Popeye the Sailor from that old cartoon, definitely made the right decision when consuming a can of spinach regularly.  Eating leafy, green vegetables, like spinach, bok choy, and broccoli help make you stronger and improve your immune system defenses.  Researchers have been studying this effect and discovered the chemicals, specific cells, and receptors that play an important role in the functioning of the immune system.

Specifically, intra-epithelial lymphocytes (IELs), cells in the gut and skin, play a vital part in improving immune defenses. In one study, after mice were fed a vegetable-poor diet, 70-80% of their IELs disappeared.  IELs form the layer of cells just below the outer epithelial layer and act as a first line of defense while also mending wounds. Marc Veldhoen and his team of the Babraham Institute in Cambridge found that IELs rely on cell-surface proteins called aryl hydrocarbon receptors (AhR). These receptors are controlled by the essential dietary elements found in green vegetables. Studies show that mice that are deficient in this vital receptor lack control over the bacteria on their intestinal surface.

Results from another experiment show that mice fed a diet missing the significant and vital compounds in green vegetables have reduced AhR activity and decreased numbers of IELs. These mice are also more susceptible to injury and infection.

Scientists believe these experimental findings in mice may also apply to humans.  So just like mom says: “be sure to eat your vegetables!”

Discussion Question: What are some other ways to improve your immune defense besides eating green vegetables?

News article: http://www.sciencedaily.com/releases/2011/10/111013121509.htm
Journal article: http://www.cell.com/abstract/S0092-8674(11)01136-6

Picture: http://en.wikipedia.org/wiki/File:Ong_choy_water_spinach.png