There are no official guidelines to assist in answering this question. I will search for relevant research papers instead.
From the Research
Calcium Supplements and Phosphate Levels
- The effect of calcium supplements on phosphate levels is a topic of interest in the context of osteoporosis prevention [(1,2,3)].
- A study published in The British journal of nutrition found that microcrystalline hydroxyapatite (MCH) increased phosphate concentrations and the Ca-phosphate product, whereas calcium citrate and carbonate did not have this effect 1.
- A meta-analysis published in Nutrition journal found that phosphate supplements decreased urine calcium excretion and increased calcium balance, regardless of calcium intake or the degree of protonation of the phosphate supplement 2.
- Another study published in the Journal of the American College of Nutrition found that increasing calcium intake decreased phosphorus absorption, and that high Ca:P ratios can occur with the use of non-phosphate calcium salts 3.
Implications for Osteoporosis Prevention
- The relationship between calcium supplements, phosphate levels, and osteoporosis prevention is complex [(4,5)].
- While calcium supplements may have a role in preventing osteoporosis, their effect on phosphate levels and overall bone health must be considered [(1,2,3)].
- Some studies suggest that calcium supplements may not be necessary for individuals with adequate dietary calcium intake, and that they may even have negative effects on cardiovascular health [(4,5)].