A lack of magnesium will cause muscle contractions and spasms. When those spasms affect the heart its called a heart attack. Doctors appears to be oblivious to dangers of low magnesium and are incredibly ignorant about nutrition. Blood tests show no magnesium deficiency because modern medicine only checks the blood and disregards the fact only 1% of the magnesium is in the blood, the rest in in the cells and the body pulls it out if blood gets low. Its almost like they are total ignorant about nutrition, which they are.