Phosphate, Phosphatonins reduce active Vitamin D - many studies
Excess phosphate in modern foods blocks calcium, which causes a variety of health problems - Aug 2024
Hidden Ingredient in Your Food Is Hurting Your Health: The Phosphate Problem
"Modern diets often contain 2 to 3 times more phosphorus than recommended, while calcium intake frequently falls below recommended levels. Phosphate additives are prevalent in processed meats, cheese, baked goods, soft drinks, and even grocery store fresh meat"
" Food labels aren't required to list phosphate content,... "
"The relationship between calcium and phosphorus is so crucial that nutritionists often speak of the calcium to phosphorus ratio (Ca:P) as a key indicator of dietary health. Ideally, this ratio should be close to 1:1 or higher , meaning we should consume roughly equal amounts of calcium and phosphorus, or slightly more calcium than phosphorus in our diets."
Food manufacturers use phosphate additives for various reasons:
To increase water-holding capacity in meats
To increase meat pH and slow discoloration
To reduce cooking losses
To retard oxidative rancidity
To protect against microbial growth
Common Sources in Food
Processed meats — Bacon, sausages, hot dogs, and deli meats often contain added phosphates as preservatives and to improve texture.
Cheese — Many types of processed, industrial cheese and cheese spreads have added phosphates to enhance texture and melting properties.
Baked goods — Packaged bread, cakes, cookies, and other baked items may have added phosphates as leavening agents.
Soft drinks — Some carbonated beverages, especially colas, contain phosphoric acid, a type of phosphate.
Ready-to-eat meals — Frozen dinners and other convenience foods can contain phosphates to improve shelf life and texture.
Instant foods — Instant noodles and soups may contain phosphates to enhance flavor and texture.
See in Vitamin D Life Ultra-processed foods associated with worse health and lower Vitamin D - many studies
Phosphatonins: From Discovery to Therapeutics - Oct 2022
Endocr Pract . 2022 Oct 6;S1530-891X(22)00625-5. doi: 10.1016/j.eprac.2022.09.007
Kittrawee Kritmetapak 1 , Rajiv Kumar 2
Phosphate is crucial for cell signaling, energy metabolism, nucleotide synthesis, and bone mineralization. The gut-bone-parathyroid-kidney axis is influenced by parathyroid hormone (PTH), 1,25-dihydroxyvitamin D (1,25(OH)2D), and phosphatonins, and facilitates maintenance of phosphate homeostasis. Phosphatonins including fibroblast growth factor 23 (FGF23), secreted frizzled-related protein 4 (sFRP4), matrix extracellular phosphoglycoprotein (MEPE), and fibroblast growth factor 7 (FGF7) play a pathogenic role in several hypophosphatemic disorders. Excess FGF23 inhibits sodium-dependent phosphate cotransporters (NaPi-2a and NaPi-2c), resulting in hyperphosphaturia and hypophosphatemia. Additionally, FGF23 suppresses 1,25(OH)2D synthesis in the proximal renal tubule, and thus it indirectly inhibits intestinal phosphate absorption. Disorders of FGF23-related hypophosphatemia include X-linked hypophosphatemia (XLH), autosomal dominant hypophosphatemic rickets (ADHR), autosomal recessive hypophosphatemic rickets (ARHR), fibrous dysplasia/McCune-Albright syndrome, and tumor-induced osteomalacia (TIO). Complications of conventional therapy with oral phosphate and vitamin D analogs comprise gastrointestinal distress, hypercalcemia, nephrocalcinosis, and secondary/tertiary hyperparathyroidism. In both children and adults with XLH and TIO, the anti-FGF23 antibody burosumab exhibits a favorable safety profile and is associated with healing of rickets in affected children and improvement of osteomalacia in both children and adults. This review summarizes current knowledge regarding the phosphate homeostasis, phosphatonin pathophysiology, and clinical implications of FGF23-related hypophosphatemic disorders, with specific focus on burosumab treatment.
📄 Download the PDF from Vitamin D Life
Vitamin D and Phosphate Interactions in Health and Disease - March 2022, book chapter
DOI: 10.1007/978-3-030-91623-7_5 10 pages
Nuraly S. Akimbekov, Ilya Digel, Dinara K. Sherelkhan & Mohammed S. Razzaque
Vitamin D plays an essential role in calcium and inorganic phosphate (Pi) homeostasis, maintaining their optimal levels to assure adequate bone mineralization. Vitamin D, as calcitriol (1,25(OH)2D), not only increases intestinal calcium and phosphate absorption but also facilitates their renal reabsorption, leading to elevated serum calcium and phosphate levels. The interaction of 1,25(OH)2D with its receptor (VDR) increases the efficiency of intestinal absorption of calcium to 30–40% and phosphate to nearly 80%. Serum phosphate levels can also influence 1,25(OH)2D and fibroblast growth factor 23 (FGF23) levels, i.e., higher phosphate concentrations suppress vitamin D activation and stimulate parathyroid hormone (PTH) release, while a high FGF23 serum level leads to reduced vitamin D synthesis. In the vitamin D-deficient state, the intestinal calcium absorption decreases and the secretion of PTH increases, which in turn causes the stimulation of 1,25(OH)2D production, resulting in excessive urinary phosphate loss. Maintenance of phosphate homeostasis is essential as hyperphosphatemia is a risk factor of cardiovascular calcification, chronic kidney diseases (CKD), and premature aging, while hypophosphatemia is usually associated with rickets and osteomalacia. This chapter elaborates on the possible interactions between vitamin D and phosphate in health and disease.
97 references online
Phosphate reduction reduced active Vitamin D levels by 50% (not seen by typical Vitamin D tests)
The mechanism runs through FGF23. High serum phosphate stimulates osteocytes to release FGF23, which then does two things to vitamin D:
- Suppresses CYP27B1 (1α-hydroxylase) in the kidney, reducing conversion of 25(OH)D to active 1,25(OH)₂D.
- Induces CYP24A1, accelerating catabolism of both 25(OH)D and 1,25(OH)₂D into inactive metabolites.
So phosphate doesn't block activation directly — it triggers the FGF23 axis that simultaneously throttles activation and speeds up degradation. Net effect is the same: less circulating active vitamin D.
A few points worth flagging for your content:
- Inorganic phosphate additives (the "phos-" ingredients in processed foods, colas, processed meats) are nearly 100% bioavailable, while organic phosphate in whole foods is partially bound as phytate and less absorbable. So additive load matters disproportionately to the FGF23 response — this is the angle most consumers don't see.
- This is the same axis implicated in CKD's vitamin D problems: as kidneys fail, phosphate retention drives FGF23 sky-high, which is a major reason CKD patients become 1,25(OH)₂D deficient even before serum phosphate looks abnormal.
- The phosphate–FGF23–vitamin D loop also feeds back on calcium and PTH, so any "phosphates suppress vitamin D" framing is really part of a broader Pi/Ca/PTH/FGF23/vitamin D regulatory network.
Reducing high intake of Phosphorus increased 1,25(OH)₂D by 50%
Claude AI - April 2026
The Portale work (JCI, the foundational data)
Portale et al. did the most informative controlled feeding studies on this. In the first one (PMC303852), seven normal men had dietary phosphorus reduced from 2,300 to 625 mg/day for 8–9 days each. The result was a 58% increase in serum 1,25(OH)₂D, with a 24-h mean phosphorus drop of only 12%. Serum 1,25(OH)₂D varied inversely with phosphorus (r = −0.77, p < 0.001).
In a follow-up (PMID 3753709), six healthy men went from 1,500 mg/day → 500 mg/day → 3,000 mg/day phosphorus. Phosphorus restriction produced an 80% rise in 1,25(OH)₂D (38 → 68 pg/ml), driven by a doubling of the production rate (1.8 → 3.8 µg/d) with no change in clearance.
So in the high-to-low direction: roughly every ~1,000–1,700 mg/day reduction in phosphorus produced a 50–80% rise in calcitriol. Going the other way, the supplemented (3,000 mg/day) arm pushed 1,25(OH)₂D below the 1,500 mg/day baseline.
Antoniucci 2006 — three-arm dose response with FGF23
Subjects consumed a constant base diet of 500 mg phosphorus, supplemented to three intakes (each 9 days): control 1,500 mg/d, supplemented 2,300 mg/d, restricted 625 mg/d. FGF-23 fell from 30.7 ± 8.7 pg/ml on the supplemented diet to 19.6 ± 7.0 pg/ml on the restricted diet — roughly a 36% drop in FGF23 across an ~1,675 mg/day swing in phosphorus.
The additive-specific number
For your "soda question" framing, the closest direct match is Gutiérrez 2015: about 600 mg of phosphorus added specifically as additives raised FGF23 by 23% in one week. They didn't report 1,25(OH)₂D, but given FGF23 is the proximate suppressor, the directional effect on calcitriol is clear.
Translating to "2 cans of pop"
This is where you have to extrapolate, because nobody has run the trial in this exact form. A 12 oz cola contains roughly 30–45 mg of phosphorus from phosphoric acid (Coca-Cola ~30 mg, Pepsi ~40 mg; clear sodas like Sprite, 7-Up, Mountain Dew use citric acid and have negligible phosphorus). So 2 cans/day adds ~60–90 mg of highly bioavailable inorganic phosphorus.
Working backward from the controlled studies (very rough linear approximation, which the data doesn't strictly support but gives a defensible ceiling):
- Portale: ~1,000–1,700 mg/day swing → 58–80% calcitriol change → roughly 4–6% per 100 mg
- Gutiérrez additive study: 600 mg/day → 23% FGF23 rise → roughly 4% per 100 mg
So two cans of cola/day (≈80 mg added phosphorus) ≈ 3–5% suppression of active vitamin D as a defensible estimate. Your "10%" figure would be closer to what you'd expect from 2 cans plus typical processed-food additive load (a typical American diet adds ~500–1,000 mg/day from additives alone over a fresh-food baseline).
A more impactful framing for your audience might be:
"A daily diet of processed foods can contain ~600 mg more phosphorus than the same diet built from fresh ingredients. Controlled feeding studies show that this is enough to raise FGF23 by ~23% within a week — and FGF23 directly suppresses your kidney's conversion of vitamin D to its active form while accelerating its breakdown."
That's the Gutiérrez 2015 finding stated almost verbatim, and it lands harder than the soda-specific framing because most people now get more added phosphorus from processed cheese, deli meat, "self-basting" poultry, and shelf-stable baked goods than from cola.
Caveats worth flagging on Vitamin D Life
Three things complicate any clean dose-response statement:
The FGF23 response has a lag of up to a week, so acute intake doesn't predict steady-state suppression. Some studies have failed to observe FGF23 changes in healthy individuals on low or high phosphate diets, while others see them only after a lag of up to one week. The Portale numbers are 9-day steady-state values.
The response curve is almost certainly non-linear — diminishing returns at the high end, and the suppression is sharper when you're already vitamin D sufficient. Increasing dietary phosphorus does not raise FGF23 in the absence of VDR, meaning vitamin D-deficient people may have a blunted FGF23 response — though they're also less able to compensate.
In CKD, the dose-response is broken: in CKD stage 3–4 patients on a 1,500 mg phosphorus diet plus placebo, FGF23 levels actually rose, and dietary restriction plus lanthanum lowered urinary phosphate but not FGF23 in this short-term study. So the message for healthy populations vs. CKD populations diverges.