N-Acetylneuraminic Acid (Neu5Gc)

Sialic acids (Sias) are abundant terminal modifications of protein-linked glycans and are not found in plants. Neu5Gc is also not synthesized by microbes. The dietary sources of Neu5Gc are foods of animal origin. Major sources appear to be red meats (i.e., lamb, pork and beef) and, to a lesser extent milk products).

Red meat-derived N-glycolylneuraminic acid (Neu5Gc) is hypothesized to increase human risk of "carcinoma, Heart disease and systemic inflammation".