Human cells have receptors on their membrane surface which allows certain compounds to cross over into the cell. These receptors are very specific in regards to the type of binding molecule (ligand) they will bind with. Sugar and Vitamin C have a similar structure and therefore enter cells using the same receptor – the Glut-1 receptor. Insulin (the ligand) moves both glucose and ascorbic acid into cells, including phagocytic immune cells. These cells remove microbes, tumor cells and debris from the blood.
Almost all animals have the ability to manufacture vitamin C within their bodies and have no need to consume it from external sources, with the exceptions being guinea pigs, primates, and humans. The vitamin C is manufactured from glucose, and because of this, the Glut-1 receptor prefers glucose and will choose sugar over Vitamin C when it has the option to. As such, Glucose and ascorbic acid are in constant competition for insulin the insulin that is available. This means (for those of you playing along at home) that the more sugar you are consuming, the less vitamin C you are absorbing.
But wait, there’s more. As hinted at above, phagocytic immune cells can destroy pathogens. They do this by creating superoxide and other reactive oxygen species through a series of chemical reactions known as the HMP shunt. Ascorbic acid stimulates this process and glucose inhibits it, making it harder to fight diseases and viruses. Ascorbic acid has the ability to deactivate this if too much is in the system. The HMP shunt also produces ribose and deoxyribose which are necessary to for making DNA and RNA.
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