Nutrition basics · Evidence identifiers checked 2026-10-11 · Version 0.1.0 · Not yet reviewed by a clinician
Cutting Salt: Where It Actually Comes From
What dose-response trials found about sodium and blood pressure, why the salt shaker is a small part of the problem, and what to do if most of your sodium comes from other people's kitchens.
Most advice about salt sends you to the shaker, and the intake data say that is roughly a tenth of the problem. A study of sodium sources in US adults found that sodium added outside the home, in processing and in restaurants, supplied 70.9% of total intake; sodium naturally in food supplied 14.2%, salt added in home cooking 5.6% and salt at the table 4.9%. On the benefit side, a dose-response meta-analysis of trials found an approximately linear relationship between achieved sodium intake and blood pressure across 0.4 to 7.6 g of sodium a day, with no flattening, and steeper falls in people with hypertension. A longer-term review found that cutting about 4.4 g of salt a day lowered systolic pressure by 4.18 mmHg and diastolic by 2.06 mmHg on average. Low-sodium salt substitutes work for many people but carry a specific risk in kidney disease and with potassium-sparing medicines.
Not medical advice. This is a plain-language summary of published research for generally healthy adults. It is AI-drafted, has not been reviewed by a clinician, and nothing here diagnoses or treats anything.
What the evidence supports
Sodium added outside the home, in processing and restaurants, supplied 70.9% of total intake in US adults; home cooking salt was 5.6% and table salt 4.9%. c-01
Achieved sodium intake and blood pressure showed an approximately linear relationship across 0.4 to 7.6 g of sodium a day, with no flattening at either end, and a steeper fall in people with hypertension. c-02
A reduction of about 4.4 g of salt a day lowered systolic blood pressure by 4.18 mmHg and diastolic by 2.06 mmHg on average. c-03
Low-sodium salt substitutes can help, but the review flags possible high blood potassium in people with chronic kidney disease or on medicines that reduce potassium excretion. c-04
One next step: Find your two biggest sodium sources this week and change one of them, rather than removing the salt shaker.
The short version
Where the sodium actually is
An intake study of US adults found sodium added outside the home, in processing and in restaurants, accounted for 70.9% of total intake and was the leading source in every subgroup analysed. Sodium naturally present in food supplied 14.2%, salt added in home cooking 5.6% and salt added at the table 4.9%. A separate analysis found pizza, soup and chicken among the top sources across racial and ethnic groups.
The practical consequence is uncomfortable: removing the salt shaker addresses about five percent of your intake. That is still worth doing, but it is not the strategy that moves the number.
A dose-response meta-analysis of randomised trials found an approximately linear relationship between achieved sodium intake and blood pressure across 0.4 to 7.6 g of sodium a day, with no flattening at either end, and a steeper fall in people who already have hypertension. There is no threshold below which it stops mattering and none above which it stops helping.
A review of longer-term modest reduction gives the size: about 4.4 g less salt a day came with 4.18 mmHg lower systolic and 2.06 mmHg lower diastolic pressure on average. That is a modest, real change in a risk factor, not a treatment for established hypertension.
Low-sodium salt substitutes replace some of the sodium with potassium and can help reduce intake without changing what you cook. The review of them flags a specific safety issue: possible high blood potassium in people at risk, including those with chronic kidney disease or taking medicines that reduce potassium excretion. For most people that is not a problem; for those groups it is a reason to ask a clinician or pharmacist first.
Given where sodium comes from, the highest-yield moves are product choices: check the sodium per serving on the two or three things you buy most often, swap one processed item for a lower-sodium version, and choose one restaurant meal differently. Cooking changes are worth keeping, particularly if you eat a lot of home-cooked food, but no source here tested a home-only strategy against total intake, so it should not carry the whole plan.
Three common beliefs, checked against the intake data and blood pressure trials behind this page.
Pick what you believe first; the evidence answer is revealed after, so you can see where your assumption and the studies part company. Nothing is scored against you.
The salt shaker is the main source of sodium.
Sodium added outside the home supplied 70.9% of intake in a study of US adults; salt added in home cooking was 5.6% and at the table 4.9%.
If your blood pressure is normal, cutting salt does nothing.
A dose-response meta-analysis found a roughly linear relationship across the full range studied in people with and without hypertension, though the fall was steeper in those with hypertension.
Low-sodium salt substitutes are safe for everyone.
Mostly true, with an important exception: the review notes possible high blood potassium in people with chronic kidney disease or taking medicines that reduce potassium excretion.
A bigger change with a broader benefit: home cooking was associated with better diet patterns in other studies in this corpus. For sodium specifically, it addresses about 5.6% of intake in the US data.
Time; and it does not fix restaurant and packaged food sodium.
Choose one or two dishes you order regularly and ask how they are prepared, or pick a lower-sodium option. This is the part of intake most people never see.
Harder to control than home cooking; needs asking.
Estimate where your daily sodium comes from across packaged, restaurant and home cooking, and show which lever is biggest.
Free: source breakdown by percentage; biggest available lever; text export and print; all citations and cautions Plus (optional, $5 one-time, price being tested): calendar (.ics) shopping reminders; unlimited share images; share card without the 'Made with CortexLit' footer Works offline. No account. Every source and caution stays free.
Estimate the blood pressure change associated with a given salt reduction, and flag when a substitute needs medical advice.
Free: full estimate for your planned reduction; safety check on potassium substitutes; text export and print; all citations and cautions Plus (optional, $5 one-time, price being tested): calendar (.ics) review reminders; unlimited share images; share card without the 'Made with CortexLit' footer Works offline. No account. Every source and caution stays free.
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Evidence cards
Each card links a claim from this page to its sources. "Certainty" is our informal editorial judgement of how sure we can be, based on study design, size, consistency, and how closely it fits everyday life. Sources were weighted by type: Cochrane and systematic reviews 1.0, guidelines 0.9, randomized trials 0.8, observational studies 0.5, lab, mechanism or animal work 0.2. That ranking isn't the same thing as certainty.
c-01 In a study of sodium sources in US adults from three geographic regions, sodium added to food outside the home (in processing and restaurants) supplied 70.9% of total sodium intake and was the leading source in every subgroup. Sodium naturally in food supplied 14.2%, salt added in home cooking 5.6% and salt added at the table 4.9%.
Certainty: lowObservational (association only)
Who was studied, what was found, and the limits
Who: US adults in three geographic regions Measured: Proportion of sodium intake by source Finding: 70.9% added outside the home; 5.6% home cooking; 4.9% at the table
Why this certainty: A dietary intake study that quantifies sources rather than assuming them, though observational and specific to the US. (Informal editorial assessment, not a formal GRADE rating.)
Limits: Observational; US food supply, so proportions differ by country; self-reported intake. Applies to: Where to focus if the goal is a real reduction.
Identifier carried over from the 2026-10-11 abstract-level verification batch; not re-queried in this run. Source record
c-02 In a dose-response meta-analysis of trials, achieved sodium intake and blood pressure showed an approximately linear relationship across the full range studied (0.4 to 7.6 g of sodium a day), with no flattening at low or high intakes. Results were similar in people with or without hypertension, though the decrease was steeper in people with hypertension.
Certainty: moderateHuman trials (cause and effect)
Who was studied, what was found, and the limits
Who: Adults with and without hypertension in randomised trials Measured: Blood pressure against achieved sodium intake Finding: Approximately linear across 0.4-7.6 g sodium a day; steeper fall with hypertension
Why this certainty: A meta-analysis of randomised trials with dose-response modelling, so the relationship is causally interpretable. (Informal editorial assessment, not a formal GRADE rating.)
Limits: Blood pressure is a surrogate; trial sodium intakes were achieved under study conditions. Applies to: Why any reduction helps and why no threshold is worth waiting for.
Identifier carried over from the 2026-10-11 abstract-level verification batch; not re-queried in this run. Source record
c-03 In a review of longer-term modest salt reduction, a reduction of about 4.4 g of salt a day lowered systolic blood pressure by 4.18 mmHg and diastolic by 2.06 mmHg on average. Blood pressure status, age, ethnic group and the size of the sodium reduction explained much of the variation between trials.
Certainty: moderateHuman trials (cause and effect)
Who was studied, what was found, and the limits
Who: Adults in trials of longer-term modest salt reduction Measured: Systolic and diastolic blood pressure Finding: -4.18 mmHg systolic, -2.06 mmHg diastolic per ~4.4 g less salt a day
Why this certainty: A review of longer-term randomised trials, so the effect is causal for blood pressure. (Informal editorial assessment, not a formal GRADE rating.)
Limits: Blood pressure is a surrogate for cardiovascular outcomes; the size of reduction varies between people. Applies to: What a realistic reduction buys you on blood pressure.
Identifier carried over from the 2026-10-11 abstract-level verification batch; not re-queried in this run. Source record
c-04 In a review of low-sodium salt substitutes for cardiovascular health, most substitutes replace some sodium with potassium. The review notes concerns about possible high blood potassium (hyperkalaemia) in people at risk, such as those with chronic kidney disease or taking medicines that reduce potassium excretion.
Certainty: moderateHuman trials (cause and effect)
Who was studied, what was found, and the limits
Who: Adults using low-sodium salt substitutes in trials and studies Measured: Cardiovascular outcomes and blood potassium Finding: Substitutes reduce sodium but risk hyperkalaemia in susceptible people
Why this certainty: A review that reports the safety caveat alongside the benefit. (Informal editorial assessment, not a formal GRADE rating.)
Limits: Risk applies to specific groups; not a reason to avoid substitutes generally. Applies to: Who should check with a clinician before switching salt.
Identifier carried over from the 2026-10-11 abstract-level verification batch; not re-queried in this run. Source record
c-05 In a study of sodium sources by racial and ethnic group, nearly all US adults exceeded sodium recommendations. Pizza, soup and chicken were top sodium sources across groups, while for Asian American adults some top sources, such as soy-based condiments, were unique to that group.
Certainty: lowObservational (association only)
Who was studied, what was found, and the limits
Who: US adults analysed by racial and ethnic group Measured: Top dietary sodium sources and reduction behaviours Finding: Pizza, soup and chicken were top sources overall; some sources unique to specific groups
Why this certainty: An observational intake study that shows the top sources are ordinary foods rather than unusual ones. (Informal editorial assessment, not a formal GRADE rating.)
Limits: Observational; US food supply; group averages do not describe individuals. Applies to: Which specific foods to check first in your own week.
Identifier carried over from the 2026-10-11 abstract-level verification batch; not re-queried in this run. Source record
c-06 Because most sodium is added before food reaches your table, the largest available reductions for most people come from which products and restaurant meals they choose rather than from how much salt they add while cooking.
Certainty: moderateEvidence gap
Who was studied, what was found, and the limits
Who: The sodium-source evidence used here Measured: Whether home cooking changes alone shift total intake Finding: No source in this batch measured home-only interventions against total sodium intake
Why this certainty: The source breakdown makes home-only strategies arithmetically limited, but a trial of home-only changes was not found. (Informal editorial assessment, not a formal GRADE rating.)
Limits: Home cooking changes may matter more in countries where less sodium is added in processing. Applies to: Setting expectations for a home-cooking strategy.
Identifier carried over from the 2026-10-11 abstract-level verification batch; not re-queried in this run. Source record
Where studies disagree
How much of intake can home changes reach: The source study attributes 70.9% of sodium to processing and restaurants and only about 10% to home cooking and table salt, while the blood pressure trials show meaningful reductions from modest total cuts. Both can be true: the trials reduced total intake, not just home salt, so a home-only strategy reaches only part of the effect. (src-01, src-02)
Sources for this entry
Every identifier below was verified against PubMed on 2026-10-11 in an earlier batch. This run carried the identifiers over rather than re-querying them, and no retraction database was checked. Verification was at abstract level; full text was not read.
Harnack 2017 Harnack LJ, Cogswell ME, Shikany JM, et al. Sources of Sodium in US Adults From 3 Geographic Regions. Circulation. 2017;135(19):1775-1783. doi:10.1161/CIRCULATIONAHA.116.024446. PMID: 28483828. PMID 28483828 · observational study · confidence weight 0.5 · abstract level
Sodium added to food outside the home (in processing and restaurants) supplied 70.9% of total sodium intake and was the leading source in every subgroup. Sodium naturally in food supplied 14.2%, salt added in home cooking 5.6% and salt added at the table 4.9%.
Filippini 2021 Filippini T, Malavolti M, Whelton PK, et al. Blood Pressure Effects of Sodium Reduction: Dose-Response Meta-Analysis of Experimental Studies. Circulation. 2021;143(16):1542-1567. doi:10.1161/CIRCULATIONAHA.120.050371. PMID: 33586450. PMID 33586450 · systematic review meta analysis · confidence weight 1.0 · abstract level
Achieved sodium intake and blood pressure showed an approximately linear relationship across the full range studied (0.4 to 7.6 g/day), with no flattening at low or high intakes. Results were similar in people with or without hypertension, though the decrease was steeper in people with hypertension.
He 2013 He FJ, Li J, Macgregor GA. Effect of longer-term modest salt reduction on blood pressure. Cochrane Database Syst Rev. 2013;2013(4):CD004937. doi:10.1002/14651858.CD004937.pub2. PMID: 23633321. PMID 23633321 · cochrane systematic review · confidence weight 1.0 · abstract level
A reduction of about 4.4 g of salt a day lowered systolic blood pressure by 4.18 mmHg and diastolic by 2.06 mmHg on average. Blood pressure status, age, ethnic group and the size of the sodium reduction explained much of the variation between trials.
Brand 2022 Brand A, Visser ME, Schoonees A, et al. Replacing salt with low-sodium salt substitutes (LSSS) for cardiovascular health in adults, children and pregnant women. Cochrane Database Syst Rev. 2022;8(8):CD015207. doi:10.1002/14651858.CD015207. PMID: 35944931. PMID 35944931 · cochrane systematic review · confidence weight 1.0 · abstract level
Most low-sodium salt substitutes replace some sodium with potassium. The review notes concerns about possible high blood potassium (hyperkalaemia) in people at risk, such as those with chronic kidney disease or taking medicines that reduce potassium excretion.
Cheng 2025 Cheng J, Thorndike AN, Yi S. Racial and Ethnic Differences in Sodium Sources and Sodium Reduction Behaviors Among US Adults: NHANES 2017 to 2020 Prepandemic. J Am Heart Assoc. 2025;14(11):e037997. doi:10.1161/JAHA.124.037997. PMID: 40434876. PMID 40434876 · observational survey · confidence weight 0.5 · abstract level
Nearly all US adults exceed sodium recommendations. Pizza, soup and chicken were top sodium sources across racial and ethnic groups; for Asian American adults, some top sources (such as soy-based condiments) were unique.