Researchers discovered that purple potatoes might help prevent high blood pressure by changing the bacteria in your gut. In a study with rats, those eating purple potato flour had lower blood pressure and different gut bacteria compared to those eating regular yellow potatoes. The purple potatoes contain special plant compounds called anthocyanins that appear to work with your gut bacteria to produce helpful substances. Scientists also used genetic analysis to confirm that eating potatoes is safe for people trying to manage their blood pressure. These findings suggest that adding purple potatoes to your diet could be a natural way to support heart health.

The Quick Take

  • What they studied: Whether eating purple potato flour could lower blood pressure and how it might work by changing gut bacteria
  • Who participated: Two groups of laboratory rats: one group naturally prone to high blood pressure and one group with normal blood pressure. Rats were fed either purple potato flour or regular yellow potato flour for 9 weeks
  • Key finding: Purple potatoes reduced blood pressure by more than 18% in rats with normal blood pressure. They also lowered a hormone that raises blood pressure (angiotensin II) by about 33% in rats prone to high blood pressure, and changed the types of bacteria in their guts in beneficial ways
  • What it means for you: Purple potatoes may be a helpful food to eat if you’re concerned about blood pressure, though human studies are still needed. The suggested amount is about 2.5-5 ounces of purple potato daily. Talk to your doctor before making major dietary changes, especially if you take blood pressure medication

The Research Details

Scientists conducted an experiment with two types of laboratory rats over 9 weeks. One group of rats naturally develops high blood pressure, while the other group has normal blood pressure. Both groups were split into two diets: one group ate purple potato flour and the other ate regular yellow potato flour. The researchers measured blood pressure, checked blood chemicals related to blood pressure control, analyzed the types of bacteria living in the rats’ guts using genetic testing, and studied the chemical compounds produced by those bacteria.

The scientists also used computer modeling to see how the special compounds in purple potatoes (called anthocyanins) might attach to and affect proteins that control blood pressure. Additionally, they performed a genetic analysis called Mendelian randomization to determine if eating potatoes could actually cause changes in blood pressure in humans, rather than just being associated with it.

This research approach is important because it combines multiple ways of studying the problem. By looking at blood pressure changes, gut bacteria, chemical compounds, and genetic data all together, the researchers could understand not just whether purple potatoes help, but also how they might work. The computer modeling and genetic analysis help confirm that the results are likely real and not just coincidence. This multi-layered approach gives us more confidence in the findings.

This study was conducted in a controlled laboratory setting with standardized conditions, which is good for understanding cause and effect. However, the study used rats, not humans, so results may not directly apply to people. The researchers used established scientific methods for measuring bacteria and chemicals. The genetic analysis (Mendelian randomization) adds strength by suggesting the relationship isn’t just coincidental. The main limitation is that this is preliminary research that needs to be confirmed in human studies before making strong recommendations.

What the Results Show

Purple potato flour produced different effects depending on the rat’s starting condition. In rats with normal blood pressure, purple potatoes reduced systolic blood pressure (the top number) by more than 18%, which is a meaningful decrease. In rats naturally prone to high blood pressure, the purple potatoes didn’t significantly lower blood pressure directly, but they did reduce a hormone called angiotensin II by about 33%, which is a chemical that normally raises blood pressure.

The most interesting finding was how purple potatoes changed the gut bacteria. Rats eating purple potatoes developed more diverse bacterial communities and had more of a type of bacteria called Bacteroidota while having less of another type called Firmicutes. This shift in bacterial balance is considered healthy because it’s associated with better metabolic function.

The purple potatoes also increased the production of short-chain fatty acids (SCFAs), which are beneficial compounds produced when gut bacteria break down food. These fatty acids are important for heart and gut health. The computer modeling showed that anthocyanins from purple potatoes can bind strongly to proteins that control blood pressure, suggesting they have direct biological activity.

The metabolomics analysis (studying all the chemical compounds produced) revealed that purple potatoes activated pathways related to bile acid metabolism and fatty acid production. The correlation analysis showed important connections between the chemical compounds produced and the types of bacteria present, suggesting they work together as a system. The genetic analysis found no evidence that potato intake causes high blood pressure in humans, which is reassuring for safety.

This research builds on earlier studies showing that colorful potatoes contain beneficial compounds. Previous research has suggested that gut bacteria play a role in blood pressure regulation, and this study provides a specific mechanism through which purple potatoes might work. The findings align with other research showing that plant compounds and gut bacteria interact to affect cardiovascular health. However, most previous studies on potatoes and blood pressure have been less comprehensive in examining the gut bacteria connection.

The study was conducted in rats, not humans, so the results may not directly translate to people. The study didn’t test the actual purple potato flour in humans, only in rats, so we don’t know if the same effects would occur in people eating real purple potatoes. The study didn’t compare purple potatoes to other foods that might have similar effects. The exact dose that would be effective in humans is estimated but not proven. Some of the chemical measurements were done in laboratory conditions that may not perfectly reflect what happens in a living body.

The Bottom Line

Based on this research, purple potatoes appear to be a safe and potentially beneficial food to include in your diet if you’re concerned about blood pressure (moderate confidence level). The estimated helpful amount is about 75-150 grams of purple potato daily, which is roughly 2.5-5 ounces or about one medium purple potato. This should be part of an overall healthy diet that includes other fruits, vegetables, and whole grains. This research does not suggest purple potatoes can replace blood pressure medication, but they may be a helpful addition to a healthy lifestyle.

This research is most relevant for people interested in natural ways to support heart health and blood pressure management. It’s particularly interesting for people who enjoy potatoes and want to choose varieties with more health benefits. People with high blood pressure or a family history of high blood pressure may want to discuss adding purple potatoes to their diet with their doctor. This is not a replacement for medical treatment if you have diagnosed high blood pressure. People with kidney disease should consult their doctor since potatoes contain potassium.

Based on the rat study, changes in gut bacteria and blood pressure took about 9 weeks to develop. In humans, it might take several weeks to a few months to see potential benefits. You wouldn’t expect immediate results, but consistent consumption over time may provide benefits. Individual results will vary based on overall diet, exercise, genetics, and other factors.

Want to Apply This Research?

  • Track daily purple potato consumption (in ounces or grams) and weekly average blood pressure readings if you monitor at home. Set a goal of 2.5-5 ounces of purple potatoes 3-5 times per week and log when you eat them
  • Replace some of your regular potato servings with purple potatoes in meals you already eat. Try purple mashed potatoes, roasted purple potato wedges, or purple potato salad. Start with one meal per week and gradually increase frequency. Pair with other heart-healthy foods like leafy greens and whole grains
  • Track purple potato intake weekly and note any changes in how you feel over 8-12 weeks. If you monitor blood pressure at home, record weekly averages. Keep a simple food log noting meals with purple potatoes and any digestive changes (since changing diet can affect gut bacteria). Share results with your healthcare provider at your next visit

This research was conducted in laboratory rats and has not been tested in humans. The findings are preliminary and should not be used as a substitute for medical treatment or advice from your healthcare provider. If you have high blood pressure or take blood pressure medication, consult your doctor before making significant dietary changes. People with kidney disease or those taking certain medications should discuss potato consumption with their healthcare provider. Individual results may vary, and this food should be part of an overall healthy lifestyle that includes exercise, stress management, and other evidence-based approaches to heart health.