- [Dr. Patrick]: The first question is, "What is the minimum daily dose
of sulforaphane that has shown to...that has been shown to provide health benefits? How
much sulforaphane does a 200-gram serving of broccoli, or broccoli sprouts, contain?"
- [Dr. Fahey]: Yeah, so, you know, I have to preface these,
my launching into the answers to some of these questions, by saying, yeah, you went
through the extensive and wonderful questions, many of them, as did I, a number of days ago.
This is a kind of question that comes up all the time. And to those of you who are non-scientists,
I tend to talk...we scientists, and certainly chemists and biochemists, tend to talk in
micromoles. So if you look at any of our papers, we talk micromoles. I've... I will
try to give you an answer that's translated into milligrams. But this is, of course,
complex and something that's still in play and is still being researched by many people.
So it all depends on the amount of glucoraphanin, the precursor of sulforaphane,
that is in broccoli, or sprouts. I'm going to avoid a long diatribe on glucoraphanin and
myrosinase and sulforaphane because I have the feeling that if you listen to Rhonda at all or
gone to our podcast...the podcast that she and I did together or some of her subsequent podcasts,
most people know about the fact that glucoraphanin is a precursor found in the plants,
myrosinase is an enzyme found in the plants and in your body,
your microbiome, and they react and they form sulforaphane.
- [Dr. Patrick]: I think that's so interesting, that we have the enzyme in
our gut. Meaning we're meant to get the precursor to convert it into sulforaphane.
We contain the enzyme in our gut. I just love that. Anyways, go ahead.
- [Dr. Fahey]: So absolutely, all of us do. And I mean that, all however many
hundred of you there are in this call all have myrosinase-containing bacteria in your gut.
Unless you've just blasted yourself with antibiotics and had a...you
know, an enema and just cleaned out your intestinal system, then maybe you don't
have any. And we've done these sorts of experiments actually with real people.
So there are two ways of doing this, of hydrolyzing the glucoraphanin that's
present in broccoli. One is when you chew it, you release the enzyme from the broccoli
tissue or broccoli sprouts or broccoli seeds. And the second way is from your
microbiome. And if you take supplements, you're either getting just glucoraphanin or there are now
supplements with a combination of glucoraphanin and myrosinase. And there are very few, if any,
good ones with just sulforaphane. And we'll get to that later, I'm sure, we have to.
So the question was about the dose. And if you're...
The best advice that we can give...that I can give now is that all the clinical
studies seem to be pointing towards a dose of something between about 50 and 100 micromoles
of sulforaphane a day. I discuss that a little bit in the sprouting PDF that Rhonda has just put out.
But the question that was originally posted talks about a 200-gram.
So let's start with the question, a 200-gram serving of broccoli. That's a pretty lot for
most people, I think. That's a very healthy serving of broccoli, market-stage broccoli.
However, broccoli...for broccoli sprouts that's a huge serving. Most people
that I'm aware of, including myself, would not enjoy cramming down 200 grams of broccoli sprouts.
So I'll just base a ballpark estimation on 100 grams of either broccoli or sprouts.
And based on the amount of glucoraphanin that's in them and our knowledge of conversion in yield,
you might get about anywhere between 4 milligrams of glucoraphanin to 100, 150
from 100 grams of broccoli. And that would yield about...anywhere from about
half a milligram to something like 18 milligrams of sulforaphane. That's of broccoli.
Why is there a huge range? There's a huge range because, A, all of the broccoli is different,
it's different based on the way it's treated in store, the way it's grown,
the genetics of the broccoli. And secondly, all of you are different
and your gut microbiomes are going to yield different amounts of sulforaphane.
So there's a huge range. And with broccoli sprouts, 100 grams would
give you somewhere between, I don't know, about 5 milligrams and 350... Sorry, between about 5
or 6 milligrams and about 60 milligrams of sulforaphane.
So those are just rough approximations. Cooking destroys myrosinase. So if you're cooking
broccoli or broccoli sprouts, then you're just counting on the bacteria in your gut.
I mentioned the person-to-person variation,
there's no way, unfortunately, to know if you're a good converter. There's no way to
know how much sulforaphane or glucoraphanin is in broccoli or broccoli sprouts because you have
to get them tested in a lab. And there are no commercial labs that do these tests routinely.
So this is still a problem. And, you know, you...I mentioned this in the PDF that Rhonda has posted.
But unfortunately you as a consumer are, you know, even if you spend, say, $10 on broccoli
seeds and sprout them yourself, it would cost you $150 to send one sample of those broccoli
seeds out to a commercial lab to get them tested to see if they're high glucoraphanin or not.
So as I... You know, I don't make the rules, I just abide by them, or try to.
But, so unfortunately, as it stands now, it's very difficult to know what you're getting. So we just
have to work...we just have to talk in terms of rough averages. And when Paul Talalay and I
did our first publication on broccoli sprouts, you know, our point was that a serving of, say,
something like a couple of ounces, 60 grams or so, of broccoli sprouts gave you as much
glucoraphanin as, you know, a quarter of a pound or a half a pound of market-stage broccoli.
And so these are all... One final word, just that the quantity of glucoraphanin and sulforaphane
you get from broccoli sprouts from a couple of ounces we think is a reasonable amount to put you
in a zone where you're getting some protective effect. And so it's this...roughly this level
that most of the clinical studies have targeted. Because god forbid your clinical studies should
be positive and work. You want to be able to translate that to something people can eat.
I think the answers to all the rest of my questions will be shorter, Rhonda. And you've
been gracious not to jump in and interrupt, but I hope that sort of addressed the question
though.