As the days get shorter, three things quietly start working against you: your mood, your immune system, and your memory. The good news — all three are largely in your control, if you know what to check and what to take.
Vitamin D — your mood and immune switch
Dr. Michael Holick, one of the leading researchers on vitamin D absorption, has spent decades showing that effectiveness isn’t about how much you take — it’s about how much actually ends up in your bloodstream. His work links healthy vitamin D levels to better mood, stronger immune defense, and better bone health, especially as sunlight drops off this time of year.
His recommendation: get tested, and aim to keep your blood level in the 50-80 range.
I’ve watched this play out with our own patients — when D levels sit in that range, mood noticeably improves and colds become less frequent. It’s one of the simplest levers you can pull this fall.
Here’s the catch Holick’s research uncovered: your small intestine has to be working at full capacity to absorb D properly, and stress — physical or emotional — quietly reduces that capacity. That’s why so many people take vitamin D and still test low. It’s also why we use Perque’s D3 Cell Guard: it’s built specifically around this absorption problem in collaboration with Perque.
Omega-3 — the number most people don’t know they’re missing
Omega-3 supports memory and mood, but here the issue is intake and absorption. The target is an Omega-3 Index of 9% on bloodwork — most people, even those eating fish regularly, test well below that. The only way to know where you stand is to test it.
Vitamin C — your demand dose
Vitamin C boosts your immune system’s effectiveness, but how much you need isn’t fixed — it moves with your stress load, and “stress” here means anything from a busy week at work or school to an oncoming virus.
Here’s how to find your number: take Perque Potent C until your bowels get loose — that’s your demand dose. Back off slightly from there to your normal, comfortable level. When you’re feeling run down or worried about a bug going around, that dose should go back up.
What I want you to do
Test your Vitamin D and Omega-3 levels — Dose your Vitamin C on a regular basis.
Test Yearly.
Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis. Michael F. Holick. PMID: 14985208
- PMID: 14985208
- DOI: 10.1093/ajcn/79.3.362
Holick, M.F. Optimal Vitamin D Status for the Prevention and Treatment of Osteoporosis. Drugs Aging 24, 1017-1029 (2007).
https://link.springer.com/article/10.2165/00002512-200724120-00005#citeas