Surprisingly, the researchers also discovered that using antiseptic mouthwash regularly might interfere with some of these benefits. WHY THE MOUTH MATTERS FOR THE HEART When we eat nitrate-rich foods like beetroot, spinach, or lettuce, the bacteria in our mouth convert those nitrates into nitric oxide - a compound that helps relax blood vessels and improve blood flow. This study, published in Free Radical Biology and Medicine, shows that our oral microbiome (the community of bacteria in our mouth) can influence how well nitrate-rich diets benefit our heart health. The trial involved 39 young adults (18-30 years old) and 36 older adults (67-79 years old). Participants went through three different two-week phases:

• Drinking nitrate-rich beetroot juice.
• Drinking a placebo beetroot juice (with almost no nitrate).
• Using antiseptic mouthwash twice a day.

Each phase was separated by a two-week break. Researchers collected tongue swabs, measured blood pressure, and assessed blood vessel function before and after each phase. KEY FINDINGS OF THE STUDY Older adults benefited the most from beetroot juice: Their blood pressure dropped by about 7 mmHg after two weeks of drinking nitrate-rich beetroot juice. This is considered clinically significant and could reduce the risk of heart attacks and strokes. Younger adults saw little change: Since their blood pressure was already in the healthy range, beetroot juice didn't make a big difference. Oral bacteria played a big role: In older adults, beetroot juice reduced certain types of bacteria (like Prevotella) that are linked to inflammation and poor health, while boosting bacteria that help with nitric oxide production. Mouthwash could reduce benefits: In younger adults, regular antiseptic mouthwash lowered the diversity of oral bacteria and made their blood vessels less responsive, compared to when they were drinking beetroot juice. Although the mouthwash didn't drastically change blood nitrate levels, it appeared to interfere with the bacteria that help maintain heart health. WHAT THIS MEANS FOR YOU For the elderly, adding nitrate-rich foods like beetroot juice to the diet could be a simple, affordable way to improve blood pressure and heart health. For younger adults, the benefits are less obvious, but avoiding overuse of strong antiseptic mouthwash could help maintain a healthy oral microbiome, even in the long run. The study also hints that in the future, probiotics or prebiotics for the mouth might be developed to support heart health. The findings highlight how closely the mouth health is tied to the rest of our body. As the researchers note, disrupting the bacteria in the mouth - whether through poor diet or excessive use of antiseptic mouthwash - could affect not just oral health but also heart and vascular health.