Hidden sources of phosphorus: presence of phosphorus-containing additives in processed foods.

INTRODUCTION AND OBJECTIVES: An increased consumption of processed foods that include phosphorus-containing additives has led us to propose the following working hypothesis: using phosphate-rich additives that can be easily absorbed in processed foods involves a significant increase in phosphorus in the diet, which may be considered as hidden phosphorus since it is not registered in the food composition tables. MATERIALS AND METHOD: The quantity of phosphorus contained in 118 processed products was determined by spectrophotometry and the results were contrasted with the food composition tables of the Higher Education Centre of Nutrition and Diet, those of Morandeira and those of the BEDCA (Spanish Food Composition Database) Network. RESULTS: Food processing frequently involves the use of phosphoric additives. The products whose label contains these additives have higher phosphorus content and higher phosphorus-protein ratio. We observed a discrepancy with the food composition tables in terms of the amount of phosphorus determined in a sizeable proportion of the products. The phosphorus content of prepared refrigerated foods hardly appears in the tables. CONCLUSIONS: Product labels provide little information on phosphorus content. We observed a discrepancy in phosphorus content in certain foods with respect to the food composition tables. We should educate our patients on reviewing the additives on the labels and on the limitation of processed foods. There must be health policy actions to deal with the problem: companies should analyse the phosphorus content of their products, display the correct information on their labels and incorporate it into the food composition tables. Incentives could be established to prepare food with a low phosphorus content and alternatives to phosphorus-containing additives.

The impact of processing meat and fish products on phosphorus intake in chronic kidney disease patients.

INTRODUCTION AND OBJECTIVES: The use of phosphate additives in meat and fish processing leads to a phosphorus overload that we cannot quantify through labelling or food composition tables. We analysed this increase by measuring phosphorus content in these products by spectrophotometry. MATERIALS AND METHOD: We determined the phosphorus/protein ratio in fresh meat and fish products with varying degrees of processing by spectrophotometry (phosphorus) and the Kjeldahl method (proteins). We contrasted these results with those reflected in the food composition tables. RESULTS: The phosphorus/protein ratio was higher in processed meat products (15.83 mg/g) than in battered (11.04 mg/g) and frozen meat products (10.5mg/g), and was lower in fresh (8.41 mg/g) and refrigerated meat products (8.78 mg/g). Fresh white fish had a phosphorus/protein ratio of 8.58mg/g, while it increased by 22% (10.3mg/g) in frozen white fish and by 46% (12.54 mg/g) in battered fish. The information in the tables was poor and confusing, and no reference is made to the brands tested. CONCLUSIONS: Processing meat and fish products poses a serious obstacle to the reduction of phosphorus intake. The current regulatory framework does not assist us in the objective of reducing phosphorus additives, since it considers them safe for public consumption. Overcoming these barriers requires a coordinated effort to demonstrate that a high intake of these additives may be harmful to the general population and it should be more closely examined by regulators.