Potassium, calcium and magnesium are NOT heavy metals ... even in their pure state, they are minerals that are readily dissolved in water solution .. as opposed to mercury, lead or aluminum. THOSE are heavy metals.

K (potassium), Ca (calcium) and Mg (magnesium) are vital minerals called electrolytes, without which the human body could not function at all. They are vital for transmission of nerve impulses, muscle contraction (in particular the heart muscle and the muscles in our arms and legs called skeletal muscles).

K, Ca and Mg are found in EVERYTHING you eat. Since they are dissolved in water ... increases in urine output can cause to levels being depleted, especially K and Mg. Certain disease states can cause the body to retain these electrolytes .. kidney failure especially, and certain blood pressure and heart medications. Most foods contain these minerals in greater or lesser amounts. Dark green leafy vegetables and ocean fish are rich in potassium and magnesium especially.

The daily requirement for potassium is 2500 mg per day -- some of this is recycled by the body, some will come from food. When there is increased water loss .. eg, the early stages of low-carbing, heavy exercise & sweating, etc .. a supplement ensures that levels remain adequate. The daily requirement for magnesium is 450 mg, and for calcium it's 1,000 to 1,500 mg per day. The World Health Organization has recognized that chronic deficiency of calcium is the leading cause of osteoporosis in adults over age 50.

Healthy kidneys are designed to prevent a buildup of these electrolytes. Unfortunately, there's not a similar mechanism to ensure that they are not lost, and so they must be replaced on a daily basis or levels will drop.

A blood test is certainly worthwhile .. but I think your doctor is over-reacting and, dare I say, misinformed.

Doreen