From the Guidelines
Calcium supplements can decrease phosphate levels by forming insoluble complexes in the intestinal tract, which reduces phosphate absorption.
Key Points
- Phosphate supplements should not be given together with calcium supplements or foods with high calcium content, such as milk, as precipitation in the intestinal tract reduces absorption 1.
- Calcium supplements are not recommended for patients with X-linked hypophosphataemia due to the potential risk of hypercalciuria and decreased phosphate absorption 1.
- Nutritional calcium intake should be kept within the normal range for age to avoid excessive calcium absorption and potential adverse effects on phosphate levels 1.
- Phosphate supplements should be given as frequently as possible, for example, 4–6 times per day in young patients with high ALP levels, to maintain stable blood levels 1.
- Active vitamin D (calcitriol or alfacalcidol) is given in addition to oral phosphate supplements to counter calcitriol deficiency, prevent secondary hyperparathyroidism, and increase phosphate absorption from the gut 1.
From the Research
Effect of Calcium Supplements on Phosphate Levels
The relationship between calcium supplements and phosphate levels in the prevention of osteoporosis is complex. Key points to consider include:
- Calcium supplements can affect phosphate levels, as bone mineral consists of calcium phosphate, and phosphorus is essential for bone health 2
- High-dose calcium supplements can bind to food phosphorus, making it unavailable for absorption, which may lead to negative phosphorus balances 2
- A calcium phosphate supplement may be preferable to other forms of calcium supplements, as it can spare food phosphorus and support bone health 2
Risks and Benefits of Calcium Supplementation
While calcium supplements are often used to prevent osteoporosis, their effectiveness and safety are debated. Consider the following:
- Some studies suggest that calcium supplements may have a negative risk-benefit effect, with increased risks of gastrointestinal side effects, renal calculi, and myocardial infarction 3
- Calcium supplementation may not be effective in preventing fractures, with some studies showing little evidence of a relationship between calcium intake and bone density or fracture risk 3, 4
- The optimal intake of calcium and its role in osteoporosis prevention are still unclear, and further studies are needed to determine the health effects of calcium supplementation 5, 6
Importance of Phosphorus Nutrition
Phosphorus nutrition is essential for bone health, and adequate phosphorus intake is necessary to support bone augmentation and maintenance. Key points include: