For the first time, researchers from King’s College London have identified a link between chewing sugary gum after consuming vegetables high in nitrates—such as beetroot, spinach, and kale—and a reduction in blood pressure. The findings were published in the British Journal of Clinical Pharmacology.
Nitrates are absorbed by vegetables from the soil, but for the body to make use of them, they must be converted into nitrites through the action of bacteria in the mouth. Nitrites produce a range of effects, including the relaxation and widening of blood vessels, which facilitates blood flow and helps lower blood pressure.
Because the cardiovascular benefits depend on oral bacteria converting nitrate into nitrite that the body can use, scientists are investigating ways to enhance this process. One underexplored theory suggests that increasing the acidity of saliva could boost this chemical reaction.
To test this idea, the researchers examined whether chewing sugar-containing gum—which creates an acidic environment and lowers pH in the mouth—could increase nitrite production.
“Does the acidity of saliva in the mouth influence the conversion of inactive nitrate into more active nitrite, and if so, how? That’s a fundamental question, as it affects several important physiological functions, including blood pressure. Yet this process remains poorly understood,” said Andrew Webb from the School of Cardiovascular and Metabolic Medicine & Sciences at King’s College London. “While most studies suggest that increased acidity suppresses nitrate conversion, this had never been examined in the body over several hours. Interestingly, we previously found that combining grapefruit juice with beetroot lowered saliva acidity and hindered the conversion of nitrate to nitrite in saliva. So we wanted to formally test whether the opposite effect—raising saliva acidity—would promote the conversion of nitrate to nitrite.”
Healthy volunteers were randomly assigned to two groups: one group chewed sugar-containing gum, while the other chewed sugar-free gum for three to six hours after consuming beetroot juice. Throughout the study, blood and saliva samples were analyzed, and blood pressure was measured. After at least a week, the volunteers returned to repeat the experiment, this time chewing the alternative type of gum.
When volunteers chewed sugar-containing gum, saliva acidity increased (as measured by a 1.4 drop in pH) compared to when they chewed sugar-free gum. Participants also showed a 45% higher amount of nitrites in the mouth and 25% more nitrites circulating in the body than when they chewed sugar-free gum.
The sweetened gum also significantly lowered both systolic blood pressure (when the heart pumps blood) and diastolic blood pressure (when the heart rests between beats) by nearly 3.5 mmHg compared with sugar-free gum.
While the researchers emphasize that chewing sugary gum is not a therapeutic method for people trying to manage their blood pressure, this discovery could have implications for athletes who already use beetroot to enhance their athletic performance.
“The effect was only temporary, lasting a few hours, and regular consumption of sugary products is not recommended for dental health. Still, the classic culinary tradition of serving a sweet dessert—such as fruit—after a starter and main course, especially if those dishes include nitrate-rich leafy greens and vegetables, might temporarily boost the blood-pressure-lowering effect and improve physical fitness,” added Webb. “We also suggest that sugar-flavored gum would have a stronger effect compared to drinking sweetened beverages, since it stays in the mouth for a longer time.”
“The bacteria living in our mouths play a crucial role in converting nitrates from foods like beetroot into beneficial compounds that help relax blood vessels and lower blood pressure. Our findings indicate that the presence of sugar may create a more favorable environment for this process,” added co-author Charlotte Mills from the University of Reading. “We are certainly not recommending that people regularly chew sugary gum. Frequent sugar consumption is harmful to dental health and also negatively affects cardiometabolic health when consumed in excess. Instead, our results support the idea that we can improve how the body processes dietary nitrates, and future research should focus on developing tooth-friendly, metabolically safe approaches that achieve the same effect.”
“The challenge now is to identify alternative strategies that are both effective and suitable for long-term use. Since dietary nitrates are already recognized as a sports supplement, there is potential to optimize their use among athletes. If we can improve nitrate conversion, we could enhance the physiological benefits athletes gain from nitrate-rich foods. We found that even something as simple as the type of gum used alongside beetroot juice can influence how efficiently the body converts dietary nitrates into compounds that help lower blood pressure,” the study authors noted.
As next steps, the scientists propose conducting a larger study involving athletes to more thoroughly investigate the relationship between chewing sugary gum, blood pressure, and athletic performance.
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