Qin L Z, Jin L Y, Qu X M, Wang S L
Salivary Gland Diseases Center and Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing 100050, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2020 Jul 9;55(7):433-438. doi: 10.3760/cma.j.cn112144-20200410-00204.
Dietary nitrate which mainly comes from green leafy vegetables, is absorbed into blood circulation by the intestinal mucosa. Parotid gland is an important organ for transporting nitrate. Nitrate in blood is taken up by sialin, a nitrate transporter and concentrated in salivary glands and secreted into saliva. The salivary nitrate is partially reduced to nitrite and nitric oxide by oral bacteria, and then salivary nitrate and nitrite return into blood circulation with swallowing and intestinal mucosal absorption. As a non-classic source of nitric oxide, nitrate-nitrite-nitric oxide pathway plays an important role on physiological and pathological conditions, especially on the condition of hypoxia and ischemia. These functions include body protection, such as gastrointestinal tract, cardiovascular system, anti-inflammation, regulation of glucose/lipid metabolism, improvement of sport ability, maintaining gut microbiome hemostasis, and alleviating senility. The traditional view on nitrate as a harmful substance to human body has been proved to be lack of scientific evidence. With further research and application, as a pioneer from the mouth to the whole body, nitrate is expected to play a crucial part in human health, and prevention and treatment of systemic diseases.
膳食硝酸盐主要来自绿叶蔬菜，通过肠黏膜被吸收进入血液循环。腮腺是运输硝酸盐的重要器官。血液中的硝酸盐被一种硝酸盐转运体——唾液酸转运蛋白摄取，并在唾液腺中浓缩，然后分泌到唾液中。唾液中的硝酸盐被口腔细菌部分还原为亚硝酸盐和一氧化氮，然后唾液中的硝酸盐和亚硝酸盐随着吞咽和肠黏膜吸收回到血液循环中。作为一氧化氮的非经典来源，硝酸盐-亚硝酸盐-一氧化氮途径在生理和病理条件下，尤其是在缺氧和缺血状态下发挥着重要作用。这些功能包括身体保护，如胃肠道、心血管系统、抗炎、调节葡萄糖/脂质代谢、提高运动能力、维持肠道微生物群稳态以及缓解衰老。传统上认为硝酸盐对人体有害的观点已被证明缺乏科学依据。随着进一步的研究和应用，作为从口腔到全身的先驱，硝酸盐有望在人类健康以及全身性疾病的预防和治疗中发挥关键作用。
