Phosphorous and Health

On September 9, Dr. Holly Kramer presented a grand rounds presentation for the Loyola Department of Preventive Medicine which focused on inorganic phosphorous and its potential effects on health. Inorganic phosphorous simply refers to phosphorous which is added to processed foods as a preservative. For example, coke has 40 mg of inorganic phosphorous in every 12 ounce serving. A typical serving is 20 ounces which is almost 80 mg of phosphorous, or approximately 10% of the daily recommended allowance of phosphorous. Previous research which utilized food frequency questionnaires from a random sample of the U.S. population showed that phosphorous intake is increasing while calcium intake is decreasing. This is important because it is recommended that adults consume as much calcium as phosphorous (1:1 ratio). In infants, calcium intake should be higher than phosphorous. Prolonged and high phosphorous intake may increase levels of fibroblast growth factor-23 (FGF-23), a protein which leads to increased urine excretion of phosphorous and reduced levels of active forms of vitamin d. In adults with severe kidney disease, high levels of FGF-23 are associated with increased mortality. Certainly as the consumption of processed foods continues to rise, more research is needed to determine the health effects of increased intake of inorganic phosphorous, especially among adults with normal kidney function. The fact that phosphorous intake influences the health of individuals with kidney disease has substantial policy implications. Currently, food suppliers are not required to indicate the amount of phosphorous in foods via food labels. Over 10 million adults have kidney disease in the U.S. and information on phosphorous in foods is important for their health.