Microscopic image of mitochondria beside the title “Treating the Cause, Not the Symptom: The Mitochondrial Thread in Chronic Disease,” with Dr. Kara Fitzgerald branding.

Treating the Cause, Not the Symptom: The Mitochondrial Thread in Chronic Disease

Every clinician has patients who don’t fit the textbook. The hypertensive patient whose blood pressure won’t budge despite a full medication ladder. The patient with relentless fatigue that no bloodwork explains. On the surface, these look like unrelated puzzles – underneath, they may be pieces of the same one. The common thread is mitochondrial. Every cell produces energy through mitochondria, and every unit of energy they make comes with a small cost: reactive oxygen species generated as a byproduct of the process.

Graphic for “The Epigenetic Impact of Younger You: A New EWAS Study,” featuring a DNA helix surrounded by berries, green tea, broccoli, turmeric, and other polyphenol-rich foods.

The Epigenetic Impact of Younger You – A New EWAS Study

A clinician’s guide to our new EWAS analysis of the Methylation Diet & Lifestyle Study, the dietary and lifestyle pattern behind Dr. Fitzgerald’s Younger You Program. It’s funny how things eventually come full circle. Way back in 2016, when we first presented our thoughts on the potential hazards of high-dose methyl donor supplements to the Institute for Functional Medicine audience, and later when we started our original clinical study, we weren’t thinking about bioage clocks. In fact, the prevailing view at the time was that biological age (as measured by epigenetic age) wasn’t changeable.

Dr. Kara Fitzgerald graphic titled “Your Body Is Always Listening: How Heat and Light May Support Nervous System Recovery,” set against an abstract amber and golden background.

Your Body Is Always Listening: How Heat and Light May Support Nervous System Recovery

Adaptation has two halves. Most conversations about heat therapy focus on the first half: hormetic stress. It’s the controlled challenge that prompts the body to build and grow more resilient. But a stressor is only useful if the body can complete the loop and recover from it. The second half of adaptation usually gets less attention, and this is the downshift. It’s the mechanism of how the body restores itself and returns to baseline. In the context of aging and resilience, much of the real clinical value lives there.

Graphic for Dr. Kara Fitzgerald’s article, “Should the Future of Root Cause Medicine Include Engineered Food?” featuring a futuristic plate of engineered foods and plants.

Should the Future of Root Cause Medicine Include Engineered Food? This Might Make You Think

We think this might be controversial – let us know your thoughts! As a functional medicine clinician, our daily work often revolves around a simple yet profound philosophy: the body has an innate ability to heal if we remove the obstacles and provide the right inputs. For decades, the “right inputs” have often been synonymous with “back to basics,” including whole, unprocessed foods and organic farming. The image this conjures is of going back to our traditional agricultural roots. We have long viewed “engineered food” as the problem, the very source of the ultra-processed, hyper-palatable “food-like substances” that drive the chronic disease epidemic we see today. Now a new report, “Engineering Food Systems to Enable Precision Nutrition,” recently released by the Engineering Research Visioning Alliance (ERVA) and supported by the U.S. National Science Foundation, demands a reconsideration of the boundaries of our field. Its central argument is provocative: while nutrition problems manifest biologically, they cannot be solved through biological research alone. The translation of personalized, root-cause care into scalable, population-level health is currently constrained not by our lack of biological discovery, but by our lack of engineering capability.

Dr. Kara Fitzgerald blog graphic titled “FSH Testing in Perimenopause: Why One Test Isn’t Enough,” with hormone trend lines and a brain illustration.

FSH Testing in Perimenopause: Why One Test Isn’t Enough

FSH is having a quiet moment in longevity medicine — though most of us have not noticed yet. Follicle-stimulating hormone is still treated, in most practices, as a simple yes-or-no test: ordered once, or at most twice, to confirm menopause (or evaluate fertility), then set aside. But a growing body of research is reframing FSH as something more interesting: a longitudinal signal that may track how a woman’s bone, muscle, brain, and metabolism are aging. These are the very tissues we now think of as longevity organs. If that reframe holds, then the way most of us use FSH is leaving a great deal of information on the table.

Ceramide serum with dropper beside the title “The Ceramide Paradox,” exploring ceramides in skin barrier health, metabolic dysfunction, inflammation, and aging.

The Ceramide Paradox: Navigating the Nuances

Most likely you know about ceramides for skin health. Interestingly, ceramides are also emerging biomarkers of metabolic health, caught up in the crosshairs as chronic inflammation promotes the formation of dysfunctional ceramide types, which then participate in furthering inflammatory processes. However, patients should not avoid ceramide-containing foods as these dietary sources can help restore balance. While many questions remain, several practical takeaways are already clear:

Illustration of protein and gut microbes above the intestinal lining, representing protein digestion, the microbiome, and muscle health.

Why More Protein Isn’t Always the Answer

Protein continues to be a hot topic in nutrition and longevity medicine. Much of that interest stems from the growing recognition that skeletal muscle is a longevity organ that influences metabolism, mitochondrial function, immune regulation, and cognitive health. As a result, maintaining muscle mass and function has become a cornerstone of healthy aging, and clinicians are increasingly encouraging patients to consume more protein.

Illustration of the intestinal lining with colorful gut microbes, paired with the title “Rethinking Gut Permeability: PUFA Metabolism, the Microbiome, and Immune Activation.”

The PUFA-Microbiome Axis: Rethinking Intestinal Permeability Beyond Tight Junctions

What an obscure mouse strain reveals about antigen uptake, immune reactivity, and gut barrier function. In functional medicine, we think about PUFA (polyunsaturated fatty acid) metabolism constantly. Yet we don’t often think about where that metabolism actually happens first: in the gut itself, in intimate conversation with the microbiome. This month, Romilly Hodges, CNS, walks us through a fascinating scientific story, starting with a single gene in an obscure mouse strain that provides a surprisingly rich window into fatty acid metabolism in the gut, including how it shapes barrier function (broadening our thinking beyond tight junctions), immune reactivity, and antigen uptake. The implication is that we need to be considering the microenvironment of PUFA metabolism in the digestive tract.

Lion’s Mane mushroom and the title “One Mushroom. Two Patients.” for a Dr. Kara Fitzgerald blog on targeted Lion’s Mane formulations.

One Mushroom, Two Patients: A Practitioner’s Case for Targeted Lion’s Mane Formulation

There’s a question worth asking every time you prescribe Lion’s Mane: which patient are you prescribing it for? Most integrative practitioners already use Lion’s Mane, but few consider the variables. Raw material, preparation type, extract, and dose all affect therapeutic outcomes. To confound matters further, the market positioning of Lion’s Mane tends to be a poor reflection of both tradition and clinical research. The clearest example is that it gets labeled as a nootropic, something anyone might use for sharper thinking. That framing attracts consumers, but it does not hold up in clinic.

A woman looking out a sunlit window surrounded by imagery representing fertility, mitochondria, and reproductive health, illustrating a holistic approach to fertility preservation beyond egg freezing.

Fertility Preservation Beyond Egg Freezing

A 31-year-old patient sits across from me and says, “My friends are all freezing their eggs. Should I be doing that too?” It is a question I hear constantly. And while oocyte cryopreservation is a legitimate tool for specific situations, the way it is being marketed has created a damaging assumption: that fertility is a fixed, steadily declining resource that technology must eventually rescue.