In this episode, I discuss a recent systematic review on herbal use in type 2 diabetes. Imagine my surprise when I saw fennel (Foeniculum vulgare) listed as one of eight herbs that the authors consider contraindicated in T2D. I share some reflections on how this seems to be a misunderstanding based on unfamiliarity with herbal medicine and/or poor citations.
The episode highlights why it's so important to track down original references and to be cautious with literature summaries.
Here are the two papers I mention in this episode:
- Boulares, E., Bragazzi, N. L., Yin, T. S. C., Choi, S. J., Park, J. H., & Han, D. (2026). Assessing the safety of herbal medicine use among type 2 diabetes mellitus patients: A systematic review and meta-analysis. Complementary Therapies in Medicine, 97, Article 103319. https://doi.org/10.1016/j.ctim.2026.103319
- Levorato, S., Dominici, L., Fatigoni, C., Zadra, C., Pagiotti, R., Moretti, M., & Villarini, M. (2018). In vitro toxicity evaluation of estragole-containing preparations derived from Foeniculum vulgare Mill. (fennel) on HepG2 cells. Food and Chemical Toxicology, 111, 616-622. https://doi.org/10.1016/j.fct.2017.12.014
Have a question or topic you'd like to see discussed in a future episode? Please let me know: https://www.intheclinic.com
Thanks for listening.
I'd love to hear from you. Leave me a voicemail with feedback or submit a question (click the pink "Send Camille a Message" button on the side of the page) 💚
Camille's Helpful Links for Practitioners
WEBVTT
00:00:00.017 --> 00:00:03.257
Welcome to In the Clinic with Camille. My name is Camille Freeman.
00:00:03.437 --> 00:00:07.097
I'm an herbalist and nutritionist, and in this podcast, I share little tips
00:00:07.097 --> 00:00:09.837
and tidbits that might be helpful for other practitioners.
00:00:10.397 --> 00:00:14.697
Today, I wanted to talk about a pet peeve of mine. This is something that happens
00:00:14.697 --> 00:00:20.337
a lot when I am researching for a class, a lecture, doing research for a client,
00:00:20.497 --> 00:00:22.997
etc. I find that I am reading a.
00:00:25.227 --> 00:00:29.007
Something they just said here is interesting, new to me, it doesn't sound right,
00:00:29.247 --> 00:00:32.787
I want to know more about it, and so I look at the reference that they have
00:00:32.787 --> 00:00:35.847
cited in the paper, and I do a little bit of digging around,
00:00:35.867 --> 00:00:39.007
I track down that reference, and I find, what?
00:00:39.647 --> 00:00:42.927
What are they talking about? This doesn't have anything to do with or directly
00:00:42.927 --> 00:00:46.087
contradicts with the statement that I originally read.
00:00:46.087 --> 00:00:53.187
And to me, this is a perfect example of why we cannot always trust AI literature
00:00:53.187 --> 00:00:59.387
summaries or even review articles or discussion sections or things like that.
00:00:59.487 --> 00:01:03.067
A lot of people don't know what they're talking about when it comes to herbs.
00:01:03.167 --> 00:01:07.667
They don't have the full context of interpreting and understanding what they're seeing.
00:01:07.807 --> 00:01:09.747
And I would say the same is true for supplements, nutrition,
00:01:09.907 --> 00:01:13.327
etc. And so we wind up with people who are confidently incorrect,
00:01:13.327 --> 00:01:19.007
and apparently peer reviewers who just don't catch this perhaps are not also
00:01:19.007 --> 00:01:21.767
experts in this field as well, etc.
00:01:22.047 --> 00:01:27.127
So let me give you the specific example that has me all in a flurry today.
00:01:27.347 --> 00:01:31.567
I saw that there is a new article that just came out this month.
00:01:31.707 --> 00:01:35.727
It's only the 3rd of May, and this paper was published in May of 2026.
00:01:36.287 --> 00:01:40.167
And it is called Assessing Safety of Herbal Medicine Use Among Type 2 Diabetes.
00:01:40.807 --> 00:01:44.407
It's a systematic review and meta-analysis. I was like, great,
00:01:44.527 --> 00:01:47.547
I would like to look at this because I have clients that I work with that have
00:01:47.547 --> 00:01:51.947
type 2 diabetes and I just, you know, always want to stay on top of what we know, etc.
00:01:52.507 --> 00:01:56.247
So I go to the paper. Thankfully, I always love this. It's open access.
00:01:56.447 --> 00:01:59.987
It's free-full text. It's published in Complementary Therapies in Medicine.
00:02:00.957 --> 00:02:04.497
So I go and I look at it and I'm like, oh, yes, you know, it was actually a
00:02:04.497 --> 00:02:08.137
very interesting paper because it talks about around the world,
00:02:08.197 --> 00:02:11.197
different herbs that are commonly used for type 2 diabetes.
00:02:11.217 --> 00:02:14.697
And a lot of them are herbs that I don't know a lot about and they're commonly
00:02:14.697 --> 00:02:15.897
used in different parts of the world.
00:02:15.957 --> 00:02:18.777
So that's always kind of interesting just to learn more and so forth.
00:02:19.117 --> 00:02:23.117
But, you know, overall, this was not groundbreaking information for me.
00:02:23.237 --> 00:02:26.497
Just, you know, lots of summarizing of information, that sort of thing.
00:02:26.497 --> 00:02:32.297
However, I got to a part in the paper where they started talking about classification
00:02:32.297 --> 00:02:36.177
of herbs that they identified that people are using for type 2 diabetes.
00:02:36.457 --> 00:02:40.857
And they have different criteria, and they have one criteria that's called contraindicated.
00:02:41.117 --> 00:02:46.357
And the description that they use in the paper says, The available evidence
00:02:46.357 --> 00:02:53.917
shows severe adverse impacts of herbal medicine use on diabetes mellitus patients or toxicity.
00:02:54.137 --> 00:02:59.017
That's how they define contraindicated. I was like, okay, let's hear more about that.
00:02:59.157 --> 00:03:02.857
Then I go down further in the paper, and I see that they have,
00:03:02.937 --> 00:03:08.337
of all the different herbs that these people were taking, they decided that
00:03:08.337 --> 00:03:12.197
eight of them, maybe seven, were contraindicated.
00:03:12.337 --> 00:03:14.237
And some of them, I'm like, okay, I don't really know anything about these.
00:03:14.377 --> 00:03:20.317
But there on the list, I see funiculum vulgar, which, in case you are not up
00:03:20.317 --> 00:03:22.517
to date on neuroscientific names is phenyl.
00:03:22.817 --> 00:03:29.137
I'm like, wow, that's interesting that phenyl would fit into that previous category that I just mentioned.
00:03:29.657 --> 00:03:32.917
I would not think about that at all. I work with phenyl quite frequently.
00:03:33.617 --> 00:03:37.117
And while I don't think it's appropriate in every circumstance,
00:03:37.457 --> 00:03:41.577
it's certainly not one that I would think would cause severe harm or adverse
00:03:41.577 --> 00:03:44.277
events for people who are who have type 2 diabetes.
00:03:44.617 --> 00:03:49.117
So I'm like, let me just try to find out what kind of citations they're using.
00:03:49.577 --> 00:03:51.757
And they said that,
00:03:52.648 --> 00:03:57.188
You know, in the paper, it goes on and it tells a little bit about where they got that.
00:03:57.348 --> 00:04:05.148
And it says that they found that phenyl, a couple of these herbs were,
00:04:05.168 --> 00:04:07.508
let's see, let me read you the exact same.
00:04:07.588 --> 00:04:11.348
The remaining contraindicated herbs, blah, blah, blah, to include phenyl,
00:04:11.608 --> 00:04:16.068
showed potential glucose-lowering or insulin-sensitizing effects in animals,
00:04:16.108 --> 00:04:19.888
but were also linked to serious adverse effects.
00:04:19.888 --> 00:04:25.128
And then they have three citations in there, 86, 87, and 88.
00:04:25.848 --> 00:04:30.008
So I'm like, let me just go find about that because severe or serious adverse
00:04:30.008 --> 00:04:31.908
effects is something that I would like to know about.
00:04:32.128 --> 00:04:36.428
So I go down into the reference section and I look at 86, 87,
00:04:36.448 --> 00:04:40.788
and 88, and those have nothing to do with any of this. They're all about herb drug interactions.
00:04:41.468 --> 00:04:43.068
It's like, oh, okay.
00:04:44.168 --> 00:04:46.788
And I kind of poke around. I'm like, okay, fennel's not in there.
00:04:46.848 --> 00:04:48.868
And that's not a serious adverse effect.
00:04:49.488 --> 00:04:53.248
And then I'm like, okay, clearly they've mislabeled their references.
00:04:53.268 --> 00:04:56.988
So I'm scanning the reference list, looking for anything having to do with fennel.
00:04:57.268 --> 00:05:00.388
And I come across a paper about fennel.
00:05:01.002 --> 00:05:06.262
It's reference number 74, by the way. And the paper is called In Vitro Toxicity
00:05:06.262 --> 00:05:11.542
Evaluation of Estrogol Containing Preparations Derived from Funiculum Vulgare
00:05:11.542 --> 00:05:14.342
on HEPG2 cells, blah, blah, blah.
00:05:14.642 --> 00:05:18.602
So I'm like, okay, well, this is the only thing in here that has to do with phenyl specifically.
00:05:18.842 --> 00:05:22.822
Let me find that paper. So I go, I look at that paper, and I'm like,
00:05:22.882 --> 00:05:25.002
wow, this is a paper that was published in 2018.
00:05:25.682 --> 00:05:29.882
It is, as the title suggests, it's an in vitro study.
00:05:30.302 --> 00:05:35.702
It is looking at human cells, but they are not attached to a human any longer.
00:05:36.242 --> 00:05:40.402
And what they found in this paper is actually the opposite.
00:05:40.682 --> 00:05:43.702
They found that, I thought it was actually an interesting design,
00:05:44.382 --> 00:05:49.102
they were looking at fennel seed powder and fennel seed essential oil to assess
00:05:49.102 --> 00:05:53.662
them for toxicity in this model, which, to be super clear, does not translate
00:05:53.662 --> 00:05:57.742
into adverse effects in a human. It's just kind of step one as you're assessing safety.
00:05:58.242 --> 00:06:02.762
However, what they found is that the fennel seed powder, just fennel seeds ground
00:06:02.762 --> 00:06:07.802
up, didn't have any sign of toxicity in the cell line that they were testing
00:06:07.802 --> 00:06:10.982
at all, in any way. And in fact, they said that.
00:06:11.670 --> 00:06:15.550
There was really no cause for concern because it's very, very high doses,
00:06:15.830 --> 00:06:17.690
relatively speaking, that they're using.
00:06:17.890 --> 00:06:22.970
They did find that the fennel seed essential oil, while it didn't cause damage
00:06:22.970 --> 00:06:29.610
to the DNA, there was a little bit of concern when it came to certain aspects
00:06:29.610 --> 00:06:32.510
of safety in this particular cell line.
00:06:33.050 --> 00:06:41.010
However, the end, let me just read to you the highlights of this paper,
00:06:41.230 --> 00:06:42.770
which I will also link in the show notes.
00:06:42.990 --> 00:06:48.470
The highlights are, fennel seed powder did not show any sign of toxicity in human hepatoma cells.
00:06:48.730 --> 00:06:52.570
Fennel seed essential oil did not cause any primary or fixed DNA damage.
00:06:52.790 --> 00:06:58.070
Fennel seed essential oil induced cytostasis, apoptosis, and cell cycle arrest.
00:06:58.750 --> 00:07:02.310
So basically what they said is maybe there's minor cause for concern with fennel
00:07:02.310 --> 00:07:05.610
seed essential oil, although obviously additional studies would be needed.
00:07:05.790 --> 00:07:07.650
It's dose dependent, blah, blah, blah.
00:07:07.870 --> 00:07:11.490
But really there wasn't any cause for concern whatsoever from the fennel seed powder.
00:07:11.910 --> 00:07:19.310
So contrary to what they said in this article that came out this month, there is not cause.
00:07:19.736 --> 00:07:24.236
As far as we know, any specific cause for concern for fennel itself.
00:07:24.416 --> 00:07:30.396
Now, they did not distinguish in this study between fennel seed and fennel seed essential oil.
00:07:30.576 --> 00:07:34.596
And we do not know if the people who are taking this for diabetes are taking
00:07:34.596 --> 00:07:38.916
it the essential oil, the fennel seed powder, or some other type of fennel.
00:07:39.016 --> 00:07:42.476
Because again, it's pretty clear to me that some of these folks just don't have
00:07:42.476 --> 00:07:46.676
perhaps a good understanding of herbal medicine and maybe didn't know to ask
00:07:46.676 --> 00:07:49.096
that or didn't know to put it in the discussion that like, hey,
00:07:49.216 --> 00:07:51.136
there's some things about this that we don't understand.
00:07:51.436 --> 00:07:58.036
So maybe it doesn't make sense to list fennel as contraindicated,
00:07:58.176 --> 00:08:01.256
one of the few herbs that are contraindicated in type 2 diabetes.
00:08:01.716 --> 00:08:05.976
Because what now happens is people who are in medical fields that don't have
00:08:05.976 --> 00:08:09.356
a lot of herbal training, but that are doing their due diligence and researching,
00:08:09.596 --> 00:08:12.556
they go and they read a paper like this and they're like, oh my goodness,
00:08:12.556 --> 00:08:17.796
Fennel is in here as a contraindicated for potential safety concerns for toxicity.
00:08:18.845 --> 00:08:23.465
Serious side effects known. That's what they're implying in this paper.
00:08:23.605 --> 00:08:26.605
And then they're going to tell their clients, hey, you should be staying away
00:08:26.605 --> 00:08:30.165
from this dangerous, toxic fennel stuff without the nuance of like,
00:08:30.265 --> 00:08:32.985
yes, you probably shouldn't be ingesting fennel essential oil,
00:08:33.285 --> 00:08:35.845
especially in large quantities for numerous reasons.
00:08:36.025 --> 00:08:40.305
But that fennel seed, ground up fennel, there really isn't, as far as I know,
00:08:40.445 --> 00:08:45.485
a lot of cause for concern in human populations, especially at doses that most
00:08:45.485 --> 00:08:46.585
people would be normally taking.
00:08:46.825 --> 00:08:49.365
So anyway, it really drives me up the wall when this happens,
00:08:49.545 --> 00:08:52.145
and especially that it's not being caught in peer review.
00:08:52.305 --> 00:08:55.485
I understand that as authors, we can't always know about everything,
00:08:55.505 --> 00:09:00.845
but my goodness, oh, like there's so much that we can do, so much to work with
00:09:00.845 --> 00:09:02.885
around fennel, and it breaks my heart.
00:09:03.125 --> 00:09:05.825
And who knows? I'm not familiar with some of the other herbs on this list,
00:09:05.885 --> 00:09:09.525
so I don't have the nuance to try to do the same type of breakdown for those.
00:09:09.605 --> 00:09:12.225
But I also wonder, is there some similar misunderstanding?
00:09:12.485 --> 00:09:14.925
Are we looking at the same plant part? Are we looking at the same dose?
00:09:14.925 --> 00:09:19.005
Are we looking at the same preparations? Does this actually make sense in the
00:09:19.005 --> 00:09:25.265
context of somebody applying this to clinical work, to work with patients if
00:09:25.265 --> 00:09:27.245
you're in the medical field, or whatever it is?
00:09:28.460 --> 00:09:32.920
So that's me up on my little soapbox for today. I'm going to leave it there for right now.
00:09:33.040 --> 00:09:35.900
If you want to check out these papers yourself, or if perhaps you know something
00:09:35.900 --> 00:09:39.960
about this that I don't, maybe I've missed something. I'm always open to being corrected.
00:09:40.360 --> 00:09:44.040
So if you feel that phenol actually is contraindicated in type 2 diabetes,
00:09:44.040 --> 00:09:48.580
and you know about a bunch of research to the contrary, I would love to know about it.
00:09:48.620 --> 00:09:53.160
I did a preliminary search just to make sure that I wasn't completely missing
00:09:53.160 --> 00:09:54.480
a whole aspect of literature.
00:09:55.000 --> 00:09:58.480
It is Sunday, and I was like, I don't know if I want to do like a multi-hour
00:09:58.480 --> 00:10:02.440
deep dive, but from my preliminary search, I didn't see anything new that I hadn't seen before.
00:10:02.760 --> 00:10:07.220
So anyway, let me know if you have something that I should know about.
00:10:07.420 --> 00:10:11.140
Otherwise, please make sure if you see something that looks weird or off in
00:10:11.140 --> 00:10:14.860
a paper, make sure to track down the references and really follow that rabbit
00:10:14.860 --> 00:10:17.060
trail back to figure out where is this coming from?
00:10:17.180 --> 00:10:22.620
Because it's surprising to me how often the reference that is cited does not
00:10:22.620 --> 00:10:26.480
actually match up with what is being said in the paper,
00:10:26.760 --> 00:10:30.580
either because the references got mixed up, the person didn't fully understand
00:10:30.580 --> 00:10:34.680
the context, they got it from somebody else, you know, lines got crossed, whatever it is.
00:10:34.800 --> 00:10:38.660
But if we want to be safe and effective in doing our best work,
00:10:38.760 --> 00:10:42.180
we really have to sometimes follow these rabbit holes ourselves and get to the
00:10:42.180 --> 00:10:43.240
bottom of what's being said.
00:10:43.620 --> 00:10:46.940
Okay, I hope you have an amazing day. If you want to stay in touch,
00:10:47.100 --> 00:10:49.820
I would love for you to join my practitioner notes email.
00:10:50.120 --> 00:10:54.080
It goes out every Thursday. It's just a short little essay followed by some
00:10:54.080 --> 00:10:56.340
recommendations, things that I thought were interesting that week,
00:10:56.360 --> 00:11:00.760
and anything that I'm doing that's upcoming in case you want to come to a class,
00:11:00.760 --> 00:11:03.480
a workshop, or stay connected in other ways.
00:11:04.020 --> 00:11:06.640
Otherwise, thanks so much for listening, and I will talk to you soon.
00:00:00.017 --> 00:00:03.257
Welcome to In the Clinic with Camille. My name is Camille Freeman.
00:00:03.437 --> 00:00:07.097
I'm an herbalist and nutritionist, and in this podcast, I share little tips
00:00:07.097 --> 00:00:09.837
and tidbits that might be helpful for other practitioners.
00:00:10.397 --> 00:00:14.697
Today, I wanted to talk about a pet peeve of mine. This is something that happens
00:00:14.697 --> 00:00:20.337
a lot when I am researching for a class, a lecture, doing research for a client,
00:00:20.497 --> 00:00:22.997
etc. I find that I am reading a.
00:00:25.227 --> 00:00:29.007
Something they just said here is interesting, new to me, it doesn't sound right,
00:00:29.247 --> 00:00:32.787
I want to know more about it, and so I look at the reference that they have
00:00:32.787 --> 00:00:35.847
cited in the paper, and I do a little bit of digging around,
00:00:35.867 --> 00:00:39.007
I track down that reference, and I find, what?
00:00:39.647 --> 00:00:42.927
What are they talking about? This doesn't have anything to do with or directly
00:00:42.927 --> 00:00:46.087
contradicts with the statement that I originally read.
00:00:46.087 --> 00:00:53.187
And to me, this is a perfect example of why we cannot always trust AI literature
00:00:53.187 --> 00:00:59.387
summaries or even review articles or discussion sections or things like that.
00:00:59.487 --> 00:01:03.067
A lot of people don't know what they're talking about when it comes to herbs.
00:01:03.167 --> 00:01:07.667
They don't have the full context of interpreting and understanding what they're seeing.
00:01:07.807 --> 00:01:09.747
And I would say the same is true for supplements, nutrition,
00:01:09.907 --> 00:01:13.327
etc. And so we wind up with people who are confidently incorrect,
00:01:13.327 --> 00:01:19.007
and apparently peer reviewers who just don't catch this perhaps are not also
00:01:19.007 --> 00:01:21.767
experts in this field as well, etc.
00:01:22.047 --> 00:01:27.127
So let me give you the specific example that has me all in a flurry today.
00:01:27.347 --> 00:01:31.567
I saw that there is a new article that just came out this month.
00:01:31.707 --> 00:01:35.727
It's only the 3rd of May, and this paper was published in May of 2026.
00:01:36.287 --> 00:01:40.167
And it is called Assessing Safety of Herbal Medicine Use Among Type 2 Diabetes.
00:01:40.807 --> 00:01:44.407
It's a systematic review and meta-analysis. I was like, great,
00:01:44.527 --> 00:01:47.547
I would like to look at this because I have clients that I work with that have
00:01:47.547 --> 00:01:51.947
type 2 diabetes and I just, you know, always want to stay on top of what we know, etc.
00:01:52.507 --> 00:01:56.247
So I go to the paper. Thankfully, I always love this. It's open access.
00:01:56.447 --> 00:01:59.987
It's free-full text. It's published in Complementary Therapies in Medicine.
00:02:00.957 --> 00:02:04.497
So I go and I look at it and I'm like, oh, yes, you know, it was actually a
00:02:04.497 --> 00:02:08.137
very interesting paper because it talks about around the world,
00:02:08.197 --> 00:02:11.197
different herbs that are commonly used for type 2 diabetes.
00:02:11.217 --> 00:02:14.697
And a lot of them are herbs that I don't know a lot about and they're commonly
00:02:14.697 --> 00:02:15.897
used in different parts of the world.
00:02:15.957 --> 00:02:18.777
So that's always kind of interesting just to learn more and so forth.
00:02:19.117 --> 00:02:23.117
But, you know, overall, this was not groundbreaking information for me.
00:02:23.237 --> 00:02:26.497
Just, you know, lots of summarizing of information, that sort of thing.
00:02:26.497 --> 00:02:32.297
However, I got to a part in the paper where they started talking about classification
00:02:32.297 --> 00:02:36.177
of herbs that they identified that people are using for type 2 diabetes.
00:02:36.457 --> 00:02:40.857
And they have different criteria, and they have one criteria that's called contraindicated.
00:02:41.117 --> 00:02:46.357
And the description that they use in the paper says, The available evidence
00:02:46.357 --> 00:02:53.917
shows severe adverse impacts of herbal medicine use on diabetes mellitus patients or toxicity.
00:02:54.137 --> 00:02:59.017
That's how they define contraindicated. I was like, okay, let's hear more about that.
00:02:59.157 --> 00:03:02.857
Then I go down further in the paper, and I see that they have,
00:03:02.937 --> 00:03:08.337
of all the different herbs that these people were taking, they decided that
00:03:08.337 --> 00:03:12.197
eight of them, maybe seven, were contraindicated.
00:03:12.337 --> 00:03:14.237
And some of them, I'm like, okay, I don't really know anything about these.
00:03:14.377 --> 00:03:20.317
But there on the list, I see funiculum vulgar, which, in case you are not up
00:03:20.317 --> 00:03:22.517
to date on neuroscientific names is phenyl.
00:03:22.817 --> 00:03:29.137
I'm like, wow, that's interesting that phenyl would fit into that previous category that I just mentioned.
00:03:29.657 --> 00:03:32.917
I would not think about that at all. I work with phenyl quite frequently.
00:03:33.617 --> 00:03:37.117
And while I don't think it's appropriate in every circumstance,
00:03:37.457 --> 00:03:41.577
it's certainly not one that I would think would cause severe harm or adverse
00:03:41.577 --> 00:03:44.277
events for people who are who have type 2 diabetes.
00:03:44.617 --> 00:03:49.117
So I'm like, let me just try to find out what kind of citations they're using.
00:03:49.577 --> 00:03:51.757
And they said that,
00:03:52.648 --> 00:03:57.188
You know, in the paper, it goes on and it tells a little bit about where they got that.
00:03:57.348 --> 00:04:05.148
And it says that they found that phenyl, a couple of these herbs were,
00:04:05.168 --> 00:04:07.508
let's see, let me read you the exact same.
00:04:07.588 --> 00:04:11.348
The remaining contraindicated herbs, blah, blah, blah, to include phenyl,
00:04:11.608 --> 00:04:16.068
showed potential glucose-lowering or insulin-sensitizing effects in animals,
00:04:16.108 --> 00:04:19.888
but were also linked to serious adverse effects.
00:04:19.888 --> 00:04:25.128
And then they have three citations in there, 86, 87, and 88.
00:04:25.848 --> 00:04:30.008
So I'm like, let me just go find about that because severe or serious adverse
00:04:30.008 --> 00:04:31.908
effects is something that I would like to know about.
00:04:32.128 --> 00:04:36.428
So I go down into the reference section and I look at 86, 87,
00:04:36.448 --> 00:04:40.788
and 88, and those have nothing to do with any of this. They're all about herb drug interactions.
00:04:41.468 --> 00:04:43.068
It's like, oh, okay.
00:04:44.168 --> 00:04:46.788
And I kind of poke around. I'm like, okay, fennel's not in there.
00:04:46.848 --> 00:04:48.868
And that's not a serious adverse effect.
00:04:49.488 --> 00:04:53.248
And then I'm like, okay, clearly they've mislabeled their references.
00:04:53.268 --> 00:04:56.988
So I'm scanning the reference list, looking for anything having to do with fennel.
00:04:57.268 --> 00:05:00.388
And I come across a paper about fennel.
00:05:01.002 --> 00:05:06.262
It's reference number 74, by the way. And the paper is called In Vitro Toxicity
00:05:06.262 --> 00:05:11.542
Evaluation of Estrogol Containing Preparations Derived from Funiculum Vulgare
00:05:11.542 --> 00:05:14.342
on HEPG2 cells, blah, blah, blah.
00:05:14.642 --> 00:05:18.602
So I'm like, okay, well, this is the only thing in here that has to do with phenyl specifically.
00:05:18.842 --> 00:05:22.822
Let me find that paper. So I go, I look at that paper, and I'm like,
00:05:22.882 --> 00:05:25.002
wow, this is a paper that was published in 2018.
00:05:25.682 --> 00:05:29.882
It is, as the title suggests, it's an in vitro study.
00:05:30.302 --> 00:05:35.702
It is looking at human cells, but they are not attached to a human any longer.
00:05:36.242 --> 00:05:40.402
And what they found in this paper is actually the opposite.
00:05:40.682 --> 00:05:43.702
They found that, I thought it was actually an interesting design,
00:05:44.382 --> 00:05:49.102
they were looking at fennel seed powder and fennel seed essential oil to assess
00:05:49.102 --> 00:05:53.662
them for toxicity in this model, which, to be super clear, does not translate
00:05:53.662 --> 00:05:57.742
into adverse effects in a human. It's just kind of step one as you're assessing safety.
00:05:58.242 --> 00:06:02.762
However, what they found is that the fennel seed powder, just fennel seeds ground
00:06:02.762 --> 00:06:07.802
up, didn't have any sign of toxicity in the cell line that they were testing
00:06:07.802 --> 00:06:10.982
at all, in any way. And in fact, they said that.
00:06:11.670 --> 00:06:15.550
There was really no cause for concern because it's very, very high doses,
00:06:15.830 --> 00:06:17.690
relatively speaking, that they're using.
00:06:17.890 --> 00:06:22.970
They did find that the fennel seed essential oil, while it didn't cause damage
00:06:22.970 --> 00:06:29.610
to the DNA, there was a little bit of concern when it came to certain aspects
00:06:29.610 --> 00:06:32.510
of safety in this particular cell line.
00:06:33.050 --> 00:06:41.010
However, the end, let me just read to you the highlights of this paper,
00:06:41.230 --> 00:06:42.770
which I will also link in the show notes.
00:06:42.990 --> 00:06:48.470
The highlights are, fennel seed powder did not show any sign of toxicity in human hepatoma cells.
00:06:48.730 --> 00:06:52.570
Fennel seed essential oil did not cause any primary or fixed DNA damage.
00:06:52.790 --> 00:06:58.070
Fennel seed essential oil induced cytostasis, apoptosis, and cell cycle arrest.
00:06:58.750 --> 00:07:02.310
So basically what they said is maybe there's minor cause for concern with fennel
00:07:02.310 --> 00:07:05.610
seed essential oil, although obviously additional studies would be needed.
00:07:05.790 --> 00:07:07.650
It's dose dependent, blah, blah, blah.
00:07:07.870 --> 00:07:11.490
But really there wasn't any cause for concern whatsoever from the fennel seed powder.
00:07:11.910 --> 00:07:19.310
So contrary to what they said in this article that came out this month, there is not cause.
00:07:19.736 --> 00:07:24.236
As far as we know, any specific cause for concern for fennel itself.
00:07:24.416 --> 00:07:30.396
Now, they did not distinguish in this study between fennel seed and fennel seed essential oil.
00:07:30.576 --> 00:07:34.596
And we do not know if the people who are taking this for diabetes are taking
00:07:34.596 --> 00:07:38.916
it the essential oil, the fennel seed powder, or some other type of fennel.
00:07:39.016 --> 00:07:42.476
Because again, it's pretty clear to me that some of these folks just don't have
00:07:42.476 --> 00:07:46.676
perhaps a good understanding of herbal medicine and maybe didn't know to ask
00:07:46.676 --> 00:07:49.096
that or didn't know to put it in the discussion that like, hey,
00:07:49.216 --> 00:07:51.136
there's some things about this that we don't understand.
00:07:51.436 --> 00:07:58.036
So maybe it doesn't make sense to list fennel as contraindicated,
00:07:58.176 --> 00:08:01.256
one of the few herbs that are contraindicated in type 2 diabetes.
00:08:01.716 --> 00:08:05.976
Because what now happens is people who are in medical fields that don't have
00:08:05.976 --> 00:08:09.356
a lot of herbal training, but that are doing their due diligence and researching,
00:08:09.596 --> 00:08:12.556
they go and they read a paper like this and they're like, oh my goodness,
00:08:12.556 --> 00:08:17.796
Fennel is in here as a contraindicated for potential safety concerns for toxicity.
00:08:18.845 --> 00:08:23.465
Serious side effects known. That's what they're implying in this paper.
00:08:23.605 --> 00:08:26.605
And then they're going to tell their clients, hey, you should be staying away
00:08:26.605 --> 00:08:30.165
from this dangerous, toxic fennel stuff without the nuance of like,
00:08:30.265 --> 00:08:32.985
yes, you probably shouldn't be ingesting fennel essential oil,
00:08:33.285 --> 00:08:35.845
especially in large quantities for numerous reasons.
00:08:36.025 --> 00:08:40.305
But that fennel seed, ground up fennel, there really isn't, as far as I know,
00:08:40.445 --> 00:08:45.485
a lot of cause for concern in human populations, especially at doses that most
00:08:45.485 --> 00:08:46.585
people would be normally taking.
00:08:46.825 --> 00:08:49.365
So anyway, it really drives me up the wall when this happens,
00:08:49.545 --> 00:08:52.145
and especially that it's not being caught in peer review.
00:08:52.305 --> 00:08:55.485
I understand that as authors, we can't always know about everything,
00:08:55.505 --> 00:09:00.845
but my goodness, oh, like there's so much that we can do, so much to work with
00:09:00.845 --> 00:09:02.885
around fennel, and it breaks my heart.
00:09:03.125 --> 00:09:05.825
And who knows? I'm not familiar with some of the other herbs on this list,
00:09:05.885 --> 00:09:09.525
so I don't have the nuance to try to do the same type of breakdown for those.
00:09:09.605 --> 00:09:12.225
But I also wonder, is there some similar misunderstanding?
00:09:12.485 --> 00:09:14.925
Are we looking at the same plant part? Are we looking at the same dose?
00:09:14.925 --> 00:09:19.005
Are we looking at the same preparations? Does this actually make sense in the
00:09:19.005 --> 00:09:25.265
context of somebody applying this to clinical work, to work with patients if
00:09:25.265 --> 00:09:27.245
you're in the medical field, or whatever it is?
00:09:28.460 --> 00:09:32.920
So that's me up on my little soapbox for today. I'm going to leave it there for right now.
00:09:33.040 --> 00:09:35.900
If you want to check out these papers yourself, or if perhaps you know something
00:09:35.900 --> 00:09:39.960
about this that I don't, maybe I've missed something. I'm always open to being corrected.
00:09:40.360 --> 00:09:44.040
So if you feel that phenol actually is contraindicated in type 2 diabetes,
00:09:44.040 --> 00:09:48.580
and you know about a bunch of research to the contrary, I would love to know about it.
00:09:48.620 --> 00:09:53.160
I did a preliminary search just to make sure that I wasn't completely missing
00:09:53.160 --> 00:09:54.480
a whole aspect of literature.
00:09:55.000 --> 00:09:58.480
It is Sunday, and I was like, I don't know if I want to do like a multi-hour
00:09:58.480 --> 00:10:02.440
deep dive, but from my preliminary search, I didn't see anything new that I hadn't seen before.
00:10:02.760 --> 00:10:07.220
So anyway, let me know if you have something that I should know about.
00:10:07.420 --> 00:10:11.140
Otherwise, please make sure if you see something that looks weird or off in
00:10:11.140 --> 00:10:14.860
a paper, make sure to track down the references and really follow that rabbit
00:10:14.860 --> 00:10:17.060
trail back to figure out where is this coming from?
00:10:17.180 --> 00:10:22.620
Because it's surprising to me how often the reference that is cited does not
00:10:22.620 --> 00:10:26.480
actually match up with what is being said in the paper,
00:10:26.760 --> 00:10:30.580
either because the references got mixed up, the person didn't fully understand
00:10:30.580 --> 00:10:34.680
the context, they got it from somebody else, you know, lines got crossed, whatever it is.
00:10:34.800 --> 00:10:38.660
But if we want to be safe and effective in doing our best work,
00:10:38.760 --> 00:10:42.180
we really have to sometimes follow these rabbit holes ourselves and get to the
00:10:42.180 --> 00:10:43.240
bottom of what's being said.
00:10:43.620 --> 00:10:46.940
Okay, I hope you have an amazing day. If you want to stay in touch,
00:10:47.100 --> 00:10:49.820
I would love for you to join my practitioner notes email.
00:10:50.120 --> 00:10:54.080
It goes out every Thursday. It's just a short little essay followed by some
00:10:54.080 --> 00:10:56.340
recommendations, things that I thought were interesting that week,
00:10:56.360 --> 00:11:00.760
and anything that I'm doing that's upcoming in case you want to come to a class,
00:11:00.760 --> 00:11:03.480
a workshop, or stay connected in other ways.
00:11:04.020 --> 00:11:06.640
Otherwise, thanks so much for listening, and I will talk to you soon.