Fructose has a well earned bad reputation in metabolic health circles. It gets metabolized almost entirely in the liver, and unlike glucose, its breakdown isn’t regulated by the body’s actual energy needs. Feed the liver a lot of fructose and it responds by cranking out triglycerides, storing visceral fat, raising blood pressure, and nudging the body toward insulin resistance. I explored this problem from an unusual angle with a colleague of mine in an editorial for Open Heart, looking at whether a simple, inexpensive amino acid, glycine, might counteract a meaningful chunk of that damage.
Why Glycine, Specifically
Glycine isn’t just a building block for protein. It activates its own dedicated chloride channels on a wide range of cell types, including immune cells, platelets, endothelial cells, and heart muscle cells. Depending on how a given cell handles chloride internally, activating these channels can either calm the cell down or, in a specific and useful way, trigger a cascade of protective signaling.
The interesting part is that normal blood glycine levels sit right around the threshold needed to activate these channels, which means that supplementing with glycine, something that reliably raises blood levels several fold, will meaningfully increase how active these channels are throughout the body. That’s a genuinely elegant setup from a pharmacology standpoint, a naturally occurring molecule sitting right at its own activation threshold, where a modest dietary increase can push signaling meaningfully higher for health benefits.