Review scope

This summary is based on the published abstract. We have not appraised the full methods, tables or supplementary material. Details absent from the abstract remain unverified.

Question and design

75 healthy adult cats, 25 per group. Foods with total phosphorus of 4 or 5 g/1,000 kcal, including 1 g phosphorus from sodium tripolyphosphate; calcium:phosphorus ratios above one. Comparator: Lower-phosphorus control food.

What was measured?

Blood and urine markers, kidney filtration, ultrasound and bone density.

Main findings

The abstract reports no adverse kidney, bone or general-health effects. Several mineral and biochemical measurements changed.

Study strengths

Randomised parallel groups and repeated functional measurements.

Limitations

Results depend on phosphate source, calcium balance, population and duration. They do not establish safety for all formulations or cats with kidney disease.

Researchers’ conclusion

The authors proposed a no-observed-adverse-effect level for the tested STPP formulations.

Evidence.pet interpretation

Read alongside higher-phosphorus studies with different salts and calcium ratios. Total phosphorus alone does not explain the comparison.

Funding and conflicts

Full funding and conflict declarations were not appraised for this abstract-based summary.

Source and review date

Coltherd JC et al. Seven-month feeding study investigating no observed adverse effect levels for phosphorus in adult-cat diets. British Journal of Nutrition. 2021;126(11):1626–1641. Title shortened; DOI identifies the paper.

Read the primary source · DOI record

STU-042. Reviewed 25 September 2026. Next review 25 December 2026.