Dietary nitrate intake and the risk of dementia: a population‐based study
Tosca O.E. de Crom, Meike W Vernooij, M. Kamran Ikram, Trudy Voortman, M. Arfan Ikram, Lauren Blekkenhorst- Psychiatry and Mental health
- Cellular and Molecular Neuroscience
- Geriatrics and Gerontology
- Neurology (clinical)
- Developmental Neuroscience
- Health Policy
- Epidemiology
Abstract
Background
Nitric oxide is a free radical that can be produced from dietary nitrate and positively affect cardiovascular health. With cardiovascular health playing an important role in the etiology of dementia, we hypothesized a link between dietary nitrate intake and the risk of dementia. We therefore aimed to evaluate the association of total, vegetable and non‐vegetable dietary nitrate intake with the risk of dementia and to explore underlying mechanisms involving imaging markers of vascular brain health, i.e. cerebral perfusion, total brain volume, white matter hyperintensity volume, microbleeds, and lacunar infarcts.
Method
Dietary nitrate intake was assessed using food frequency questionnaires in 9,543 dementia‐free participants (mean age 64 years, 58% women) from the prospective population‐based Rotterdam Study. All participants were followed for the incidence of dementia, and 3,949 of the participants underwent a magnetic resonance imaging scan of the brain during a maximum of three consecutive examination rounds (average interval between scans 4.6 years). We used Cox models to determine the association between dietary nitrate intake and incident dementia. We further used linear mixed models and logistic regression models to assess the association of dietary nitrate intake with changes in imaging markers over time.
Result
Participants consumed on average 102.9 (standard deviation: 66.7) grams of dietary nitrate per day, which came on average for 81% from vegetable sources. During a mean follow‐up of 14.5 years, 1,472 participants developed dementia among whom 1,078 had Alzheimer’s disease. A higher intake of total and vegetable dietary nitrate intake was associated with a lower risk of dementia (hazard ratio (HR) [95% confidence interval (CI)] per 50 mg/day increase: 0.92 [0.87‐0.98] and 0.92 [0.86‐0.97], respectively), but no association between non‐vegetable dietary nitrate intake and the risk of dementia was observed (HR [95% CI]: 1.15 [0.64‐2.07]). Results were similar for Alzheimer’s disease. Dietary nitrate intake was also not associated with brain imaging markers.
Conclusion
A higher dietary nitrate intake from vegetable sources is associated with a lower risk of dementia. We found no evidence that this association was driven vascular brain health.