Sodium intake and cortisol levels in 630 adults
What it found
Eating more sodium raised cortisol in urine and slightly lowered it in morning blood samples in 630 adults.
The changes happened within one week.
What they found
Studies in people
More sodium, more urinary cortisol
When participants ate the high-sodium diet, their average 24-hour urinary cortisol rose by 47% compared with the low-sodium diet. About 84% of the 630 people showed this increase.
False-positive screening risk
On the high-sodium diet, far more people crossed every cutoff used to flag high cortisol in urine. Using the strictest cutoff, 17% of people were flagged compared with only 4% on the low-sodium diet.
Morning blood cortisol fell slightly
Morning blood cortisol was a little lower after the high-sodium diet than after the low-sodium diet. About 59% of participants showed this small drop.
Same pattern across blood pressures
Urinary cortisol went up on the high-sodium diet whether participants had normal blood pressure or stage I high blood pressure.
What the authors conclude
- They conclude that eating more sodium substantially raises cortisol in urine and slightly lowers it in morning blood samples.
- The authors advise doctors to think about a patient's sodium intake when reading cortisol tests, because it may lead to false-positive results.
- They suggest clinicians might measure sodium in the same urine sample or recommend moderate sodium intake in the days before testing.
How it was done
Doctors use a 24-hour urine test for cortisol to check for a condition where the body makes too much of this hormone. The authors wanted to see if how much sodium people eat could change those test results and cause false alarms.
Six hundred thirty generally healthy adults each followed two diets for five to seven days: one very low in sodium (230 mg per day) and one very high (4600 mg per day). At the end of each diet, they collected all their urine for 24 hours and gave a morning blood sample. Participants stopped certain blood pressure medicines one to three months before testing.
What it can’t tell you
- The study used extreme sodium amounts that are higher and lower than what most people actually eat day to day. Real-world changes in sodium intake might cause smaller shifts in cortisol.
- Participants and researchers knew which diet was being eaten at each stage, so expectations could have influenced some results.
- This trial tested short-term diet changes over five to seven days, so it cannot show what happens with long-term sodium habits.
Who paid
- Funding
- Funded by NHLBI NIH HHS; NIDDK NIH HHS; NCATS NIH HHS (from the PubMed record).
- Conflicts
- Conflicts of Interest: AV reports consulting fees unrelated to the contents of this work from Corcept Therapeutics, HRA Pharma, Orphagen Pharmaceuticals, Catalys Pacific. AV, AXC, AVH and GWH have nothing to disclose
- Authors work at
- Brigham and Women's Hospital, USA; Flinders Medical Centre, Australia; Flinders University, Australia
The paper
- Title
- Dietary sodium intake and cortisol measurements
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Chen AX, Haas AV, Williams GH, Vaidya A (2020). Dietary sodium intake and cortisol measurements. Clinical endocrinology. doi:10.1111/cen.14262Free full textPubMed 32511774DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error