High salt intake raises blood pressure and the risk of cardiovascular disease in a well-supported, near-linear manner. Eating less salt lowers blood pressure measurably and quickly, even if you are already taking medication. Above 3 grams of sodium per day, the risk of developing high blood pressure also rises.
Eating a lot of salt raises your blood pressure, and that has been well established. A crossover study in 213 adults (aged 50-75) showed that switching from a high-salt to a low-salt diet lowered systolic blood pressure (the 'top number') by an average of 8 mmHg within one week. This applied to 73% of participants, regardless of whether they were already taking blood-pressure-lowering medication (PMID 37950918). A supplementary randomised study in diabetic patients with high blood pressure found a reduction of as much as 14 mmHg after 8 weeks of eating less salt (PMID 35388704).
The risk of cardiovascular disease rises measurably with salt intake. A meta-analysis of 36 studies involving more than 616,000 participants showed that people with a high salt intake had a 19% greater chance of developing cardiovascular disease. For each additional gram of sodium per day, this risk increased by approximately 6% (PMID 32992705). A systematic review of 11 cohort studies also confirmed that the risk of developing high blood pressure begins to increase above 3 grams of sodium per day, while the recommendation is a maximum of 2 grams (PMID 35246796).
Beyond the heart and blood vessels, salt has also been linked to other health problems. A 2025 review article mentions higher chances of stomach cancer, kidney stones, bone loss (osteoporosis) and stroke with high salt intake. Salt may also negatively affect the gut microbiome and the immune system (PMID 40086509). A large observational study of more than 215,000 participants (UK Biobank) found that each additional gram of sodium per day was associated with an 11-16% higher risk of eczema. Because this was a cross-sectional study, causality cannot be established here (PMID 38837130).
The good news: eating less salt demonstrably helps. Salt restriction as part of a broader lifestyle change, such as the DASH diet, reduced alcohol consumption and more physical activity, can lower systolic blood pressure by approximately 3.5 mmHg and reduce cardiovascular risk by around 30% (PMID 37161520). Salt restriction also works well in combination with other measures and has been found to be a safe approach.
A note for athletes: during prolonged exercise, a balanced intake of both salt and fluids is important. Both too much and too little salt can cause problems for endurance athletes, such as an abnormally low sodium level in the blood (hyponatraemia) or muscle cramps. The exact relationship has not yet been fully clarified (PMID 35329337). For the average non-exercising adult, however, eating less salt is almost always beneficial.
The blood pressure effects are based on an RCT and a randomised study. The cardiovascular disease risk comes from a meta-analysis of 36 studies (n=616,000). The hypertension dose-response relationship is based on a meta-analysis of 11 cohort studies. The broader health risks (stomach cancer, kidney stones, bones) and the eczema association are observational and associative in nature. The sports claim is based on a systematic review but with limited causality.