Having deficiencies in vitamins, minerals, antioxidants or other essential micronutrients have been shown to suppress the immune system which can contribute to chronic disease processes. A simple blood test can measure the micronutrient levels within the white blood cells, specifically the lymphocytes. Since lymphocytes have about a 6-month lifespan, the nutrient levels accumulated in these cells represent a history of one’s nutrient status, rather than just a snapshot of recent nutrient intake.