Rajendra Anjana, Bondonno Nicola P, Zhong Liezhou, Radavelli-Bagatini Simone, Murray Kevin, Rainey-Smith Stephanie R, Gardener Samantha L, Blekkenhorst Lauren C, Magliano Dianna J, Shaw Jonathan E, Daly Robin M, Anstey Kaarin J, Lewis Joshua R, Hodgson Jonathan M, Bondonno Catherine P
Nutrition and Health Innovation Research Institute, School of Medical and Health Sciences, Royal Perth Hospital Research Foundation, Edith Cowan University, Perth, WA, Australia.
The Danish Cancer Society Research Centre, Copenhagen, Denmark.
Front Nutr. 2024 Aug 21;11:1327042. doi: 10.3389/fnut.2024.1327042. eCollection 2024.
Dietary nitrate is potentially beneficial for cardiovascular, cerebrovascular, and nervous systems due to its role as a nitric oxide (NO) precursor. Increased nitrate intake improves cardiovascular health and therefore could protect against dementia, given the cardiovascular-dementia link.
To investigate the association between source-dependent nitrate intake and dementia-related mortality. As individuals with diabetes are at higher risk of dementia, a secondary aim was to investigate if the associations between nitrate and dementia varied by diabetes mellitus (DM) and pre-diabetes status.
This study involved 9,149 participants aged ≥25 years from the well-characterised Australian Diabetes, Obesity, and Lifestyle (AusDiab) Study followed over a period of 17 years. Intakes of plant-sourced, vegetable-sourced, naturally occurring animal-sourced nitrate, and processed meat (where nitrate is an allowed additive)-sourced nitrate were assessed from a 74-item food frequency questionnaire completed by participants at baseline and nitrate databases were used to estimate nitrate from these different dietary sources. Associations between source-dependent nitrate intake and dementia-related mortality were assessed using multivariable-adjusted Cox proportional hazards models adjusted for demographics, lifestyle, and dietary factors.
Over 17 years of follow-up, 93 (1.0%) dementia-related deaths occurred of 1,237 (13.5%) total deaths. In multivariable-adjusted models, participants with the highest intakes of plant-sourced nitrate (median intake 98 mg/day) had a 57% lower risk of dementia-related mortality [HR (95% CI): 0.43 (0.22, 0.87)] compared to participants with lowest intakes of plant-sourced nitrate (median intake 35 mg/day). A 66% lower risk was also seen for higher intakes of vegetable-sourced nitrate [HR (95% CI): 0.34 (0.17, 0.66)]. No association was observed for animal-sourced nitrate, but the risk was two times higher amongst those who consumed the most processed meat-sourced nitrate intake [HR (95%): 2.10 (1.07, 4.12)]. The highest intake of vegetable-sourced nitrate was associated with a lower risk of dementia-related mortality for those with and without DM and pre-diabetes.
Encouraging the intake of nitrate-rich vegetables, such as green leafy vegetables and beetroot, may lower the risk of dementia-related mortality, particularly in individuals with (pre-) diabetes who are at a higher dementia risk.
膳食硝酸盐作为一氧化氮（NO）的前体，对心血管、脑血管和神经系统可能有益。鉴于心血管疾病与痴呆症之间的联系，增加硝酸盐摄入量可改善心血管健康，从而可能预防痴呆症。
研究来源依赖性硝酸盐摄入量与痴呆症相关死亡率之间的关联。由于糖尿病患者患痴呆症的风险较高，次要目的是研究硝酸盐与痴呆症之间的关联是否因糖尿病（DM）和糖尿病前期状态而异。
本研究纳入了来自特征明确的澳大利亚糖尿病、肥胖与生活方式（AusDiab）研究的9149名年龄≥25岁的参与者，随访时间为17年。通过参与者在基线时填写的74项食物频率问卷评估植物源、蔬菜源、天然动物源硝酸盐以及加工肉类（硝酸盐为允许添加剂）源硝酸盐的摄入量，并使用硝酸盐数据库估算这些不同饮食来源的硝酸盐含量。使用针对人口统计学、生活方式和饮食因素进行多变量调整的Cox比例风险模型评估来源依赖性硝酸盐摄入量与痴呆症相关死亡率之间的关联。
在17年的随访中，1237例（13.5%）总死亡中有93例（1.0%）与痴呆症相关。在多变量调整模型中，植物源硝酸盐摄入量最高（中位数摄入量为98毫克/天）的参与者与植物源硝酸盐摄入量最低（中位数摄入量为35毫克/天）的参与者相比，痴呆症相关死亡率风险降低了57%[风险比（95%置信区间）：0.43（0.22，0.87）]。蔬菜源硝酸盐摄入量较高时，风险也降低了66%[风险比（95%置信区间）：0.34（0.17，0.66）]。未观察到动物源硝酸盐与痴呆症相关死亡率之间的关联，但加工肉类源硝酸盐摄入量最高的人群中，风险高出两倍[风险比（95%）：2.10（1.07，4.12）]。蔬菜源硝酸盐摄入量最高与糖尿病患者和糖尿病前期患者以及非糖尿病患者的痴呆症相关死亡率较低有关。
鼓励摄入富含硝酸盐的蔬菜，如绿叶蔬菜和甜菜根，可能会降低痴呆症相关死亡率的风险，特别是在痴呆症风险较高的糖尿病（前期）患者中。
