Researchers tested whether giving people information about their genes and using a smartphone app could help them eat less salt. The study included nearly 300 Japanese workers with high blood pressure who had a specific gene that makes them sensitive to salt. Some people got genetic information plus an app, some got just the app, and some got nothing. After three months, surprisingly, the groups that used the app and genetic information didn’t eat significantly less salt than the control group. This finding suggests that even with personalized tools and technology, changing eating habits is harder than scientists thought.

The Quick Take

  • What they studied: Can telling people about their genes and giving them a smart app help them reduce salt intake if they have high blood pressure?
  • Who participated: 289 employees (mostly men, average age 51) from a Japanese electronics company who had high blood pressure and a specific genetic variation that makes them sensitive to salt
  • Key finding: After 3 months, people who received genetic information plus an AI app reduced their salt intake by only 0.2 grams per day compared to the control group—a difference too small to be meaningful. The app-only group showed even less improvement.
  • What it means for you: Personalized genetic information and smartphone apps alone may not be enough to help people significantly reduce salt intake. Changing eating habits likely requires additional support, motivation, or different approaches beyond technology and genetic data.

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of research studies. Researchers randomly divided 312 participants into three groups: one group received both genetic profile information and access to an AI-powered app designed to help reduce sodium intake, a second group received no intervention at all, and a third group received only the app without genetic information. The study took place over three months at a Japanese electronics company from September to December 2024.

To measure salt intake, researchers collected urine samples from participants and used a special formula (called INTERSALT) to estimate how much salt they were eating daily. This method is more accurate than asking people to remember what they ate. Researchers also measured blood pressure, body weight, and asked participants about their intentions to change their eating habits.

The study focused specifically on people with elevated blood pressure who carried a particular genetic variation (AGT M235T) that makes them more sensitive to salt’s effects on blood pressure. This genetic targeting was meant to identify people who would benefit most from salt reduction.

This research design is important because it allows researchers to compare what happens when people get different types of help. By having a control group that received nothing, scientists could see if the genetic information and app actually made a difference beyond just people naturally changing their behavior over time. The use of urine samples to measure salt intake is also more reliable than relying on people’s memory of what they ate.

This study has several strengths: it was published in a highly respected medical journal (JAMA Network Open), it used objective measurements of salt intake rather than self-reporting, and it included a proper control group. However, the study was conducted only at one company in Japan with mostly male employees (90%), so results may not apply equally to women or different populations. The relatively short 3-month timeframe may not be long enough to see lasting behavior change. Additionally, 23 participants dropped out, which is a small loss but worth noting.

What the Results Show

The main finding was disappointing for researchers hoping that personalized genetic information combined with technology would help people eat less salt. At the start of the study, participants were eating an average of 11.3 grams of salt per day—which is higher than recommended levels. After three months, the group that received both genetic information and the AI app reduced their salt intake by only 0.2 grams per day compared to the control group. This tiny difference (less than 2% reduction) was not statistically significant, meaning it could have happened by chance.

The app-only group (without genetic information) performed even worse, reducing salt intake by essentially zero grams compared to controls. This suggests that simply having access to an app designed to reduce sodium didn’t motivate people to change their eating habits. The control group, which received no intervention, actually maintained their salt intake at baseline levels, which is what researchers expected.

When researchers looked at secondary outcomes like blood pressure, body weight, and people’s stated intentions to change their diet, there were no meaningful differences between groups either. This suggests the intervention didn’t influence these related health measures.

The study measured several other health outcomes beyond salt intake. Blood pressure readings (both systolic and diastolic) showed no significant differences between groups at the three-month mark. Body mass index (a measure of weight relative to height) also remained similar across all three groups. Interestingly, when researchers asked participants about their intentions to reduce salt intake, there were no significant differences in motivation between groups, suggesting the genetic information and app didn’t increase people’s desire to change their eating habits.

Previous research has suggested that personalized interventions—treatments tailored to individual characteristics—might be more effective than one-size-fits-all approaches. Some studies have also shown that smartphone apps can help with health behavior change. However, this study suggests that combining these two approaches (genetic personalization plus digital tools) may not be as powerful as hoped. The findings align with growing evidence that digital health interventions often show smaller real-world effects than laboratory studies suggest, and that genetic information alone doesn’t automatically motivate behavior change.

Several important limitations should be considered. First, the study included mostly men (90%) from a single company in Japan, so results may not apply to women or people in other countries with different food cultures. Second, three months is a relatively short time to expect major dietary changes—people may need longer to develop new eating habits. Third, the study didn’t measure whether participants actually used the app or how often they checked their genetic information, so we don’t know if lack of use contributed to the poor results. Fourth, the study didn’t include any additional support like counseling or coaching, which might have improved outcomes. Finally, the relatively small reduction in salt intake at baseline (11.3 g/day) compared to some other populations means there may have been less room for improvement.

The Bottom Line

Based on this research, personalized genetic information and smartphone apps alone appear insufficient for reducing salt intake in people with high blood pressure. If you’re trying to reduce salt intake, you may need additional support such as: working with a dietitian or nutritionist, joining a support group, receiving regular coaching or check-ins, and making gradual changes to your food choices. The confidence level for this recommendation is moderate—this is one study, but it suggests that technology and genetics alone need to be combined with other strategies.

This research is particularly relevant for people with high blood pressure who are considering using genetic testing or apps as their primary tool for dietary change. It’s also important for healthcare providers and app developers to understand that personalization alone may not drive behavior change. However, this doesn’t mean genetic information or apps are useless—they may work better when combined with other support systems. People without high blood pressure or those not genetically sensitive to salt may see different results.

Based on this study, expecting significant salt reduction within three months from an app and genetic information alone is unrealistic. If you’re using these tools, you should plan for a longer timeframe (6-12 months) and combine them with other strategies like dietary counseling, regular monitoring, and gradual habit changes. Real dietary behavior change typically takes several months to become established.

Want to Apply This Research?

  • Track daily salt intake using a food diary feature that logs sodium content of meals, combined with weekly urine sodium measurements if possible. Set a specific target (such as reducing from 11g to 9g daily) and monitor progress monthly rather than weekly to avoid discouragement from normal fluctuations.
  • Rather than relying solely on the app, use it as one tool within a broader strategy: set specific, achievable weekly goals (like ‘replace one salty snack with a low-sodium alternative’), log meals consistently, and share progress with a healthcare provider or accountability partner through the app’s sharing features.
  • Establish a long-term tracking system that includes: weekly food logging in the app, monthly blood pressure checks, quarterly urine sodium tests, and regular check-ins with a healthcare provider. Use the app’s reminder and notification features to maintain consistency, and celebrate small wins to maintain motivation over the 6-12 month period needed for lasting change.

This research suggests that genetic information and smartphone apps alone may not significantly reduce salt intake in people with high blood pressure. However, this is one study with specific limitations (mostly male participants, short duration, single location). Before making changes to your diet or relying on genetic testing for health decisions, consult with your healthcare provider or a registered dietitian. This information is not a substitute for professional medical advice, diagnosis, or treatment. If you have high blood pressure or cardiovascular concerns, work with your doctor to develop a comprehensive treatment plan that may include dietary changes, medication, and lifestyle modifications.