RecruitingInterventional

Salt: blood pressure elevation, alternative assessments and taste sensitivity

High blood pressure is a leading cause of heart disease, and salt is often a major trigger. Around half the population has 'salt-sensitive' blood pressure, meaning salty foods cause their pressure to jump. Unfortunately, testing for this currently takes three weeks of strict diets and round-the-clock testing, which is impractical for everyday doctors. This study tests a much quicker option called the IPROS test. Researchers want to see if checking blood pressure for two hours after a small salt drink can give accurate results. Healthy adults aged 21 to 50 living in the UK, Switzerland, or Italy can join. Taking part involves tracking your food on an app, attending a research clinic, wearing a blood pressure monitor, and following two short one-week eating plans. The goal is to give doctors a practical tool to spot health risks earlier.

At a glance

Status

Recruiting

Sponsor

Lake Lucerne Institute (LLUI)

Enrolment target

300

Start

19 Aug 2026

Estimated completion

01 Mar 2028

Hypertension

What is this study about?

Blood pressure measures how hard your heart has to work to pump blood around your body. When it stays too high, it puts extra strain on your heart, blood vessels, and kidneys. For many people, eating salty food causes blood pressure to rise quickly. Doctors call this 'salt sensitivity'. Knowing if you are sensitive to salt can help you make the right food choices to protect your long-term heart health.

At the moment, finding out whether someone is salt-sensitive is very difficult. It requires an intense three-week programme with strict meals and constant monitoring. Because of this, standard GP clinics cannot offer the test. Researchers at St Mary’s University in the UK, alongside teams in Switzerland and Italy, are investigating a much faster alternative. This new test checks your body's immediate reaction over just two hours after taking a single, measured dose of salt.

By comparing this quick test against standard meal plans and daily tracking, the researchers want to prove whether the two-hour check is reliable. If it works, doctors could one day use it in routine appointments to give people clear, personalised advice on how much salt is safe for them to eat.

Key takeaways

Researchers are testing a new two-hour test to spot salt-sensitive blood pressure.
The study is open to healthy adults aged 21 to 50 living in Europe with normal blood pressure.
Participation involves food logging, wearing a monitor, two short diet weeks, and clinic visits.
There are no medical treatments involved, but you will learn about your own blood pressure.
You are free to leave the study at any point without it affecting your usual healthcare.

Who may be eligible?

This study is open to healthy men and women aged between 21 and 50 who have lived in Europe for at least one year. You must have normal resting blood pressure (below 130/80 mmHg) and be able to give written consent. For the UK branch, you will need a good understanding of English to complete the questionnaires and follow instructions.

You cannot take part if you have already been diagnosed with high blood pressure or take any medicines that alter your blood pressure. You also cannot join if you have existing heart conditions, kidney disease, or other long-term illnesses that affect blood circulation.

Finally, this study is not suitable for anyone who is currently pregnant or breastfeeding, as pregnancy naturally changes how the body manages fluids and blood pressure.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am between 21 and 50 years old.
I have lived in Europe for at least one year.
My resting blood pressure is normal (below 130/80 mmHg).
I do not have high blood pressure, kidney disease, or heart conditions.
I am not taking any blood pressure tablets.
I am not pregnant or currently breastfeeding.

Answer every question to see your result.

What does participation involve?

Taking part lasts around three to four weeks in total. First, you will complete an online questionnaire to check if you are eligible. Next, you will have a short welcome session (online or in person) to learn how to use a smartphone app to log everything you eat and drink for seven days.

You will then visit the research clinic for your baseline check. The team will measure your body composition, test your taste sensitivity, collect a simple DNA sample (such as a cheek swab or saliva), and run the two-hour salt test while monitoring your blood pressure.

After this visit, you will take part in a diet study. You will follow a set eating plan for one week, take a one-week break where you eat normally, and then follow a second set plan for one week. At the end of each diet week, you will collect your urine over a 24-hour period so researchers can measure salt levels. You will also wear a comfortable, approved blood pressure monitor throughout the study.

Potential risks and benefits

Taking part does not provide any medical cure, but you will receive detailed information about your blood pressure and how your body handles salt. The small salt dose used in the test might cause mild, temporary effects such as feeling thirsty, holding a little extra fluid, or a brief, harmless rise in blood pressure. If your tests happen to show unexpected high blood pressure, the researchers will let you know so you can speak to your GP. Joining is entirely voluntary, and you are free to stop and leave the study at any time without giving a reason.

Locations (4)

St Mary's University, Twickenham
Approximate
Twickenham, England
Lake Lucerne Institute (LLUI)
City only
Lucerne, Switzerland
University of Trieste
Approximate
Trieste, Italy
Institute for Maternal and Child Health - IRCCS Burlo Garofolo
City only
Trieste, Italy

Common questions

What does being 'salt-sensitive' mean?

It means your blood pressure rises more than average after you eat salty foods, which can increase your risk of heart problems over time.

Is the salt drink dangerous?

No. The dose is carefully measured and safe for healthy adults. Any small rise in blood pressure is temporary and reversible.

Will taking part cost me anything?

No, taking part in clinical research is free, and the study provides all necessary monitoring equipment and dietary guidance.

What happens if the researchers notice my blood pressure is high?

The study team cannot provide an official medical diagnosis, but they will give you your readings and advise you to visit your GP for a formal check.

Do I have to stay in hospital during the study?

No. Aside from visits to the research centre, you will carry out your food logging and wear the monitor during your normal daily routine at home.

How to find out more

Catherine Graham

cat.graham@llui.org +41 (0)795263836 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.