The crossword solution for the term 'SPINACH IS RICH IN IT' is IRON, which has 4 letters. Spinach is a leafy green vegetable that is a good source of IRON, which is an essential mineral for the human body. IRON helps to transport oxygen throughout the body and is important for energy production and metabolism. Spinach is also rich in other vitamins and minerals, such as calcium, magnesium, and potassium.