Getting the recommended 700 milligrams per day of phosphorus will help you form strong bones and DNA and will keep your kidneys, muscles, heart and nerves functioning properly. It is possible, however, to get too much of a good thing, with intakes above the tolerable upper intake level of 4,000 milligrams per day potentially causing adverse effects. People with chronic kidney problems need to be especially careful with their phosphorus intake, since getting too much phosphorus in the diet will increase the stress on their kidneys.
Consuming too much phosphorus can interfere with the balance of phosphorus and calcium in your body, according to a study published in the "Journal of Clinical Biochemistry and Nutrition" in May 2007. If you have excessive amounts of phosphorus circulating in your blood, it can combine with calcium and cause tissue in your organs and muscles to harden, or calcify. This calcification can damage your kidneys or other organs and interfere with their function. However, this usually only occurs in people with kidney damage, in those who have difficulty regulating their calcium levels, or in people with a condition called hypoparathyroidism, which occurs when your body doesn't make enough of the parathyroid hormone.
Increased Heart Disease Risk
A diet that is very high in phosphorus may also increase your heart disease risk, according to a study published in the "Journal of the American Society of Nephrology" in July 2009. Excessive phosphorus can impair the function of your endothelial cells, which line your blood vessels, and increase your risk for hardening of the arteries, or atherosclerosis, which is one of the major risk factors for heart disease.
Decreased Bone Density
According to an article published in "The American Journal of Clinical Nutrition" in July 2013, the amount of phosphorus in the typical American diet is increasing, as many processed foods and sodas are made with phosphorus-containing additives. If you consume more phosphorus than calcium, your body may need to pull calcium from your bones to keep the proper balance of these two nutrients in the blood. This can cause your bone density to decrease, increasing your risk for osteoporosis.
Phosphorus may interact with medications that you take, so check with a doctor before taking phosphorus supplements or before significantly increasing your dietary phosphorus intake. If, for example, you take both phosphorus supplements and potassium-sparing diuretics, it increases your risk for dangerously high blood levels of potassium, which can cause an abnormal heartbeat.