Cabbage is a cruciferous vegetable belonging to the same Brassica genus as broccoli, kale, watercress, brussel sprouts, turnips and rape seed. Cabbage has historically been grown in cooler climates where it yields a higher weight per acre of land in comparison to other crops. The main varieties of cabbage are savoy cabbage, green cabbage and red cabbage. While red cabbage and green cabbage tend to have smooth leaves, savory cabbage has more ruffled leaves that give it a distinctive shape. Cabbage is highly nutrient dense and contains high amounts of vitamin C, folic acid, vitamin B6. As with most fruits and vegetables, cabbage is also high in potassium, and in addition contains high amounts of calcium, magnesium and manganese. Of course as with all minerals, the content in the plant material is dependent on the soil concentrations of minerals. In addition, cabbage is rich is the amino acid L-glutamine, and this gives it some unique properties.
L-glutamine is an amino acid that plays an important role in protein metabolism through its ability to take part in the transfer of nitrogen groups between amino acids. In this regard it works closely with another structurally similar amino acid called glutamate. Glutamine is particularly concentrated in muscle tissue, and can be used as a source of energy by neurones. Enterocytes also utilise large amounts of glutamine and for this reason much of the ingested glutamine never makes it into blood, instead being used up in the enterocytes of the gut and a fuel source. The ability of glutamine to fuel enterocytes increases their growth rates and glutamine is therefore effective as a healing agent for the gut. This explains the ability of cabbage to help with the treatment of gastrointestinal complaints including the treatment of peptic ulcers. Originally the component of cabbage that was beneficial to the gut was identified as vitamin U, but this was later subsequently identified and L-glutamine.