Estimating daily consumption of broccoli sprout compounds

Strikethroughs are mainly from Week 18 and Week 19 of Changing to a youthful phenotype with broccoli sprouts measurements.

Rainy day thought for the 13th week of lockdown: What are methods of estimating the minimum contents of broccoli sprouts for those of us who aren’t willing to turn their kitchen into a laboratory?

With the 3-day-old broccoli sprouts have the optimal yields study as a reference, minimum values of the six broccoli cultivated varieties studied were:

  1. Lowest weight of 100 seeds: .33 grams.
  2. 100 of that cultivar’s 3-day-old sprouts weighed 1.55 grams.
  3. A different cultivar had the lowest total phenolics (gallic acid equivalents): 0.94 mg per gram of 3-day-old sprouts.
  4. That second cultivar also had the lowest total flavonoids (rutin equivalents): 1.02 mg per gram of 3-day-old sprouts.
  5. A third cultivar had the lowest weight of sulforaphane in its seeds: 2.43 mg per gram of seeds.
  6. Reduction of sulforaphane content during germination from seeds to 3-day-old sprouts is evident from the below chart. The only 3-day-old sprout chart number the study provided was the best case, though. I requested the study data, but in the meantime..I enlarged the chart, measured the worst cultivar as a 8.5 cm bar where the seed bar was 16 cm. Its 3-day-old sprout sulforaphane yield was ~53% of its seed yield.

sprout ages 1B

Another caveat for contents: Researchers had to process broccoli seeds and 3-day-old broccoli sprouts in order to make measurements. Total phenolics and total flavonoids may not have been affected by processing. However, processing generated sulforaphane.

Broccoli seeds and 3-day-old broccoli sprouts contain little or no sulforaphane. They have glucoraphanin and myrosinase enzyme which are structurally separated. Disturbing their cells mixes the two, and the enzyme hydrolyzes glucoraphanin and other glucosinolates into sulforaphane and other healthy compounds.


I start out each daily batch with two tablespoons of broccoli seeds of an unknown cultivar. I counted 812 broccoli seeds in a teaspoon (yes, I did), and multiplied by 6 for 4,872 total seeds.

Runt-of-the-litter calculations for the six broccoli cultivars studied are:

  • (4,872 / 100) x .33 g = 16.08 10.7 g x 2 = 21.4 g broccoli seeds [my measurements];
  • (4,872 / 100) x 1.55 g = 75.52 65.5 x 2 = 131 g 3-day-old broccoli sprouts [my measurements];
  • 75.52 131 g x 0.94 mg per gram of 3-day-old sprouts = 70.99 123.1 mg total phenolics [worst-case];
  • 75.52 131 g x 1.02 mg per gram of 3-day-old sprouts = 77.03 133.6 mg total flavonoids [worst-case];
  • 16.08 21.4 g broccoli seeds x 2.43 mg per gram of seeds = 39.07 52.0 mg sulforaphane [worst-case].

I’ll use the Microwave broccoli to increase sulforaphane levels study as a reference for an alternate sulforaphane calculation. The cultivar wasn’t mentioned, only that it was ordinary broccoli purchased in Silver Spring, Maryland, grocery stores.

One assumption is that microwaving broccoli sprouts will have the same effects as microwaving broccoli florets to increase sulforaphane content. Are the similarities between broccoli floret and broccoli sprout characteristics enough to say whether or not that’s a valid assumption?

Another assumption is that there’s no beginning amount of sulforaphane in 3-day-old broccoli sprouts. Microwaving them on full power to 60°C produces all of the sulforaphane.

A third assumption is that the sulforaphane increase from .22 to 2.45 µmol / g of the tested broccoli florets fairly represents other broccoli florets.

((2.45 – .22 µmol / g)

x 75.52 131 g 3-day-old broccoli sprouts)

/ 5.64 μmol conversion of amount to weight

= 29.86 51.8 mg sulforaphane


Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease concluded:

“The daily SFN [sulforaphane] dose found to achieve beneficial outcomes in most of the available clinical trials is around 20-40 mg.”

My daily consumption of broccoli sprout compounds is greater than this clinical trial range, with evidenced calculations of 29.86 51.8 ≈ 30 52 mg sulforaphane from microwaving 131 g of 3-day-old broccoli sprouts. I’ll include this estimate in Week 8 of Changing to a youthful phenotype with broccoli sprouts.

Microwave broccoli to increase flavonoid levels demonstrated 108.5% to 129.8% increases in quercetin and kaempferol levels from microwaving ordinary broccoli purchased in a Beltsville, Maryland, grocery store. I won’t use their method of a 1200W microwave on full power for one minute, but microwaving may be expected to increase the worst-case calculation of 77.03 133.6 ≈ 77 134 mg total flavonoids.

Broccoli seed suppliers are missing a marketing opportunity by not specifying their cultivars. They could be advertising specific benefits, etc.

The first study showed that sulforaphane contents vary widely among broccoli cultivars, from the 2.43 mg used above to 12.07 mg per gram of seeds. The best-case would be 21.4 g broccoli seeds x 12.07 mg per gram of seeds = 258.3 mg sulforaphane!

If your product was almost 5 times better than a competitor’s, why wouldn’t you advertise it?

3 thoughts on “Estimating daily consumption of broccoli sprout compounds

  1. Hello,

    I just came across your blog. This is awesome info, similar to what Dr. Rhonda Ptraick had done some time ago.

    What is your current regimen with broccoli seeds, do you microwave them for 35 secs or 65 secs? Do you microwave the broccoli florets too or only the seeds? What cultivar did you come across the had shown the high sulforaphane production?
    Also, would you please explain your rinsing protocol?

    I’d experimented with sprouting about 3 yrs ago, BUT had to stop because PubMed is full of info about resistant bacterias and viruses persisting on the seeds. Also, Dr. Rhonda had food poisoning from the seeds. I could not find a good enough, MULTI (from PubMed studies, a single step is not enough) step protocol to sterilize the seeds. Thank you

    Liked by 1 person

    • Thanks for commenting, Sam!
      Please post a few PubMed references for experimental data on dangers of home sprouting broccoli seeds, because I haven’t come across any. I’ve read several studies that have multi-step sterilizing protocols for their laboratories, such as 3-day-old broccoli sprouts have the optimal yields.
      Tomorrow I’ll start my 27th week of eating broccoli sprouts every day. My kitchen isn’t a laboratory, I’ve never had food poisoning from broccoli sprouts. and I don’t follow seed sterilizing protocols. If I do have an incident, I’ll take responsibility for creating those conditions and make adjustments.
      My current practices are in Grow a broccoli sprouts Victory Garden today! I try other methods, and take measurements to decide if they’re worthwhile. My son wants me to try mason jars with strainer lids, so that’s next.
      I’ve read a few postings by and about the person you mentioned. Our approaches to scientific evidence differ in that I’m interested in addressing causes of problems, which requires more than superficially treating symptoms. This approach led to me eating a clinically relevant amount of broccoli sprouts every day, and resolved many causes for me.

      Like

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