Although most people are familiar with spinach's vitamins and other health benefits, not everyone should eat spinach.
According to the Mayo Clinic, fatigue can be caused by iron deficiency anemia, where red blood cells are unable to transport oxygen — resulting in fatigue. In spite of the fact that spinach isn't exactly a cure-all for this type of anemia, its iron content can prove beneficial for someone with it (via Consumer Reports). According to the USDA, 100 grams of baby spinach contain 1.26 milligrams of iron, while 100 grams of mature spinach contain 1.05 milligrams.
Additionally, spinach contains large amounts of vitamin K, which interferes with blood thinners such as warfarin, helping with fatigue caused by iron deficiency anemia. If you are on warfarin or a blood thinner, consult your doctor before adding spinach (or other vitamin K-rich foods) to your diet.
