolites were ~3–5 times higher in sprout consumers compared to BSE [broccoli sprout extract] consumers.
  • In sprout consumers, plasma concentrations were 2.4-fold higher after consuming the second dose than after the first dose.
  • Calculated SFN bioavailability from broccoli sprouts exceeded 100%.”

That study was from 2015, though. Are better products than broccoli sprout extracts available now?


Image from the US Library of Congress

During Week 5 of Changing an inflammatory phenotype with broccoli sprouts, back in May when I still believed impossible things like we would:

I contacted a distributor of a dried broccoli sprout powder for evidence of their claim:

“Independent assays confirm that EnduraCELL yields more Sulforaphane per gram and per dose than any other broccoli sprout ingredient available! These assays showed that EnduraCell yields around 3.5 times more SULFORAPHANE than the next highest broccoli sprout product.”

I’ve asked three times for the lab assays. They declined each time to provide the data. In correspondence the company founder said:

“Each 700 mg capsules yields around 15mg sulforaphane.”

The company founder has written several reviews, one of which is entitled Sulforaphane and Other Nutrigenomic Nrf2 Activators: Can the Clinician’s Expectation Be Matched by the Reality? In Section 6.5 Sulforaphane it stated:

“By calculation, MYR [myrosinase]-active whole broccoli sprout supplement yielding 1% SFN could deliver 10 mg SFN per gram of powder, corresponding to ~12 grams of fresh broccoli sprouts (dried powder retains ~8% moisture).

The 2017 study’s dosage of “100 µmol [17.3 mg] sulforaphane as standardized broccoli sprout extract” weighed a gram or less, for a 1.73% sulforaphane yield. A broccoli sprout powder may have a 15 mg / 700 mg = 2.14% sulforaphane yield.

Using calculations from Estimating daily consumption of broccoli sprout compounds and Our model clinical trial for Changing to a youthful phenotype with broccoli sprouts, I eat 131 grams of 3-day-old broccoli sprouts daily. That would be 131 g / 12 = 10.9 grams of a broccoli sprout powder.

The equivalent sulforaphane dosage would be 10.9 g x 21.4 mg per gram = 233.3 mg! That’s obviously too high. What isn’t right?

Subsequent investigation of a distributor’s site found this table:

autism sprout powder

The study referenced for equivalence was Sulforaphane treatment of autism spectrum disorder (ASD). Calculations:

  • The 100 µmol sulforaphane amount for 90 kg participants weighed 17.73 mg per https://pubchem.ncbi.nlm.nih.gov/compound/sulforaphane.
  • The equivalent broccoli sprout powder sulforaphane yield is 0.01773 / 3.6 g = 0.4925%. That’s 5 mg of sulforaphane per gram of broccoli sprout powder.
  • 0.4925% / 2.14 % = 0.23. Decrementing the above sulforaphane weight gives 233.3 mg x .23 = 54 mg.

The answer to my question What isn’t right? I relied on private correspondence rather than what a vendor publicly disclosed.


I’m not particularly concerned about analytical uncertainties for myself. Whatever the numbers are, microwaving techniques for fresh broccoli sprouts increase them.

I immerse 3-day-old broccoli sprouts in 100 ml distilled water, then microwave them on 1000W full power for 35 seconds to achieve up to but not exceeding 60°C (140°F) per Microwave broccoli to increase sulforaphane levels. Worst-case estimates are 52 mg sulforaphane with microwaving.


My answer to Armando’s question would be No for sulforaphane supplements. I’d consider a whole broccoli sprout powder after lab assays were personally verified.

2 thoughts on “Are sulforaphane supplements better than microwaved broccoli sprouts?

    • Hi Raphael! Thanks for commenting.

      Prostaphane information from their website:
      “One to three capsules per day (up to 6 capsules in special cases) for three to six months.
      For one capsule: 10 mg of free, stabilized sulforaphane [CH3-SO-(CH2)4-NCS] from broccoli seeds.
      Ingredients: Maltodextrin, vegetal capsule (hydroxy propyl methylcellulose), broccoli seeds extract (Brassica Oleracea) titrated in sulforaphane, thickeners: acacia gum and magnesium stearate”

      It would be convenient for a person to get 30 mg of sulforaphane daily by swallowing three capsules of broccoli seeds extract. A comparable worst-case calculation in the Estimating link above for eating two tablespoons of broccoli seeds daily is 39 mg sulforaphane.

      It would be inconvenient to create sulforaphane twice a day by chewing one tablespoon of broccoli seeds for five minutes or so to release myrosinase and glucoraphanin before swallowing. I’ll guess that sulforaphane could be created by microwaving broccoli seeds up to 60°C in a small amount of water then straining out the water. I’ll try that to see if it’s more palatable.

      It’s even more inconvenient to spend an hour a day growing broccoli sprouts. A worst-case estimate is that a person would create 30 mg sulforaphane with microwaving 3-day-old broccoli sprouts.

      A study compared in Measuring sulforaphane plasma compounds used Prostaphane. It was published in 2016, though, and used tablets, not capsules. Among the interesting things those researchers found were:
      “We evaluated stability of the SF concentration in these tablets when maintained at -20 °C. The decline in SF content in 2 separate lots, shipped in boxes containing blisterpacks of tablet measured over 1.5 years, equates to about 17.8% per year.”

      They stipulated an amount of 94.4 μmol SF in two Prostaphane tablets. The sulforaphane amount given to study subjects would have been specified at 112.8 μmol if they had found a 10 mg weight of sulforaphane in each tablet.

      I didn’t see any prices in the link, maybe because I’m in the US? Eating two tablespoons of broccoli seeds every day for six months would cost < $250.

      Like

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