Galactose is a single sugar that can combine with another single sugar (glucose) to form lactose or milk sugar. Lactose is broken back down to glucose and galactose by the enzymes lactase and β-galactosidase. Glucose is more stable than galactose. Since galactose is more reactionary, it is more readily incorporated into glycoproteins and glycolipids.

Galectins are a family of lectins (glycoproteins) that prefer to bind with galactose. They interact with glycoproteins and glycolipids on the surface of the cell. They interact with proteins in the nucleus and in the cytoplasm inside the cell to affect biological processes. Galectins have important roles in cancer. They contribute to the conversion of normal cells into tumor cells, blood vessel creation to support tumors (angiogenesis) and tumor metastasis. They can modulate the immune and inflammatory responses and may help tumors escape being seen by the immune system. Some of this sounds like a bad thing but science is still investigating exactly how it works. But there is no doubt galactose plays an important role in human biology.

Galactosamine is galactose with an N-acetyl group replacing a hydroxyl (OH) group. Galactosamine is found in follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Galactosamine is a constituent of hyaluronic acid, a powerful water-binding agent. Hyaluronic acid is found in many types of tissues, including brain, skin and connective tissues. It acts as a lubricating agent in the synovial fluid of joints and in connective tissue. Inside the eye, hyaluronic acid acts as a lubricating agent in the transparent jellylike fluid.

The foods we can find galactose in are: dairy, gums, sugar beets, and the gelatin, gluey substance which oozes out of plants (mucilage). In addition, it can be found in celery, honey, cherries, kiwifruit, beans, peas, plums, and dried figs. N-acetyl galactosamine is found in shark cartilage but the body can make this N-acetyl amino form if it has sufficient quantities of galactose. You can also request resources at

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