Drink a shot of beetroot juice, then chew a piece of Hubba Bubba for the next several hours, and your blood pressure drops slightly more than if you had chewed sugar-free gum instead. That is the finding of a small randomized crossover trial from King's College London and the University of Reading, published in June in the British Journal of Clinical Pharmacology.
The effect was modest, close to 3 mmHg systolic and 2 mmHg diastolic compared with sugar-free gum. The mechanism is the interesting part, and it runs against what most of the existing literature predicted. The researchers are unusually blunt that nobody should take this as advice.
The Bacteria in Your Mouth Do the Hard Part
Nitrate-rich vegetables such as beetroot, spinach, kale, and lettuce pull nitrate from soil. Nitrate on its own does very little. It has to be converted into nitrite, and the organisms that perform that conversion are bacteria living on the tongue.
Swallowed nitrate is concentrated by the salivary glands and secreted back into the mouth, where those bacteria reduce it to nitrite. The nitrite is swallowed again, absorbed into the bloodstream and reduced further to nitric oxide, which relaxes and widens blood vessels. Blood pressure falls as a result. That loop, known as the enterosalivary circulation, means the mouth keeps working on a salad long after the meal ends.
Because oral bacteria are the bottleneck, researchers have been probing what makes them more or less efficient. Salivary acidity was an obvious candidate that had barely been tested in whole living people over a span of hours.
Hubba Bubba Versus Wrigley's Extra
Fourteen healthy volunteers each completed two visits in a seven-hour crossover protocol, with visits separated by at least a week. On both, they drank a shot of beetroot juice, roughly 70 milliliters, containing about 400 milligrams of nitrate, an amount comparable to a large leafy salad. They then chewed either sugar-containing Hubba Bubba bubble gum or sugar-free Wrigley's Extra for three to six hours while researchers sampled blood and saliva and tracked blood pressure. At the second visit, they chewed the other gum.
The sugary gum, which is acidic, lowered salivary pH by 1.4 units compared with the sugar-free comparator. That shift tracked with everything downstream. Nitrite in the mouth rose 45% and nitrite circulating around the body rose 25%. Blood pressure fell by the amounts noted above, and the differences were statistically significant.
A Result That Ran Against the Textbook
Corresponding author Dr. Andrew Webb, a clinical senior lecturer at King's College London and an honorary consultant physician at Guy's and St Thomas' Hospital NHS Foundation Trust, has pointed out that most prior research suggested increasing acidity would inhibit nitrate conversion, not enhance it. Crucially, that earlier work came largely from isolated oral experiments rather than from whole-body studies lasting several hours.
His team had already stumbled into the inverse of this result. Pairing grapefruit juice with beetroot juice made saliva less acidic and suppressed nitrite production. The gum experiment was designed to formally test the opposite direction, and it worked. Speaking to The Epoch Times, Webb summarized the pattern as "More acidity, more activity."
There are real limits on how far this can be pushed. The participants were healthy volunteers, not people with diagnosed hypertension, and a difference of that size in that group is not equivalent to a treatment effect in someone with high blood pressure. The comparison was sugary gum against sugar-free gum, both on top of beetroot juice, not gum against nothing. The published effect lasted for hours, and the paper does not address repeated or long-term use.
Beetroot juice itself has a stronger evidence base, though not an unqualified one. A 2024 systematic review and meta-analysis of hypertensive patients found that beetroot juice lowered clinical systolic blood pressure, with effects lasting up to 90 days, but concluded that the evidence does not support a sustained reduction over a full 24 hours.
The Reason Researchers Are Warning People Off
The King's College London team went out of its way to head off the obvious misreading. Webb noted that the effects were "only short-term, lasting several hours" and that long-term use of sugar-containing products would not be recommended for dental health.
Co-author Dr. Charlotte Mills of the University of Reading was equally direct in the same announcement. "We are certainly not suggesting that people should start chewing sugary gum regularly," she said, adding that frequent sugar consumption harms dental health and, in excess, cardiometabolic health. She framed the result as proof of concept: evidence that the body's processing of dietary nitrate can be improved, and a prompt to find tooth-friendly, metabolically sound ways to achieve the same shift.
The most plausible near-term application is not blood pressure at all. Dietary nitrate is already a recognized sports supplement, and the researchers have proposed a larger study of athletes to determine whether the same mechanism can enhance the performance benefits of nitrate-rich foods.
Webb also offered a gentler version for the dinner table, suggesting that the classic sequence of a nitrate-rich starter and main course followed by a sweet dessert, which could be fruit, may produce a temporary version of the same effect. He added that gum should outperform a sugary drink here simply because it stays in the mouth longer. Both points remain hypotheses rather than tested findings.
Anyone managing high blood pressure should keep taking prescribed medication and discuss dietary changes with a clinician rather than acting on a single small trial in healthy volunteers.
Key Questions Answered
What did the study find?
Chewing sugar-containing gum after beetroot juice lowered salivary pH, increased nitrite in saliva by 45% and in blood by 25%, and reduced blood pressure by close to 3 mmHg systolic and 2 mmHg diastolic compared with sugar-free gum.
Should people start chewing sugary gum to lower blood pressure?
No. The researchers explicitly advise against it. The effect lasted only hours, and regular sugar exposure harms teeth and, in excess, cardiometabolic health.
Why does gum affect blood pressure at all?
Bacteria in the mouth convert dietary nitrate into nitrite, which the body turns into nitric oxide, a compound that relaxes blood vessels. Making saliva more acidic appeared to speed up that conversion.
Was this a large trial?
No. It was a small randomized crossover study involving 14 healthy volunteers, each serving as their own control across two visits.
Does this apply to people with high blood pressure?
Not established. Participants were healthy, and the study was not designed to test people with hypertension.
What happens next?
The researchers have proposed a larger study in athletes, since dietary nitrate is already used as a sports supplement, and have called for tooth-friendly alternatives that produce the same effect.
