Dear friend,

That word is "normal."

A new study from the University of California, San Francisco, published in Annals of Neurology, is the clearest illustration of why.

Researchers followed 231 healthy older adults — average age 71, none with dementia or cognitive impairment. Their average B12 level was nearly three times the official minimum. By every standard lab report, these people were fine.

This matters most for two groups: Older adults, because B12 absorption becomes less efficient with age. And those eating a plant-rich or Nutritarian diet — because while I will always argue that a plant-rich diet is the healthiest way to eat, B12 (and DHA-EPA) are the two nutrients you cannot reliably get from plants. B12 is the single supplement that is non-negotiable.

Which brings me to how I think about supplementation in the first place.

When I formulated my daily multivitamins, this study's lesson was already the guiding principle. I use methylcobalamin — the active form of B12, the very form these researchers measured. And I dose it well above the bare minimum, because research shows we absorb only a small fraction of what we take, and I have never been interested in merely preventing deficiency.

Alongside B12, my multivitamin formula fills the other gaps a plant-rich diet can leave — vitamin D3, zinc, iodine — while deliberately leaving out the ingredients you don't need and shouldn't have, like folic acid and vitamin A. If you've been meaning to take a closer look at the foundation of your supplement routine, this may be the week to do it. And don’t forget the only refrigerated DHA-EPA in the world—that is needed for brain protection too.