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Reduce your Biological Age in Just 8-Weeks

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Dr. Kara Fitzgerald’s work in epigenetics revolves around the concept of “nutrigenomics” and “nutrigenetics,” which are areas that investigate how nutrients and dietary factors can influence gene expression and how an individual’s genetic makeup may affect their response to different nutrients.

She has been at the forefront of applying epigenetic principles in the context of functional medicine to help patients optimize their health. By understanding an individual’s unique genetic makeup and epigenetic influences, she aims to tailor personalized therapeutic strategies that can positively impact gene expression and improve health outcomes.

Through her clinical practice, research, and educational efforts, Dr. Fitzgerald has contributed to advancing the understanding and application of epigenetics in functional medicine. She emphasizes the importance of lifestyle factors, diet, and other environmental influences in modulating gene expression to promote better health and prevent disease.

In this week’s Everything Epigenetics podcast, Dr. Fitzgerald speaks with me about the growing popularity of biological age, healthspan, lifespan, and longevity, and why you should care about these important concepts. We also discuss how to know if you’re methylating correctly, if aging should be considered a disease, and the impact of epigenetics on longevity.

Furthermore, we dive into her Younger You program and how it has proven to reverse biological age. Dr. Kara and I then chat about why she continues to stay focused on this space, why this new research is important, how we should think about this in the context of other anti-aging interventions that are being studied, and more.

Dr. Fitzgerald is on the faculty at IFM, is an IFM Certified Practitioner and lectures globally on functional medicine. She runs a Functional Nutrition Residency program, and maintains a podcast series, New Frontiers in Functional Medicine and an active blog on her website, Her clinical practice is in Sandy Hook, Connecticut.

In this podcast you’ll learn about:

– Dr. Kara Fitzgerald’s unique approach of translating what’s happening in the science into actionable information
– The methylation cycle
– DNA methylation
– Why biological aging, healthspan, lifespan, and longevity are so important
– How lifestyle affects epigenetics
– The impact of epigenetics on longevity
– The Younger You program
– Aging as a disease
– Dr. Fitzgerald’s flagship study titled “Reversal of Epigenetic Age with Diet and Lifestyle in a Pilot Randomized Clinical Trial”
– How exercise, meditation, and sleep can affect DNA methylation and biological age

– Dr. Fitzgerald’s future research

Karen Sugden is a scientist from Duke University in the Department of Psychology and Neuroscience. As part of the Moffit and Caspi research team, her current research focus is on the collection and analysis of biological information in large longitudinal cohorts, most notably the Dunedin Longitudinal Study and E-Risk Study. In particular, she is interested in applying molecular and bioinformatic approaches to understand the biological mechanisms relating to factors such as behavior and aging. Karen has a special interest in using epigenetic information as a tool to quantify how differences in people’s life experiences might affect, or be affected by, one’s rate of aging. Karen started out working in human clinical pathology before changing track to genetics, graduating with a B.Sc. from the University of Liverpool in the UK, She then joined the Social, Genetic and Developmental Psychiatry (SGDP) Centre at King’s College London, where in 2004 she received a Ph.D in the study of genetic and genomic influences on behavior and mental health. It is here that Karen was first fortunate enough to work with Professors Moffit and Caspi on the Dunedin Study, a relationship that continues to this day.


hannah_went (00:07.4)

In today’s episode, we talked to Dr. Kara Fitzgerald. Welcome to the Everything Epigenetics podcast, Dr. Fitzgerald, I’m so excited to have you.

kara_fitzgerald (00:16.514)

It’s great to be with you, Hannah, again, actually.

hannah_went (00:20.108)

Yeah, I know. It seems like yesterday we spoke, I think, two years ago, both Ryan Smith and myself, we interviewed you about your findings and<br> your studies. So it seems like yesterday, but so happy to be working alongside of you.

kara_fitzgerald (00:33.401)

Yeah, yeah, absolutely.

hannah_went (00:38.076)

I really want to get the ball rolling here. There’s so many things we can talk about, but most people know you from this study that you created. And really, before we get into the weeds of that, I just want to know how this journey started for you. How did you start to look at epigenetic methylation markers even before your study?

kara_fitzgerald (00:40.695)


kara_fitzgerald (00:56.187)


Yeah. Yeah, yeah, yeah. I know it’s such an interesting story. It’s interesting for me, even. I sort of like telling it because it was a bunch of serendipity. I mean, I had the fortune to do postdoctoral training in laboratory science and our lab was kind of, it was a clinical lab, advanced at that time. It’s going on probably 15 years now, but we were the first clinical lab to release a DNA.

hannah_went (01:03.16)

I’m sorry.

kara_fitzgerald (01:27.63)

stool analysis. So we were using PCR to look at the microbiome and it was the first test out there available to clinicians of its kind. And it was like we had stuck our toe into the omics revolution, which now you guys are in the middle of. But we were sort of in this precursor place. And I think it just gave me an appreciation of the science as it was moving.

And that was during my training. And I continued to just really be interested in what was happening in our ability to sort of see into the epigenome, the genome, the microbiome, the metabolome, the proteome, et cetera, et cetera. But I’m a clinician, you know, I’m a clinician by training. And so I’m working with patients. And so just toggling how can we translate what we’re seeing happen in the science.

hannah_went (02:14.296)

I’m sorry.

kara_fitzgerald (02:22.878)

into actionable information. And it was about 2016, actually, that was when we released the methylation and diet and lifestyle. So it was around 2013, 2014, that I was tucking into the literature on epigenetics. And the best studied of all of the epigenetic marks is DNA methylation. And that’s the placement or the removal of a methyl group.

onto the promoter region of a particular gene. It’s denoted in the literature as these red lollipops are really kind of, I think it’s kind of cool. And so when there’s a lot of red lollipops on a promoter region of a gene, that gene’s effectively inhibited from being transcribed and those lollipops can be kept from being placed, so inhibited from placement or actually actively removed and that gene can be turned on, activated, transcribed.

So I started to tuck into the literature at that time on epigenetics, mostly DNA methylation, and mostly in cancer.

kara_fitzgerald (03:31.222)

So the tumor microenvironment very effectively takes over epigenetic expression from us for its own nefarious growth. So it will inhibit tumor suppressor genes. It will hypermethylate and shut down tumor suppressor genes, inhibiting their role of protecting us from cancer. And it will turn on oncogenes and other genes that promote cancer. So it gets into the mix and does…

you know, and manipulates methylation pretty aggressively. It manipulates other epigenetic marks as well, but best studied is methylation. And, you know, when I was reading this, Hannah, I had, you know, my overwhelming question as a doctor was, you know, we know in functional medicine that we’re influencing methylation. We’re no, so,

those red lollipops, we make them in something called the methylation cycle. It’s a very nutrient demanding cycle. B12 is involved, folate is involved, choline, betaine, a handful of minerals and other vitamins are players in the methylation cycle. We can get an idea of the functionality of the methylation cycle by measuring something called homocysteine, which a lot of us have had measured.

when it’s been most characterized around cardiovascular disease and elevated homocysteine is associated with cardiovascular disease. But we also know that it’s associated with problematic methylation in the DNA. I mean, you know, so it’s more, it’s a surrogate marker for more activity than just, you know, what’s happening in cardiovascular function. And we in functional medicine know the methylation cycle.

We know how to manipulate it. We know how to play with methylation in our patients. And it’s a key piece of what we do and what we analyze. It’s only with the advent of epigenetics, of DNA being able to really look at DNA methylation, that we can begin to see that what we’re doing here in the methylation cycle is influencing DNA methylation. And so when I was reading those papers back in the day, I had to wonder,

kara_fitzgerald (05:41.162)

you know, could there be any circumstances where if we’re pushing methylation forward, if we’re really moving that methylation cycle by giving people lots of B vitamins, could we be negatively influencing, say, someone who has a precancerous process happening? You know, could we be, could our methyl donors, could our B12 and folate actually be influencing

turning off those all-important term with suppressor genes. And that was one of the first big questions that I had at that time. And it niggled me enough with some other pieces. There were other things going on. It wasn’t exclusively related to cancer, but it kind of bugged me enough that we embarked on creating a diet and lifestyle to influence DNA methylation. We decided we wanted to really change course.

hannah_went (06:12.471)


kara_fitzgerald (06:39.91)

And that’s what we did. And I think on that journey, and I know I need to stop and hear from you, but on that journey, we realized that, these lifestyle interventions are as impactful. It was just an awakening experience that we ended up getting to study and really has kind of changed the trajectory of my career, but that’s the nugget of how it all started.

hannah_went (06:43.992)

I’m going to go to bed.

hannah_went (07:04.276)

Yeah, I find that just so interesting. And you said a couple of things there. Number one, you mentioned the omics revolution. We are living in that. I love, and yeah, we are living in this revolution where we’re taking in all of these multi-omic factors and actually being able to apply them in terms of clinical decision-making and clinical care. And I think it’s great, you know, that was almost seven years ago, back in 2016, when you really questioned, you know, are these molecules actually…

kara_fitzgerald (07:06.044)

Thank you.

kara_fitzgerald (07:13.388)


hannah_went (07:33.92)

you know, maybe hurting or influencing this methylation process in a way which we don’t want them to. So I think being able to challenge the status quo and say, okay, let’s back up a little bit and let’s really dive into what these markers may mean. You know, without that critical thinking, we would never be in this spot today where you, you know, that MDL program, so to speak, almost turned into that younger you program that you have now and what most people really know you by. So I think, you know,

kara_fitzgerald (07:55.107)


hannah_went (07:58.848)

people need to ask the right questions, challenge what is available, because that is really how the science succeeds. And that is why I just find your program so interesting, even more so because it’s just solely based on that diet and lifestyle factor too. So it’s not like you’re asking people to spend a bunch of money or to put a ton of time and effort. People are busy, people are so busy. Time is the most precious value that one can give. So we don’t have time to go and…

kara_fitzgerald (08:07.851)

Thanks for watching!

kara_fitzgerald (08:19.457)


hannah_went (08:28.328)

sit in a hyperbaric oxygen chamber for hours on end, you can actually shift these methylation markers in your favor by following a couple of, by following your Younger You program. So I’m just really excited about the work you’re doing and super thankful for you to be in this space and have you to look up to and follow.

kara_fitzgerald (08:46.25)

Yeah, that’s pretty cool. Yeah, I mean, well, you know, we can go back to Randy Journal and Waterland and their seminal work in the early 2000s demonstrating the power of nutrients and changing, you know, the agouti gene and, you know, turning it off and turning those blonde obese mice into, you know, brown, skinny wild type mice. I mean, and see the potential of nutrition’s influence on the genome. And so…

hannah_went (09:05.367)


kara_fitzgerald (09:12.87)

It’s awesome to be a part of that conversation where we’re now looking at what’s happening in humans and seeing, wow, yeah, in eight weeks time, you can really change gene expression, you know, as measured through DNA methylation. I mean, it is, you know, it’s extraordinary. It’s extraordinary to have, to be in this revolution and to have these tools to be able to look at with that, you know, that level of detail. And the other kind of extraordinary thing to me is the juxtaposition.

between being in the omics revolution where we have this new exquisite insight that’s only expanding when we move into multi-omics tools. But what I’m studying is old school nutrition and lifestyle interventions. It’s very sort of like from where we came, but we’re putting the lens of this incredibly modern time that we’re in on.

what you know a very old school intervention. So that’s a cool juxtaposition in my mind as well.

hannah_went (10:16.124)

Yeah, definitely. And I love that you bring up Dr. Jertl’s study. I spoke with him a couple of days ago, a couple of weeks ago actually, but it’s been 20 years. It’s the 20th year anniversary. So he thinks it’s almost time to write this epigenetics in review, this really nice review. And I said, do it. I said, we need it. We would love that and need an update from him. So I want to point the conversation in a space that’s become very

kara_fitzgerald (10:26.627)

I know. It’s amazing. Yep.

kara_fitzgerald (10:31.927)


Mm-hmm. Yep.

hannah_went (10:45.08)

popularized right now, right? There’s all these trend words in this space. To name a few things like biological aging, there’s health span, there’s lifespan, longevity. Why are all of these so important right now? How did those relate back to your younger you program? And you can see them in hashtags and every Instagram posts now. Can you talk a little bit about that?

kara_fitzgerald (11:04.81)

Yeah, I know. Yeah, it’s pretty exciting to see all the attention that this field is getting. It’s a little bit, you know, it’s a little crazy in some ways, but it’s very, very exciting as well. So biological age is the rate our bodies are physiologically aging at, you know, and we can measure it. We can measure it looking at these patterns of DNA methylation. You know, there’s a number of different clocks or, you know, the…

the pace of aging, the do it in pace of aging tool that you guys offer that or that two diagnostics offer that we’re using now as well. So there’s ways that we can look at certain DNA methylation patterns that reflect the rate of physical aging. And that doesn’t necessarily correlate with chronological age. So we can be aging faster physiologically than our chronological age or we can be actually aging.

And that was, you know, the first piece that we looked at in our research was whether or not our study participants’ biological age changed in our eight-week intervention. And so we had a control group too, which is really, which is amazing because I know a lot of the studies, well, I think more recent studies are starting to have controls, but you know, this is a new field.

So as compared to our control group, without any intervention, our study participants slowed or reversed bio age over three years, 3.24 years. And then the within group comparison was around two years actually. They’re themselves at baseline as compared to the after the eight weeks. Yeah, super, really interesting. And you know, again, Hannah, like I came to this conversation.

in 2016, you know, through the lens of thinking about cancer epigenetics and through the lens of functional medicine. And that’s why we created this multimodal intervention. In 2016, as you know, we didn’t think biological age reversal was possible, right? It was not possible. There was no evidence in the literature, no studies, nothing had been published demonstrating such a thing would happen. We were starting to have the clocks, like, you know, Horvath’s flagship.

kara_fitzgerald (13:22.238)

Multitissue Clock was out at the time, but I wasn’t holding my breath that we reversed bioage. I was pretty confident and perhaps cocky, but I thought that we would change gene expression. I was reasonably confident that because we were looking at the epic array that we might really see some change to gene expression. But even then there was…

hannah_went (13:33.473)


kara_fitzgerald (13:47.026)

scant evidence in humans. I mean, I was leaning heavily on in vitro research and animal research. It’s like scant evidence in humans. I mean, it wasn’t that long ago. So our study was well underway when the TRIM study was published, when the first study showing bio age reversal was actually published. We were underway and it was to massive fanfare, as you know. It was like time stood still for a moment when that study came out. And then ours was…

hannah_went (14:10.754)


kara_fitzgerald (14:13.878)

maybe the third after that, I think the vitamin D study came out, but we didn’t anticipate reversing bio-H. We wanted to look at it as one of our, it was an exploratory endpoint, but man, I have to tell you, it was incredibly exciting when we learned that we had made a difference in the Horvath clock. So we’re in this era now where

we can see that we’ve got some say over how fast we’re aging. And that’s incredibly empowering. I think for some people, it’s funny, Jeff Bland was telling me that with this power it comes great responsibilities. I think there’s probably some people who are disappointed that they’re really in the driver’s seat of their own health.

hannah_went (14:51.413)

and then.

kara_fitzgerald (15:01.898)

But for most of us in this space, we’re incredibly excited that we can make a difference like this. So we can slow bio-age down, and by doing so, we can extend our health span, which really needs to be shouted from the rooftops, and perhaps extend our lifespan. You know, we have a pretty good lifespan, but the quality of our life in the United States, but really around the world, is pretty horrible. Lifespan does not track with health span at all.

hannah_went (15:01.95)

I’m sorry.

hannah_went (15:07.701)


kara_fitzgerald (15:31.274)

So the first thing, knowing that we can slow biological aging, would be to match up lifespan and healthspan together, so we have this nice, robust quality of life. And then secondly, yeah, maybe extending these out further as well. But we’re at this very exciting time where we’re paying attention to this in a way that we haven’t before at all. I think eventually, much,

focus, much centered focus will be on the aging phenomena and how we can slow it down rather than siloing disease investigations. Let’s look at cancers over here, neurodegeneration is over here, diabetes is over here, heart disease is over here, they’re all siloed and separated but they are all the classic chronic diseases of aging. If we focus on aging as a whole, we may really, really impact.

all of these and impact healthspan. You know, it just, I mean, the power of that transformation, I mean, not just the cost savings, but just the quality of life, like just the change to humanity. I mean, it’s just the possibilities absolutely extraordinary. And it’s an all hands on deck activity. Like all of us are needed to change this paradigm. We’re all needed.

So I’m just excited to be a part of it.

hannah_went (17:05.161)

I couldn’t agree more and it’s funny that you mentioned, you know, a lot of us are excited to be in the driver’s seat but some of us may not be so excited, right, because they don’t want to control for things that they now know they can control for. So it makes for a really interesting, you know, health shift or paradigm. And it again is crazy just how much knowledge and we’re finally understanding how this process works. Because I believe that…

kara_fitzgerald (17:31.95)

Thanks for watching!

hannah_went (17:33.052)

there will be some changes in the next coming years where maybe aging will be recognized and really defined as a disease because it’s this outwards projection, it’s this primary cause, right? All of those disease phenotypes like the diabetes, the arthritis, everything you just named there, those are an outwards projection, those are secondary from aging itself. So I think you’ll see this huge change and this huge trend that leads more toward the preventative care.

kara_fitzgerald (17:54.626)

Thank you.

hannah_went (18:01.108)

Right, because again, that’s going to increase costs, savings. We could go into all the benefits of really focusing and changing that preventative care.

kara_fitzgerald (18:03.37)

Yes. Yes, yes, yes. Yes. I have to say, I’m not sure I’m in love with the idea of aging as a disease. I mean, it is kind of provocative and maybe we need it for the, you know, the NIH, the powers that be to sort of train their lens and billions and billions of dollars on aging. Maybe it needs to be boxed like that, but you know.

hannah_went (18:16.682)

I hear.

kara_fitzgerald (18:31.298)

I talk about this in the end chapter of my book. Wisdom happens on the aging journey as well. I am in my 50s, a better, calmer, more, I think, I don’t know, more loving, more sophisticated. Like there are certain things that have happened in my aging journey that are actually net benefit. And we wanna be mindful about…

hannah_went (18:37.901)


hannah_went (18:47.264)

Yeah. Oh yeah.

kara_fitzgerald (18:58.818)

honor, respecting this, you know, and I, this is tangential, but plenty of people are probably in line for their Yamanaka cocktail. And I would say that one needs to think carefully, you know, at what information is going to be wiped away with this Yamanaka cocktail. So it, I mean, it’s, so I understand your point from a, from a, from a epidemiological standpoint, but

hannah_went (19:09.048)

I’m sorry.

kara_fitzgerald (19:28.897)

But there’s other information going on in the aging journey that we want to respect.

hannah_went (19:29.536)


hannah_went (19:34.496)

Oh, for sure, I think maybe logistically or book definition, I don’t know, again, for reasons for the grants and different things, who knows where aging will go or if it will be defined as a disease. But again, I completely agree that aging is beautiful. I don’t, aging always has this negative connotation and that is something we can now slow the progression of because it’s more about the health span. I know I don’t want to be,

kara_fitzgerald (19:39.521)


kara_fitzgerald (20:01.738)


hannah_went (20:03.132)

60 or 80 years old and not be able to walk to the bathroom or take my dog on a walk. You know, I love animals. I want to be able to have animals up until, you know, the rest of my life. So it’s if we can extend that health span, I think we can almost shift even that conversation about aging, you know, gracefully or having that more positive connotation.

kara_fitzgerald (20:07.362)

Yeah, that’s right.

kara_fitzgerald (20:14.737)


kara_fitzgerald (20:22.271)

Yeah, yeah, 100%, 100%. I guess I’m getting up on my, I’m being kind of provocative. Because I do think it’s, I think it’s, yeah. I mean, I think that it’s an important conversation. It’s an important thing to kind of throw in the ring in this dialogue.

hannah_went (20:27.952)

No, I love it.

hannah_went (20:39.424)

Definitely, yeah. So I wanna bring it back into your study. I want you to tell us a little bit more about that because I think, again, people are so attracted to it. They are finally knowing that they can make changes just based off of lifestyle. They are in the driver’s seat. They are in control. You hear those things like, you know, your DNA is not your destiny or food is medicine. So can you give us some insight into, you know, the protocol, the plan, and each of those, you know, respective categories?

kara_fitzgerald (21:01.813)


Mm-hmm. Yep.

Yeah, so it’s a, you know, the diet is, you know, it’s a, it’s a recognized healthy eating pattern. We built, we built it brick by brick to influence DNA methylation. It’s packed, it’s actually very veggie dense. There’s about seven to nine cups of veggies a day, cruciferous, lots of greens, colorful, you know, fruits, berries are in there. It’s a low glycemic plan.

There’s animal protein, eggs are, you know, methyl donors superstars are very rich in choline. Animal protein I think is important, particularly liver. Liver is a multivitamin in a food matrix, so liver is included. We do, by the way, in the book, I did create a vegan version for people who don’t do animal products, but we didn’t research it. This is what we researched. So dents in methyl donors, dents in folate and B12, choline, betaine, you know, beats are in there.

the full complement of B vitamins. And then there’s this whole, a ton of what we call methylation adaptogens. So these, so methyl donors and these methylation adaptogens are epinutrients. All of them have some evidence in the literature that they influence epigenetics, that they influence gene expression. And really by and large, it’s DNA methylation, the bulk of the science is on DNA methylation. And as I say in the book at the time, most of it was in

kara_fitzgerald (22:33.574)

in animal studies, but they influence DNA-methyltransferases or 1011 translocation enzymes, the enzymes involved in turning genes on and off. It’s pretty awesome. So we packed the diet full of these. It’s low glycemic, as I said, a gentle intermittent fasting structure, 12 hours on, 12 hours off. It’s keto-leaning. We wanted some background ketosis because ketones, as you know…

can influence gene expression as well favorably and potently. They’re potently anti-inflammatory. So that was the diet arm. And these polyphenols actually, just to circle back in case anybody isn’t familiar with them, are things like curcumin and tumeric, green tea, you know, the EGCG and other catechins in green tea, luteolin in tomatoes, resveratrol, quercetin, you know, and on and on and on.

In the book, one of my most favorite parts is the Nutrient Appendix. It’s 30 pages of these epinutrients, of these things that can influence gene expression. So many, many foods in a healthy whole foods diet do that. And we just packed them in. We just packed in as much as we can. It turns out exercise is an epinutrient also. Exercise really, as you know, influences DNA methylation and epigenetic expression.

big time. In fact, there was a pretty cool paper that came out arguing that the way that exercise works its magic is through influencing epigenetics. Exercise acts like these polyphenols that I just mentioned. When you’re looking at epigenetics, it’s extraordinary. So exercise was in there. We wanted to do something around stress. So the data on stress, I think, is gasoline on the fire of aging journey.

hannah_went (24:27.425)

Oh yeah.

kara_fitzgerald (24:30.288)

The toxic influence of stress, and we can actually inherit some of this, can negatively influence gene expression and push aging, the diseases of aging, inflammation, and so forth. So we brought meditation into our program as well. Just a very simple, twice-daily breathing exercise. The research on meditation, on Tai Chi, on yoga, et cetera, just like exercise, shows

it to be potently active in terms of favorably regulating gene expression. We wanted people to sleep. We can’t make them, but we supported them with sleep hygiene tips. Good sleep is essential for health span, life span. And again, there is literature showing that insomnia, and this is human data, pushes biological age forward. So it…

hannah_went (25:08.996)

I’m sorry.

kara_fitzgerald (25:25.698)

It accelerates the aging journey when you’re not sleeping. Let’s see, what else did we do? We gave people a greens powder, so extra of those all-important epinutrients. We gave people a probiotic, specifically a strain that we thought might increase gut production of folate. So a healthy microbiome produces basically a multivitamin. If we’ve got a good gut, a lot of those nutrients we need for gene expression are gonna be made right there.

hannah_went (25:50.008)

Thank you.

kara_fitzgerald (25:55.626)

And we did, so there were no B vitamins, so just the probiotic and the greens powder. And we did increase circulating folate significantly, circulating specifically methylfolate in our participants as compared to the controls. So that was the program.

hannah_went (26:10.336)

So it’s all about these natural additions or removals of those methyl groups.

kara_fitzgerald (26:18.566)

Yes, just giving the body all of the ingredients, like all of the information to do what it needs to. It seems like, I mean, my idea, so my working hypothesis is that we need lots of methyl donors. We need to be able to make those red lollipops. So we need a B vitamin dense diet and we need supplements sometimes as well. I am not at all anti-supplement when it’s appropriately prescribed. But it seems like we want to couple.

hannah_went (26:43.734)


kara_fitzgerald (26:47.798)

that methyl donor information that we give the body with this polyphenol information that we give the body with the green tea and the curcumin, etc. So it kind of, I think that it may direct where methylation is happening towards a healthier, more youthful pattern.

hannah_went (27:06.352)

Yeah, I know. I love that you hit all of those, you know, target areas like the exercise, the sleep, the diet, you know, the probiotic, the greens, the stress, which when anyone comes to me and ask me, you know, their number one reversal or like you said, it’s pouring, it’s like pouring gasoline on the fire. The data behind, you know, stress levels and the increase in biological aging and shifting those methylation markers to not be in your in your favor is substantial. So the last time

kara_fitzgerald (27:12.818)



kara_fitzgerald (27:24.235)


kara_fitzgerald (27:34.136)


hannah_went (27:35.016)

I know I’ve had increased, you know, biological aging before. I’m definitely due for another retest, but I completely denote all of that to stress. So I have been doing some, you know, meditation, relaxation responses. It only takes, you know, start out with 10 minutes. That’s what I’ve been doing at night, right? So, and trying to build that up little by little. And I really liked hot yoga when I was doing that too. I just think it just is so calming for the body and the mind. So something I’m personally trying to work on to help, you know, with mine.

kara_fitzgerald (27:43.202)

Do you? Yeah. Good.

kara_fitzgerald (27:49.006)

Thanks for watching!


kara_fitzgerald (28:01.823)

Awesome, Hannah. Yeah. Well, I think it’s important that you share what you’re doing and what your struggles are with. For me, doing the book launch, here I am in Mexico. We’re living here now for a couple of months and I can already see my heart rate variability increasing. For the bulk of the early, most intense part of the book launch, I was great.

I did well, but by the end of 2022, man, my heart rate variability really tanked. Even with good self-care habits, I think just the intensity, the demands of that journey.

hannah_went (28:34.676)


hannah_went (28:40.616)

Oh, definitely. Yeah. Do you have a wearable then? Or how are you tracking? OK. Oh, you have the aura ring. OK. Perfect. Yeah, I’ve never done a wearable. I’m getting the whoop here soon. We’ll see what happens. But I’m excited to track a little bit. And then again, kind of micromanage some of those outputs and see how I can be a little bit better.

kara_fitzgerald (28:44.586)

Yep. I have an aura. Yeah. And I love it.

kara_fitzgerald (28:52.751)

Oh cool. Good.

kara_fitzgerald (28:59.288)


Yeah, yeah.

hannah_went (29:03.444)

So just summing up your study, can you round it out? Tell us what you found, you know, that the exact reversals again, and then that timeframe, I know that’s over that eight week period. Why, and tell us why that’s such a big deal and maybe the most surprising finding for you.

kara_fitzgerald (29:15.517)


kara_fitzgerald (29:21.174)

Yes. So we did the diet and lifestyle intervention for eight weeks. We had a study group of 18 individuals and then we had a control group and they obviously the controls didn’t do anything and the study group followed the diet. Let me actually, well followed the whole program and the study group had contact with our nutrition team which I think made this study successful. They met with, they were required to meet with a nutritionist at least weekly.

for the first month and then as needed thereafter. And most of them just continued right along with the nutritionist. I think that made our adherence data awesome. Like these guys really stuck with the program. And we may look at publishing that. Yeah, I know nutrition interventions in general are kind of notorious for having compromised data. And I think we did a pretty good job because the nutrition involvement.

hannah_went (29:58.145)

in it.

hannah_went (30:01.644)

Yeah, that’s great.

hannah_went (30:13.182)


kara_fitzgerald (30:15.65)

So it was that eight week diet and lifestyle intervention plus the two supplements that I mentioned, the probiotic and the greens powder.

kara_fitzgerald (30:25.374)

And we looked at the epic array. So that’s about close to a million methylation sites. And the first thing that we looked at was the Horvath clock, which when we started our study was really the only one out amazingly. And we collect in saliva. And so we needed a multi-tissue clock. And so we looked at the Horvath. And yeah, it was pretty extraordinary to see that we, I mean, I remember it.

hannah_went (30:51.096)


kara_fitzgerald (30:55.102)

I remember it like it was yesterday when I learned that we had made such an impact on biological age in our group as compared to the control group and even the within group comparison. It was very exciting. And now, well, and I think actually just talking about the whole journey of writing the paper up and then putting it into peer review and one of the reviewers just said this is something that we can all do.

hannah_went (31:07.701)


hannah_went (31:17.601)

Isn’t it?

kara_fitzgerald (31:23.482)

As to your point, when we started the conversation, like this is broadly adoptable. This isn’t going, this isn’t having hyperbaric or IV therapy or access to, you know, a CRISPR cocktail or some of the biohacking things. This is having a reasonable access to reasonable food, you know, and engaging in some very doable exercise. It’s not a rocket science intervention at all. So it was, it was really exciting to.

hannah_went (31:24.102)

Oh wow.

hannah_went (31:29.1)


hannah_went (31:49.208)

That’s amazing.

kara_fitzgerald (31:53.174)

get that comment from peer review. And it made me sort of more motivated in wanting to move to writing it for consumers. I mean, mostly I’ve been an educator of other professionals in my career, not in the consumer space, but this was motivating. I mean, I think this is very reasonable information that we just needed to get out there.

hannah_went (32:17.152)

Yeah, just so amazing. Again, can’t love your study more with that age reverse. So I couldn’t imagine seeing the initial results and thinking, is this real? Is this actually happening? And kind of the way it changed your life trajectory and your course. And now consumers all around the world know about your study and they’re changing their lifestyle because of you. I just think that is.

kara_fitzgerald (32:30.657)


hannah_went (32:42.272)

that is so motivating. It’s huge. It’s that revolution we’re undergoing. So it makes me just so happy.

kara_fitzgerald (32:48.462)

That’s cool. Yeah, I know. Yeah, likewise. And you know, I’m really excited for our coming papers. Like we were talking offline about… We influenced… So the Horvath Clock we looked at is only 353 methylation sites. But I know we influenced many, many thousands more methylation sites. And that’s going to be our next. So we’re going to move away from the… So the biological age investigation is huge. And we’re…

hannah_went (32:52.041)


kara_fitzgerald (33:18.238)

We’re continuing to look at it and we’ll refine our intervention. And I’ll keep, as you said, it’s a career change for me and I’m really focusing on it. But we also changed a heck of a lot of other chains. And that’s going to just be really fun to look at and tease out and publish on. And hopefully that’ll be coming out, you know, coming down the pike very soon.

hannah_went (33:30.602)

Oh yeah.

hannah_went (33:39.22)

Yeah, and what are you most excited about that’s coming? Would it be that study? Do you have any other things that are on the pipeline?

kara_fitzgerald (33:46.45)

I am. There’s a lot that I’m pretty excited about. So yeah, tucking into, so continuing to look at our intervention. We’ve got a case series in review now looking at the other genes that we influenced and understanding them. And I think individualizing the program now, sort of, we have this core intervention that we studied.

hannah_went (33:49.924)

Mm-hmm. Hahaha.

hannah_went (34:11.337)


kara_fitzgerald (34:16.042)

which is good, but what if I prescribe it for you and for your metabolic needs? What if I tweak it a little bit for the person sitting in front of me, which is what we do in functional medicine. It’s what we’re really good at, this individualized, sort of the systems investigation, very individualized. So we take the principles that we’ve figured out in the Younger You program, and then we further individualize it. What kind of findings might we see then?

What kind of findings might we see if we layer in some of the supplements coming down the pike that we’re pretty jazzed up at? Like, what if, I mean, a really simple one, vitamin D, right? I mean, vitamin D, I think, is on to its third paper showing bioage reversal. You know, just…

hannah_went (35:01.784)

Oh yeah. I love that. Yeah, just because you have the baseline. Like you said, we need to start somewhere. Your original study is great. It provides insight on where someone can start because then you have your baseline. You go on this, you know, your program, your younger you, you get your results back. You know, let’s push the limits. Let’s get even younger. Let’s get even better.

kara_fitzgerald (35:14.19)


kara_fitzgerald (35:24.142)

I’m sorry.

hannah_went (35:26.276)

So then, yeah, personalizing it a little bit and really having that end of one precision-based medicine, which is exactly what healthcare providers like yourself are diving into. I think that can be even super interesting as well, because the dosing may be different. Someone may need ABC, someone may need XYZ. So I think that could be an interesting approach as well.

kara_fitzgerald (35:35.038)


kara_fitzgerald (35:40.422)


Yep. I do think it would be interesting. And then, of course, if I had funding, it would be nice to do a larger study using our original protocol. Or if another, I know some scientists reached out to me from China not too long ago, and we’re going to take this on, but COVID slowed it down. You know, it would be, I’d love to collaborate. Actually, I’ve talked quite a bit about different collaboration opportunities. And I would just really love to do that.

hannah_went (35:50.27)


hannah_went (36:03.169)


hannah_went (36:11.732)

Yeah, definitely. All starts with the funding. So, you know, the distribution will take the funding.

kara_fitzgerald (36:14.415)

Yeah, it’s a lot. It’s like clinical research. Yeah, it’s incredibly expensive doing a randomized control trial. It just is.

hannah_went (36:23.072)

Oh, and I don’t think people realize how much, you know, work up front goes into that, right? On the back end for, you know, my company, True Diagnostic, I’ve seen the work that’s being put in into a lot of grants because I’ve, you know, proofread some of them and have gone through. And now I really understand when my professors in college would say, you know, no office hours today I’m writing a grant or something, I’m like, what? You know, surely it’s just a little paper. But I mean, it’s just, it’s so much goes into this. So appreciating the view from the inside out is.

kara_fitzgerald (36:26.9)


kara_fitzgerald (36:36.677)


kara_fitzgerald (36:43.961)


kara_fitzgerald (36:47.741)

huge. Yeah.

hannah_went (36:51.416)

Yeah, something I have a whole new lens for.

kara_fitzgerald (36:53.498)

Yeah, yeah, it’s a massive, massive undertaking and the duration like yeah, we’re we had an eight week intervention, but it took us over a year. You know, we had to have a rolling recruitment. It took a while for the right people to come along who are willing to adhere for the for the eight weeks and so yeah we didn’t we started we started recruiting in 2018 maybe we were works we started out with IRB in late 2017 recruiting in 2018 we didn’t finish until 2020.

hannah_went (37:01.913)

Thank you.

hannah_went (37:22.516)

Right, yeah, I think patient recruitment is huge too, right? So, you know, getting people involved in the right type of people, you have the inclusion, the exclusion criteria, you know, and I think I wanted, right, exactly. And I think it’s great, I forgot to mention that your, people who are actually in the group who are performing the therapy, they got access to those nutritionists. I think that’s phenomenal. And something that’s really unique about your study, and again, the control group, because those first,

kara_fitzgerald (37:31.882)

Yeah, yeah, we wanted healthy men. Yeah, it took, yeah, yeah.

kara_fitzgerald (37:49.699)

Thank you.

hannah_went (37:52.044)

clinical trials like came out proving the reversal of the biological aging or other aspects, they don’t necessarily have a control group. So that’s something that’s extremely unique to your research study too.

kara_fitzgerald (38:02.474)

Yeah, I think we’re just really fortunate. We had good funding.

hannah_went (38:07.592)

Right. And we’re just scratching the surface. So excited for what’s to come in your new studies. I’ll definitely keep an eye out. I’m sure I’m going to have you on again, you know, here in a couple of years when you have another just great, great paper and something we need to talk about more. So we’ve come to the end of this amazing podcast interview for the listeners who want to connect with you. Where can they find you? And I’ll definitely put this in the show notes as well.

kara_fitzgerald (38:15.906)

Thanks, Anna.

kara_fitzgerald (38:34.026)

Awesome. So you can, we have a free biological age quiz, which is really kind of a fun way to enter into the conversation for yourself. And you can access that at So you can find our bio age quiz. You can actually access doing a bio age test with a nutrition consult through that website as well, which is pretty cool. You can talk to one of our nutritionists who’s, you know, well, well trained in our protocol.

hannah_went (38:38.153)


hannah_went (38:57.58)

Very cool.

kara_fitzgerald (39:04.234)

And then my website,, is where the podcast is that I do, and where information on our clinic and blogs, et cetera, et cetera. You can find all that information over there.

hannah_went (39:15.4)

and an amazing podcast. I would recommend anyone listening to this one to go give hers a listen. And then my final, final point, this is a curve ball question I give to everyone at the end of my podcast. If you could be any animal in the world, Dr. Fitzgerald, what would you be and why?

kara_fitzgerald (39:18.423)


kara_fitzgerald (39:26.921)


kara_fitzgerald (39:34.046)

Oh my god, that’s really, really funny. I mean, all right, I guess I’d have to be a naked mole rat, right?

hannah_went (39:41.777)

Oh, there you go.

kara_fitzgerald (39:44.91)

And if you’re wondering why I picked that, I have a blog on it. I wrote a blog on Echobrach a long time ago. But yeah, they’re bad ass, right? They live forever. They don’t get any cancer. They, you know, they’re incredible little subterranean rodents that are pretty ugly. But man, they live the good life. Cool.

hannah_went (39:52.071)

Yeah, yeah.

hannah_went (40:03.796)

I love that you picked that animal. No one has said that yet, so it’s very unique. I will dig up your blog post and put it in the show notes too so people who are thinking, what the heck, can have a little bit more insight.

kara_fitzgerald (40:15.577)

Yeah, you can see a picture of a naked mole rat. Yeah, isn’t that funny?

hannah_went (40:19.152)

Yeah, no, that’s great. So we’ll see if anyone else gives me that same answer because I mean, that’s the point, living forever and no cancer. So no, I really appreciate it, Dr. Kara Fitzgerald. Thank you so much for your time and we’ll talk soon.

kara_fitzgerald (40:35.175)

All right, it’s been a pleasure. Thanks.

About this Guest Expert

Dr. Kara Fitzgerald
Kara Fitzgerald, ND, is a leader in integrative and functional medicine, focuses on researching the DNA methylome and its modulation through diet and lifestyle, and is known for her contributions to functional medicine education, clinical practice, and her publications on reversing biological aging.

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