Researchers followed over 6,400 Iranian adults for ten years to see if eating foods that make the body more acidic affects heart health and death rates. They measured how acidic each person’s diet was using three different methods. They found that people eating moderately acidic diets had a higher risk of dying from heart disease, but surprisingly, eating the most acidic foods didn’t show the same risk. The study suggests there’s a “sweet spot” where moderate acidity becomes risky, though eating very acidic foods didn’t increase risk as much as expected. This unusual pattern suggests both very acidic and very alkaline diets might affect the body differently than scientists thought.

The Quick Take

  • What they studied: Whether eating foods that create acid in the body increases the risk of dying from heart disease or other causes
  • Who participated: 6,482 adults (about 60% women) aged 35-65 years living in Iran who were followed for 10 years
  • Key finding: People eating moderately acidic diets had about 2 times higher risk of heart disease death compared to those eating the least acidic diets, but those eating the most acidic foods didn’t show this increased risk
  • What it means for you: This suggests that moderate dietary acidity might be more harmful than very high acidity, which is unexpected and needs more research before making major diet changes. Don’t drastically change your diet based on this single study.

The Research Details

This was a long-term follow-up study where researchers tracked the same group of people over 10 years. At the start, they measured how acidic each person’s diet was by analyzing what they ate using three different calculation methods: NEAP, PRAL, and DAL. These methods look at foods’ acid-producing potential in the body. Researchers then watched to see who developed heart disease, who died from heart disease, and who died from any cause during the 10-year period.

The researchers used statistical tools to compare people in different groups based on their dietary acid levels. They divided people into four groups (quartiles) from lowest to highest acid load and compared the highest-risk groups to the lowest. They also used advanced statistical models to look for curved relationships, not just straight-line patterns, because sometimes risk doesn’t increase in a simple, steady way.

This approach is valuable because it follows real people over a long time, which is stronger evidence than short-term studies. The 10-year timeframe allows researchers to see actual health outcomes rather than just measuring blood markers. Using three different measurement methods strengthens confidence in the findings. The advanced statistical analysis helps reveal unexpected patterns, like the surprising finding that the highest acid diets weren’t the riskiest.

This study has several strengths: it’s a large group of people followed for a long time, it used multiple measurement methods, and it adjusted for many other health factors. However, it was conducted in Iran, so results may not apply equally to all populations. The study measured diet at only one point in time, so it couldn’t track diet changes over the 10 years. The unexpected pattern (moderate risk being higher than high risk) is unusual and needs confirmation in other studies.

What the Results Show

The study found a surprising pattern with dietary acid load and heart disease death. When researchers looked at people eating moderately acidic diets (the second and third groups), they had roughly double the risk of dying from heart disease compared to those eating the least acidic diets. However, people eating the most acidic diets (the highest group) didn’t show this increased risk—their risk was much closer to the lowest-acid group.

This nonlinear pattern (where risk doesn’t increase steadily) appeared consistently across two of the three measurement methods (PRAL and DAL). The researchers found this pattern was statistically significant, meaning it wasn’t likely due to chance. Interestingly, the study found no significant connection between dietary acid load and overall death rates from any cause, nor did it find a clear link to developing heart disease in the first place—only to dying from it once someone had heart disease.

When researchers looked at the third measurement method (NEAP), they found a connection to heart disease death only in the second group, suggesting this method was less consistent than the others. The advanced statistical models confirmed the curved relationship, showing that risk peaks at moderate acid levels rather than increasing steadily. This pattern suggests the body may respond differently to moderate versus very high dietary acid loads, possibly through different metabolic pathways.

Previous research has suggested that acidic diets might harm bone health and increase inflammation, but this study’s findings about heart disease mortality are somewhat unexpected. Most researchers assumed that higher acid would mean higher risk, but this study found the opposite pattern. This unusual finding suggests that the relationship between diet acidity and heart health is more complex than previously thought, and that very acidic diets might trigger different protective mechanisms than moderate acidity.

The study measured diet only once at the beginning, so researchers couldn’t track whether people’s eating habits changed over the 10 years. The study was conducted in Iran, so results may not apply to people in other countries with different genetics and food cultures. The researchers couldn’t prove that dietary acid directly caused the increased risk—only that it was associated with it. The unexpected pattern (moderate being riskier than high) is unusual and needs to be confirmed in other studies before drawing firm conclusions. Additionally, the study didn’t find connections to overall death rates or developing heart disease, only to dying from it, which limits how broadly these findings apply.

The Bottom Line

Based on this single study, there’s no strong reason to make major changes to your diet focused on acid load. The findings are interesting but unexpected and need confirmation in other populations. If you have existing heart disease or heart disease risk factors, discuss your diet with your doctor—they can provide personalized advice based on your complete health picture. General healthy eating principles (plenty of vegetables, whole grains, lean proteins) remain sound regardless of these findings.

People with existing heart disease or high risk for heart disease should be aware of this research, though it shouldn’t drive immediate diet changes without medical guidance. Researchers and nutritionists should pay attention because the findings challenge existing assumptions. People in other countries should be cautious about applying these results, as the study was conducted in Iran. Healthy people without heart disease risk factors have less reason to worry about dietary acid load based on this study alone.

If dietary acid load does affect heart disease risk, the effects appear to develop over years, not weeks or months. This study tracked people for 10 years, suggesting any protective or harmful effects take considerable time to appear. Don’t expect to see changes in how you feel based on adjusting dietary acid load.

Want to Apply This Research?

  • Track the types of foods eaten (acidic vs. alkaline) weekly rather than daily, noting categories like grains, proteins, vegetables, and fruits. This provides enough detail to see patterns without overwhelming users with daily calculations.
  • Instead of focusing on acid load, encourage users to track overall diet quality: servings of vegetables, whole grains, and lean proteins. These are proven healthy habits that naturally influence dietary acid load without requiring complex calculations.
  • For users interested in dietary acid load, implement a monthly review comparing food choices across weeks. Include educational content explaining that moderate changes are more sustainable than extreme shifts toward very acidic or very alkaline diets. Connect diet tracking to other heart health markers like activity level and stress management.

This research describes associations found in one study and should not be used to make medical decisions without consulting your healthcare provider. The findings are preliminary and show an unexpected pattern that requires confirmation in other studies. If you have heart disease, cardiovascular risk factors, or are considering major dietary changes, speak with your doctor or a registered dietitian before making changes based on this research. This study was conducted in an Iranian population and may not apply equally to all groups. Individual dietary needs vary based on personal health conditions, medications, and other factors that only your healthcare provider can assess.