Magnesium - a chemical element with the symbol Mg. The mineral element that is classified as a macronutrient because it is found in the human body in significant amounts. In the human body, magnesium is stored mainly in the bones and muscles, and only 1% of the element is found in the blood. It is a compound that is widely distributed in food, and is found in both animal and plant products. Nutritional sources of magnesium include whole grain cereals, dry pulses, as well as nuts and green leafy vegetables Potassium - a chemical element with the symbol K, which is the most abundant intracellular cation in the human body.