Salt intake, blood pressure and heart disease in people and animals
What it found
Cutting salt lowered blood pressure in trials of over 12,000 people, and swapping regular salt for a lower-sodium version reduced strokes in about 21,000 people.
Animal studies show how extra salt harms the kidneys, brain, blood vessels and immune system.
What they found
Studies in people
Blood pressure in people
In an analysis of 133 trials with over 12,000 adults, cutting daily salt by 5 to 8 grams lowered the top blood pressure number by about 4 mmHg. A second analysis of 85 trials with over 10,000 people found similar drops.
Heart disease and strokes
A large trial in rural China gave about 21,000 people a salt substitute made of 75% sodium chloride and 25% potassium chloride. Compared to regular salt, the substitute was linked to about 14% fewer strokes and 12% fewer deaths from any cause.
Taste adjustment takes time
People naturally prefer salty food even when their bodies do not need it. It takes weeks or months of eating less salt for the taste buds to adjust so that lower-salt food starts to taste good again.
Animal and lab studies
Organ damage in animals
Research in animals shows that high salt intake drives disease in the kidneys, brain, blood vessels and immune system. For example, in mice, extra salt caused blood vessel tightening and raised blood pressure through changes in muscle cells.
Studies in people and animals
Gut bacteria changes
Eating too much salt changed the gut bacteria in both mice and people. These changes were linked to inflammation and higher blood pressure.
Other findings
Hidden salt in food
Most people eat about 10 to 15 grams of salt a day, well above the World Health Organization target of under 5 grams. Much of this comes from processed foods or from saline injected into meat during processing, making it hard to control by just using less salt at the table.
What the authors conclude
- They argue that the combined evidence from many sources strongly supports cutting salt to lower blood pressure and reduce heart disease risk.
- They say the most effective way to reduce salt intake is through population-wide efforts involving governments, education and the food industry, rather than relying on individuals alone.
- They point out that hidden salt in processed foods makes it very difficult for shoppers to control how much salt they eat.
How it was done
People around the world eat far more salt than their bodies need, and this is linked to high blood pressure and heart disease. The authors wanted to bring together all the evidence on how salt affects health and what works to help people eat less of it.
The authors gathered and examined results from human trials, observational studies and animal research on salt intake. They looked at data from over 12,000 people in one analysis and over 10,000 in another, plus a village trial of about 21,000 people. They also reviewed lab studies in mice, rats and dogs to understand how salt acts inside the body.
What it can’t tell you
- Observational studies can show links between salt and disease but cannot prove that salt directly causes heart attacks or strokes.
- Animal studies often use much higher amounts of salt over shorter periods than people typically eat, so they may not perfectly reflect what happens in humans over many years.
- Trials testing salt substitutes added potassium at the same time, so scientists cannot fully separate the effects of having less sodium from the effects of having more potassium.
Who paid
- Funding
- Funded by Wellcome Trust; Medical Research Council; British Heart Foundation; Chief Scientist Office (from the PubMed record).
- Authors work at
- The University of Edinburgh, UK
The paper
- Title
- The impact of excessive salt intake on human health
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Hunter RW, Dhaun N, Bailey MA (2022). The impact of excessive salt intake on human health. Nature reviews. Nephrology. doi:10.1038/s41581-021-00533-0Free full textPubMed 35058650DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error