Researchers studied over 16,000 people with a serious condition that combines heart disease, kidney problems, and metabolic disorders. They tracked what people ate and followed them for about 8 years to see who stayed healthy and who didn’t. People who ate the healthiest diets—like Mediterranean, DASH, or other nutrient-rich patterns—had significantly lower chances of dying from any cause or from heart disease. The study suggests that making better food choices could be one of the most important things people with these conditions can do to live longer.

The Quick Take

  • What they studied: Whether eating healthier foods helps people with combined heart disease, kidney problems, and metabolic issues live longer
  • Who participated: 16,589 adults aged 30 and older from across the United States, tracked from 2005 to 2018. All participants had cardiovascular-kidney-metabolic syndrome, a serious condition affecting the heart, kidneys, and metabolism
  • Key finding: People who followed the healthiest eating patterns had about 30-40% lower risk of dying from any cause, and 20-40% lower risk of dying from heart disease specifically, compared to those eating the least healthy diets
  • What it means for you: If you have heart disease, kidney problems, or metabolic disorders, improving your diet quality may be one of the most powerful things you can do to improve your health and longevity. However, dietary changes work best alongside medical treatment prescribed by your doctor

The Research Details

This was a cohort study, which means researchers followed a large group of people over time and tracked what happened to them. The study used information from the National Health and Nutrition Examination Survey, a major U.S. government health study that collects detailed information about what Americans eat and their health outcomes. Researchers looked at 16,589 people with cardiovascular-kidney-metabolic syndrome and measured their diet quality using four different scoring systems: the Mediterranean Diet Score, the Healthy Eating Index, the DASH diet score, and the HEI-2020. They then followed these people for an average of 8.2 years and recorded who died and from what causes.

The researchers used statistical methods called Cox proportional hazards regression to analyze the data. This fancy-sounding technique allows scientists to compare death rates between groups while accounting for other factors that might affect the results, like age, smoking status, exercise habits, and income level. By adjusting for these other factors, the researchers could isolate the effect of diet quality on survival.

The study measured diet quality by looking at how well people followed healthy eating patterns. Higher scores meant people ate more fruits, vegetables, whole grains, and lean proteins while eating less processed foods, added sugars, and unhealthy fats. The researchers then divided people into five groups based on their diet scores and compared the healthiest eaters (top 20%) to the least healthy eaters (bottom 20%).

This research approach is important because it shows real-world results in actual people living with serious health conditions. Rather than just studying diet in healthy people, this study focused specifically on those with cardiovascular-kidney-metabolic syndrome, making the findings directly relevant to this high-risk population. The long follow-up period of 8+ years and large sample size make the results more reliable than smaller, shorter studies. Additionally, using multiple diet quality scoring systems strengthens the findings by showing that different healthy eating approaches all produced similar protective benefits.

This study has several strengths: the large sample size of over 16,000 people, the long follow-up period, the use of standardized dietary assessment methods, and the careful adjustment for many other health factors. However, readers should know that dietary information was collected at one point in time, so we don’t know if people’s eating habits changed during the follow-up period. The study is observational, meaning we can see that diet and mortality are connected, but we cannot prove that diet directly caused the lower death rates—other unmeasured factors could play a role. Additionally, the study population was primarily U.S.-based, so results may not apply equally to other countries with different food availability and cultural eating patterns.

What the Results Show

The main finding was clear and consistent across all four diet quality measures: people who ate the healthiest diets had substantially lower death rates. For all-cause mortality (death from any reason), people in the top 20% of diet quality had death rates that were 30-38% lower than those in the bottom 20%. Specifically, the Mediterranean diet approach showed a 37% lower risk, the Healthy Eating Index showed a 38% lower risk, the DASH diet showed a 37% lower risk, and the HEI-2020 showed a 30% lower risk.

When looking specifically at deaths from heart disease and related conditions, the protective effects were also strong. People eating the healthiest diets had 20-38% lower risk of cardiovascular death compared to those eating the least healthy diets. The Mediterranean and Healthy Eating Index approaches showed the strongest protection at 34-38% lower risk, while the DASH diet and HEI-2020 showed 20-27% lower risk.

Importantly, these protective effects were seen across different groups of people. Whether someone was younger or older, male or female, had higher or lower income, or different racial/ethnic backgrounds, eating a healthier diet was associated with better survival. This consistency across different population groups suggests that diet quality matters for everyone with this condition, not just certain subgroups.

The study also showed a dose-response relationship, meaning that as diet quality improved, the protective benefit increased. People didn’t need to be perfect—even moving from the worst diet quality to a medium diet quality showed meaningful improvements in survival rates.

The analysis revealed that the protective effects of healthy eating were consistent whether researchers looked at different age groups, income levels, or other demographic characteristics. This suggests that diet quality is universally important for people with cardiovascular-kidney-metabolic syndrome. The study also showed that all four different healthy eating approaches—Mediterranean, DASH, Healthy Eating Index, and HEI-2020—provided similar protective benefits, suggesting that there are multiple valid ways to eat healthier rather than one single ‘best’ diet.

These findings align with and extend previous research showing that healthy eating patterns reduce mortality risk in the general population. However, this study is particularly valuable because it specifically examined people with the serious combination of heart disease, kidney problems, and metabolic disorders. Previous studies had looked at these conditions separately, but this research shows that diet quality matters across all three conditions simultaneously. The magnitude of benefit found here (30-40% reduction in mortality risk) is consistent with or even stronger than what has been seen in other high-risk populations, suggesting that people with multiple serious health conditions may benefit especially from dietary improvements.

Several limitations should be considered when interpreting these results. First, the study measured diet at only one point in time, so we don’t know if people’s eating habits changed over the 8+ year follow-up period. Second, this is an observational study, meaning we can see that diet and survival are connected, but we cannot prove that diet directly caused the improved survival—other factors we didn’t measure could be involved. Third, the study relied on people’s memory and self-reporting of what they ate, which can be inaccurate. Fourth, the study population was primarily from the United States, so results may not apply equally to people in other countries with different food systems and eating cultures. Finally, while the researchers adjusted for many health factors, there may be other unmeasured factors that influenced the results.

The Bottom Line

If you have cardiovascular-kidney-metabolic syndrome (heart disease, kidney problems, and metabolic disorders), this research provides strong evidence (high confidence) that improving your diet quality should be a priority. Focus on eating more fruits, vegetables, whole grains, legumes, nuts, and lean proteins while reducing processed foods, added sugars, and unhealthy fats. You don’t need to follow one specific diet perfectly—the research shows that Mediterranean, DASH, and other healthy eating approaches all work well. Start by making small, sustainable changes rather than trying to overhaul your diet overnight. Work with your doctor and possibly a registered dietitian to develop a plan that fits your specific health needs, kidney function, and any dietary restrictions you may have.

This research is most relevant for people who have been diagnosed with cardiovascular-kidney-metabolic syndrome or who have multiple conditions including heart disease, chronic kidney disease, and metabolic disorders like diabetes or obesity. It’s also valuable for family members and caregivers of people with these conditions. Healthcare providers treating these patients should consider dietary counseling as an important part of treatment. People with only one of these conditions (just heart disease, just kidney disease, or just diabetes) may still benefit from these findings, but should discuss their specific situation with their doctor. Healthy people without these conditions should note that these findings support the general recommendation to eat a healthy diet, though the specific urgency may be lower.

Realistic expectations for seeing health benefits from dietary changes vary. Some benefits like improved blood pressure and blood sugar control may appear within weeks to a few months. However, the major benefits for reducing mortality risk likely take longer—the study followed people for an average of 8+ years. This doesn’t mean you should wait years to see any benefit; rather, it means that the most dramatic life-extending benefits develop over time. Start making dietary changes now, but understand that you’re making an investment in your long-term health rather than expecting immediate dramatic changes.

Want to Apply This Research?

  • Track daily servings of key food groups: aim to log at least 2-3 servings of vegetables, 1-2 servings of fruit, 1-2 servings of whole grains, and 1 serving of lean protein daily. Use the app to monitor your weekly average and set a goal to increase these categories by 10-20% each month
  • Use the app to identify one specific meal to improve each week. For example, week 1: swap white bread for whole grain bread at breakfast. Week 2: add an extra vegetable to dinner. Week 3: replace one sugary snack with nuts or fruit. This gradual approach is more sustainable than trying to change everything at once
  • Set up weekly check-ins to review your diet quality score. Most apps can calculate a simple score based on the foods you log. Track not just calories, but the quality of foods—aim for a 70%+ score on healthy food choices. Also monitor related health markers if available: blood pressure, blood sugar, and weight. Take measurements monthly rather than daily to see meaningful trends without getting discouraged by normal fluctuations

This research provides evidence that diet quality is associated with better survival outcomes in people with cardiovascular-kidney-metabolic syndrome. However, this study cannot prove that diet changes will directly improve your health or lifespan. Diet should be part of a comprehensive treatment plan that includes medications prescribed by your doctor, regular medical monitoring, and other lifestyle changes like exercise and stress management. If you have heart disease, kidney disease, diabetes, or metabolic disorders, consult with your healthcare provider or a registered dietitian before making significant dietary changes, especially regarding sodium, potassium, phosphorus, and protein intake, which may need to be adjusted based on your specific kidney function. This information is for educational purposes and should not replace professional medical advice.