Here’s my confession: I write a newsletter that tells you to get your bloodwork done, and I still put off my own homocysteine test for eight years. Turns out even rebels get squeamish about numbers that might talk back.
I finally had mine run. Low-normal — genuinely good news, and also not very instructive for you. But the number was never really the point. Getting past eight years of not looking was.
The reasons aren’t abstract to me anymore, either. When I finally looked, it wasn’t just my heart I was protecting. Homocysteine does something most heart-health messaging leaves out entirely: it damages blood vessels and neurons through two separate mechanisms, at the same time. Same molecule, two lines of attack — which is exactly why it belongs in a conversation about your brain, not just your heart.
It’s an amino acid your body makes as a byproduct of normal metabolism, and B12, folate, and B6 are what clear it back out. When that clearing process runs low on fuel, homocysteine builds up, and it doesn’t sit there quietly — it drives oxidative stress that damages vessel walls directly and neurons directly. Elevated levels are one of the more consistently replicated markers tied to Alzheimer’s risk specifically; in longitudinal research, risk roughly doubles above 14 µmol/L.
And if you’ve been on a proton pump inhibitor long-term, this is one more reason to know your number. PPIs can interfere with B12 absorption over time, which is one route to elevated homocysteine in the first place. The evidence there is real but not settled for everyone on a PPI — same caveat I gave you back then.
Last Week, Briefly
If you missed it: there’s the inflammation you can feel — the fire alarm kind, loud and fast to resolve — and there’s the smoldering behind the drywall kind, silent. That kinds ends up in a different room depending on the woman. Bloodwork usually misses it, because the standard tests are sensitive to ‘a fire exists’ but not to ‘which room.’ This week, we’re following it into the room that scares people most.
The Breach
Your brain has its own firewall — the blood-brain barrier — and last week I told you it isn’t always fireproof. Here’s what actually breaches it.
Gut first. When the gut lining gets permeable (“leaky gut”, though your doctor may not love the term), bacterial byproducts called LPS slip into general circulation. Once there, They can cross the blood brain barrier and trigger inflammation in the brain and exacerbate diseases such as Alzheimer’s and Parkinson’s, the same inflammatory immune cells from last week’s piece — kicking off neuroinflammation directly.
Gums, too. This one surprises people every time I mention it: gingipains, the toxic enzymes from the bacteria behind gum disease, have been found directly in Alzheimer’s brain tissue — not just inflammation traveling there, the bacteria’s own toxins showing up in the hippocampus. Flossing just got a lot more interesting.
And blood sugar. I’ve called Alzheimer’s “type 3 diabetes” for years, and Dr. David Perlmutter uses the same term in his new book. It’s worth knowing it isn’t an official diagnosis — neither the ADA nor the WHO recognizes it — but the mechanism behind the phrase is real: insulin resistance measurably weakens blood-brain barrier integrity, letting inflammatory cells cross more easily. The label is unofficial. What it’s describing isn’t.
What’s Actually Worth Testing
Here’s where I’ll take the middle-of-the-road stance instead of the rebellious one: you don’t necessarily need to test for all of this. Homocysteine is worth everyone getting — it’s cheap, specific, and (as you now know) I finally practice what I preach. But hs-CRP, fasting insulin, and the newer brain-specific markers like p-tau217 and GFAP are most worth ordering if you are managing any of the lifestyle diseases — diabetes, high blood pressure, extra weight around the middle, metabolic syndrome, a family history of dementia, or a lifestyle that’s been more survival than optimization lately. If that’s not you, your money and anxiety are probably better spent on the habits below than on a battery of tests.
If you do fall into that higher-need group, KBMO’s Cardiovascular Inflammation Test is worth knowing about — one blood draw covering hs-CRP, fasting insulin, HOMA-IR, a full lipid panel including ApoB and Lp(a), glucose, A1c, and vitamin D. It’s efficient specifically because most of what raises your risk travels together; ordering these one at a time gets expensive and slow. Worth knowing what it doesn’t cover, though: no homocysteine. That one is likely covered by your insurance, so start there if out of pocket isn’t an option.
Get Serious About This
None of this works without the boring part. Here’s the checklist worth actually taking seriously, not just nodding along to:
- Eat in a genuinely anti-inflammatory pattern — plenty of plants and fiber, keep carbs to a reasonable level, include plenty of clean protein and healthy fats. In this coach’s world that includes eggs, meats, fish, butter.
- Move most days. It doesn’t have to be intense, but it should move the needle on heart rate some days, muscle the others.
- Protect your sleep like it’s a medical intervention, because it is.
- Treat your gums like part of your health chart, not a separate errand — see the dentist, actually floss. (Talking to myself here.)
- Get curious about your blood sugar in real time, not just once a year. A continuous glucose monitor (CGM), even worn for a couple of weeks, shows you the actual swings — which meals spike you, how sleep and stress affect you, and whether “normal” fasting glucose is your normal. If not, it can be, I promise.
Next
This was the basic-to-get-or-stay-healthy list — the habits worth having in place before anything fancier makes sense. Once they’re actually in place, there’s a further tier: the more advanced levers people reach for once diet and movement are handled and they want to push further. That’s a future piece, not this one.
Til next week,
Stay rebellious,
