Researchers studied over 12,800 American adults with high blood pressure to see if eating a healthier diet could protect their kidneys. They found that people who ate healthier diets (measured by a special scoring system) were less likely to have a condition called albuminuria, where protein leaks into the urine—a sign of kidney damage. People with the healthiest eating patterns had about 25% lower chances of having this kidney problem compared to those eating the least healthy diets. This suggests that improving what you eat might be a simple way to help protect your kidneys if you have high blood pressure.

The Quick Take

  • What they studied: Whether eating a healthier diet is connected to having less kidney damage (specifically, protein in the urine) in people with high blood pressure.
  • Who participated: 12,829 American adults aged 20 and older who have high blood pressure. About 2,163 of them (17%) had signs of kidney damage with protein in their urine.
  • Key finding: People who ate the healthiest diets were 25% less likely to have protein leaking into their urine compared to those eating the least healthy diets. For every 13-point improvement in diet quality score, the chances of kidney damage dropped by about 9%.
  • What it means for you: If you have high blood pressure, eating a healthier diet may help protect your kidneys from damage. However, this study shows a connection, not proof that diet causes the improvement. Talk to your doctor about dietary changes, especially if you already have kidney problems.

The Research Details

This was a cross-sectional study, which means researchers looked at information collected from the same time period rather than following people over years. They used data from the National Health and Nutrition Examination Survey (NHANES), a large government program that regularly checks the health of Americans from 2007 to 2020.

Researchers looked at what people ate using 24-hour dietary recall interviews, where participants describe everything they ate in the previous day. They scored each person’s diet using the Healthy Eating Index 2015 (HEI-2015), which rates how well someone follows nutrition guidelines. They also measured kidney health by checking urine samples for albumin (a protein that shouldn’t be in urine), which is a sign of kidney damage.

The researchers used statistical methods to see if people with higher diet scores had less kidney damage, while accounting for other factors like age, weight, smoking, and exercise.

This approach is important because it uses real-world data from a nationally representative sample of Americans, making the findings more likely to apply to the general population. By measuring actual diet and kidney health at the same time, researchers could identify patterns. However, because it’s a snapshot in time rather than following people forward, we can’t be completely sure that diet changes cause better kidney health.

Strengths: Large sample size of over 12,000 people, nationally representative data, careful adjustment for other health factors. Weaknesses: Cross-sectional design means we can’t prove cause-and-effect, diet was measured by recall (people might not remember exactly what they ate), and the study only shows associations, not proof that diet prevents kidney damage.

What the Results Show

Among the 12,829 adults with high blood pressure studied, 2,163 (about 17%) had albuminuria (protein in urine indicating kidney damage). The average diet quality score was 53.9 out of 100, suggesting most Americans aren’t eating as healthily as recommended.

People in the highest diet quality group (top 25%) had significantly lower chances of kidney damage compared to those in the lowest group (bottom 25%). Specifically, the odds of having kidney damage were 25% lower in the healthiest eating group. This difference remained even after researchers accounted for other factors like age, weight, smoking, exercise, and other health conditions.

When looking at the relationship as a continuous scale, every 13-point improvement in diet quality score was associated with a 9% lower chance of kidney damage. The relationship appeared to be linear, meaning steady improvements in diet quality correlated with steady improvements in kidney health.

The study found that the connection between diet quality and kidney health was consistent across different statistical models used to analyze the data. The relationship held true even when researchers adjusted for multiple health factors, suggesting that diet quality has an independent association with kidney protection beyond other health behaviors.

Previous research has shown that healthy eating patterns protect heart and kidney health in general populations. This study adds to that evidence by specifically examining the Healthy Eating Index 2015 in people with high blood pressure, a group at particularly high risk for kidney damage. The findings align with existing knowledge that diet influences kidney function, though this is one of the more comprehensive looks at this specific relationship in a large US population.

This study cannot prove that eating healthier causes better kidney health—it only shows they’re connected. People with healthier diets might also exercise more, take medications more consistently, or have other healthy habits. Diet was measured based on what people remembered eating, which may not be completely accurate. The study is a snapshot in time, so we don’t know if these relationships hold true as people’s diets change over years. Additionally, the study included only people with diagnosed high blood pressure, so results may not apply to people without hypertension.

The Bottom Line

If you have high blood pressure, consider working with a doctor or dietitian to improve your diet quality by eating more vegetables, fruits, whole grains, and lean proteins while reducing sodium, added sugars, and processed foods. This may help protect your kidneys. (Moderate confidence: based on observational data showing association, not proven cause-and-effect.) Have your kidney function checked regularly through urine and blood tests, especially if you have high blood pressure.

This research is most relevant for adults with high blood pressure who want to reduce their risk of kidney damage. It’s also important for people with a family history of kidney disease or diabetes. People already diagnosed with kidney disease should follow their doctor’s specific dietary recommendations, which may differ from general healthy eating guidelines. Anyone considering major dietary changes should consult their healthcare provider first.

Improvements in kidney health from dietary changes typically take weeks to months to show up in blood and urine tests. You may notice other benefits like better energy, improved blood pressure readings, or weight loss within 2-4 weeks of eating healthier. Significant kidney protection benefits may take 3-6 months or longer to become measurable.

Want to Apply This Research?

  • Track daily diet quality by logging meals and noting how many servings you eat from each food group (vegetables, fruits, whole grains, lean proteins, dairy). Rate your overall diet quality each day on a scale of 1-10 to monitor improvement over time.
  • Set a specific goal like ‘Add one extra vegetable serving to dinner’ or ‘Replace one sugary drink with water daily.’ Use the app to log these changes and celebrate weekly wins. Take a weekly photo of your meals to visually track healthier choices.
  • Review your diet quality score weekly and monthly to identify patterns. Share results with your doctor at regular checkups. If you have high blood pressure, track both diet quality and blood pressure readings together to see if improvements correlate. Set reminders for annual kidney function tests (urinalysis and blood work) to monitor long-term kidney health.

This research shows an association between healthy eating and better kidney health in people with high blood pressure, but does not prove that diet changes will prevent kidney disease. Individual results vary based on genetics, medications, and other health factors. This information is not a substitute for professional medical advice. If you have high blood pressure or kidney concerns, consult your healthcare provider before making significant dietary changes. People with existing kidney disease may need specialized diets different from general healthy eating guidelines. Always work with your doctor or a registered dietitian to create a personalized nutrition plan appropriate for your specific health conditions.