What’s younger? Your brain or your body?

Neuroscientists are obsessed with the idea of the “brain age gap,” a way to measure how your brain is aging compared to your actual age.

I saw this gap play out with my 95-year-old grandmother. Her mind stayed razor sharp; it was her body that failed her. 

Now I see the opposite in clinic—40-somethings asking if they’re losing it because they forgot a name. 

Spoiler: It’s much less likely to be a sign of early dementia than what I call SMMD (Social Media Memory Disorder), a symptom of the constant overload of information that makes it hard to hold on to anything. 

But those moments are worth paying attention to—your brain ages faster than you think. 

Here’s what to do about it.

🤓 What to know: Your brain starts shrinking at age 40.

We talk a lot about aging bodies, but not enough about aging brains.

The brain starts shrinking around age 40, losing 5% of its volume each decade (Frontiers in Aging Neuroscience, 2022). 

Cognitive decline starts long before disease develops. This is when many of us start noticing dips in working memory and processing speed.

🧠 What ages the brain?

Brain aging is fueled by a mix of metabolic, hormonal, vascular, and inflammatory stressors. Here are the big ones:

• Blood sugar spikes → Damage blood vessels + impair insulin in the brain

• Cardiovascular disease → Brain needs 20% of your oxygen—reduced flow = reduced cognition

• Inflammaging → Chronic inflammation breaks down neurons + energy production

• Low omega-3s → Your brain is 60% fat. Neurons rely on healthy fats (especially DHA) to fire properly

• Pregnancy → Depletes DHA if not replenished with supplementation

• Menopause → Estrogen supports mood, memory, and cognitive ability; its loss during menopause loss drives higher Alzheimer’s risk (Frontiers in Molecular Biosciences, 2025)

• Heavy metals → Lead + mercury impair mitochondria + cognition over time

• Nutrient gaps → Low B12, vitamin D, magnesium, folate impair memory and the brain’s ability to send electrochemical signals

⚠️ Signs your brain might be aging faster than your body

The reality is, 1 in 9 people will be diagnosed with Alzheimer’s after the age of 65 (two-thirds of them are women) and almost all of us will start noticing symptoms of cognitive decline in our mid-40s (British Medical Journal, 2012). 

But early brain aging doesn’t look like dementia. It looks like:

• Forgetting words mid-sentence

• Struggling to multitask

• Slower learning or recall

• Brain fog after meals

• Mood shifts or irritability

• Feeling mentally "tired" faster

More serious signs:

• Trouble remembering new info

• Getting lost in familiar places

• Difficulty understanding or finishing sentences

• Noticeable personality changes

🔍 How to measure your brain age

There’s no single “brain age” test, but we can measure how the brain is aging across structure, function, metabolism, and biology.

🧠 Structural Imaging (MRI)

• Measures: Brain shrinkage, white matter integrity, hippocampal volume

• Why it matters: A full-body MRI like Prenuvo (available through Parsley) can tell if your brain is shrinking faster than expected

🧠 PET Scans

• Measures: Glucose metabolism (declines decades before symptoms start), amyloid plaques and tau tangles (early markers of Alzheimer’s) 

• Why it matters: The most powerful tool we have for detecting early neurodegenerative changes.

🧠 SPECT Imaging

• Measures: Blood flow to different brain regions 

• Why it matters: Low perfusion is a red flag for aging and mood changes

🧠 Neural Activity Mapping (MEG + EEG)

• Measures: Electrical activity and neural communication

• Why it matters: “Brain age” algorithms can estimate biological brain age via signal speed

🧠 Functional Cognitive Testing

• Measures: memory, processing speed, executive function, attention. 

• Why it matters: Tools like CNS Vital Signs (CNSVS) give you a real-time performance snapshot. 

🧠 Epigenetic Age Tests

• Measures: DNA methylation patterns via tests like TallyAge 

• Why it matters: Accelerated biological age is strongly correlated to decreased brain function (Nature Scientific Reports, 2024).

💪 What to do: Prioritize nutrient support, cardio, HRT, and heat therapy.   

Here’s what I recommend to patients (and practice myself):

🧪 Step 1: Test biomarkers that predict cognitive aging

• ApoB (< 80) → high levels accelerate vascular aging, including in the brain.

• Fasting insulin (1-6) + HOMA-IR (< 1.5) → insulin resistance is a major driver of cognitive decline.

• Omega-3 index (> 6) → low DHA directly impairs neuronal membranes.

• Heavy metals (mercury < 3; lead < 1) → both accumulate in the brain and impair mitochondrial function.

• hs-CRP (< 1) → systemic inflammation = “inflammaging.”

• Food sensitivity test (KBMO) → Uncovers gut-brain inflammation

💪 Step 2: Strength 2-3x per week; cardio 2x per week. 

BDNF is the driver of neuroplasticity—your brain’s ability to learn, adapt, repair, and stay young—and it declines as you age. 

Exercise is the #1 way to boost it. 

• Cardio: Even one session increases BDNF; harder efforts = bigger boost (European Journal of Neuroscience, 2017).

• Strength training: increases baseline BDNF levels in older adults by improving insulin sensitivity, reducing inflammation (Geriatric Nursing, 2023).

💊 Step 3: Supplement to plug nutrient gaps + lower inflammation

• Omega-3s (EPA + DHA): 1–1.5g/day supports neuron health; boosts BDNF after ~10 weeks (Clinical Nutrition ESPEN, 2023). 

• Magnesium threonate: More effectively crosses the blood-brain barrier than glycinate; helps memory (BMC Neuroscience, 2020). 

• Urolithin A: Supports brain energy metabolism by removing damaged mitochondria (Nature Metabolism, 20219).

• Vitamin D, B12, folate: Critical for cognition, mood, myelination

🌸 Step 4: Consider HRT during menopause

Started within 10 years of menopause (or before age 60), estrogen therapy can:

• Lower risk of Alzheimer’s disease (Alzheimer’s Risk and Therapy, 2024)

• Slow biological aging (JAMA Network Open, 2024)

Read my full HRT protocol here. 

🤓 Step 5: Challenge your brain with novelty

Engaging in challenging, creative activities can make the brain act 3–6 years younger (Nature Communications, 2025).

Try:

• Taking up dance, art, or music 

• Trying a new sport (my husband picked up ice hockey in his 30s; my mother started Pilates in her 90s)

🔥 Step 6: Add heat therapy to your recovery 

• 20+ minutes of sauna (176–194°F) or a hot bath (108°F) reliably raise BDNF levels (PLOS One, 2021).

⚡️ Quick Hits

 🥜 Peanuts are making fewer parents nuts. 

A new study in Pediatrics found peanut allergies have been cut in half (!) since parents started introducing peanuts earlier—typically around 4–6 months, thanks to updated guidelines. How cool is that?!

Besides Trader Joe's Bamba Peanut Snacks (sometimes), my favorite peanut-y thing to make for my kiddos is apple slices & peanut butter (it’s a classic for a reason). 

💪Grip it real good. 

A UK study of 93K+ adults over 13 years found stronger midlife grip strength predicted slower disease progression and lower mortality. Those with a stronger grip in their 40s–60s were less likely to develop obesity-related diseases or die early. 

My favorite way to boost grip strength? Rock climbing, where “getting a grip” pays off.

🚶Walking for the win. 

New research shows walking a few thousand steps a day can slow cognitive decline in older adults at higher risk of Alzheimer’s. As someone with a family history, I take prevention seriously, and, according to science, one small step for your body is one giant leap for your brain. (FWIW, benefits peak around 5K–7.5K steps.) 

To see what other levers I’m pulling, see my personal Alzheimer’s & Dementia prevention plan. 

If you like health takes that are both clever and credible, subscribe to 5HT! 

💛 The Momgevity Files

I’m just getting back from health and wellness candyland—otherwise known as Eudamonia, the consumer health summit in West Palm Beach, now in its second year—where 5,000 people gathered to hear expert talks, explore the latest health and wellness products, work out with their favorite teachers, and connect with like-minded wellness enthusiasts.

I’m exhausted in the best of ways. I spoke three times: I recorded a live podcast with Dr. Will Cole; joined a mainstage panel on AI in healthcare with Dr. Mark Hyman, a functional medicine pioneer, and Dr. Dave Rabin, founder of ApolloNeuro; and delivered a keynote on female longevity on Saturday that I’m especially proud of. I also gave press interviews, hosted one-on-one office hours with attendees, and caught up with friends like Rich Roll, Dr. Jessica Shepherd from HERS, Dr. Amy Bilken (one of my favorite hormone experts) and Jeff Krasno and Schuyler Grant of One Commune. (P.S. Announcement coming soon on my first longevity retreat with Commune!)

Our Parsley Health team was there too. We don’t usually do booths at events like this, but we made an exception—and I’m so glad we did. The hundreds of people who stopped by to ask questions or get their Parsley Symptom Score with one of our health coaches reminded me why we do this. The exhibit hall was a sight to behold: from massage robots to vibrating chairs that stimulate dopamine, to a new kind of air filter using AI algorithms to detect and remove mold and pollution from your home, the advances in tech for optimal health were fascinating.

The best part of the event for me personally was being with my people. Over the past few years, I’ve spent a lot of time at traditional healthcare industry conferences—rooms filled with execs from insurance companies, government agencies, large employers, hospital systems, and investment funds. It’s been a privilege to share functional medicine in those settings. But where I truly feel at home is among people whose personal and professional passion for health and wellness runs deep. It’s one thing to try to incrementally improve the existing system. It’s another to completely rethink the model of proactive, preventive health from the ground up.

Two personal highlights to share:

First, my talk, Nine Ways to Supercharge Female Longevity, had such strong registration that I was assigned to the grand ballroom—the same stage where Dr. Andrew Huberman spoke that day. It was a massive space with a giant stage and enormous screens. I was paranoid it would be empty—people sign up for talks, but with so much happening at once, they don’t always show. The night before, I ran around asking friends to come—even for 15 minutes—so I wouldn’t be lecturing to just seven people in a cavernous room. A friend texted me the morning of the talk with a kind reminder: “No one fills up the big room their first time in it. You grow into it, you make it yours.” 

Happily, over 300 attendees showed up to hear my female longevity protocol and the stories of my grandmothers, my mom, and my daughter. 

I think I made the room mine.

As I was running to my room to change for dinner, I ran into Dr. Jeffrey Bland—the man who founded the field of functional medicine over 30 years ago. He started the Institute for Functional Medicine, co-founded Bastyr (the naturopathic college in Seattle), and has launched numerous companies from Metagenics to Big Bold Health. He is a legend. We stopped to say hello, and out of nowhere he said: “Robin, I am so proud of you. What you have created in Parsley is what I dreamed would happen for functional medicine. You made it real.” Nearly in tears, I told him what an honor it is to play even a small part in continuing his work. 

He’s a north star for me: I want to keep creating throughout my life in a way that transforms health, just as he has, and at such a high level. We hugged. It was a powerful moment for both of us.

The ninth step in my female longevity protocol is Community. People with strong social connections live significantly longer, while loneliness carries the same mortality risk as smoking 15 cigarettes a day—for a lifetime.

I feel incredibly lucky and grateful to have such a clear sense of purpose and to be part of an inspired, inspiring community. It was hard to be away from my kids for yet another trip, but this one filled me with enthusiasm and clarity for what’s ahead. The kind that carries you a long way. The kind that reminds you why longevity matters in the first place.

Stay strong, stay curious, and breathe, 

Robin

As always, this newsletter is for informational and educational purposes only and is not intended as medical advice. Always consult your healthcare provider before making any health decisions or changes to your treatment plan.