Beet Juice vs. Beet Powder
We wanted to determine if beetroot juice was more or less effective than beet powder.
These are two of the most common beetroot supplements, after all.
We excluded trials with inadequate data for this sub-analysis. We further excluded trials that used other beetroot supplements.
(This included whole beets, beet crystals, beet bread, beetroot gel, etc.)
And we excluded trials that used beet juice that was mixed with other juices, like apple juice.
This allowed us to compare pure beetroot juice vs. beetroot powder.
For beetroot juice (91 trials):
- 89 trials used bottled beetroot juice. This was often commercially available beetroot juice.
- 2 trials used fresh (raw) beets to make 100% beetroot juice.
58.2% (53 of 91) clinical trials showed that beetroot juice is unlikely to lower blood pressure significantly better than placebo in the general adult population.
For beet powder (6 trials):
- 4 trials used beetroot powder. This was mixed with water to make a beetroot juice.
- 2 trials used beetroot powder in capsule form.
66.7% (4 of 6) clinical trials showed that beetroot powder is unlikely to lower blood pressure significantly better than placebo in the general adult population.
Many of the clinical trials we examined asked participants to avoid mouthwash during the study.
We’ll briefly explain the basics (R, R):
Beets contain nitrate. Once beet juice is consumed, the nitrate levels in the bloodstream rise.
At this point, this nitrate has one of two fates:
- ~65–75% of the nitrate is excreted in the urine, sweat, and feces.
- ~25% of the nitrate is taken up by the salivary glands.
Thereafter, nitrate-containing saliva is secreted into the mouth.
Oral bacteria then convert some of this salivary nitrate into nitrite.
The nitrite is swallowed and then undergoes various biochemical reactions. These reactions convert nitrite into nitric oxide.
Nitric oxide dilates (expands) the blood vessels. Dilation of the blood vessels lowers blood pressure.
Some types of antibacterial mouthwash may reduce the number of helpful bacteria in the mouth. (R, R, R)
This, in theory, then lowers the amount of nitric oxide the body can produce from beet juice. In turn, this lowers the chances that beet juice can lower blood pressure.
Is this theory confirmed by practice?
One clinical trial studied the bacteria in the mouths of people supplemented with beet juice. (R)
This study found that, over time, the bacterial population changed. It changed into one that was more favorable for the conversion of beet-derived nitrate into nitrite.
However, beet juice didn’t lower blood pressure significantly better than placebo despite all of that.
Another trial tested the effect of beet juice on blood pressure. Simultaneously the study tested the bacteria in the participants’ mouths. (R)
The researchers confirmed that the participants’ oral bacteria could convert nitrate to nitrite. Despite this, the beet juice didn’t lower blood pressure significantly better than placebo.
Two clinical trials on beet juice and blood pressure confirmed the presence of helpful bacteria in the mouth. Bacteria that should convert nitrate to nitrite and, by extension, help lower blood pressure.
Both trials failed to show that beet juice lowers blood pressure better than placebo.
Here are a few speculations:
The simplest one is that beet juice simply doesn’t lower blood pressure. Regardless of oral bacteria or use of mouthwash.
Another possibility is that clinical trial design or execution led to erroneous results. So it’s still possible beet juice does help some people.
Perhaps it’s something else, though.
Conversion of salivary nitrate into nitrite by oral bacteria is important.
That said, oral bacteria convert only ~5% of dietary nitrate into nitrite. (R)
(Higher conversion amounts are possible.)
And this conversion is only one step in the process of creating nitric oxide.
It could be that other steps or processes play a more outsized role in the way beets affect blood pressure.
In other words:
Any effect that mouthwash has on the way beets lower blood pressure may simply be overshadowed by other factors.
Spitting may interrupt the process that converts nitrate into nitric oxide. (R)
(See the Mouthwash discussion section for a description of this process.)
Overall, this implies that spitting may hurt beet juice’s ability to lower blood pressure.
Is this theory confirmed by practice?
One small clinical trial asked participants to consume beet juice and spit for several hours thereafter. Spitting, indeed, blocked the reduction of systolic blood pressure vs. control. (R)
At one point in this study:
People who didn’t spit reduced their systolic blood pressure by as much as ~10 mmHg more than people who spit.
It’s difficult to square this result with the results of the Mouthwash discussion section.
The “spitting trial” was not double-masked. It was also very small. It could simply be an erroneous result. Further research is warranted.
Or, as per the Mouthwash discussion, it points to a more important process at play here.
Spitting, after all, greatly reduces the ingestion of salivary nitrate/nitrite. It is not equivalent to the use of mouthwash.
The impact of mouthwash may simply be much smaller.
Perhaps, then, spitting is a far more powerful method of blunting beet juice’s effect on blood pressure.
According to basic science research:
Smoking may harm the body’s ability to convert nitrate into nitric oxide. (R)
This implies that smokers are less likely to benefit from beet juice, should beet juice lower blood pressure.
Again, what does practical evidence have to say?
One clinical trial examined the effect that beet juice has on the blood pressure of people who smoke. (R)
The trial compared this effect to people who don’t smoke.
The results suggests that smoking might indeed blunt beet juice’s ability to lower systolic blood pressure.
Low Oxygen Conditions
Low oxygen (hypoxic) conditions may impact beet juice’s ability to lower blood pressure.
Scientists believe that hypoxia may enhance the body’s ability to convert dietary nitrate into nitric oxide. (R)
This, in turn, might help lower blood pressure.
In other words:
Under hypoxic conditions, beet juice may be more effective at lowering blood pressure than in normal oxygen conditions.
That’s the theory, anyways.
What about practice?
High altitudes are naturally low in oxygen.
Two clinical trials studied the effect of beet juice on blood pressure at high altitudes. (R, R)
In both trials, beet juice did not lower blood pressure significantly better than placebo.
One clinical trial studied the effect of beet juice on blood pressure in lab (simulated) low oxygen conditions during exercise. (R)
Beet juice lowered blood pressure better than placebo.
A further trial studied the effect of beet juice on blood pressure in people with hypoxic chronic obstructive pulmonary disease, COPD. (R)
The COPD was severe enough to require supplemental oxygen. In this case, beet juice did not lower blood pressure significantly better than placebo.
Generally speaking, then:
Clinical trials don’t confirm that beets lower blood pressure better in hypoxic conditions.
Beets vs. True Placebos
In the General Population results section of this article, we identified 55 randomized, double-masked, placebo-controlled trials.
Specifically, the placebo was a nitrate-depleted version of beet juice or beet powder.
Only 36 of these 55 trials confirmed that the placebo was a true organoleptic match.
The placebo in these 36 trials wasn’t just devoid of nitrates. It was also confirmed as indistinguishable from real beet juice or powder by the senses (taste, texture, smell, etc).
The other 19 trials didn’t confirm an organoleptic match. This may mean that the participants could tell they were taking real beet juice or placebo. Or not.
We can’t be sure.
We didn’t want to assume things. So we excluded these 19 trials from this sub-analysis. After all, inadequately masked placebos are a recognized problem in clinical literature. (R)
All else equal:
A trial with a placebo that is completely indistinguishable from the real thing (real beet juice) offers more reliable data.
Here’s what the data from the 36 organoleptic-matched trials shows:
66.7% (24 of 36) organoleptic-matched clinical trials found that beet juice and beet powder are unlikely to lower blood pressure significantly better than placebo in the general adult population.
Our review of 122 trials largely demonstrates that beets are unlikely to lower blood pressure in most people.
(At least not significantly better than placebo.)
Many trials compared beet juice to nitrate-depleted beet juice (placebo). This placebo was otherwise identical to beet juice in terms of taste and texture.
Scientists suspect that the nitrate removal process is unlikely to remove many other substances from beet juice. At least not to any significant extent. (R)
Antioxidants found in beet juice may also affect a person’s blood pressure. At least over the long term and in specific doses. (R)
When studies compare beet juice to nitrate-depleted beet juice, it’s theoretically possible for the “placebo” to actually exert a beneficial effect on blood pressure as well.
(Via the antioxidants in the placebo.)
If that’s true, the “placebo” might also lower blood pressure to a degree. That would mask the beneficial effect that normal beet juice has on blood pressure.
By extension, it would be harder to show that beet juice is more effective than nitrate-depleted beet juice.
None of this has been proven, however.
It’s merely speculation at this point.
For a more objective clue:
Our review identified 2 clinical trials that used beet powder in capsule form. The beetroot powder capsules naturally contained nitrate.
The placebo capsules contained starch. The placebo was indistinguishable from the beetroot capsules by the senses.
The placebos didn’t contain antioxidants. This means the placebo capsules wouldn’t mask the effect of the nitrate in beet powder.
In both trials:
Beetroot powder capsules didn’t lower blood pressure significantly better than placebo.
This implies that beet juice devoid of nitrate, even if it has beneficial antioxidants, likely doesn’t mask any blood pressure lowering effect of normal beet juice.
Scientists believe that it’s the nitrate content that is mainly responsible for beets’ effect on blood pressure. (R)
Not so much the antioxidants.
Variations in temperature may influence blood pressure. (R)
Lower ambient (surrounding) temperatures might increase blood pressure. Conversely, hotter air temperatures might lower blood pressure.
Of the 122 clinical trials we examined, most failed to mention that they controlled for room temperature.
This means they may have measured blood pressure at different temperatures for different participants. Perhaps the researchers did control for room temperature and simply didn’t state so in the article.
We didn’t want to assume anything.
Of the 36 organoleptic-matched trials we identified (see Beets vs. True Placebos):
Only 6 explicitly stated they used a consistent room temperature when measuring blood pressure.
Here’s what the data from these 6 trials shows:
66.7% (4 of 6) temperature-controlled clinical trials found that beet juice and beet powder are unlikely to lower blood pressure significantly better than placebo in the general adult population.
Of the trials we examined, 75 were labeled as “double-blind” (“double-masked”).
This label (“double-blind”) was given by the researchers of these 75 studies, not us.
Many people assume double-blind means that the study’s subjects can’t tell if they got beet juice or placebo.
This isn’t always the case.
“Double-blind” does not have a standardized meaning in medical literature.
It doesn’t automatically mean that doctors and patients are unaware who got a treatment or placebo.
Besides doctors and patients, clinical trials have other participants.
There are up to 11 types of individuals that could be blinded in a clinical trial.
This includes doctors, patients, statisticians, technicians, outcomes assessors, etc. (R)
The term “double-blind” is often ambiguous, not defined, or even misused.
To avoid falling into this trap, we split the 75 double-blind studies into three categories:
1. Studies where we couldn’t determine if the participants could tell the difference between beet juice/powder and placebo.
- 28% (21 of 75) double-blind trials fit this criteria.
- 42.9% (9 of 21) trials with potentially masked participants found that beet juice is unlikely to lower blood pressure significantly better than placebo.
2. Studies where the participants almost certainly could tell the difference between beet juice/powder and placebo.
- 18.7% (14 of 75) double-blind trials fit this criteria.
- The placebo was often orange, prune, or blackcurrant juice.
- 50% (7 of 14) of trials with unmasked participants found that beet juice is unlikely to lower blood pressure significantly better than placebo.
3. Studies where the participants likely couldn’t tell the difference between beet juice/powder and placebo.
- 53.3% (40 of 75) double-blind trials fit this criteria.*
- 70.0% (28 of 40) of trials with masked participants found that beet juice is unlikely to lower blood pressure significantly better than placebo.
The trend is clear.
A trial with a properly blinded participant is less likely to report that beets are significantly more effective than placebo.
* The reason there are 40 such trials here as opposed to the 36 in the Beets vs. True Placebos section, is because the latter relied solely on trials with nitrate-depleted beet juice or nitrate-depleted beet powder as placebo. The 4 additional trials in this section include organoleptically-matched, nitrate-depleted, placebos that may not be beet-based. For example: starch-based placebo pills.
We examined 117 trials (where data allowed) for abstract bias.
By abstract bias, we mean the following:
The results and conclusions in study abstracts can be quite misleading. (R)
For example, a study may claim that beets lowered blood pressure in the abstract.
But the data in the trial itself fails to support such an assertion.
A reader who skims the abstract alone may walk away thinking that beets help lower their blood pressure, when they may not.
We found that 11.97% (14 of 117) clinical trials had misleading abstract data.
Most often, the misdirection had to do with the following:
The abstract claimed that beet juice lowered blood pressure, without further details.
The data actually showed that beet juice didn’t lower blood pressure better than placebo.
Where did the misdirection occur?
1. People who took beet juice experienced a decrease in blood pressure.
2. But so did the people who took a placebo.
3. The effect of beet juice wasn’t significantly different from placebo.
The abstract stated #1 without mentioning #3.
Financial conflicts of interest often correlate to favorable clinical trial results. (R)
Where data allowed, we examined 103 placebo-controlled trials for financial conflicts of interest. The remaining trials did not provide any disclosure, funding, or conflict of interest statements.
26.2% (27 of 103) trials had a strong potential for such conflicts of interest.
Often, this meant the trial was funded by a beet industry company.
Or a researcher/author on the team had a stake in a beet supplement company.
This figure (26.21%) is likely a conservative estimate. See our discussion in the Undisclosed Conflicts section for why that’s likely the case.
Of the 76 trials that claimed to have no conflicts of interest:
38.2% (29 of 76) trials that declared no conflicts of interest found that beets lower systolic and/or diastolic blood pressure better than placebo.
Of the 27 trials with conflicts of interest:
51.9% (14 of 27) trials with conflicts of interest found that beets lower systolic and/or diastolic blood pressure better than placebo.
At least with this data:
Trials with close ties to the beet industry were 36% more likely to report a beneficial effect for beet juice or beet powder.
(36% = relative percent increase, not absolute.)
Evidence shows that falsified data or fake clinical trials are a problem in medical literature. (R)
Especially from specific countries.
In our review:
73 trials were conducted in the U.S. or U.K.
38 trials were conducted in the rest of the world.
The other trials were excluded for this analysis due to a lack of data or because they were non-inferiority trials.
Trials conducted in the U.S. or U.K. were 1.85 times more likely to find that beets lowered blood pressure significantly better than placebo/control.
We are not implying any of the trials we identified are fake or contain fake data.
Instead, this finding may be strongly explained by financial conflicts of interest.
32.9% of trials in the U.K. and U.S. had financial conflicts of interest.
But only 7.9% of trials in the rest of the world did so.
A point of care:
We only looked for, and examined, clinical trials published in the English language.
This may skew the ultimate interpretations of this subsection of our review.
Old vs. New Trials
Where data permits:
31 trials were published before 2015.
81 trials were published in 2015, and onwards.
Studies published before 2015 were 1.98 times more likely to show that beets lower blood pressure significantly more than placebo/control.
The explanation for this may be rather straightforward.
Studies published in 2015 and later were often more rigorously designed.
Studies published in or after 2015 were 5.1 times more likely to use a placebo with organoleptic match vs. trials published before 2015.
In other words:
More recent trials are less likely to show that beets lower blood pressure. And that may be because these recent trials tend to have a more rigorous design.
Our literature review and analysis never intended for a “forensic” audit of trial disclosures.
However, we stumbled upon something through a stroke of luck.
We found that several trials claimed to have no conflicts of interest when, in fact, there clearly were.
This is because at least one author was a director or shareholder in a beet-related supplement company at the time of the trial. We confirmed this via public company documents. Yet this fact was never disclosed.
Undisclosed conflicts of interest are a common problem in medical literature. (R)
Our literature review and analysis sought to answer the following clinical question:
“How does the consumption of beetroot juice or beetroot powder affect systolic or diastolic (central or peripheral) arterial blood pressure in adults?”
Primary interventions of interest: supplementation with beetroot juice or beetroot powder.
Secondary interventions of interest: any other beetroot products.
Primary outcomes of interest: systolic or diastolic (central or peripheral) arterial blood pressure.
Inclusion & Exclusion Criteria
The purpose of this literature review was to determine the direction of the effect that beetroot supplements have on a person’s systolic or diastolic blood pressure.
We included studies that focused on the root of the Beta vulgaris plant. This meant we excluded studies that used the beet plant’s stems or leaves.
We excluded any studies where the beetroot intervention was mixed with another product or supplement, such as another plant or juice— unless the non-primary intervention comparator arm(s) excluded the beetroot product in an otherwise generally equivalent fashion, thereby allowing us to isolate the effect of beetroot in such cases.
We included studies where the primary or secondary endpoint data was a measure of systolic or diastolic blood pressure (central or peripheral). We excluded studies that provided data solely for other measures of blood pressure, such as mean arterial pressure or pulmonary pressure.
In order to gather the best available evidence for any potential cause-and-effect relationship pertinent to the clinical question, we focused on data solely from clinical trials and any meta-analyses thereof. This means we excluded observational and basic science literature and any meta-analyses thereof, any interim analyses, conference abstracts, whitepapers, and other non-peer-reviewed data.
We excluded all studies published in a non-English language.
We excluded all studies on individuals under the age of 18 years.
Our clinical question, and primary interventions/outcomes of interest, largely defined our search strategy.
An initial literature search was conducted in October of 2023, using two distinct searches to maximize the number of relevant clinical trials we could find.
(See the Last Literature Review date in the beginning of this article to see when we last searched for any new trial data on this topic.)
Using PubMed, search #1 used search terms focused on identifying published studies where the primary intervention was any beet-based product (high sensitivity, low specificity intervention search) using a combination of keywords and wildcards.
Specific search terms, common to the primary outcomes of interest, were added (high specificity, low sensitivity outcomes search).
The search terms were applied to the titles and abstracts of PubMed’s database.
Filters for clinical trials on humans, practice guidelines, and errata/retractions were applied.
Search #1 yielded 215 results.
Search #2 was a “sweep”.
The sweep is an acknowledgement that PubMed doesn’t contain all studies of interest (or may not at the time of our search) and that PubMed filters are imperfect and, on occasion, miscategorize or fail to categorize studies of interest. Moreover, search #1 is neither a perfect nor exhaustive search on its own.
Using search #1, we identified 13 systematic reviews and meta-analyses (SRMAs) of relevance to our clinical question.
We examined all of the studies included in these SRMAs of interest to identify any clinical trials missed by search #1.
We further identified several key clinical trials in search #1, trials that contained detailed lists of potential clinical trials of interest to our clinical question.
Search #2 yielded an additional 42 clinical trials for us to examine.
Of the 257 potentially relevant clinical trials we identified, 122 provided direct relevance to our clinical question while also honoring our search inclusion/exclusion criteria.
Our literature review and analysis has its limitations.
We did not include studies published in a language other than English.
Our search strategy was sensitive to our primary interventions of interest with respect to search terms related to beets. It’s possible some study authors used a combination of terms that used a form of nitrate as a euphemism for a beet-related product. Our search may have missed such trials where beets or beet products weren’t mentioned in the title/abstract but were actually used in the trial. Moreover, our search strategy was specific, but could have been more sensitive, for our primary outcome of interest.
We believe that our second search (the “sweep”) largely addressed the sensitivity/specificity concerns outlined above. However, we cannot exclude the possibility that the sweep also missed trials of interest, especially those with primary interventions or primary outcomes of interest not mentioned in the title nor abstract.
Virtually all trials that found that beets lower blood pressure mentioned this fact in the title/abstract. This means we likely found nearly all of the trials with a positive effect for beets. Trials that didn’t find that beets lower blood pressure were less likely to report this lack of effect in the title/abstract. Therefore, we believe that if we missed any relevant trials, it was likely trials that did not find a difference between beets and placebo. This means that beets may be even less effective than our analysis suggests. In other words, we believe that our analysis might be systematically biased in favor of beets as a result of our review’s limitations.
The studies that we examined had many limitations of their own. Some studies attempted to control the dietary nitrate intake of participants by allowing or not allowing the consumption of nitrate-rich food sources outside of the experimental conditions. Studies used different blood pressure measurements (at home, in clinic, or ambulatory). The trials measured blood pressure at different times of the day. Some studies controlled for ambient temperature and others did not. These and other limitations may skew the interpretation of the true direction and magnitude of the effect beets have on blood pressure.
We declare no conflicts of interest. We do not sell any supplements and this review hasn’t been sponsored by, nor is it affiliated with, any outside entity in any way.