Impact of Food Additives on Phosphorus Metabolism

INTRODUCTION: Phosphorus-based food additives are common in processed foods. These additives may increase blood levels of phosphorus and phosphorus-regulatory hormones such as fibroblast growth factor 23 (FGF23), both of which have been implicated in cardiovascular disease. The purpose of this study was to examine the effects of food additives on phosphorus and FGF23 in healthy adults.

METHODS: Thirty-four healthy adults participated in this study, with balanced enrollment by sex and race. Separate menus for low- and additive-enhanced diets were developed. After baseline measures were collected, participants were fed standardized diets over the following four weeks. During the first two weeks, participants were fed a diet designed to provide ~2,000 kcal and 1200-1500 mg of phosphorus per day using foods known to be free of phosphorus additives. For the subsequent two weeks, participants were fed an additive-enhanced diet containing food items similar to the low-additive diet, but enriched with phosphorus additives. Blood and urine specimens were collected throughout the study period.

RESULTS: The mean age of the study population was 28 ± 8 years. The measured phosphorus content of the additive-enhanced diet was ~635 mg higher than the low-additive diet. After two weeks on the additive-enhanced diet, levels of FGF23 increased by 11% (P=0.02). Additionally, serum phosphorus concentrations significantly decreased by 9% (P=0.002). There were no other significant changes in parameters of mineral metabolism.

DISCUSSION: A diet high in phosphorus can increase levels of FGF23 in healthy people, which may negatively influence long-term health outcomes.