Vitamin C assists the absorption of dietary Iron.

Dietary iron is absorbed in two forms; haem and non-haem. Haem iron is soluble and readily absorbed through the small intestine. Non-haem iron is less readily absorbed. It is found in plant foods, and must first be cleaved from food components. Chelates and ligands are compounds that bind metal irons and may either inhibit or enhance absorption. Enhancers of iron absorption include acids. At a low PH, ascorbic acid enhances the absorption of non-haem iron by acting as a reducing agent. By reducing dietary ferric iron to ferrous iron, this complex, termed ferrous ascorbate chelate remains soluble and enhances the uptake of non-haem iron. The addition of 20mg of ascorbic acid has been shown to increase non-haem absorption by 39%.