Harnack · Circulation 2017 · cross-sectional study · n=450

Sources of Sodium in US Adults From 3 Geographic Regions.

Cited 189 times in the scientific literature.

Level 4 - case-series / case-control

Cross-sectional observational dietary survey

PubMed 28483828 · doi:10.1161/CIRCULATIONAHA.116.024446 · record verified 2026-08-29

What was done

Researchers measured dietary sodium sources in 450 adults recruited equally across three US metropolitan regions (Birmingham, AL; Palo Alto, CA; Minneapolis-St. Paul, MN; n=150 per site). Recruitment targeted equal numbers of men and women across four racial/ethnic groups (Black, Asian, Hispanic, and non-Hispanic White). Each participant completed four record-assisted 24-hour dietary recalls incorporating duplicate sampling of salt added at home and at the table.

What was found

Sodium added to food outside the home was the primary contributor to intake across all demographic subgroups, accounting for 70.9% of total sodium (ranging from 66.3% among individuals with high school education or less to 75.0% in adults aged 18–29 years). Naturally occurring sodium inherent to food accounted for 14.2%, salt added in home cooking accounted for 5.6%, and salt added at the table accounted for 4.9%. Home tap water, dietary supplements, and non-prescription antacids contributed less than 0.5% each.

Why it matters

These findings provide direct quantitative evidence that individual discretionary salt use accounts for only a minor fraction (~10.5%) of dietary sodium intake in the US, demonstrating that population-level sodium reduction depends primarily on modifying commercially processed and restaurant foods.

Limits

The sample was geographically restricted to three urban areas and, while balanced across demographic strata, was not nationally representative. Self-reported dietary recalls and duplicate sampling remain susceptible to reporting errors and social desirability bias despite standardisation protocols.

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