Researchers tested whether reducing salt, adding potassium, and consuming beetroot juice could lower blood pressure in people with hypertension. In a one-week study with 90 participants, they found that cutting salt was the clear winner—it lowered systolic blood pressure by about 7 points. Interestingly, potassium supplements showed a small benefit, but beetroot juice with nitrate didn’t help during this short timeframe. This research suggests that if you have high blood pressure, focusing on eating less salt may be your best dietary strategy, at least in the short term.

The Quick Take

  • What they studied: How three different dietary changes—eating less salt, adding potassium supplements, and drinking beetroot juice—affect blood pressure when used alone or together
  • Who participated: 90 adults with high blood pressure were divided into 8 groups and given different combinations of these dietary changes or fake versions (placebos) for one week
  • Key finding: Reducing salt intake lowered systolic blood pressure by 7 millimeters of mercury (mmHg), which is a meaningful drop. This effect was very strong and clear (p < 0.0001). Potassium showed a small benefit, but beetroot juice made no difference during the one-week study
  • What it means for you: If you have high blood pressure, cutting back on salt appears to be the most important dietary change you can make. However, this was a short-term study, so long-term benefits may differ. Talk to your doctor before making major dietary changes or starting supplements

The Research Details

This was a randomized controlled trial, which is one of the strongest types of research studies. Ninety people with high blood pressure were randomly assigned to eight different groups. Each group received a diet handout and different combinations of supplements: some got lower salt, some got higher salt, some got potassium pills, some got beetroot juice, and some got fake versions of these (placebos). Nobody knew which group they were in—not the participants and not the researchers—which is called “double-blind” and helps prevent bias.

The study lasted just one week. Before and after, researchers measured each person’s blood pressure over 24 hours (using a portable monitor), took blood samples, and collected urine samples. This allowed them to see exactly what changed and why.

The salt reduction was significant: the low-sodium group ate about 130 millimoles less salt per day, while the high-sodium group ate normal amounts. Potassium supplements provided 40 millimoles per day, and beetroot juice contained 13 millimoles of nitrate.

Using a randomized controlled trial design is important because it helps prove cause-and-effect relationships. By randomly assigning people to groups and using placebos, researchers can be confident that salt reduction actually caused the blood pressure drop, rather than other factors. The double-blind approach prevents expectations from influencing results. Measuring 24-hour blood pressure is more accurate than a single reading, and checking blood chemicals helps explain how these foods work in the body.

This study has several strengths: it’s a randomized controlled trial (the gold standard), it used double-blinding to prevent bias, and it measured blood pressure over 24 hours for accuracy. However, the study lasted only one week, which is very short. The sample size of 90 people is moderate—larger studies might show different results. The study was published in a peer-reviewed journal, meaning other experts reviewed it before publication. The main limitation is that we don’t know if these results would hold up over weeks or months.

What the Results Show

The most striking finding was that reducing salt intake lowered systolic blood pressure (the top number) by 7 millimeters of mercury on average. This is a meaningful reduction—for context, blood pressure medications typically lower pressure by 5-15 mmHg. The effect was very strong statistically (p < 0.0001), meaning there’s less than a 1 in 10,000 chance this happened by random luck.

In contrast, people who ate normal or high amounts of salt showed no change in blood pressure. This clear difference between the low-salt and high-salt groups is the study’s main message: salt reduction works.

The researchers also looked at a hormone called aldosterone and its relationship to another hormone called renin. They found that changes in the aldosterone-to-renin ratio were connected to blood pressure changes in the low-salt groups. This suggests that salt affects blood pressure partly through these hormones, though the exact mechanism needs more study.

Potassium supplements showed a small benefit: people in the low-potassium group had slightly lower blood pressure than those in the high-potassium group (p = 0.03). However, this effect was much weaker than salt reduction and the researchers didn’t provide the exact number. Beetroot juice with nitrate showed no effect on blood pressure during this one-week period (p = 0.31), meaning any difference could easily be due to chance. This was surprising to some researchers because nitrate has shown promise in other studies, but one week may have been too short to see benefits.

This study confirms what many previous studies have shown: reducing salt is one of the most effective dietary ways to lower blood pressure. The 7 mmHg reduction matches what other research has found. The finding about potassium is consistent with previous research suggesting potassium has a modest blood pressure-lowering effect. The negative result for beetroot juice is interesting because some earlier studies suggested nitrate might help, but those studies often lasted longer or used different populations. This suggests that short-term nitrate supplementation may not be enough to make a difference.

The biggest limitation is that this study lasted only one week. Blood pressure changes and the body’s adaptation to dietary changes often take longer to fully develop. With only 90 participants split into 8 groups, each group was relatively small (about 11 people per group), which reduces statistical power. The study didn’t track whether people actually followed the diet or took supplements as instructed. We also don’t know if results would be the same in different populations—for example, people of different ages, races, or with different types of hypertension might respond differently. Finally, the study didn’t measure diastolic blood pressure (the bottom number) effects as clearly as systolic effects.

The Bottom Line

If you have high blood pressure, reducing salt intake appears to be the most evidence-based dietary change you can make based on this research (high confidence for short-term effects). Increasing potassium intake may provide a small additional benefit (moderate confidence). Beetroot juice or nitrate supplements don’t appear necessary based on this one-week study, though longer-term research might show different results (low confidence for short-term use). Always work with your doctor before making dietary changes, especially if you take blood pressure medications or have kidney problems.

This research is most relevant for adults with diagnosed high blood pressure who want to manage it through diet. It’s particularly useful for people looking for non-medication approaches or wanting to enhance their medication’s effects. People with normal blood pressure probably don’t need to worry about these specific interventions. Those with kidney disease, heart failure, or taking certain medications should consult their doctor before changing salt or potassium intake, as these conditions affect how the body handles these minerals.

Based on this study, you might expect to see blood pressure changes within days to a week of reducing salt. However, the body often continues to adapt over weeks and months, so benefits may increase over time. Most blood pressure medications take 2-4 weeks to show full effects, and dietary changes may follow a similar timeline. Don’t expect dramatic overnight changes—the 7 mmHg reduction found here is meaningful but modest.

Want to Apply This Research?

  • Track daily sodium intake (aim for less than 2,300 mg per day, or ideally 1,500 mg) alongside morning blood pressure readings taken at the same time each day. Record both systolic and diastolic readings to see patterns over weeks
  • Set a specific goal like ‘reduce added salt by 50% this week’ and use the app to log salt sources (processed foods, restaurant meals, home cooking). Create reminders to check nutrition labels for sodium content before eating packaged foods
  • Track blood pressure weekly rather than daily to see meaningful trends without getting discouraged by normal daily fluctuations. Compare your average reading from week 1 to week 4 to assess whether salt reduction is working for you personally. Also monitor how you feel—increased energy or fewer headaches might indicate improvement

This research summary is for educational purposes only and should not replace professional medical advice. High blood pressure is a serious condition that requires medical supervision. Before making significant dietary changes, reducing salt intake, or starting any supplements—especially potassium—consult with your doctor or a registered dietitian. This is particularly important if you have kidney disease, heart failure, diabetes, or take medications that affect potassium or sodium levels. The findings presented here are from a one-week study and may not apply to long-term dietary changes or all populations. Your doctor can help determine the best approach for your individual situation.