Spinach is a rich source of protein, iron, magnesium, potassium, folate and vitamin A. The antioxidant alpha-lipoic acid present in spinach helps in lowering blood glucose level and increases insulin sensitivity of the body. The high potassium content reduces high blood pressure by negating the effects of sodium in the body. In addition, it is also a rich source of vitamin K, a vitamin rare to find in vegetables that helps in improving bone health. The antioxidant glutathione found in spinach protects DNA from oxidation and also flushes out pollutants and carcinogens from the body. The best way to juice this intensely healthy vegetable is by rinsing the leaves and putting it in the juicer.