Research Update: High-Phosphorus, Nutrient-Poor Foods

You may want to add phosphorus to the list of concerns related to purchasing and consuming highly processed foods and beverages, like soft drinks and deli meats, for example. Emerging evidence suggests that high intakes of the mineral phosphorus could increase the risk of cardiovascular disease, as well as mortality.

Getting more than you bargained for. Phosphorus, an essential nutrient found in many protein-rich foods, such as eggs, milk, fish, meat, nuts, legumes, and whole grains, is primarily used by the body for the repair and growth of cells and tissues. But the supply of phosphorus in our food system is increasing; the nutrient is now added to products like soft drinks, flavored waters, deli meats, processed cheeses, and baked goods as a preservative, anti-caking and leavening agent. Examples of these additives include dicalcium phosphate, disodium phosphate, monosodium phosphate, sodium acid pyrophosphate, tricalcium phosphate, and trisodium triphosphate. Since food manufacturers are not required to label the amounts of phosphorus in products, you may be unaware of how much you’re consuming.

Negative impact on health. Elevated FGF23 (fibroblast growth factor-23), a hormone that regulates phosphate excretion, may be an indicator of heart disease, according to Geoffrey Block, M.D., director of clinical research at Denver Nephrology, a medical practice group with a clinical research division. High intake of dietary phosphorus elevates the level of FGF23 in the blood, which may raise the risk for mortality. This is of particular concern for people with impaired kidney function, as they may not be able to excrete phosphorous adequately, which can lead to calcium deposits in the arteries and heart disease. Phosphorus is a concern even if you have healthy kidneys. A 2007 study from the Archives of Internal Medicine suggests that serum phosphorus levels can take a toll on heart health among adults, with or without kidney disease. Individuals with the highest levels of serum phosphorus were found to have a 55 percent increased risk for heart disease compared to those with the lowest levels. Another study reported at the National Kidney Foundation in 2008 found that mortality risk increased by 24 percent among people with higher levels of phosphate in their blood.

Just the right amount. The perfect balance of phosphorus is desirable; you need it for energy production and healthy bones and teeth. The RDA is set at 700 milligrams (mg) for adults over 19 years of age, but most adults consume 1,000 - 1,600 mg per day. We need more research to clarify the role that high phosphorus intake plays on health, but it does appear to be another factor to consider when making the best eating choices. Your best advice is to get enough phosphorus from eating nutrient-rich whole foods, such as lean meats, poultry, fish, dairy products, beans, vegetables, fruits and nuts; and limit nutrient-poor, highly processed foods, such as sodas, snack foods, and baked goods. That’s good advice for just about everything.

This was Research Update was written by McKenzie for the May 2013 issue of Environmental Nutrition.