Spinach
Popeye knew what he was doing. Spinach may boost the immune system, as it contains many essential nutrients and antioxidants, including flavonoids, carotenoids, vitamin C and vitamin E. Vitamins C and E can help support the immune system. Other health benefits include helping eye health, cancer prevention, and reduced levels in blood pressure.
It is even said to prevent some hair loss thanks to its high concentration of iron. It’s best to eat spinach as fresh as possible as it loses nutrients with each passing day until 8 days after harvest. When fresh its leaves are crisp to bite. Raw spinach is also 91% water so it can be consumed in large quantities with no fear of weight gain. Win-win.