From the Guidelines
To increase dietary phosphorus, it is essential to focus on consuming natural, organic sources of phosphate, such as dairy products, protein-rich foods, nuts, seeds, whole grains, and legumes, rather than relying on processed foods with phosphate additives, due to the potential harm of excessive phosphorus intake, particularly for those with kidney disease, as highlighted by the 2017 KDIGO guideline update 1. When considering dietary phosphorus intake, it's crucial to understand the difference between organic and inorganic phosphate sources. Animal- and plant-based foods contain organic phosphate, which has varying levels of bioavailability, with animal-based phosphate being more absorbable (40-60%) than plant-based phosphate (20-50%) 1.
Key Foods for Phosphorus Intake
- Dairy products (milk, cheese, yogurt)
- Protein-rich foods (meat, poultry, fish, eggs)
- Nuts and seeds (especially pumpkin seeds and sunflower seeds)
- Whole grains
- Legumes (beans, lentils) It's also important to note that processed foods can contribute significantly to phosphate intake, with some adding up to 1,000 mg of phosphate to an individual's daily diet 1. However, the preferred approach is to emphasize natural sources and fresh, homemade foods over processed ones to minimize the risk of excessive phosphorus intake and its associated health issues, such as faster progression of kidney disease 1.
Considerations for Phosphorus Supplementation
Phosphorus supplements, typically in the form of phosphate salts, should only be considered under medical supervision, as excess phosphorus can lead to serious health complications, especially in individuals with kidney disease 1. The general recommendation for daily phosphorus intake is 700 mg for adults, and most people achieve this through a balanced diet without needing supplements 1.
From the Research
Increasing Dietary Phosphorus Intake
To increase dietary phosphorus intake, consider the following food sources:
- Grains: the largest dietary phosphorus source, with an increase of 68 mg/day in phosphorus intake from grains between 2001 and 2014 2
- Meats: the second largest dietary phosphorus source, with an increase of 25 mg/day in phosphorus intake from meats between 2001 and 2014 2
- Milk products: although phosphorus intake from milk products decreased by 75 mg/day between 2001 and 2014, they are still a significant source of phosphorus 2
Phosphorus Balance and Regulation
Phosphorus balance is maintained by multiple systems, including:
- The gut: responsible for the absorption of two thirds of the 4-30 mg/kg/day of phosphate intake 3
- The kidney: filters 90% of the plasma phosphate and reabsorbs it in the tubuli, with the ability to excrete high loads of phosphate and rid the body of phosphate overload 3
- The endocrine system: regulates the phosphate balance by influencing the kidney, gut, and bone through the vitamin D-PTH axis 3
Potential Negative Impact on Bone Health
High dietary phosphorus intake may have negative effects on bone health, particularly if calcium intake is inadequate:
- Higher total habitual dietary phosphorus intake has been associated with higher serum parathyroid hormone (PTH) and lower serum calcium concentrations in healthy individuals 4
- Long-term dietary phosphorus loads and long-term hyperphosphatemia may have important negative effects on bone health, including increased serum PTH and fibroblast growth factor 23 (FGF23) concentrations 4