I realize that high cholesterol levels are found in heart disease, but nutritionists contend this is but a symptom of the disease, not the cause. High cholesterol is symptomatic of many other diseases as well and is caused by an underlying nutritional deficiency, dietary intake and lifestyle. A deficiency of the B vitamins and magnesium harm artery walls and weaken the heart muscles. Rancid and hydrogenated oils are very toxic to the heart. Lack of exercise, high stress levels and depression all contribute to heart disease.