Food Additive Extends the Life of Your Food But May Shorten Yours

By: David A Fein, MD
Medical Director

There’s an ingredient that has been steadily increasing in the American diet and it might be killing you. It’s not sugar, it’s not fat and it’s not cholesterol. The culprit is phosphorus and more than one-third of Americans have a diet that is high in this common element. Results of a study recently published in the American Journal of Clinical Nutrition show that a high intake of phosphorus can more than double your risk of early death.

Inorganic phosphates are added to processed foods as preservatives and are the chief sources of phosphorus in the U.S. diet. While organic phosphates are present naturally in many foods, it appears that the absorption of phosphorus from the inorganic phosphates that are added to processed foods is much greater.

Researchers at Case Western Reserve University previously found that 44% of the 2,394 top-selling branded grocery products contain phosphorus additives. The additives were present in 72% of prepared frozen foods, 70% of dry food mixes, 65% of packaged meats, 57% of baked goods, 54% of soups, and 51% of yogurts. Phosphorus-added foods were not only widespread, they cost less than foods free of phosphorus additives.

The new data, from an on-going study known as NHANES III, followed 9,686 individuals for a median of 14.6 years. The recommended daily allowance for phosphorus is 700 mg per day or less. During this study, the overall mortality rate for those who consumed more than 1,400 mg of phosphorus per day was 2.23 times higher than for those with lower phosphorus intake. The risk of dying from cardiovascular disease in the high phosphorus group was more than 3.4 times higher.

While it might be tempting to blame the higher death rate on other lifestyle factors associated with a diet high in phophorus (eating more processed foods might be associated with being unhealthy in other ways), it turns out that those who had a higher phosphorus intake at the start of the study actually tended to have healthier lifestyles.

The study concluded that a high phosphorus intake is associated with “increased mortality in a healthy U.S. population”. There are animal studies that might shed some light on why a high phosphorus intake increases health risks. Those studies have shown an increase in arterial calcification (part of the process of atherosclerosis leading to heart attacks and strokes) as well as decreased elasticity of artery walls. There may also be effects on tissue growth factors that lead to changes in heart and kidney function. It has also been previously recognized that there is an association between high blood phosphate levels and increased cardiovascular mortality in patients with chronic kidney disease.

While there are there no published studies that have proven that reducing phosphorus intake would reduce the risk of death, it seems prudent to limit your intake of foods with high levels of phosphates, including many sodas that use phosphoric acid for flavoring, and check the labels of any processed foods to see if phosphates are listed as an ingredient.