William A. Wallace, Ph.D. (@WilliamWallace)

Vitamin D isn't really a vitamin. It's a steroid hormone that crosses the blood-brain barrier and acts on receptors throughout the brain, including the hippocampus and entorhinal cortex, where Alzheimer's tau accumulates first. A Framingham Heart Study analysis tracked this for 16 years. 793 adults...

I posted something similar yesterday, but here is a different graphical representation of nutrient absorption in the GI tract, explained simply: 1️⃣ Stomach – preparation and partial absorption The stomach begins protein digestion through acid and enzymes while absorbing a few small molecules such ...

Your muscles aren’t just moving weight, they’re protecting your brain. Every rep you lift sends signals far beyond the muscle. The brain feels it. Blood vessels feel it. Your long-term cognitive health feels it. A single, well-designed strength-training routine influences: 🔹 Endothelial function ...

Understanding exercise intensity, effort, and physiological stress This figure integrates both resistance training and endurance training frameworks to explain how exercise intensity, effort perception, and physiological stress align across different types of activity. It connects objective perform...

When gut imbalance turns into whole-body inflammation This figure shows how an unhealthy gut microbiome can set off a chain reaction that affects metabolism, hormones, and nearly every major organ system. When the gut barrier weakens, bacterial toxins leak into the bloodstream, driving a cycle of c...

Digestion made "simple": where each nutrient gets in Your gut isn’t just one tube. Different nutrients are absorbed at different checkpoints. Here’s the simple breakdown: 1️⃣ Mouth & Stomach Carbs begin breaking down with salivary amylase. Proteins start with stomach acid + pepsin. Vitamin B12 ...

Your brain is an energy machine, and it’s far pickier than you think. Most people assume thinking “burns a ton of calories.” The truth? Even your hardest mental work raises brain energy use by only about 5%. That’s because most of the brain’s energy budget is already being spent before you even st...

Your body is running dozens of supply chains at once… and you never notice. Some nutrients get stored for the long haul. Some get used immediately. Some get locked away in specific tissues so they’re ready the moment you need them. And all of it happens silently, every hour of every day This char...

Understanding glucose. How your body manages energy. Glucose metabolism is how your body turns food into energy, storing and releasing it as needed. Different organs and processes work together, influenced by hormones, to keep blood sugar steady and fuel your cells. 1️⃣ Blood Glucose Glucose from ...