 Ergothionine is an unusual amino acid. It was discovered a century ago, but ignored until recently when it was discovered that we have a transporter protein in our body specifically designed to pull it out of our diets into our tissues, implying that it plays an important physiological role. What does it do? Well, our first clue was the tissue distribution. It's concentrated in places where there's lots of oxidative stress. The lens of our eye, the liver, as well as really sensitive areas like bone marrow and semen. And so they thought it might be a cytoprotectant, a cell protector. And that's what they found. Not only does it get into the nucleus of our cells to protect our DNA, it can even get into our mitochondria, the power plants of our cell. Ergothionine appears to function as a potent intramidocondrial antioxidant, which I've talked about before. Because we can only get it through diet and the toxicity associated with depletion when you starve cells of ergothionine, they don't do so well, the researchers suggest that ergothionine may represent a new vitamin. Well, we could certainly use all the mitochondrial protection we can get. So where can we find it in our diet? Well, it's not made by plants. It's not made by animals either, but by little microbes in the soil. Thankfully, we don't have to eat dirt. It's taken up through the root systems of plants and gets transferred to those who eat them and those who eat those who eat plants. And so it ends up widely distributed in both the plant and animal kingdoms. That's true, but a little misleading. Yes, it's found in a variety of foods, but some more than others. It's not found in fruit, not found in dairy. Fish have up to 0.7, eggs have up to 0.7 in the yolk, twice as much in nuts and seeds, vegetables up to three, grains up to four. There's a bunch in organ meats, particularly the kidneys of pigs and the livers of chickens, beans, however, up to 13.5. So yes, technically in both plant and animal kingdoms, but not really evenly distributed. Any kingdoms we missed, though? There is a third kingdom of multicellular organisms. How could we forget? Fungus. Mushrooms are the superstars here, nearly 40 times more than the closest competitor.