From the Guidelines
Limiting dietary phosphate intake to 800-1000 mg daily is crucial for maintaining balanced phosphate levels and supporting Klotho expression, particularly in individuals with kidney disease or those at risk for mineral metabolism disorders. This recommendation is based on the most recent and highest quality study available, which suggests that excessive phosphate consumption can suppress Klotho expression and contribute to vascular calcification and accelerated aging 1.
Key Considerations
- Focus on natural food sources like fruits, vegetables, and unprocessed proteins while avoiding phosphate additives in processed foods
- Phosphate binders such as calcium acetate, sevelamer, or lanthanum carbonate may be prescribed for those with kidney disease to take with meals at doses determined by a physician
- Regular exercise, adequate vitamin D intake (600-800 IU daily), and maintaining normal potassium levels help support Klotho expression
- Regular monitoring of serum phosphate levels (target range 2.5-4.5 mg/dL) is recommended, especially for those with kidney disease or other risk factors for mineral metabolism disorders
Rationale
The relationship between dietary phosphate intake and Klotho levels is complex, and excessive phosphate consumption can have negative effects on kidney and cardiovascular function. The study published in the Annals of Internal Medicine in 2018 1 provides the most recent and highest quality evidence on this topic, and its recommendations should be prioritized in clinical practice.
Additional Factors
- High phosphate intake, particularly from processed foods and sodas, can contribute to vascular calcification and accelerated aging
- Klotho is a protein that regulates phosphate metabolism and has anti-aging properties, and its levels naturally decline with age and kidney disease
- The optimal PTH level for patients with CKD stage G3a to G5 is not known, but treatment should focus on patients with overt hyperphosphatemia and avoid inappropriate calcium loading 1
From the Research
Relationship Between Dietary Phosphate Intake and Klotho Levels
- The relationship between dietary phosphate intake and Klotho levels is complex, with evidence suggesting that high dietary phosphate intake can lead to decreased Klotho expression 2.
- Klotho is a putative aging suppressor gene that plays a crucial role in the regulation of phosphate and calcium in the body, and its expression is decreased in individuals with chronic kidney disease (CKD) 2.
- Decreased Klotho expression is thought to be an early biomarker of CKD and can lead to FGF-23 resistance, hyperphosphatemia, and hypovitaminosis D 2.
- Maintaining normal phosphate levels with phosphate binders in patients with CKD may help reduce mineral and vascular derangements and slow the progression of CKD 3, 2.
Mechanisms of Phosphate-Induced Klotho Suppression
- High dietary phosphate intake can lead to hyperphosphatemia, which can suppress Klotho expression and lead to CKD-MBD-like phenotypes 2.
- The mechanisms of phosphate-induced Klotho suppression are not fully understood but may involve the activation of the renin-angiotensin-aldosterone system (RAAS) and stimulation of sympathetic tone 4.
- Elevated dietary phosphate intake has been associated with increased cardiovascular mortality and morbidity, and may contribute to the development of hypertension and cardiovascular disease 4.
Clinical Implications
- Careful dietary management to reduce high phosphate intake is recommended to slow the progression of CKD and prevent complications 3.
- Phosphate binders may be used to maintain normal phosphate levels in patients with CKD, and may help reduce mineral and vascular derangements 3, 2.
- Further research is needed to fully understand the relationship between dietary phosphate intake and Klotho levels, and to develop effective strategies for preventing and treating CKD and related disorders 5, 6.