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 weights 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?

15 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

    • 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.

  2. Hi Gettingwell4,

    I’ll dig up the studies and post. By the way, where do you source your seeds? Did you ask the vendor for COAs?

  3. Why on Earth would ANYONE want to bother sprouting the seeds unless it was absolutely necessary? Am I missing something? Not only is it a total pain, but like almost all green vegetables, they taste horrible (actually they taste worse than most). So seeds are super cheap and easy to flour. How do you process them and what are things to consider? I keep trying to figure this out online and all I get are these garden people who like growing sprouts. I want to know how one utilizes the seeds only (I can flour it etc. myself).

  4. Is there a reason for trying to maximize the sulforaphane content prior to ingestion as opposed to adding myrosinase in the form of mustard seeds? I’ve been throwing a tablespoon of broccoli seeds into a grinder along with 1/8 tablespoon of mustard seeds. For good measure, I also throw in a tablespoon of flax seeds and 1/8 tablespoon of black cumin. I mix it all with a bit of peanut butter and cinnamon. Believe it or not, it is quite palatable. I actually look forward to having it each day. The addition of some dates and blueberries makes it a nice desert, as crazy as that sounds.

    • Hi Keithbenjamin! Thanks for commenting.
      Sulforaphane is ephemeral, and could degrade quickly with grinding seeds. Several studies I’ve curated have recommended as did A follow-on study to 3-day-old broccoli sprouts have the optimal yields:
      “It was best to enzymatically convert to SF before oral intake.” i.e. just before. That study developed evidence of sulforaphane degradation over time.
      I mentioned two studies in Week 19 that found sulforaphane reacted with protein, fats, and fiber. But any broccoli intake is good. What do you think?
      I tried eating ground mustard seeds with broccoli sprouts, but my stomach objected. Currently eat a twice daily mixture of one-third mustard sprouts, one-third red cabbage sprouts, and one-third broccoli sprouts starting in May. Batches are one teaspoon of each, 10.7 g total. Mustard sprouts make the other two taste better.

      • Thank you for your response! Is sulforaphane generated from microwaving any less ephemeral than that generated from grinding?

        I don’t pretend to understand all the science involved, but my assumption is that I am ingesting very little actual sulforaphane, but high quantities of glucoraphanin, which is later converted to SF in the gut (helped along with the myrosinase from the mustard seed). The reaction of SF with fats and fiber, however, is obviously a concern. Perhaps a better approach is to just swallow the ground broccoli and mustard seeds (alone) with water on an empty stomach?

        Thanks again!

        • You’re doing fine, Keithbenjamin. The third study of Microwaving broccoli sprouts may not affect phenolic levels found with another broccoli compound, indole-3-carbinol (I3C):
          “Availability of I3C was significantly enhanced with grinding. Grinding [blending] not only resulted in difference of particle size, but might also break plant cell walls and release enzymes such as myrosinase, which might have hydrolyzed glucobrassicin and caused a greater releasable I3C level.”
          Pretty sure the same thing happens with glucoraphanin and other glucosinolates as it did with glucobrassicin. The study went on to say:
          “Microwaving significantly elevated the extractable amount of I3C from broccoli regardless of the blenders used. For instance, availability of I3C in broccoli was increased by 3.1, 9.1 and 1.9 folds respectively using blenders 1, 2 and 5 with microwaving as compared to their unmicrowaved counterparts.”
          My son has been after me for a long time to use a blender. I live in a condo, though, and start my day eating sprouts at 4:30 a.m.

          • I went the sprout route for several months, but did achieve any level of consistency and really just struggled with the consumption. Upon learning that the seeds actually contain significantly more glucoraphanin and then concluding that erucic acid was essentially a non-concern, I decided I could sustainably resume my SF habit with ground seeds. But, now that you’ve popped my sulforaphane desert bubble, I think I’ll go ahead and switch to the soaked, microwaved, and blended seeds and just pound them down with some water and mustard seed.

            I’ve enjoyed reading through your posts, the ones I can understand anyway. 😉 I’ve been following Rhonda Patrick and David Sinclair for a few years, so at least I have a bit of primer.

            I see you were on subs. Were you a nuke by any chance?

            • Great, Keithbenjamin, keep consistent.
              Thanks for asking. I was a forward Electronics Technician on my first two subs, and the Supply Officer on the second two. They are all razor blades now, though. 🙂 How about you?

              • I was a nuke ELT on the Enterprise. They’re still trying to figure out how to go about turning her in razor blades.

          • I’m on day 4 of my soaked/microwaved broccoli seed puree routine and all I can say is, man, does that stuff go through me! I am glad I work from home. I’m hoping I can power through it and eventually my gut will adjust. Interesting that I didn’t have any gut problems when I mixed it with the peanut butter.

            • Whatever you can do to keep up an intake, Keithbenjamin!
              Subjects in the Eat broccoli sprouts every day rodent study benefited by keeping their gut microbiota engaged with hydrolyzing broccoli glucoraphanin, even when those researchers intentionally destroyed myrosinase enzyme and sulforaphane in cooked broccoli. Took them two weeks to adjust, though.
              My son similarly joked about me adding a four-bean mix to the diet a few weeks ago. My gut microbiota appreciate it, but nobody else would.

              • Thanks for the encouragement! I’m fairly certain, my gut will adapt. I am noticing a subtle improvement. Lentils and hummus are already staples in my diet. 🙂 Although, I know it’s far more complex, I’d like to think the new “symptoms” are somehow an indicator of more sulforaphane production.

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