Vitamin D comes from sunlight. Vitamin N, in its usual meaning, is time in nature. But there is another kind of contact that does not wait for permission, weather, or season. Neutrinos are passing through you right now — many trillions every second, through your neurons, blood, bones, and skin, without asking anything of you.
Does any of this matter biologically? The honest answer is that we do not know, because the question has hardly been asked in a way modern physics would consider precise. The 2017 COHERENT experiment confirmed coherent elastic neutrino-nucleus scattering (CEνNS) at 6.7 sigma — proving that neutrino-matter interaction has more structure than the simplest models allowed. And the Chernobyl radiosynthesis discovery showed that biology can have unexpected relationships with ambient radiation fields.
For billions of years, life on Earth has evolved inside a constant neutrino flux. Whether any of that has ever mattered in a biological sense is one of the more interesting open questions at the edge of physics — not because anyone has found evidence that it does, but because no one has looked carefully enough to be certain that it does not.
